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Abstract

Aim: To describe the early healing events in the alveolar socket during the first 8 weeks of spontaneous healing after tooth extraction. Materials and methods: 16 adult beagle dogs were selected and five healing periods were analysed (4 h, 1 week, 2 weeks, 4 weeks, 8 weeks). Mandibular premolars were extracted and each socket corresponding to the mesial root was left to heal undisturbed. In each healing period, three animals were euthanatized, each providing four study sites. Healing was assessed by descriptive histology and by histometric analysis using as landmarks: the vertical distance between buccal and lingual crest (B'L') and the width of buccal and lingual walls at three different levels. Differences between means for each variable for each healing period were compared (ANOVA; p < 0.05). Results: B'L' at baseline was 0.45 (0.18) mm and decreased during the healing period to a final value of 0.18 (0.08) mm. The lingual width (Lw) remains almost unchanged while the buccal width (Bw) at 1 (Bw1) and 2 (Bw2) mm was reduced in about 40% of its initial value. Conclusions: Minor vertical bone reduction in both the buccal and lingual socket walls were observed. A marked horizontal reduction of the buccal bone wall was observed mostly in its coronal aspect.

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... This inflammatory phase is followed by granulation tissue formation, re-epithelialization, and formation of a connective tissue matrix (Broughton et al., 2006;Rodriguez-Merchan, 2012). Granulation tissue comprises a dense population of macrophages, fibroblasts, capillary networks, fibronectin, hyaluronic acid and endothelial cells (Rodriguez-Merchan, 2012;Discepoli et al., 2013). Macrophages, fibroblasts, and endothelial cells are interdependent during granulation tissue formation (Rodriguez-Merchan, 2012;Discepoli et al., 2013). ...
... Granulation tissue comprises a dense population of macrophages, fibroblasts, capillary networks, fibronectin, hyaluronic acid and endothelial cells (Rodriguez-Merchan, 2012;Discepoli et al., 2013). Macrophages, fibroblasts, and endothelial cells are interdependent during granulation tissue formation (Rodriguez-Merchan, 2012;Discepoli et al., 2013). Hypoxia is an important trigger for neovascularization during this phase (Schreml et al., 2010;Larjava, 2012). ...
... Healing after a tooth extraction follows the same pattern, with the inclusion of a bone healing process (Larjava, 2012;Discepoli et al., 2013). Minutes after the tooth is extracted, the alveoli are closed via blood clotting. ...
Article
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Wound healing is a primary survival mechanism that is largely taken for granted. The literature includes relatively little information about disturbed wound healing, and there is no acceptable classification describing wound healing process in the oral region. Wound healing comprises a sequence of complex biological processes. All tissues follow an essentially identical pattern to complete the healing process with minimal scar formation. The oral cavity is a remarkable environment in which wound healing occurs in warm oral fluid containing millions of microorganisms. The present review provides a basic overview of the wound healing process and with a discussion of the local and general factors that play roles in achieving efficient would healing. Results of oral cavity wound healing can vary from a clinically healed wound without scar formation and with histologically normal connective tissue under epithelial cells to extreme forms of trismus caused by fibrosis. Many local and general factors affect oral wound healing, and an improved understanding of these factors will help to address issues that lead to poor oral wound healing.
... Histomorphometric, radiographic and clinical investigations have shown that marked physiological bone resorption occurs within the first three to six months post-tooth extraction (Schropp et al., 2003;Araújo & Lindhe, 2005;Discepoli et al., 2013). Such event may complicate future prosthetic planning due to lack of amount of available bone; thus, the socket grafting or socket preservation procedure is performed to minimise the amount of bone resorption (Fee, 2016;Jung et al., 2018). ...
... Although no significant difference was noticed between the control and PLGA groups, the mean bone volume increased in all treatment groups. The outcome could be due to the deposition of new bone as early as the first week of healing following tooth extraction, which continues until the fourth week of healing (Araújo & Lindhe, 2005;Discepoli et al., 2013). However, a significant difference was observed in treatment comparisons between the control and CGF+PLGA, and between CGF and CGF+PLGA groups. ...
... An overall significant difference of mean bone height with each treatment group was observed at four weeks and eight weeks. This could be due to the onset of new bone formation within the first week and second week of healing post-tooth extraction as reported in previous animal studies (Araújo & Lindhe, 2005;Discepoli et al., 2013). In these studies, new bone formation was observed histologically following distal root extraction of premolars in the beagle dogs within the first week, whereas a woven bone was noticed at four weeks before the onset of remodelling. ...
Article
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Various grafting materials are utilised to facilitate regeneration. There is currently a paradigm shift towards applying poly lactic-co-glycolic acid (PLGA), which is regarded as an excellent scaffold for tissue engineering. Concentrated growth factor (CGF) has also been reported to promote wound healing. Nevertheless, the role of PLGA microspheres as a substitute for bone graft material with CGF in bone regeneration remains unclear. This study was designed to evaluate the effect of CGF with PLGA on bone formation and the expression of alkaline phosphatase (ALP) following socket preservation. PLGA microspheres were prepared using double solvent evaporation method and observed under scanning electron microscopy (SEM). A 6 mL of rabbit’s blood was collected from the marginal ear vein and centrifuged to obtain CGF. Blood was also collected for ALP assessment from 24 New Zealand White (NZW) male rabbits subjected to the first upper left premolar extraction. Sockets were filled with CGF, PLGA, CGF+PLGA or left empty and observed with microscopic computed tomography (micro-CT) at four weeks and eight weeks. The SEM image revealed a spherical shape with interconnected pores on the surface of the PLGA particles. Repeated measures ANOVA were used to evaluate the effect of time and treatment (p < 0.05) with significant differences in bone width, height, volume, volume fraction and expression of ALP was observed with CGF+PLGA. Both CGF and PLGA have the potential as the alternative grafting materials and this study could serve as an ideal benchmark for future investigations on the role of CGF+PLGA in bone regeneration enhancement.
... It is well known that following the extraction of a tooth, severe hard and soft tissue alterations may take place at the socket site (Pietrokovski & Massler, 1967;Schropp, Wenzel, Kostopoulos, & Karring, 2003), resulting in a subsequent reduction of both vertical and horizontal ridge dimensions (Araujo & Lindhe, 2005;Discepoli et al., 2013;Tan, Wong, Wong, & Lang, 2012;Van der Weijden, Dell'Acqua, & Slot, 2009). In many occasions, these bone dimensional changes do not allow either appropriate pontic fabrication or correct placement of endosseous implants. ...
... horizontal: 0.98 ± 0.93 mm) aspect, thus shifting the centre of the crest towards a more palatal position. This observation is in agreement with preclinical studies by Araújo and Lindhe (2005), Fickl et al. (2008) and Discepoli et al. (2013) in which the observed morphological changes were more significant at the buccal than the palatal/ lingual aspects. ...
... This resorption pattern may be due to the presence of bundle bone, in which the periodontal ligament fibres of a tooth invest, and which is lost following tooth extraction as it is a tooth-dependent structure. In preclinical studies from Araújo and Lindhe (2005) and Discepoli et al. (2013), it was observed that thin crestal regions (high resorption rate) were made up exclusively of bundle bone while the thick regions (low resorption rate) were comprised of a combination of bundle bone and lamellar bone. ...
... In a previous study on socket healing in dogs, the socket radiodensity without material placement under extraoral radiography showed no differences between the day of operation and the 3 week follow-up [38]. Together with Discepoli's study [49], this previous study described that the alveolar sockets in dogs after extraction at 3 months had not completely healed. These findings may imply that the phase of spontaneous socket healing using radiography at 3 weeks after the operation may not be detectable, and socket healing at 3 months after the operation is in progress. ...
... These findings agree with previous studies on hydroxyapatite-composited material [20,32,40,[51][52][53]. Therefore, these findings suggest that the HAP hydrogel has a positive osteogenic effect and reduces the duration of socket healing compared with the duration of socket healing without material placement [38,49]. Interestingly, Araujo's study [54] reported that an alveolar socket with material placement showed newly formed bone only at the apical part of the socket, where the material did not persist. ...
Article
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Pathological mandibular fracture after dental extraction usually occurs in dogs with moderate to severe periodontitis. A nanohydroxyapatite-based hydrogel (HAP hydrogel) was developed to diminish the limitations of hydroxyapatite for post-extraction socket preservation (PSP). However, the effect of the HAP hydrogel in dogs has still not been widely investigated. Moreover, there are few studies on PSP in dogs suffering from clinical periodontitis. The purpose of this study was to evaluate the effectiveness of the HAP hydrogel for PSP in dogs with periodontitis. In five dogs with periodontitis, the first molar (309 and 409) of each hemimandible was extracted. Consequently , all the ten sockets were filled with HAP-hydrogel. Intraoral radiography was performed on the day of operation and 2, 4, 8 and 12 weeks post operation. The Kruskal-Wallis test and paired t-test were adopted for alveolar bone regeneration analysis. The results demonstrated that the radi-ographic grading, bone height measurement, and bone regeneration analysis were positively significant at all follow-up times compared to the day of operation. Moreover, the scanning electron microscopy with energy-dispersive X-ray spectroscopy imaging after immersion showed a homogeneous distribution of apatite formation on the hydrogel surface. Our investigation suggested that the HAP hydrogel effectively enhances socket regeneration in dogs with periodontitis and can be applied as a bone substitute for PSP in veterinary dentistry.
... It is known that the alveolar process is a tooth dependent tissue, and for this reason, after the tooth extraction, some atrophy degree will result from the healing process. . To decrease the high rates of bone remodeling -50% to 40% (Schropp et al. 2003;Discepoli et al. 2013), implant placement in fresh sockets has been suggested, with the aim of preserving the original architecture (Paolantonio et al. 2001;). Nevertheless, additional studies demonstrated that remodeling will occur independently from the timing of implant installation (Covani et al. 2004;. ...
... Authors state that 40% of the initial volume of the alveolar crest is lost along the remodeling process and in some cases this number can reach 50% (Schropp et al. 2003;Discepoli et al. 2013). Even though for some time it was believed that the implants might be capable to prevent such loss (Paolantonio et al. 2001), more recent studies state that implant placement into fresh extraction sockets does not influence the remodeling process that the postextraction alveolar walls undergo. ...
Article
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Aim: To determinate the influence of the timing and position of the implant placement, as well as the presence and absence of a buccal gap, associated with different implant platforms on bone formation around implants. Methods and materials: In a first surgical stage, two premolars in one side of the mandibular arch of 07 mongrel dogs were extracted. After a 120-day healing period, a second-stage surgery was performed, in which a full flap was raised and two implants were installed. At this same stage, two contralateral premolars were extracted and two immediate implants were placed into the fresh sockets, through the "palatal approach technique" without flap elevation, totaling four implants per animal. The 28 installed implants constituted groups according to the timing (Immediate or delayed) of placement and the type of surface treatment. After 4 months, samples were collected and histomorphometric analysis was performed to determinate buccal surface BIC, lingual surface BIC, total BIC, buccal area, and lingual area of all implants. Kruskal-Wallis and pared Wilcoxon (P < 0.05) tests were performed for statistical analysis. Results: After 4-month healing period, the groups of immediate implants presented better BIC scores, mainly on the buccal surface. Data also suggest better bone area formation around the implants of these same groups. Concerning the type of implant platform, better results were found using Morse taper. Conclusion: The flapless technique with "palatal approach," Morse taper implants, and immediate implant placement all have favorable influence on the bone formation around the implants.
... This is the predominant mode of healing in oral surgery. 8 Indirect bone healing is summarized in Table 4. ...
... The bony remodelling process can last up to six months after extraction and the resorptive process can lead to loss of alveolar depth and width. 8 The healing involved in placement of dental implants is unique ( Figure 1). Any obstacles, aberrancies or disruptions to this sophisticated and precisely tuned process can result in a delay in wound healing or, worse still, a chronic wound that fails to heal. ...
Article
Wound healing is a fundamental survival mechanism, largely taken for granted. It consists of four intricately tuned phases: haemostasis, inflammation, proliferation and remodelling. Successful wound healing only occurs if each phase occurs in the correct sequence and timeframe. Moreover, the oral cavity serves as a unique and remarkable setting whereby wound healing takes place in a saliva-filled environment containing millions of micro-organisms. Many local and systemic factors can impair oral wound healing. This article provides an overview of the wound healing process, with a discussion of these respective local and systemic factors, along with the potential cellular and/or molecular mechanisms involved. CPD/Clinical Relevance: On a daily basis, dentists perform procedures such as exodontia and implant placement that rely on adequate wound healing. An improved understanding of the local and systemic factors that can impair oral wound healing can help clinicians to control these factors more accurately, resulting in improved patient outcomes.
... From the biological point of view, among the possible justifications that have been proposed are that the structure and function of the alveolar bone itself (fascicular bone/bundle bone) depends on the presence of the periodontal ligament; in fact, the periodontal ligament, the root cement, and the fascicular bone can be considered from the embryological point of view as a single functional unit (Cardaropoli et al. 2003). More recent preclinical research directly compared in the same animals the bone dimensional changes after extraction and spontaneous cicatrization compared with immediate implant placement (Vignoletti et al. 2012;Discepoli et al. 2013). In these studies, it was observed that the immediate placement of an implant after the extraction of the tooth not only did not prevent the bone resorption of the buccal plate but that it could also compromise the cicatrization of the alveolar tissues, increasing the resorption of the residual buccal plate (vertical buccal bone loss of 2.32 mm in the case of immediate implants versus 1.20 mm in cases of spontaneous cicatrization). ...
... In these studies, it was observed that the immediate placement of an implant after the extraction of the tooth not only did not prevent the bone resorption of the buccal plate but that it could also compromise the cicatrization of the alveolar tissues, increasing the resorption of the residual buccal plate (vertical buccal bone loss of 2.32 mm in the case of immediate implants versus 1.20 mm in cases of spontaneous cicatrization). In addition, it was observed that the differences found in the vertical resorption of the buccal plate increased between the second and eighth weeks, with bone loss statistically higher in the case of immediate implant placement (0.94 mm) compared with the spontaneous cicatrization of the alveolar socket (0.18 mm) (Discepoli et al. 2013) (Figures 1 and 2). ...
Article
Many different delayed and immediate implantation techniques have been researched for tooth replacement in the upper anterior jaw. Although good esthetic results can be expected, the treatment duration as well as patient morbidity is still high owing to prolonged treatment times and multiple surgeries or surgical sites. By leaving the buccal piece of the root of the failing tooth in place, the otherwise expected post-extractional resorption and remodeling processes are not initiated. The socket shield technique has consequentially shown to completely prevent soft and hard tissue alterations after immediate implantation with open healing. At the same time, it reduces treatment time and patient morbidity to one single surgery and one surgical site.
... Evidence of this bone resorption is more evident with an horizontal reduction of the buccal bone wall mostly in its coronal aspect: the presence of bone atrophy in an edentulous site is characterized by a difficulty in a correct implantology or by the need for guided bone regeneration (GBR) before or contextual to the implant surgery, in addition to the probable need to increase the soft tissues [4]. The placement of a correct implant is the first step for correct implant prosthodontics. ...
Article
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Most of research in regenerative oral surgery describes materials or techniques for increasing volumetric results for implant-supported prosthesis. The use of bio-materials in alveolar ridge preservation after tooth extraction commonly leads to a delayed recovery. Bromelain is an enzyme that belongs to a family of proteolytic enzymes derived from the stem of the pineapple plant (Ananas comosus) with effectiveness in decreasing the inflammation development and swelling. The present paper reports a prospective comparative study performed in order to test the possible use of oral bromelain 40 mg in alveolar ridge preservation. Evaluations were performed at three time points after the surgery: after 2 days (t1), after 7 days (t2) and after 14 days (t3). A statistically significant difference among patients that used bromelain and patients that used placebo resulted among the use of bromelain and lower Visual Analogue Scale (VAS) at t1 (r = −0.75, p = 0.0067), t2 (r = −0.90, p = 0.0001) and t3 (r = −0.8566, p = 0.0008). Bromelain therapy reported a statistically significant difference among patients that used bromelain and patients that used placebo even with regards to the use of bromelain and postoperative swelling at t1 (r = −0.79, p = 0.0034), t2 (r = −0.81, p = 0.0020) but not at t3 (r = −0.34, p = 0.2967). With the result of the present paper, and the poorness of contraindication of the investigated drug, bromelain may be suggested to be used for patients that undergo to alveolar ridge preservation after tooth extraction.
... Beyond its potential impact in quality of life, tooth extraction causes a local physiologic disruption that results in an initial inflammatory response and, subsequently, a variable degree of alveolar ridge atrophy, which is primarily related to bone resorption (Araujo & Lindhe, 2005;Cardaropoli et al., 2003;Evian et al., 1982;Trombelli et al., 2008). Numerous pre-clinical and clinical studies have reported that most of the bone remodelling occurs within the first few weeks after tooth extraction and it is more accentuated on the facio-coronal aspect of the ridge (Araujo & Lindhe, 2005;Avila-Ortiz et al., 2020;Chappuis et al., 2013Chappuis et al., , 2015Discepoli et al., 2013). ...
Article
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Aim: To analyze evidence pertaining to post-extraction dimensional changes of the alveolar ridge after unassisted socket healing. Material and methods: The protocol of this PRISMA-compliant systematic review was registered in PROSPERO (CRD42020178857). A literature search to identify studies that fulfilled the eligibility criteria was conducted. Data of interest were extracted. Qualitative and random effects meta-analyses were performed if at least two studies with comparable features and variables reported the same outcome of interest. Results: Twenty-eight articles were selected, of which 20 could be utilized for the conduction of quantitative analyses by method of assessment (i.e. clinical vs radiographic measurements) and location (i.e. non-molar vs molar sites). Pooled estimates revealed that mean horizontal, vertical mid-facial and mid-lingual ridge reduction assessed clinically in non-molar sites was 2.73mm (95% CI 2.36-3.11), 1.71mm (95% CI 1.30-2.12) and 1.44mm (95% CI 0.78-2.10), respectively. Mean horizontal, vertical mid-facial and mid-lingual ridge reduction assessed radiographically in non-molar sites was 2.54mm (95% CI 1.97-3.11), 1.65mm (95% CI 0.42-2.88) and 0.87mm (95% CI 0.36-1.38), respectively. Mean horizontal, vertical mid-facial and mid-lingual ridge reduction assessed radiographically in molar sites was 3.61mm (95% CI 3.24-3.98), 1.46mm (95% CI 0.73-2.20) and 1.20mm (95% CI 0.56-1.83), respectively. Conclusion: A variable amount of alveolar bone resorption occurs after unassisted socket healing depending on tooth type.
... En este sentido, destacar que una de las limitaciones de nuestro estudio es que no se ha tenido en cuenta si los implantes fueron colocados de forma inmediata o diferida. Diversos grupos de investigación ahondan en las diferencias clínicas, radiográficas e incluso histológicas entre implantes inmediatos y diferidos (48)(49)(50)(51)(52). 4. Implante con profundidad de sondaje patológica y pérdida ósea radiográfica con necesidad de intervención quirúrgica. ...
... 'Socket healing' has been well described by a few classic histologic studies that have been the textbook-reference for decades [3][4][5]. The alveolar socket is a composite wound with different cell types, implicated in different signaling circumstances, and some questions regarding those cells behavior are still to be answered. ...
Article
Full-text available
Bone change after tooth extraction has been well documented by different studies. Toot extraction is followed by loss in height and width of the alveolar process. After tooth loss, the natural healing process is governed by the formation of a blood clot, which is stabilized by a fibrin bridge, the starting structure for new bone apposition. The hematoma is then replaced by the granulation tissue which is rich in fibroblasts that synthesize the extra-cellular matrix. The adjoining of wound edges requires further contraction of the healing tissue which is exerted by myofibroblasts. Excessive myofibroblasts contraction at the early stage of healing might explain, in part, the pathophysiology of alveolar bone resorption. The authors advocate the use of collagen right after tooth extraction to sustain the soft tissue and releasing the tension at the most coronal portion of the wound, thus preventing excessive detrimental myofibroblasts contraction.
... Although the histological sequence of alveolar socket healing has been described in depth [7], the influence of local geometry upon connective tissue healing is largely unknown. The early post-extractive alveolus might be described as a wound that runs through three sequential phases: inflammatory, proliferative, and modeling/remodeling. ...
Article
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After tooth extraction, the alveolar bone tends to shrink in volume, especially on the vestibular side. The role of myofibroblasts in bone remodeling has not been sufficiently investigated. The aim of the present study was to explore the gene expression related to myofibroblasts presence and activity during a 90-day healing period after tooth extraction. The study included 36 rabbits, and a single tooth extraction was performed on each rabbit. The extractive sockets were randomly distributed to natural healing or to scarification of the wound. The sacrifices were staggered in such a manner that animals contributed with sockets representing 2, 7, 15, 30, 60, and 90 days of healing. Nanostring technology was used to evaluate the expression of a wide panel consisting in 148 genes related to the activation, induction, and suppression of myofibroblasts, socket microenvironment, and autophagy. We found that the expression profile of this custom panel was time-related. The post-extractive socket was subjected to significant gene expression changes after 15 days: the genes involved in the induction of myofibroblasts were up-regulated in the first 15-day period and down-regulated during the rest of the follow-up. The study suggested that myofibroblasts play a major role in the immediate 15-day period following tooth extraction.
... It is clear that all of these options give to the patients an alternative to the teeth lost, but they don´t solve the biological and dimensional changes that occur after tooth extraction. Tooth extraction begins a sequence of biological changes, with intense resorption of the alveolar bone, invagination of the mucosa, just in the first weeks after [4][5][6][7][8]. The quantity and extent of bone process changes are dependent on several factors, which in all of the situations leads to alveolar ridge resorption, in the three-dimensional space [9,10]. ...
Article
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Objectives: The purpose of this systematic review was to assess quantitatively and qualitatively the influence of two different factors: membranes and soft tissue graft influence for the extraction socket preservation. Material and Methods: A wide-ranging electronic search was performed in six databases up to 30 of November 2018 in order to identify all the clinical and randomized clinical trials performed in humans published with no data restriction. The inclusion criteria were extraction socket preservation with and without membranes or a soft tissue graft in a intact socket with at least six months of follow-up, have more than 12 patients or treat more than 12 sites per group and evaluated at least one of the primary outcomes measures (radiographic measures histological assessment, clinical measures). Results: From an initial search of 1524 studies only 6 papers fulfil the inclusion and exclusion criterions. All the six selected papers, presented a wide heterogeneity of treatments used, evaluated variables and observation period that made impossible to recommend any specific techniques and/or material to achieve better results. The limited data found suggest that the used of membrane reveals to achieve better results. It wasn’t possible to observe in any clinical trial that compares the used of soft tissue graft. Conclusions: New trials need to be performed in order to identify what specific techniques and/or materials are better to decrease the reabsorption of the socket after tooth extraction. Clinical trials designed to understand when/how the soft tissues grafts influence at the socket preservation is needed.
... The biological effects of electromagnetic fields depend on the intensity and frequency range of the employed signals, on their amplitude, waveform, polarization, and dose, and on the exposure time to microbes, or other agents, from invading deeper into tissues. After tooth extraction, the sequence of healing events is represented by blood coagulation, the production of chemotactic and inflammatory mediators, re-epithelialization, and bone regeneration [35,36]. In any phase of this repair process, adverse conditions that may negatively impact the healing could be present, such as alveolitis, granuloma formation, fistulae, and ulcers [37][38][39][40][41]. ...
Article
Full-text available
Several clinical studies have suggested the impact of sinusoidal and pulsed electromagnetic fields in quickening wound repair processes and tissue regeneration. The clinical use of extremely low-frequency electromagnetic fields could represent a novel frontier in tissue repair and oral health, with an interesting clinical perspective. The present study aimed to evaluate the effect of an extremely low-frequency sinusoidal electromagnetic field (SEMF) and an extremely low-frequency pulsed electromagnetic field (PEMF) with flux densities of 1 mT on a model of oral healing process using gingival fibroblasts. An in vitro mechanical injury was produced to evaluate wound healing, migration, viability, metabolism, and the expression of selected cytokines and protease genes in fibroblasts exposed to or not exposed to the SEMF and the PEMF. Interleukin 6 (IL-6), transforming growth factor beta 1 (TGF-β), metalloproteinase 2 (MMP-2), monocyte chemoattractant protein 1 (MCP-1), inducible nitric oxide synthase (iNOS), and heme oxygenase 1 (HO-1) are involved in wound healing and tissue regeneration, favoring fibroblast proliferation, chemotaxis, and activation. Our results show that the exposure to each type of electromagnetic field increases the early expression of IL-6, TGF-β, and iNOS, driving a shift from an inflammatory to a proliferative phase of wound repair. Additionally, a later induction of MMP-2, MCP-1, and HO-1 was observed after electromagnetic field exposure, which quickened the wound-healing process. Moreover, electromagnetic field exposure influenced the proliferation, migration, and metabolism of human gingival fibroblasts compared to sham-exposed cells. This study suggests that exposure to SEMF and PEMF could be an interesting new non-invasive treatment option for wound healing. However, additional studies are needed to elucidate the best exposure conditions to provide the desired in vivo treatment efficacy.
... Several studies and systematic reviews [1][2][3][4] showed that alveolar bone morphology changes following tooth extraction. Six months after tooth extraction, vertical and horizontal bone resorption was noted [5] and the height of buccal alveolar wall was located 2.2 mm apically of its oral counterpart [6]. Similar alveolar ridge alterations after tooth extraction were reported in retrospective and prospective studies on human models [7,8]. ...
Article
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Objectives To assess dimensional changes following alveolar ridge preservation using bovine-derived xenograft with 10% collagen and collagen membrane compared to ridge preservation by means of bovine-derived xenograft particles and collagen membrane or spontaneous healing in posterior sites. Materials and methods Forty subjects with 40 posterior teeth or roots candidate to extraction and presenting integrity of alveolar bone walls were randomly allocated into three groups. Patients of test group were treated by ridge preservation technique using bovine-derived xenograft with 10% collagen and collagen membrane; patients of control group 1 were treated by means of bovine-derived xenograft particles and collagen membrane while in patients of control group 2, no grafting was performed. Changes in vertical and horizontal bone dimensions were compared at baseline and after 6-month observation time. Results Statistically significant differences between baseline and 6 month were observed in all groups in terms of vertical and horizontal bone resorption (p < 0.001), except for vertical resorption in control group 2. After 6-month intergroup comparisons showed not statistically significant changes between test and control groups in terms of alveolar bone changes (p > 0.05). Conclusions Within the limits of this study, the sites grafted using bovine-derived xenograft with 10% collagen in combination with a collagen membrane showed no statistical differences in terms of vertical and horizontal bone resorption compared to control groups. Clinical relevance Ridge preservation in posterior area failed to show clinically relevant benefits in sites presenting integrity of alveolar bone walls and adequate buccal bone wall thickness.
... Extraction socket healing is a process that includes three highly integrated and overlapping phases: inflammatory (blood clot formation and inflammatory cell migration); proliferative; and modelling/remodelling. Several cellular participants, including periodontal ligament (PDL) cells, blood cells that remain in the extraction socket and bone marrow mesenchymal stem cells (BMSCs) migrating from other sites of the body, have been reported to contribute to the healing of the extraction socket (Araujo, Silva, Misawa, & Sukekava, 2015;Cardaropoli, Araujo, & Lindhe, 2003;Discepoli et al., 2013). However, whether the application of haemostatic agents affects the biological behaviours of these cells, in turn compromising early socket healing, has not yet been clarified. ...
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Aim This study aims to explore the effect of two commercially available hemostatic agents (i.e., collagen sponge and oxide cellulose) on early healing of the extraction socket. Material and methods In a murine model, bilateral maxillary first molars were extracted and the sockets were filled with or without hemostatic agents. Histology, histomorphometry and immunostaining assays were performed on samples harvested on postextraction day 1, 3, 7 and 14. In vitro studies were also designed to investigate the effect of agents on the dynamics of pH and viability of cells. Results Early socket healing was delayed by both agents but with different patterns. The migration of cells was impeded by oxide cellulose on postextraction day 1 compared with the collagen and the control group. The proliferation and osteogenic differentiation of cells were delayed by both materials. Moreover, apoptosis of periodontal ligament cells was present in the hemostatic agent groups. These effects are attributed to the compression to periodontal ligament by both agents, the acidic niche caused by oxide cellulose, and the intense foreign body reaction and inflammatory response caused by the agents. Conclusions The placement of hemostatic agents delay the early extraction healing via different biological mechanism. This article is protected by copyright. All rights reserved.
... As a consequence, a physiologic process of disuse atrophy, characterized by an intense resorption of the alveolar bone and a partial invagination of the mucosa, takes place over the first weeks after tooth extraction. (2)(3)(4)(5) In an attempt to attenuate the resorptive events that follow tooth loss and to minimize the need for ancillary ridge augmentation procedures prior to delivery of implant-and/ or tooth-supported restorations, different interceptive therapies have been proposed, including partial extraction protocols, forced orthodontic extrusion and alveolar ridge preservation (ARP) performed immediately after complete tooth extraction. (6) A wide variety of ARP treatment modalities have been described in the past 20 years, including socket preservation with bone grafting, including autografts, allografts, xenografts, and alloplasts alone or in combination with absorbable or nonabsorbable membrane . ...
... shown in multiple preclinical and clinical studies (Araujo & Lindhe, 2005;Chappuis et al., 2013Chappuis et al., , 2015Discepoli et al., 2013;Trombelli et al., 2008). The extent and magnitude of the bone remodelling process may vary depending on individual local and systemic factors, but it typically results into certain degree of horizontal and vertical alveolar ridge reduction, mainly affecting the bucco-coronal aspect (Tan, Wong, Wong, & Lang, 2012;Van der Weijden, Dell'Acqua, & Slot, 2009). ...
Article
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Purpose The aim of this systematic review was to critically analyze the available evidence on the effect of different modalities of alveolar ridge preservation (ARP) as compared to tooth extraction alone in function of relevant clinical, radiographic and patient‐centered outcomes. Material and Methods A comprehensive search aimed at identifying pertinent literature for the purpose of this review was conducted by two independent examiners. Only randomized clinical trials (RCTs) that met the eligibility criteria were selected. Relevant data from these RCTs were collated into evidence tables. Endpoints of interest included clinical, radiographic, and patient‐reported outcome measures (PROMs). Interventions reported in the selected studies were clustered into ARP treatment modalities. All these different ARP modalities were compared to the control therapy (i.e. spontaneous socket healing) in each individual study after a 3‐ to 6‐month healing period. Random effects meta‐analyses were conducted if at least two studies within the same ARP treatment modality reported on the same outcome of interest. Results A combined database, grey literature and hand search identified 3,003 records of which 1,789 were screened after removal of duplicates. Following the application of the eligibility criteria, 25 articles for a total of 22 RCTs were included in the final selection, from which 9 different ARP treatment modalities were identified: 1. Bovine bone particles (BBP) + Socket sealing (SS), 2. Construct made of 90% bovine bone granules and 10% porcine collagen (BBG/PC) + SS, 3. Cortico‐cancellous porcine bone particles (CPBP) + SS, 4. Allograft particles (AG) + SS, 5. Alloplastic material (AP) with or without SS, 6. Autologous blood‐derived products (ABDP), 7. Cell therapy (CTh), 8. Recombinant morphogenic protein‐2 (rh‐BMP2), and 9. SS alone. Quantitative analyses for different ARP modalities, all of which involved socket grafting with a bone substitute, were feasible for a subset of clinical and radiographic outcomes. The results of a pooled quantitative analysis revealed that ARP via socket grafting (ARP‐SG), as compared to tooth extraction alone, prevents horizontal (Mean = 1.99 mm; 95% CI 1.54 to 2.44; P < 0.00001), vertical mid‐buccal (Mean = 1.72 mm; 95% CI 0.96 to 2.48; P < 0.00001) and vertical mid‐lingual (Mean = 1.16 mm; 95% CI 0.81 to 1.52; P < 0.00001) bone resorption. Whether there is a superior ARP or SS approach could not be determined on the basis of the selected evidence. However, the application of particulate xenogenic or allogenic materials covered with an absorbable collagen membrane or a rapidly‐absorbable collagen sponge was associated with the most favorable outcomes in terms of horizontal ridge preservation. A specific quantitative analysis showed that sites presenting a buccal bone thickness > 1.0 mm exhibited more favorable ridge preservation outcomes (difference between ARP [AG+SS] and control = 3.2 mm), as compared to sites with a thinner buccal wall (difference between ARP [AG+SS] and control = 1.29 mm). The effect of other local and systemic factors could not be assessed as part of the quantitative analyses. PROMs were comparable between the experimental and the control group in two studies involving the use of ABDP. The effect of other ARP modalities on PROMs could not be investigated, as these outcomes were not reported in any other clinical trial included in this study. Conclusion ARP is an effective therapy to attenuate the dimensional reduction of the alveolar ridge that normally takes place after tooth extraction. This article is protected by copyright. All rights reserved.
... Initially, an impression of each hemimandible was performed to make a surgical guide indicate the implant position, which was predetermined to correspond with the distal root and the center of the crown teeth. Sixty days previous to the surgery, the left mandibular premolars (P2, P3, P4) and molar (M1) were extracted to heal the alveolus sites [21]. In the surgery to place the implants, equally to previous surgery, the teeth of the right hemimandibles were sectioned in a bucco-lingual direction using a tungsten carbide bur so that the roots could be extracted individually without damaging the remaining bony walls. ...
Article
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Background: The aim of this study was to compare histologically the dimensional behavior of peri-implant tissues during osseointegration of immediately exposed or submerged implant placement in fresh extraction and healed sites. Methods: Four fresh extraction and four delayed implant sites were placed in each hemimandible of five dogs at the bone crest level. In 2 implants of each side were installed a healing abutment (exposed) and two cover screw (submerged) and formed four groups: implant installed in fresh extraction submerged (group 1), implants in fresh extraction immediately exposed (group 2), implants installed in healed site submerged (group 3), and implants in healed site immediately exposed (group 4). After 12 weeks of healing period, histomorphometric analyses of the specimens were carried out to measure the crestal bone level values and the tissue thickness in the implant shoulder portion. Results: The measure of crestal bone level showed some higher values for implants installed in fresh extraction sites in the buccal aspect: 1.88 ± 0.42 mm for group 1 and 2.33 ± 0.33 mm for group 2, with statistical significance among all four groups tested (P < 0.001). For peri-implant tissue thickness, a significative higher statistical difference (P < 0.001) for implants installed in healed sites (groups 3 and 4) was found. Conclusions: Within the limitations of the present animal study, our findings suggest that the implants placed in fresh extraction or healed site and with regards to the moment of exposition (immediately or no) are important factors to the amount of peri-implant tissues after remodeling over a period of 12 weeks. The null hypothesis was rejected.
... De extractieholte is gevuld met bot zo'n week of 8 na de extractie. Botremodellering gaat door tot zo'n 6 maanden na de extractie en gaat gepaard met verlies van hoogte en breedte van de alveole door resorptie en remodelling (Discepoli, 2013) . De mate van botverlies is individueel verschillend en hangt af van de locatie, de aanwezigheid van buurelementen, het behandelingsprotocol, het gebruik van membranen en botsubstituten en roken (Trombelli, 2008). ...
Chapter
Een intacte gelaatshuid en een intacte mucosa in de mond zijn belangrijke verdedigingslinies. Wanneer deze doorbroken worden door een wond, een tandextractie of een operatieve ingreep, komt er een helingsproces op gang met een vaste volgorde. Na de bloedstelping volgt een fase van ontsteking, waarbij jong vaatrijk celrijk bindweefsel wordt gevormd. Vervolgens vormt de wond vanuit de randen nieuw slijmvlies, waarna de wond gaat samentrekken en een litteken achterlaat. Zowel plaatselijke als algemene factoren kunnen dit normale proces van wondheling in de mond verstoren en aanleiding geven tot een vertraagde, uitgestelde of onvolledige wondheling. Ook kan te veel littekenvorming plaatsvinden. Oorzaken van verstoorde wondheling die relevant zijn voor de tandheelkundige praktijk worden in dit hoofdstuk besproken.
... In relation to the NB formation, the control group showed more NB at the coronal and middle thirds compared to the test groups. This is in agreement with preliminary studies performed in dogs reported by Araujo et al. (2008) and Discepoli et al. (2013). In brief, they found that after 8-12 weeks of healing the mean percentage of mineralized tissues within the sockets was in a range of only 39-50%. ...
Article
Objectives: To compare different compressive forces exerted on a particulate graft material during socket preservation and their effects on bone regeneration. Material and methods: Six male dogs were used. The second, third, and fourth premolars, and the first molar were extracted bilaterally at the lower jaws. A particulate synthetic biphasic grafting material (60% HA and 40% β-tricalcium phosphate) was used. Three different standardized compressive forces were applied randomly during the socket preservation. The sample was divided into four experimental groups Test A (10 g), Test B (50 g), Test C (200 g), and Control (empty sockets). Collagen membranes were placed, and primary closure was obtained. Two months after the surgery the animals were sacrificed, and histomorphometric analysis of non-decalcified samples was performed at the coronal, middle, and apical thirds. Results: Grafted sockets resulted in higher bony contour (3 ± 0.43 mm(2) ; P < 0.05). The particles penetrated up to the apical third in the group C but not in the other test groups and controls (P < 0.05). The percentage of new bone were higher at the coronal and apical thirds for Controls and group C compared to A and B groups (P < 0.05). The residual graft was higher for group C (53 ± 1.4%), followed by group B (45 ± 3.1%) and group A (35 ± 1.9%; P < 0.05). The percentages of connective tissue were higher at the middle third without differences between groups (P > 0.05). Conclusions: Within the limitations of this experimental animal study, it might be concluded that grafted sockets compressed with 200 g force will have higher bony contours; higher compressive forces facilitate the penetration of the particulate graft material into the apical area of the socket and results in more bone formation at the coronal, middle, and apical thirds.
... 6 All techniques have advantages and disadvantages, but types 1 and 2 are usually preferred due to the short waiting period than the other techniques 7,8 and because some authors indicate that the immediate implant placement provides a decrease in the atrophy of the alveolar process and in the bone remodeling. 4,9,10 On the contrary, studies have described bone loss even following immediate implant placement and more pronounced in the buccal plate relative to the lingual plate. 11 To prevent this loss, the bone plate should be 2 mm thick, 12 but research shows that in the vestibular surface of the anterior region, 87% of cases have a thickness not exceeding 1 mm, indicating the need for bone graft in that region. ...
Article
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Since the alveolar process is tissue “dental dependent,” after the extraction of the dental element, this process suffers some degree of atrophy during the healing process, which can be reduced with the installation of immediate implants, aiming to maintain the original bone architecture. The aim of this study was to investigate the influence of the time of implant placement on bone formation around them. Seven dogs were selected and randomly divided into two groups: Group 1, where implants were placed immediately after extraction of two lower premolars without flap elevation, and group 2, where implants were delayed by 4 months after extractions. Each group received 14 implants, and 4 months after the second surgery, the samples were processed and analyzed histomorphometrically. A mean average analysis and the Kruskal–Wallis test (p < 0.05) were performed. The buccal bone–implant contact (BIC) mean average was found larger in immediate implants (42.61%) compared with delayed implants (37.69%). Group 1 had statistically higher outcomes in bone formation and BIC on the buccal bone wall. It was concluded that performing immediate implants with the palatal approach technique and leaving a buccal GAP enables a higher or at least equal rate to BIC and bone area around them, when compared with delayed implants. Actually, the patients and dentists want to do a shorter treatment with satisfactory results, but it is necessary to understand whether different times of implant placement can influence the results and longevity of the treatment. How to cite this article Rafael CF, Passoni B, Araújo C, de Araújo MA, Benfatti C, Volpato C. Can Time of Implant Placement influence Bone Remodeling? J Contemp Dent Pract 2016;17(4):270-274.
... Following oral surgery or tooth extraction, a sequence of healing processes are immediately initiated. The periodontal pocket is blocked by blood coagulation [4], and a re-epithelization mechanism is initiated, followed by granulation tissue generation [5]. After one week of tissue remodeling, bones replenishment occurs, and cavity closure is completed within a period of eight weeks after tooth extraction [6,7]. ...
Article
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Following surgery, healing within the oral cavity occurs in a hostile environment, and proper oral care and hygiene are required to accelerate recovery. The aim of the current study is to investigate and compare the bioreactivity characteristics of mouthwashes based on either chlorhexidine (CHX) or a novel bone bioactive liquid (BBL) in terms of oral healing within seven days application post-surgery. A randomized, double blind clinical trial was conducted in 81 patients, wherein the mouthwashes were applied twice a day for a period of 7 days. The visual analog scale (VAS) protocol was applied to determine pain index scores. Early wound healing index (EHI) score was determined for evaluating oral cavity healing progress. No adverse effects were observed using the mouthwashes, but CHX application resulted in stained teeth. Applications of both CHX and BBL were sufficient to reduce pain over a period of 7 days. However, the BBL group demonstrated a statistically significant reduction in VAS scores starting on day 4. The EHI scores were significantly higher in the BBL group compared with the CHX group, independent of tooth location. No differences in either VAS or EHI scores due to gender were observed. Compared with the commercially available CHX mouthwash, application of the BBL mouthwash reduced pain and accelerated oral cavity healing to a greater extent, suggesting it effectively improves the oral cavity microenvironment at the wound site in mediating soft tissue regeneration.
... The resorptive changes were accentuated on the vestibular aspect, particularly in the anterior maxilla [8,9]. In addition, findings from one pre-clinical analysis indicated two to three times higher vertical bone resorption at immediately inserted implants than at adjacent spontaneously healed sites [10]. The aforementioned findings suggest that initial physiological bone remodeling around immediately placed implants may result in the exposure of the rough implant threads, which in turn may facilitate initial bacterial colonization. ...
Article
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Background To evaluate the prevalence of peri-implant disease after immediate implant placement and loading. Material and methods This cross-sectional analysis included a total of 47 patients with 64 implants exhibiting a mean loading time of 2 to 10 years (4.23 ± 1.7 years). The surgical and prosthetic procedures were standardized in all patients. Peri-implant health and disease was assessed based on the established case definitions. Results The prevalence of peri-implant health, peri-implant mucositis, and peri-implantitis amounted to 38.3%, 57.5%, and 4.2% of the patients, respectively. Mucosal recession of 1 mm was present at 4 (6%) implants. No suppuration, pain, or implant failures were reported. Ordinal logistic regression revealed that reduced keratinized mucosa height was significantly associated with the diagnosis of peri-implant mucositis and peri-implantitis (OR = 0.514, P = 0.0125). Conclusion Immediate implant placement and loading was associated with high success rates at 2 to 10 years.
... Tooth extraction produces resorption of alveolar bone and soft tissues as a physiological response to the absence of periodontal ligament and biomechanical stimuli, 1 causing a progressive atrophy of alveolar bone and fewer possibilities of prosthetic rehabilitation in these patients. 2,3 To counteract the collapse of the alveolar ridge, different alveolar ridge preservation (ARP) techniques have been proposed using surgical techniques and biomaterials inserted inside the alveolar socket. [4][5][6] The autologous materials proposed for the use of ARP include the growth factors derived from the blood in the form of second-generation leukocyte-and platelet-rich fibrin (L-PRF) 7 with a high concentration of platelets, leukocytes, and lymphocytes, giving rise to a strong fibrin matrix with a specific 3dimensional distribution capable of releasing growth factors and proteins involved in wound healing, promoting cell proliferation, and differentiation. ...
Article
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Purpose Leukocyte- and platelet-rich fibrin (L-PRF) has been used for alveolar ridge preservation (ARP) in postextraction tooth sockets. However, current reports have measured its effectiveness in linear measurements of 3-dimensional ridge preservation. The purpose of this study was to determine the effectiveness of the use of L-PRF filling versus natural clot blood healing in ARP according to the clinical, radiographic, and volumetric measurements of postextraction tooth sockets. Materials and Methods A split-mouth randomized clinical trial was designed. Healthy patients who needed bilateral extraction of upper third molars were selected. After the tooth extraction, the socket was filled and distributed randomly with L-PRF and the contralateral socket only with the blood clot. The dimensional change of soft tissue healing around the sockets, and the length, depth, and difference of bone formation were examined using standardized periapical radiographs. Volumetric measurement variation of the sockets was evaluated by 3-dimensional scanning of dental casts. Changes of all measures were analyzed at 7 days (initial) and 3 months (final) after the tooth extraction and compared between both groups (t test; P < .05). Results Sixteen patients (aged 24.75 ± 3.53 years; 56.25% women) participated. Measurements of wound healing and the length, depth, and difference of bone formation were similar for both study groups at initial and final times. The calculation of initial-final volumetric socket variation was 15.45 ± 13.12 μL using L-PRF and 14.12 ± 11.23 μL using blood clot (P = .78). Conclusions L-PRF filling showed the same dimensional and volumetric behavior as normal blood clot healing in the ARP of postextraction tooth sockets. Future investigations will have to analyze the use of surgical models and digital instruments in ARP techniques.
... 1,2 Immediately after removing a tooth from its alveolus, a physiologic process of progressive disuse atrophy is initiated, affecting the alveolar ridge. 3,4 Depending on local and systemic factors inherent to each individual, a varying extent of horizontal and vertical resorption of the alveolar bone, as well as partial invagination of the oral mucosa, takes place over the rst few weeks after tooth extraction, being more signi cant on the buccocoronal aspect of the ridge. 5,6 In order to attenuate these resorptive events, speci c interceptive therapies have been proposed. ...
... After oral surgery or tooth extraction, the sequential healing processes initiate momently. The periodontal pocket will be blocked by blood coagulation (4), and a re-epithelization mechanism will be initiated followed by a granulation tissue generation (5). After one week of the tissue remodeling, bones replenishment occurs, and cavity closure completes within a period of eight weeks after tooth extraction (6,7). ...
Preprint
After surgery, oral cavity healing occurs in a hostile environment and requires proper oral care and hygiene to accelerate recovery. The aim of the current study is to investigate and compare the bioreactivity characteristics of chlorhexidine based (CHX) mouth rinse and a novel bone bioactive liquid (BBL) mouth rinse on oral healing within seven days application post-surgery. A randomized, double blind clinical trial conducted in 81 patients. The mouth rinses were applied twice a day for a period of 7 days. The visual analog scale (VAS) protocol was applied to measure pain index. Early wound healing score (EHI) was determined in evaluate the oral cavity healing progress. No adverse effects were observed using the mouth washes, but CHX resulted in teeth staining. CHX and BBL were sufficient to reduce pain over a period of 7 days. However, the BBL group demonstrated a statistically significant reduction in VAS stating day 4. Relative to CHX group, the EHI scores were significantly higher in the BBL group, independent from the tooth location. No gender differences were observed in both VAS and EHI scores. Relative to the commercially available CHX, BBL mouth rinse reduced pain and accelerated oral cavity healing. Suggesting an improvements of oral cavity microenvironment at the wound site that mediates soft tissue regeneration.
... Systematic reviews have demonstrated that the alveolar socket undergoes an average horizontal shrinkage between 0.9 and 3.8 mm and an average vertical reduction of 1.24 mm, within 3 to 7 months after tooth extraction [3,4]. Overall, these changes are more pronounced at the buccal plate [5]. ...
Article
Full-text available
The healing process of the tooth extraction socket often leads to significant resorption of the alveolar bone, eventually causing clinical difficulties for future implant-supported rehabilitations. The aim of the present animal study was to evaluate alveolar bone remodeling after tooth extraction in a rabbit model, either with or without the use of a plain collagen plug inside the socket, by means of micro-computed tomography. The study included the micro-tomography analysis of 36 rabbits’ incisor extraction sockets, either left empty or filled with a collagen plug. All animals were euthanized in a staggered manner, in order to address molecular, histologic, and radiographic analyses at different time-points, up to 90 days after surgery. The three-dimensional evaluation was carried out using micro-computed tomography technology on excised bone blocks including the alveolus and the contralateral bone. Both linear and volumetric measures were recorded: the percentage of bone volume change (ΔBV) within the region of interest was considered the primary endpoint of the study. The micro-CT analysis revealed mean volumetric changes of −58.1% ± from baseline to 3 months for the control group, and almost no bone loss for the test group, −4.6%. The sockets treated with the collagen plug showed significantly less dimensional resorption, while the natural-healing group showed an evident collapse of the alveolar bone three months after extraction surgery.
... 9,10 On the contrary, a more accentuated phenomenon of progressive alveolar ridge atrophy should be expected in sites that are left to heal after tooth extraction with no further intervention. 22,23 A recent systematic review that analyzed clinical evidence pertaining to postextraction dimensional changes after USH reported that non-molar sites are associated with an increased need for ancillary bone augmentation to facilitate implant therapy (69.7%) compared with molar sites (45.9%). 3 The observations are in alignment with the findings of the present study, where additional bone grafting augmentation procedures were deemed to be necessary in 60% of sites that did not received ARP therapy. ...
Article
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Background: There is limited information on the need for bone augmentation in the context of delayed implant placement whether alveolar ridge preservation (ARP) is previously performed or not. The primary aim of this retrospective cohort study was to evaluate the efficacy of ARP therapy after tooth extraction compared with unassisted socket healing (USH) in reducing the need for ancillary bone augmentation prior to or at the time of implant placement. Materials and methods: Adult subjects that underwent non-molar single tooth extraction with or without simultaneous ARP therapy were included in this study. Cone beam computed tomography scans obtained prior to tooth extraction and after a variable healing period were used to record the baseline facial bone thickness and to virtually plan implant placement according to a standard method. A logistic regression model was used to evaluate the effect of facial alveolar bone thickness upon tooth extraction and baseline therapy (USH or ARP) on the need for additional bone augmentation, adjusting for several covariates (i.e., age, sex, baseline KMW, and tooth type). Results: One hundred forty subjects that were equally distributed between both baseline therapy groups constituted the study population. Implant placement was deemed feasible in all study sites. Simultaneous bone augmentation was considered necessary in 60% and 11.4% of the sites in the USH and ARP group, respectively. The majority of these sites (64.2% in the USH group and 87.5% in the ARP group) exhibited a thin facial bone phenotype (<1mm) at baseline. Logistic regression revealed that the odds of not needing ancillary bone augmentation were 17.8 times higher in sites that received ARP therapy. Furthermore, the need for additional bone augmentation was reduced 7.7 times for every 1mm increase in facial bone thickness, regardless of baseline therapy. Conclusions: ARP therapy and thick facial alveolar bone largely reduce the need for ancillary bone augmentation at the time of implant placement in non-molar sites. This article is protected by copyright. All rights reserved.
... [6][7][8] Following tooth extraction different successive biological events occur as a response to the combined effects of local inflammation generated by trauma produced during the extraction procedures, the end of occlusal forces transmission to the periodontium resulting in lack of physiological need of those structures (e.g., bundle bone). [9][10][11][12][13][14][15] These effects promote a modification of the homoeostasis and structural characteristics of the alveolar bone, resulting in dimensional alveolar bone resorption characterized by partial horizontal and vertical reduction of the alveolar ridge, mostly perceived at the buccal bone crest. The amount of bone remodeling (i.e., extension and degree) is variable and may be influenced by the patient's individual local conditions (i.e., periodontal tissues' conditions, periodontal anatomy) and other systemic factors (i.e., smoking, diabetes), but the entire marginal buccal bone wall can be lost following tooth extraction. ...
Article
Objective: Maintenance of adequate interproximal tissue height between an implant and a natural tooth or between adjacent implants represents an esthetic challenge in implant dentistry. The aim of this case report is to describe a modified technique referred to as the beyond the gap filling (BGF) approach designed to improve the horizontal and vertical components of the facial aspect and particularly the height of interproximal bone peaks around immediately placed implants into fresh extraction sockets. Clinical considerations: Four patients (five teeth) requiring anterior tooth extraction were treated with the BGF approach that included: (a) minimally traumatic tooth extraction; (b) immediate implant placement without flap elevation; (c) installation of a narrow profile healing abutment to protect the implant during grafting; (d) grafting with a construct with 90% bovine bone granules and 10% porcine collagen packed coronally to the facial and interproximal bone walls above the level of the bone crest; and (e) delivery of an immediate restoration. Conclusions: The current report suggests that the level/height of the interproximal bone crests between an implant and a natural tooth or between two adjacent implants can be improved by the BGF approach and, consequently, papilla height can be maintained in cases with a high risk of papilla height collapse and, consequently, esthetic outcomes can be maximized. Clinical significance: The BGF is a simple technique to be used by clinicians to prevent significant papilla collapse in anterior immediate implants and consequently achieve maximum esthetic outcomes in implant dentistry.
... Findings from the present study showed a ridge width reduction in the test group at 6 and 9 months compared to the baseline with no statistically significant difference. is could be due to the loss of the bundle bone, where the periodontal ligament fibers invest, following tooth extraction [28]. is can be also in accordance with many systematic reviews which claimed that no substitute material was able to completely preserve the alveolar ridge after tooth extraction, but may limit buccal plate resorption to a certain extent [29,30]. ...
Article
Full-text available
Objective: Autogenous tooth bone graft (ATBG) was suggested as a source for bone grafting materials, especially as they have similar chemical composition to bone. This study goal was to assess the clinical and radiographic consequences of ATBG with or without L-PRF on bone deposition around immediate implants placed in periodontally hopeless sites. Materials and methods: 26 patients, with periodontally diseased teeth, underwent random assignment to receive the surgical protocol either with L-PRF over ATBG around immediately inserted implants (test group) or without it (control group). Clinical examination was observed. Radiographically, bone changes horizontally and vertically to determine marginal bone loss (MBL) and mesiodistal bone changes were made at the base line and 6 and 9 months after implant insertion. Statistical analysis utilizing paired Student's t-test was used for comparing results within the same group, whereas an independent-sample t-test was used for intergroup variable comparison. Results: All implants met the criteria of success without any complications at the follow-up period. Nonsignificant differences were detected between horizontal bone alterations in both groups at 6 and 9 months (P > .001). The test group showed statistically significant lower MBL than the control group (P < .001). The mesiodistal bone gain in the test group was significantly higher than that of the control group at the 6-month period (P < .001). The mesiodistal bone loss in the control group was significantly higher than that of the test group at the 9-month period (P < .001). Conclusion: The ATBG- L-PRF combination therapy enhances new bone formation and appeared to be a favorable procedure with immediate implant placement, particularly in severe periodontitis cases.
... In biphasic dental implant procedures, dental implants are generally placed either at the same level as the surface of the bone or directly under it. It is between the prepared osteotomy edge and the edge surface of the implant that the healing of the bone occurs [120]. Depending on the mechanical stress caused by occlusal forces, bone remodeling around the dental implant persists for at least 1year. ...
Article
Full-text available
Regenerative medicine is a field that aims to influence and improvise the processes of tissue repair and restoration and to assist the body to heal and recover. In the field of hard tissue regeneration, bio-inert materials are being predominantly used, and there is a necessity to use bioactive materials that can help in better tissue–implant interactions and facilitate the healing and regeneration process. One such bioactive material that is being focused upon and studied extensively in the past few decades is bioactive glass (BG). The original bioactive glass (45S5) is composed of silicon dioxide, sodium dioxide, calcium oxide, and phosphorus pentoxide and is mainly referred to by its commercial name Bioglass. BG is mainly used for bone tissue regeneration due to its osteoconductivity and osteostimulation properties. The bioactivity of BG, however, is highly dependent on the compositional ratio of certain glass-forming system content. The manipulation of content ratio and the element compositional flexibility of BG-forming network developed other types of bioactive glasses with controllable chemical durability and chemical affinity with bone and bioactivity. This review article mainly discusses the basic information about silica-based bioactive glasses, including their composition, processing, and properties, as well as their medical applications such as in bone regeneration, as bone grafts, and as dental implant coatings.
... Significant alveolar bone resorption occurs after the extraction of the tooth [1][2][3]. The loss of bundle bone will cause an alveolar ridge alteration in both vertical and horizontal directions during the healing process [1,2,4]. At 3 months following tooth extraction in the lower posterior area, the buccal alveolar bone height was located 2.2 mm apical to the height of the lingual alveolar wall [5]. ...
Article
Full-text available
This prospective clinical study aimed to evaluate the peri-implant hard tissue dimensional change at 6 months of immediate implant placement with bone graft materials in the posterior area using cone-beam computed tomography (CBCT). Twelve dental implants were placed concurrently following tooth extraction in the posterior area and filled with xenograft particles. The CBCT images were taken immediately after surgical procedures and then at 6 months follow-up. To evaluate the hard tissue changes, the vertical and horizontal bone thickness were analyzed and measured using ImageJ software. Paired t-test or Wilcoxon match-pair signed-rank test was done to analyze the changes of hard tissue values at the same level between immediately and 6 months following immediate implant placement. Independent t-test or Mann-Whitney U test was used to analyze the dimensional change in the vertical and horizontal direction in buccal and lingual aspects. The level of significance was set at p value = 0.05. All implants were successfully osseointegrated. At 6 months follow-up, the vertical bone change at the buccal aspect was -0.69 mm and at the lingual aspect -0.39 mm. For horizontal bone thickness, the bone dimensional changes at 0, 1, 5, and 9 mm levels from the implant platform were -0.62 mm, -0.70 mm, -0.24 mm, and -0.22 mm, respectively. A significant bone reduction was observed in all measurement levels during the 6 months after implant placement (p value < 0.05). It was noted that even with bone grafting, a decrease in bone thickness was seen following the immediate implant placement. Therefore, this technique can be an alternative method to place the implant in the posterior area.
... [1] After teeth extraction, a modeling and remodeling process occurred, this process leads to many changes in the width and height of the alveolar bone, the resorption of the buccal wall is higher than the palatal and lingual wall. [2] After extraction, the absorption emerges at 2 stages. In the first stage the bundle bone is absorbed quickly and replaced by a premature bony tissue that is soon replaced by a lamellar bone that submerges the alveolar socket within 180 days. ...
... Preclinical and clinical studies have demonstrated that tooth extraction triggers a physiologic process of structural remodeling, resulting in a variable degree of alveolar ridge volume loss, primarily due to bone resorption. [1][2][3] The presence of severe ridge deficiencies may interfere with tooth replacement therapy. High-level evidence supports the efficacy of alveolar ridge preservation therapy in attenuating bone loss after tooth extraction in intact sockets. ...
Article
Full-text available
This study evaluated a panel of clinical, dimensional, volumetric, implant-related, histomorphometric and patient-reported outcomes (PROMs) following reconstruction of dehiscence defects in extraction sockets with a minimally invasive technique using a particulate bone allograft and a non-absorbable dense polytetrafluoroethylene (dPTFE) membrane. Subjects (n=17) presenting severe buccal dehiscence defects at the time of single-rooted tooth extraction participated in the study. The mean vertical dimension of the dehiscence defects at baseline was 5.76±4.23mm. Subjects were followed up at 1, 2, 5 and 20 weeks postoperatively. The dPTFE barrier was gently removed at 5 weeks. CBCT and an intraoral scans were obtained at baseline and at 20 weeks. A bone core biopsy was harvested at 24 weeks before implant placement. Linear radiographic measurements revealed a mean increase in buccal bone height from baseline to 20 weeks of 5.66±5.1mm (p<0.0001). A total alveolar bone volume gain of 9.12% (p=0.075) was observed, while the ridge contour volume was reduced 10.83% (p=0.002). Although approximately half of the sites required some degree of additional bone augmentation at the time of implant placement, all implants could be placed in a favorable restorative position with adequate primary stability. Histomorphometric analyses revealed a mean mineralized tissue area of 31.04±15.22%, while the proportion of residual allograft particles and non-mineralized tissue were 16.23±10.63% and 52.71±9.53%, respectively. All implants survived up to 12 months after placement. PROMs were compatible with minimal discomfort at different postoperative stages and a high level of overall satisfaction upon study completion. This study demonstrated that the reconstructive procedure employed was successful and predictable in treating large, postextraction alveolar ridge deformities to optimize tooth replacement therapy with implant-supported prostheses.
... 1,2 Immediately after removing a tooth from its alveolus, a physiologic process of progressive disuse atrophy is initiated, affecting the alveolar ridge. 3,4 Depending on local and systemic factors inherent to each individual, a varying extent of horizontal and vertical resorption of the alveolar bone, as well as partial invagination of the oral mucosa, takes place over the first few weeks after tooth extraction, being more significant on the buccocoronal aspect of the ridge. 5,6 In order to attenuate these resorptive events, specific interceptive therapies have been proposed. ...
Article
Full-text available
This study aimed to characterize extraction sockets based on indirect digital root analysis. The outcomes of interest were estimated socket volume and dimensions of the socket orifice. A total of 420 extracted teeth, constituting 15 complete sets of permanent teeth (except third molars), were selected. Teeth were scanned to obtain STL files of the root complex for digital analysis. After digitally sectioning each root 2.0 mm apical to the cementoenamel junction (CEJ), root volume was measured in mm3 and converted to cc. Subsequently, a horizontal section plane was drawn at the most zenithal level of the buccal CEJ, and the surface area (in mm2) and buccolingual and mesiodistal linear measurements of the socket orifice (in mm) were computed. Maxillary first molars exhibited the largest mean root volume (0.451 ± 0.096 cc) and mandibular central incisors the smallest (0.106 ± 0.02 cc). Surface area analysis demonstrated that mandibular first molars presented the largest socket orifice area (78.56 ± 10.44 mm2), with mandibular central incisors presenting the smallest area (17.45 ± 1.82 mm2). Maxillary first molars showed the largest mean socket orifice buccolingual dimension (11.08 ± 0.60 mm), and mandibular first molars showed the largest mean mesiodistal dimension (9.73 ± 0.84 mm). Mandibular central incisors exhibited the smallest mean buccolingual (5.87 ± 0.26 mm) and mesiodistal (3.52 ± 0.24 mm) linear dimensions. Findings from this study can be used by clinicians to efficiently plan extraction-site management procedures (such as alveolar ridge preservation via socket grafting and sealing) and implant provisionalization therapy, and by the industry to design products that facilitate site-specific execution of these interventions.
... 7,9,10 Bone remodeling, as well as the clinical sequelae occurring at the alveolar ridge after tooth extraction, have been extensively described in the literature. [11][12][13][14][15][16][17] A major contributing factor in vertical remodeling has been shown to be bundle bone-a tooth-dependent tissue. 14,15 Following tooth extraction, bundle bone loses its function, is gradually remodeled, and the socket becomes filled with immature woven bone. ...
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Background: The current evidence regarding the alterations experienced by the alveolar ridge (hard tissue changes) after implant removal due to peri-implantitis is limited. Purpose: To assess the hard tissue dimensional changes following implant removal due to peri-implantitis. Material and methods: Clinical records were examined to identify patients with implants that had to be removed due to a hopeless prognosis secondary to peri-implantitis due to expendability of peri-implantitis implants for functional reasons. Patients with preoperative and postoperative cone-beam computed tomography (CBCT) scans were included. Patient-related, implant-related, and surgery-related factors were assessed based on the clinical records. Linear measurements were made to evaluate the influence of bone plate thickness (BPT), ridge width (RW), and ridge height (RH) at various levels upon the outcome of implant removal. A descriptive statistical analysis of the quantitative and qualitative variables was performed. Correlations of the variables with the primary outcome (dimensional changes) were tested using univariate and multivariate analyses (multinomial random intercept mixed model linear regressions). Results: A total of 26 patients (nimplants = 79) met the eligibility criteria. The mean decrease in RW at 1 and 3 mm below the crest was 11.3% and 4.4%, respectively (P < 0.001). Buccal and lingual RH was significantly reduced by 2.2% and 6.3%, respectively (P < 0.001). Few patient-related, implant-related, and surgery-related factors appeared to have an impact upon the hard tissue dimensional changes. Bone regeneration simultaneous to implant removal minimized the dimensional changes of the ridge both vertically (5% lesser buccal RH reduction) and horizontally (12% lesser RW reduction) when compared with spontaneous healing. The use of a reverse-torque removal kit seemed to be critical in limiting the dimensional changes of the ridge. Conclusions: Minimal hard tissue changes can be expected following implant removal due to peri-implantitis. Simultaneous bone regeneration procedures and the use of a removal kit may considerably reduce the impact upon the dimensional changes (NCT04534361).
... The mandibular premolars P2, P3, P4, and the molar M1 were extracted from both sides carefully via a minimally invasive surgical approach. Teeth were sectioned in a buccolingual direction using a tungsten-carbide bur to facilitate individual root's extraction without damaging the remaining alveolar bone walls and the alveolus was left to heal as previously described [40]. After a healing period of 12 weeks, for implant placement, full-thickness mucoperiosteal flaps were raised in the hole mandible ( Figure 1B). ...
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Background: Bioactive chemical surface modifications improve the wettability and osseointegration properties of titanium implants in both animals and humans. The objective of this animal study was to investigate and compare the bioreactivity characteristics of titanium implants (BLT) pre-treated with a novel bone bioactive liquid (BBL) and the commercially available BLT-SLA active. Methods: Forty BLT-SLA titanium implants were placed in in four foxhound dogs. Animals were divided into two groups (n = 20): test (BLT-SLA pre-treated with BBL) and control (BLT-SLA active) implants. The implants were inserted in the post extraction sockets. After 8 and 12 weeks, the animals were sacrificed, and mandibles were extracted, containing the implants and the surrounding soft and hard tissues. Bone-to-implant contact (BIC), inter-thread bone area percentage (ITBA), soft tissue, and crestal bone loss were evaluated by histology and histomorphometry. Results: All animals were healthy with no implant loss or inflammation symptoms. All implants were clinically and histologically osseo-integrated. Relative to control groups, test implants demonstrated a significant 1.5- and 1.7-fold increase in BIC and ITBA values, respectively, at both assessment intervals. Crestal bone loss was also significantly reduced in the test group, as compared with controls, at week 8 in both the buccal crests (0.47 ± 0.32 vs 0.98 ± 0.51 mm, p < 0.05) and lingual crests (0.39* ± 0.3 vs. 0.89 ± 0.41 mm, p < 0.05). At week 12, a pronounced crestal bone loss improvement was observed in the test group (buccal, 0.41 ± 0.29 mm and lingual, 0.54 ± 0.23 mm). Tissue thickness showed comparable values at both the buccal and lingual regions and was significantly improved in the studied groups (0.82-0.92 mm vs. 33-48 mm in the control group). Conclusions: Relative to the commercially available BLT-SLA active implants, BLT-SLA pre-treated with BBL showed improved histological and histomorphometric characteristics indicating a reduced titanium surface roughness and improved wettability, promoting healing and soft and hard tissue regeneration at the implant site.
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Background Autologous platelet concentrate has been widely used to encourage the regeneration of hard and soft tissues. Up to now, there are three generations of autologous platelet concentrates. Many studies have shown that the three autologous concentrates have different effects, but the specific diversities have not been studied. The purpose of this study was to explore and compare the effects of platelet-rich fibrin, concentrated growth factor and platelet-poor plasma on the healing of tooth extraction sockets in New Zealand rabbits. Methods A total of 24 healthy male New Zealand white rabbits aged 8–12 weeks were selected. The experimental animals were randomly divided into four groups: three experimental groups were respectively implanted with PPP, CGF and PRF gel after bilateral mandibular anterior teeth were extracted, and the control group did not implant any material. The alveolar bone of the mandibular anterior region was taken at 2, 4 and 8 weeks after operation. The height and width of the extraction wound were detected by CBCT, the growth of the new bone was observed by HE and Masson staining, and the expression of osteogenic genes was detected by real-time PCR. Data were analyzed using IBM SPSS statistical package 22.0. Results The radiological results showed that alveolar bone resorption in all groups gradually increased over time. However, the experimental groups showed lower amounts of bone resorption. The histological results showed that new bone formation was observed in all groups. Over time, the new bone trabeculae of the CGF group became closely aligned while those in the PPP and PRF groups remained scattered. PCR results showed that the expression of BMP-2 and ALP was higher in the experimental groups than the control group. Conclusion In conclusion, the application of PRF, CGF and PPP in tooth extraction sockets effectively promoted bone regeneration. CGF showed more effective bone induction and tissue regeneration ability in the long term.
Article
Purpose The purpose of this study was to identify factors that influence the need for a supplemental bone graft prior to dental implant placement at previously grafted alveolar cleft sites. Patients and Methods Retrospective case series of patients with cleft lip/palate who had both alveolar bone grafting (ABG) and placement of a dental implant(s) to replace a missing incisor(s) at the cleft site by the senior surgeon (BLP) at Boston Children's Hospital from 2005 through 2020. Primary outcome variable was need for a supplemental bone graft prior to dental implant placement. Predictor variables included gender, cleft type (unilateral vs. bilateral), implant site, number of implants placed, age at ABG and implant placement, time between ABG and implant, history of maxillary expansion and whether the patient had a Le Fort I osteotomy to correct maxillary hypoplasia before implant placement. Descriptive statistics were computed and comparative analyses were performed using Pearson X², Fisher exact, and Mann-Whitney U tests. Results There were 84 implants placed in 59 patients (64.2% female) with cleft lip and palate who had alveolar bone grafting of which 57.1% (N=48) required a supplemental graft prior to placement. Median time (IQR) from alveolar bone grafting to implant placement was significantly longer in patients who required additional grafting (8.1 vs. 5.4 years, p<.001). Patients who required supplemental bone were significantly younger at the time of alveolar bone grafting (10.1 vs. 12.3 years, p<.001). Cleft sites in patients who had a Le Fort I osteotomy prior to implant placement required bony augmentation more often than cleft sites in patients who did not have a Le Fort I osteotomy (58.7% vs. 33.3%, p = .03). Conclusions Patients with cleft lip/palate who undergo alveolar bone grafting should be counseled that they are likely to require a supplemental bone graft prior to implant placement.
Article
Epigallocatechin-3-gallate (EGCG) has been found to be an excellent natural product that is beneficial to wound healing, but the easy oxidation of EGCG limited its wide application. Herein, we employed the supramolecular hydrogel Nap-Phe-Phe-Tyr (NapFFY) to encapsulate EGCG for their sustained release in wound areas to promote healing activity in rats modal. The EGCG-hydrogel can prolong the action time of EGCG on the wound surface. In vitro experiments indicated that co-assembly of EGCG with NapFFY enables a sustained release of EGCG for more than 48 hours. In vivo experiments supported that sustained release of EGCG from EGCG-NapFFY (1:2) could effectively improve wound healing effect compared with pure EGCG. We anticipate that the combination of polyphenols and supramolecular hydrogel can be potentially exploited to craft strategies for the acceleration of wound healing and skin regeneration.
Article
Aim The aim of this experimental in vivo investigation was to assess the anti‐resorptive effect of low concentration pamidronate on the buccal plate in fresh extraction sockets. Materials and methods The distal roots of the third premolars were extracted bilaterally in six dogs. A collagen matrix loaded with either pamidronate (test group) or saline (control group) was positioned on the outer surface of buccal bone immediately after tooth extraction and subsequently covered with a coronally advanced flap. Histological and histomorphometric outcomes were evaluated 12 weeks later. Results The mean vertical distance between the buccal and lingual bone crest differed significantly between the test and control groups (0.52 ± 0.43 and 2.21 ± 1.15 mm, respectively; p = .037). The width of the buccal bone 1 mm below the crest was significantly wider in the test group than the control group (4.68 ± 0.68 vs. 3.44 ± 0.60 mm, p < .001). Conclusions Local application of pamidronate onto a collagen matrix may reduce the dimensional changes of the buccal bone plate both vertically and horizontally.
Article
Background: Long-term changes of trabecular microstructure in human tooth extraction socket have not been investigated. Purpose: To examine the trabecular microstructure of human residual ridges at various intervals following tooth extraction, and to determine whether bone remodeling activity can attain points of relative stability and when such points are reached. Materials and methods: Forty-four bone biopsy specimens were obtained from lower molar or premolar regions of residual ridges. Postextraction times ranged from 1.6 to 360 months. Samples were analyzed using micro-computed tomography and three-dimensional bone morphometry with histological analyses. Trabecular bone parameters were plotted against postextraction times, and a stepwise piecewise linear regression analysis was performed to determine at which points of time these parameters either increased or decreased. Results: Using piecewise linear regression, "inflection points" were found in most trabecular bone parameters between 7 and 12 months postextraction. Among the residual ridge samples, woven trabecular structure became mature, consisting of thick lamellar trabeculae with sufficient bone density, under dynamic bone remodeling until the 7th to 12th month post-tooth extraction. After this period, the mature network structure remained stable with low remodeling activity. Conclusion: Bone remodeling of trabecular structure in human residual ridge after tooth extraction had a stabilization period.
Article
Aim to radiographically evaluate the effect of immediate implant placement plus alveolar ridge preservation (ARP) with a deproteneized bovine bone mineral and a collagen matrix (IMPL/DBBM/CM) as compared to ARP (DBBM/CM) or spontaneous healing (SH) on vertical and horizontal bone dimensional changes after 4 months of healing. Materials and methods thirty patients requiring extraction of one single‐rooted tooth or premolar were randomly assigned to: IMPL/DBBM/CM, ARP DBBM/CM or SH. Cone Beam Computer Tomography (CBCT) scans, performed before tooth extraction and after 4 months, were superimposed in order to assess: changes in ridge height at the buccal and lingual aspect and in ridge width at 1mm, 3mm and 5mm apical to the bone crest. Kruskal‐Wallis test was applied for comparison of differences between groups. Results No statistically significant differences between the groups were observed for the vertical bone resorption of the buccal and the lingual side, while significant differences were found between SH group (‐3.37 ± 1.55 mm.; ‐43.2 ± 25.1%) and both DBBM/CM (‐1.56 ± 0.76 mm.; ‐19.2 ± 9.1%) and IMPL/DBBM/CM (‐1.29 ± 0.38 mm.;‐14.9 ± 4.9%) groups in the horizontal dimension at the most coronal aspect. Conclusion ridge preservation techniques using DBBM and CM reduce the horizontal bone morphological changes that occur, mostly in the coronal portion of the buccal bone plate following tooth extraction, when compared to spontaneous healing. This is true regardless of whether immediate implant placement is performed or not. This article is protected by copyright. All rights reserved.
Chapter
In the moist environment of the mouth, wound healing functions remarkably well. Teeth and their surrounding periodontal ligament follow a specific healing pattern. A number of local and general factors can severely impair this process and cause ulcers, chronic wounds, pathological fractures, infections, and necrosis. The underlying pathological conditions include either an environment that does not allow healing or a weakened underlying tissue bed which does not allow proliferation and regeneration of tissues. Some disturbing factors are specific for the mouth, whereas other wound problems are shared in all areas of the body.
Chapter
Immediately after tooth extraction, physiological and eventually pathological changes affect the healing of the alveolar ridge. This three-dimensional shrinkage of the alveolar bone is determinant to the subsequent implant placement. Different surgical protocols have been proposed as a way to limit these dimensional changes and hence to optimize implant placement from an aesthetic, patient-friendly and long-term perspective. The evidence-based efficacy of these interventions, the indications and contraindications, and the advantages and disadvantages of the different methods are thoroughly discussed.
Article
Alveolar ridge preservation (ARP) therapy is indicated to attenuate the physiologic resorptive events that occur as a consequence of tooth extraction with the purpose of facilitating tooth replacement therapy. This randomized controlled trial was primarily aimed at testing the efficacy of ARP as compared with unassisted socket healing. A secondary objective was to evaluate the effect that local phenotypic factors play in the volumetric reduction of the alveolar bone. A total of 53 subjects completed the study. Subjects were randomized into either the control group, which involved only tooth extraction (EXT n = 27), or the experimental group, which received ARP using a combination of socket grafting with a particulate bone allograft and socket sealing with a nonabsorbable membrane (dPTFE) following tooth extraction (ARP n = 26). A set of clinical, linear, volumetric, implant-related, and patient-reported outcomes were assessed during a 14-wk healing period. All linear bone assessments (horizontal, midbuccal, and midlingual reduction) revealed that ARP is superior to EXT. Likewise, volumetric bone resorption was significantly higher in the control group (mean ± SD: EXT = −15.83% ± 4.48%, ARP = –8.36% ± 3.81%, P < 0.0001). Linear regression analyses revealed that baseline buccal bone thickness is a strong predictor of alveolar bone resorption in both groups. Interestingly, no significant differences in terms of soft tissue contour change were observed between groups. Additional bone augmentation to facilitate implant placement in a prosthetically acceptable position was deemed necessary in 48.1% of the EXT sites and only 11.5% of the ARP sites ( P < 0.004). Assessment of perceived postoperative discomfort at each follow-up visit revealed a progressive decrease over time, which was comparable between groups. Although some extent of alveolar ridge remodeling occurred in both groups, ARP therapy was superior to EXT as it was more efficacious in the maintenance of alveolar bone and reduced the estimated need for additional bone augmentation at the time of implant placement (ClinicalTrials.gov NCT01794806).
Article
Oral surgery and exodontia can present challenges in veterinary patients, with a particular area of challenge being extraction and closure of the maxillary first molar (M1) in dogs. This retrospective assessment evaluated patients that had the maxillary first molar extracted with placement of a cruciate suture across the alveolus to achieve partial closure and secure the blood clot. Patients that had teeth extracted adjacent to M1 (maxillary fourth premolar [PM4] or second molar [M2]) were excluded from the study. Three groups of patients were assessed: Group A – at the time of extraction of M1, both the maxillary PM4 and M2 were still present in the oral cavity. Group B – at the time of M1extraction only PM4 or M2 was present, but not both. The tissue was completely intact at the location of the missing tooth. Group C – at the time of M1 extraction neither PM4 or M2 were present, but tissue in these locations was intact. In a three-and-a half-year time period (2015-2018), 179 dogs with 213 solitary M1 extractions were performed. Of these 213 extraction sites, 127 sites (60%) had follow up examination within a two-week postoperative period. Of these 127 sites, 126 (99.2%) appeared appropriately healed without complication. The results of this retrospective evaluation demonstrate that primary closure of a maxillary first molar extraction site may not be required for appropriate soft tissue wound healing in canine patients.
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Background:Autologous platelet concentrate has been widely used to encourage the regeneration of hard and soft tissues. Up to now, there are three generations of autologous platelet concentrates. Many studies have shown that different autologous platelet concentrates have different healing effects. However, these differences still need to be further verified and discussed. The purpose of this study was to explore and compare the effects of platelet-rich fibrin, concentrated growth factor and platelet-poor plasma on the healing of tooth extraction sockets in New Zealand rabbits. Methods:A total of 24 healthy male New Zealand white rabbits aged 8-12 weeks were selected. The experimental animals were randomly divided into four groups: three experimental groups were respectively implanted with PPP, CGF and PRF gel after bilateral mandibular anterior teeth were extracted, and the control group did not implant any material. The alveolar bone of the mandibular anterior region was taken at 2, 4 and 8 weeks after operation. The height and width of the extraction wound were detected by CBCT, the growth of the new bone was observed by HE and Masson staining, and the expression of osteogenic genes was detected by real-time PCR. Data were analyzed using IBM SPSS statistical package 22.0. Results: The radiological results showed that alveolar bone absorption in all groups gradually increased over time. However, the experimental groups showed lower amounts of bone absorption. The histological results showed that new bone formation was observed in all groups. Over time, the new bone trabeculae of the CGF group became closely aligned while those in the PPP and PRF groups remained scattered. PCR results showed that the expression of BMP-2 and ALP was higher in the experimental groups than the control group. Conclusion: In conclusion, the application of PRF, CGF and PPP in tooth extraction sockets effectively promoted bone regeneration. CGF showed more effective bone induction and tissue regeneration ability in the long term.
Article
The present study was designed in the context of the uncertain circumstances related to the best therapeutic option for ridge preservation .The research aimed to investigate the quality of early healing processes developed in the former sockets preserved with a collagen matrix alone or associated with a bone substitute in comparison with naturally-healed sockets, using an animal model previously validated. In both quadrants of the mandible of two dogs, the distal sockets of the second and fourth premolars served as experimental sites. Two sockets healed naturally, three sockets were preserved with the collagen matrix and three sockets were preserved with the collagen matrix plus a bone substitute. After one month of healing, the samples were harvested and histologically processed. The soft tissue covering the preserved ridges displayed an obviously thicker epithelial layer containing mostly areas of parakeratinized epithelium alternating with keratinized ones in comparison with naturally-healed sockets. In the apical third of the sockets, a mature bone structure was recorded for all three types of post-extraction approaches. While in naturally-healed and collagen matrix-preserved specimens the central third of the sockets contained bone with a mature aspect, in collagen matrix plus bone substitute-preserved sockets an immature appearance was observed. In the external third of the sockets, only in matrix-preserved alveoli a well-developed cancellous bone was present. The bovine bone substitute seemed to delay hard tissue development. The use of the collagen matrix could be a clinical option to preserve post-extraction ridges especially when an improvement in soft tissue quality is desired.
Article
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Preservation of alveolar bone volume following tooth extraction facilitates subsequent placement of dental implants and leads to an improved esthetic and functional prosthodontic result. The aim of the present study was to assess bone formation in the alveolus and the contour changes of the alveolar process following tooth extraction. The tissue changes after removal of a premolar or molar in 46 patients were evaluated in a 12-month period by means of measurements on study casts, linear radiographic analyses, and subtraction radiography. The results demonstrated that major changes of an extraction site occurred during 1 year after tooth extraction.
1.1. A preliminary study of the time sequence of tissue regeneration in human extraction wounds has been completed.2.2. In order to obviate some of the errors inherent in the studies of socket healing from diseased human cases or by interpolation from animal experimentation, biopsy specimens were taken from apparently healthy persons who were screened to eliminate, as far as possible, gross pathosis and variables which might interfere with normal tissue regeneration.3.3. Generally, the time sequence in normal human tissue regeneration based on this study has been summarized diagrammatically in Fig. 14 and in Table II.
Article
The purpose of this investigation is to describe histologically the undisturbed healing of fresh extraction sockets when compared to immediate implant placement. In eight beagle dogs, after extraction of the 3P3 and 4P4, implants were inserted into the distal sockets of the premolars, while the mesial sockets were left to heal spontaneously. Each animal provided four socket sites (control) and four implant sites (test). After 6 weeks, animals were sacrificed and tissue blocks were dissected, prepared for ground sectioning. The relative vertical buccal bone resorption in relation to the lingual bone was similar in both test and control groups. At immediate implant sites, however, the absolute buccal bone loss observed was 2.32 (SD 0.36) mm, what may indicate that while an apical shift of both the buccal and lingual bone crest occurred at the implant sites, this may not happen in naturally healing sockets. The results from this investigation showed that after tooth extraction the buccal socket wall underwent bone resorption at both test and control sites. This resorption appeared to be more pronounced at the implant sites, although the limitations of the histological evaluation method utilized preclude a definite conclusion.
Article
The aim of the present study was to evaluate the effects of a novel bone substitute system (Natix(®)), consisting of porous titanium granules (PTG) and a bovine-derived xenograft (Bio-Oss(®)), on hard tissue remodelling following their placement into fresh extraction sockets in dogs. Six modalities were tested; Natix(®) granules with and without a covering double-layered Bio Gide(®) membrane; Bio-Oss(®) with and without a covering double-layered Bio Gide(®) membrane; and a socket left empty with and without a covering double-layered Bio Gide(®) membrane. Linear measurements, indicative of buccal bone height loss, and an area measurement indicative of buccal bulk bone loss were made. The statistical analysis was based on the Latin Square design with two blocking factors (dog and site). Tukey's post hoc test was used to adjust for multiple comparisons. Histological observation revealed that while bone formed around both the xenograft and the titanium particles, bone was also noted within titanium granules. Of the five modalities of ridge preservation techniques used in this study, no one technique proved to be superior. The titanium granules were observed to have promising osseoconductive properties.
Article
To use multilevel, multivariate models to analyze factors that may affect bone alterations during healing after an implant immediately placed into an extraction socket. Data included in the current analysis were obtained from a clinical trial in which a series of measurements were performed to characterize the extraction site immediately after implant installation and at re-entry 4 months later. A regression multilevel, multivariate model was built to analyze factors affecting the following variables: (i) the distance between the implant surface and the outer bony crest (S-OC), (ii) the horizontal residual gap (S-IC), (iii) the vertical residual gap (R-D) and (iv) the vertical position of the bone crest opposite the implant (R-C). It was demonstrated that (i) the S-OC change was significantly affected by the thickness of the bone crest; (ii) the size of the residual gap was dependent of the size of the initial gap and the thickness of the bone crest; and (iii) the reduction of the buccal vertical gap was dependent on the age of the subject. Moreover, the position of the implant opposite the alveolar crest of the buccal ridge and its bucco-lingual implant position influenced the amount of buccal crest resorption. Clinicians must consider the thickness of the buccal bony wall in the extraction site and the vertical as well as the horizontal positioning of the implant in the socket, because these factors will influence hard tissue changes during healing.
Article
To describe histologically the early phases of soft tissue healing to implants placed into fresh extraction sockets. In 16 beagle dogs, 64 3.25-mm-wide cylindrical screw implants were inserted into the distal sockets of the third and fourth lower premolars using a one-stage trans-mucosal healing protocol. Biopsies were then taken at 1, 2, 4 and 8 weeks and prepared for histological examination. One-week specimens showed a junctional epithelium and an underlying loose connective tissue rich in inflammatory cells. At 2 weeks, signs of epithelial proliferation and a more organized connective tissue were observed. At 4 and 8 weeks, inflammation was absent; the epithelium appeared mature and in close contact with the surface of the healing abutment or the implant. The connective tissue was dense in an area close to the implant surface and the fibres were aligned parallel to the implant surface. The soft tissue dimensions at 8 weeks were approximately 5 mm, including about 3-3.5 mm of epithelium and 1-1.5 mm of connective tissue. Soft tissue healing to implants placed in fresh extraction sockets may result in a longer epithelial interface than implants placed in a healed ridge.
Article
To review the literature to assess the amount of change in height and width of the residual ridge after tooth extraction. MEDLINE-PubMed and the Cochrane Central register of controlled trials (CENTRAL) were searched through up to March 2009. Appropriate studies which data reported concerning the dimensional changes in alveolar height and width after tooth extraction were included. Approximal height change, mid-buccal change, mid-crestal change, mid-lingual change, Alveolar width change and socket fill were selected as outcome variables. Mean values and if available standard deviations were extracted. Weighted mean changes were calculated. Independent screening of the titles and abstracts of 1244 MEDLINE-PubMed and 106 Cochrane papers resulted in 12 publications that met the eligibility criteria. The reduction in width of the alveolar ridges was 3.87 mm. The mean clinical mid-buccal height loss was 1.67 mm. The mean crestal height change as assessed on the radiographs was 1.53 mm. Socket fill in height as measured relative to the original socket floor was on an average 2.57 mm. During the post-extraction healing period, the weighted mean changes as based on the data derived from the individual selected studies show the clinical loss in width to be greater than the loss in height, assessed both clinically as well as radiographically.
Article
To describe the early phases of healing at the alveolar ridge around dental implants placed into fresh extraction sockets and to study whether (i) the dimension of the socket and (ii) a new implant surface nano-topography may have any influence. Sixteen beagle dogs received 64 test (new surface) and control implants randomly placed at the distal socket of 3P3 and 4P4. The implant shoulder was levelled with the marginal buccal bone crest. Animals were sacrificed at 4 h, 1, 2, 4 and 8 weeks for histological examination. Bone loss occurred at the buccal crest between the 4-h and 1-week healing intervals, being more pronounced at the third premolar site [vertical bone loss between day 0 and 8 weeks 1.1 (0.5) mm]. The corresponding loss at the fourth premolar site was 0.3 (0.5) mm. Test sites containing implants with discrete crystalline deposition nano-particles' surface exhibited less buccal bone resorption than control sites at 8 weeks. Dimensions of the socket influenced the process of wound healing of implants placed into fresh extraction sockets, with more bone loss in the narrower sockets; however, the implant surface nano-topography seemed to have a limited effect in the healing of this implant surgical protocol.
Article
Describe the early phases of tissue integration in implants placed into fresh extraction sockets and test whether a new implant surface nano-topography (DCD nano-particles, Nanotite) promotes early osseointegration when compared with minimally rough surface implants (DAE, Osseotite). Material and Sixteen beagle dogs received 64 test and control implants randomly installed into the distal socket of (3)P(3) and (4)P(4). Histomorphometric analysis of bone to implant contact (BIC) and bone area was performed at 4 h, 1, 2, 4 and 8 weeks. Wound healing initiated with a coagulum that was substituted by a provisional matrix at 1 week. Bone formation started concomitant to a marked bone resorption. At 2 weeks, woven bone formation was evident and gradually remodelled into lamellar bone at 4 and 8 weeks. BIC increased similarly throughout the study in both groups with a tendency to higher percentages for the test devices at 2 and 4 weeks. The influence of the DCD nano-particles was more evident at the fourth premolar site. Osseointegration occurred similarly at both implant groups, although the socket dimension appeared to influence bone healing. It is suggested that the enhanced nano-topography has a limited effect in the immediate implant surgical protocol.
Article
The aim of the following experimental study was to assess bone changes in the horizontal and vertical dimension when using different socket preservation procedures. In five beagle dogs the distal roots of the 3rd and 4th premolar were extracted without elevation of a mucoperiosteal flap and the following treatments were assigned: Tx 1: The extraction socket was filled with BioOss Collagen (Geistlich Biomaterials, Wolhusen, Switzerland) and interrupted sutures were applied.: Tx 2: The extraction socket was filled with BioOss Collagen (Geistlich Biomaterials, Wolhusen, Switzerland) and a free gingival graft was sutured to cover the socket.: Tx 3: The extraction socket was left with its blood clot and interrupted sututes were applied.: Four month after surgery the dogs were sacrificed and from each extraction site two histological sections were selected for histometric analysis. The following parameters were evaluated: (1) the vertical dimension was determined by placing a horizontal line on the lingual bone wall. Then, the distance from this line to the buccal bone wall was measured. (2) The horizontal dimension was assessed at three different areas measured from the top of the lingual crest: 1 mm (Value 1), 3 mm (Value 3) and 5 mm (Value 5). The mean vertical loss of the buccal bone plate for the Tx 1 group was 2.8+/-0.2 mm. The Tx 2 group showed vertical loss of 3.3+/-0.2 mm. The Tx 3 group demonstrated 3.2+/-0.2 mm of mean vertical loss. The horizontal dimension of the alveolar process was 4.4+/-0.3/6.1+/-0.2/7.2+/-0.1 mm at the three different levels for the Tx 1 group. The Tx 2 group depicted bone dimensions of 4.8+/-0.2/6.0+/-0.2/7.1+/-0.1 mm. The horizontal dimension of the Tx 3 group was 3.7+/-0.3/6.2+/-0.2/7.0+/-0.1 mm. When the results from the horizontal measurements were tested with the analysis of variance (ANOVA), a clear significance could be found in particular for Value 1 mm between the test groups Tx 1 and Tx 2 and the control group (Tx 3) (P<0.001). Furthermore the mean of treatment 1 (Tx 1) was slightly significantly lower than of treatment 2 (Tx 2) (P<0.05). The findings from the present study disclose that incorporation of BioOss Collagen into the extraction socket has only limited impact on the subsequent biologic process with particular respect to the buccal bone plate. The horizontal measurement of the alveolar ridge depicted that the loss of the buccal bone plate was replaced to a certain amount by newly generated bone guided by the BioOss Collagen scaffold. It seems that the mechanical stability provided by BioOss Collagen and furthermore by a free gingival graft could act as a placeholder preventing the soft tissue from collapsing.
Article
The aim of the present experiment was to study events involved in the healing of marginal, central and apical compartments of an extraction socket, from the formation of a blood clot, to bone tissue formation and remodeling of the newly formed hard tissue. Nine mongrel dogs were used for the experiment. The fourth mandibular premolars were selected for study and were divided into one mesial and one distal portion. The distal root was removed and the socket with surrounding soft and mineralized tissue was denoted "experimental unit". The dogs were killed 1, 3, 7, 14, 30, 60, 90, 120 and 180 days after the root extractions. Biopsies including the experimental units were demineralized in EDTA, dehydrated in ethanol and embedded in paraffin. Serial sections 7 microm thick were cut in a mesio-distal plane. From each biopsy, three sections representing the central part of the socket were selected for histological examination. Morphometric measurements were performed to determine the volume occupied by different types of tissues in the marginal, central and apical compartments of the extraction socket at different intervals. During the first 3 days of healing, a blood clot was found to occupy most of the extraction site. After seven days this clot was in part replaced with a provisional matrix (PCT). On day 14, the tissue of the socket was comprised of PM and woven bone. On day 30, mineralized bone occupied 88% of the socket volume. This tissue had decreased to 15% on day 180. The portion occupied by bone marrow (BM) in the day 60 specimens was about 75%, but had increased to 85% on day 180. The healing of an extraction socket involved a series of events including the formation of a coagulum that was replaced by (i) a provisional connective tissue matrix, (ii) woven bone, and (iii) lamellar bone and BM. During the healing process a hard tissue bridge--cortical bone--formed, which "closed" the socket.
Article
To study dimensional alterations of the alveolar ridge that occurred following tooth extraction as well as processes of bone modelling and remodelling associated with such change. Twelve mongrel dogs were included in the study. In both quadrants of the mandible incisions were made in the crevice region of the 3rd and 4th premolars. Minute buccal and lingual full thickness flaps were elevated. The four premolars were hemi-sected. The distal roots were removed. The extraction sites were covered with the mobilized gingival tissue. The extractions of the roots and the sacrifice of the dogs were staggered in such a manner that all dogs contributed with sockets representing 1, 2, 4 and 8 weeks of healing. The animals were sacrificed and tissue blocks containing the extraction socket were dissected, decalcified in EDTA, embedded in paraffin and cut in the buccal-lingual plane. The sections were stained in haematoxyline-eosine and examined in the microscope. It was demonstrated that marked dimensional alterations occurred during the first 8 weeks following the extraction of mandibular premolars. Thus, in this interval there was a marked osteoclastic activity resulting in resorption of the crestal region of both the buccal and the lingual bone wall. The reduction of the height of the walls was more pronounced at the buccal than at the lingual aspect of the extraction socket. The height reduction was accompanied by a "horizontal" bone loss that was caused by osteoclasts present in lacunae on the surface of both the buccal and the lingual bone wall. The resorption of the buccal/lingual walls of the extraction site occurred in two overlapping phases. During phase 1, the bundle bone was resorbed and replaced with woven bone. Since the crest of the buccal bone wall was comprised solely of bundle this modelling resulted in substantial vertical reduction of the buccal crest. Phase 2 included resorption that occurred from the outer surfaces of both bone walls. The reason for this additional bone loss is presently not understood.
Article
To study dimensional alterations of the alveolar ridge that occurred following implant placement in fresh extraction sockets. Five beagle dogs were included in the study. In both quadrants of the mandible, incisions were made in the crevice region of the third and fourth pre-molars. Buccal and minute lingual full-thickness flaps were elevated. The mesial root of the four pre-molars root was filled and the teeth were hemi-sected. Following flap elevation in (3)P(3) and (4)P(4) regions, the distal roots were removed. In the right jaw quadrants, implants with a sand blasted and acid etched (SLA) surface were placed in the fresh extraction sockets, while in the left jaws the corresponding sockets were left for spontaneous healing. The mesial roots were retained as surgical control teeth. After 3 months, the animals were examined clinically, sacrificed and tissue blocks containing the implant sites, the adjacent tooth sites (mesial root) and the edentulous socket sites were dissected, prepared for ground sectioning and examined in the microscope. At implant sites, the level of bone-to-implant contact (BC) was located 2.6+/-0.4 mm (buccal aspect) and 0.2+/-0.5 mm (lingual aspect) apical of the SLA level. At the edentulous sites, the mean vertical distance (V) between the marginal termination of the buccal and lingual bone walls was 2.2+/-0.9 mm. At the surgically treated tooth sites, the mean amount of attachment loss was 0.5+/-0.5 mm (buccal) and 0.2+/-0.3 mm (lingual). Marked dimensional alterations had occurred in the edentulous ridge after 3 months of healing following the extraction of the distal root of mandibular pre-molars. The placement of an implant in the fresh extraction site obviously failed to prevent the re-modelling that occurred in the walls of the socket. The resulting height of the buccal and lingual walls at 3 months was similar at implants and edentulous sites and vertical bone loss was more pronounced at the buccal than at the lingual aspect of the ridge. It is suggested that the resorption of the socket walls that occurs following tooth removal must be considered in conjunction with implant placement in fresh extraction sockets.
Article
To determine whether the reduction of the alveolar ridge that occurs following tooth extraction and implant placement is influenced by the size of the hard tissue walls of the socket. Six beagle dogs were used. The third premolar and first molar in both quadrants of the mandible were used. Mucoperiostal flaps were elevated and the distal roots were removed. Implants were installed in the fresh extraction socket in one side of the mandible. The flaps were replaced to allow a semi-submerged healing. The procedure was repeated in the contra later side of the mandible after 2 months. The animals were sacrificed 1 month after the final implant installation. The mandibles were dissected, and each implant site was removed and processed for ground sectioning. Marked hard tissue alterations occurred during healing following tooth extraction and implant installation in the socket. The marginal gap that was present between the implant and the walls of the socket at implantation disappeared as a result of bone fill and resorption of the bone crest. The modeling in the marginal defect region was accompanied by marked attenuation of the dimensions of both the delicate buccal and the wider lingual bone wall. Bone loss at molar sites was more pronounced than at the premolar locations. Implant placement failed to preserve the hard tissue dimension of the ridge following tooth extraction. The buccal as well as the lingual bone walls were resorbed. At the buccal aspect, this resulted in some marginal loss of osseointegration.
Article
A removable denture base should cover the mandibular retromolar regions to provide proper basal seal and denture function in edentulous patients. The bony residual ridge form, attached muscles, and covering mucosa provide support, stability, and retention of the planned prosthesis. There is insufficient information regarding bone anatomy, mucosal tissues, and muscles in the retromolar region after tooth loss. The purpose of this study was to examine the tissue morphology in the mandibular retromolar area of edentulous subjects and report on the clinical inferences in prosthetic and implant dentistry. Specimens included 75 edentulous and eight dentate dry mandibles examined by macroscopic observations and linear measurements for size determinants in the left and right retromolar regions. Buccolingual histological sections of the mandibular retromolar region from seven edentulous subjects were also examined. The specimens were from the Department of Anatomy and Anthropology, Sackler School of Medicine, Tel Aviv University. The specimens evaluated in this study revealed that a bony retromolar ridge can be large, with adjacent muscles attached several millimeters below its edentulous bone crest, or small, with muscles attached to the buccal and lingual bone crests. In all examined jaws, bony mylohyoid ridges (MR) and buccal shelves with affixed muscle fibers were present regardless of the remaining mandibular bone form and size. The mylohyoid muscles attached to MRs and the buccinator muscles affixed to buccal bony shelves are some of the barriers to the chronic but limited bone resorption, following tooth loss, time of edentulism, systemic factors, and denture wear.
Article
It is common belief that immediate implant placement into extraction sites may act to preserve the alveolar process. The objective of this study was to evaluate healing dynamics at buccal peri-implant sites in relation to the dimensions of the alveolar ridge. Bilateral, critical-size, supraalveolar, peri-implant defects were created in 12 male Hound Labrador mongrel dogs following surgical horizontal cut-down of the alveolar ridge. Each jaw quadrant received three 10-mm titanium implants placed 5 mm into extraction sites of the third and fourth premolar teeth leaving 5 mm in a supraalveolar position. The mucoperiosteal flaps were advanced, adapted, and sutured for primary intention healing. Bone fluorescent markers were administered at weeks 3 and 4 postsurgery, and pre-euthanasia. Incandescent, polarized, and fluorescent light microscopies were used to assess the width of the buccal wall of the alveolar ridge and local bone remodeling over the 8-week healing interval. There was a significant association between the width of the buccal alveolar ridge and extent of bone resorption evaluated by incandescent and fluorescent light microscopy. A non-linear association was observed between the buccal ridge width and resorption of the alveolar ridge. A 2-mm threshold was established to account for this non-linearity. The strength of this association was two times greater in specimens with a buccal ridge width <2 mm compared with a wider ridge (beta=1.62 vs. 0.80) observed by fluorescent light microscopy. Accordingly, mean buccal resorption was significantly greater when the ridge width was <2 mm. Fluorescent light microscopy consistently showed greater buccal resorption compared with incandescent light microscopy (P<0.05). Agreement between the examination techniques was low (concordance correlation coefficient=0.49), especially for higher values of buccal resorption. When implants are placed into extraction sites, proximity to the buccal alveolar crest appears a major consideration. The observations herein suggest that the width of the buccal alveolar ridge should be at least 2 mm to maintain the alveolar bone level. These observations likely have general implications for implant placement using most surgical protocols.
Article
The available studies on extraction wound repair in humans are affected by significant limitations and have failed to evaluate tissue alterations occurring in all compartments of the hard tissue defect. To monitor during a 6-month period the healing of human extraction sockets and include a semi-quantitative analysis of tissues and cell populations involved in various stages of the processes of modeling/remodeling. Twenty-seven biopsies, representative of the early (2-4 weeks, n=10), intermediate (6-8 weeks, n=6), and late phase (12-24 weeks, n=11) of healing, were collected and analysed. Granulation tissue that was present in comparatively large amounts in the early healing phase of socket healing, was in the interval between the early and intermediate observation phase replaced with provisional matrix and woven bone. The density of vascular structures and macrophages slowly decreased from 2 to 4 weeks over time. The presence of osteoblasts peaked at 6-8 weeks and remained almost stable thereafter; a small number of osteoclasts were present in a few specimens at each observation interval. The present findings demonstrated that great variability exists in man with respect to hard tissue formation within extraction sockets. Thus, whereas a provisional connective tissue consistently forms within the first weeks of healing, the interval during which mineralized bone is laid down is much less predictable.
Article
The objective of the present experiment was to evaluate the effect on hard tissue modeling and remodeling of the placement of a xenograft in fresh extraction sockets in dogs. Five mongrel dogs were used. Two mandibular premolars (4P4) were hemisected in each dog, and the distal roots were carefully removed. In one socket, a graft consisting of Bio-Oss Collagen (Geistlich) was placed, whereas the contralateral site was left without grafting. After 3 months of healing, the dogs were euthanized and biopsies sampled. From each experimental site, four ground sections (two from the mesial root and two from the healed socket) were prepared, stained, and examined under the microscope. The presence of Bio-Oss Collagen failed to inhibit the processes of modeling and remodeling that took place in the socket walls following tooth extraction. However, it apparently promoted de novo hard tissue formation, particularly in the cortical region of the extraction site. Thus, the dimension of the hard tissue was maintained and the profile of the ridge was better preserved. The placement of a biomaterial in an extraction socket may promote bone modeling and compensate, at least temporarily, for marginal ridge contraction.