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Histomorphometrical assessment of vertical alveolar ridge augmentation using extracted tooth roots in the canine

DOI:10.1007/s00784-019-02960-7
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Puria Parvini
Puria Parvini
Puria Parvini
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Carla Schliephake
Carla Schliephake
Carla Schliephake
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Sarah Al-Maawi at Goethe-Universität Frankfurt am Main
Sarah Al-Maawi
Katrin Schwarz
Katrin Schwarz
Katrin Schwarz
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Abstract and Figures

Objectives To histomorphometrically evaluate the influence of autoclavation on the efficacy of extracted tooth roots (TR) used for vertical alveolar ridge augmentation. Materials and methods Upper premolars were randomly assigned to either autoclavation (TR-A) or an untreated control group (TR-C) and used as block grafts for vertical alveolar ridge augmentation in both lower quadrants (n = 4 beagle dogs). Tissue biopsies were obtained after 15 weeks of submerged healing. Histological analyses considered gain in ridge height (GRH), augmented area (AA), and the proportion of mineralized (MT) and non-mineralized tissue (NMT). Results TR-C and TR-A grafts were commonly associated with a complete replacement resorption and a marked gain in ridge height. Significant differences between groups were noted for mean GRH [TR-C: 2.35 ± 0.55 vs. TR-A: 2.46 ± 0.21 mm] and AA [TR-C: 11.88 ± 4.31 vs. TR-A: 8.65 ± 1.59 mm²] values. Within AA, both groups revealed a comparable distribution of mean MT and NMT values. The linear regression analysis pointed to a significant correlation between NMT and AA values. Conclusions Both TR-C and TR-A grafts supported vertical alveolar ridge augmentation; however, GRH was improved in the TR-A group. Clinical relevance TR grafts may serve as a potential alternative for vertical alveolar ridge augmentation.
a Clinical view of an anterior mandibular standardized box-type defect. b TR derived from maxillary premolars were randomly allocated to a standardized autoclavation procedure (right) or were left untreated (left) and used as block grafts for vertical alveolar ridge augmentation in both lower quadrants. c Clinical view of the chronic-type defect situation at 12 weeks. d Size adapted roots were positioned with their exposed dentin layer facing the alveolar bone. TR specimens were fixed by one titanium osteosynthesis screw to accomplish a vertical ridge augmentation procedure
a Clinical view of an anterior mandibular standardized box-type defect. b TR derived from maxillary premolars were randomly allocated to a standardized autoclavation procedure (right) or were left untreated (left) and used as block grafts for vertical alveolar ridge augmentation in both lower quadrants. c Clinical view of the chronic-type defect situation at 12 weeks. d Size adapted roots were positioned with their exposed dentin layer facing the alveolar bone. TR specimens were fixed by one titanium osteosynthesis screw to accomplish a vertical ridge augmentation procedure
… 
Histological landmarks defined for the histomorphometrical analysis: BC = most coronal extension of the bone crest, BD = bottom of the bone defect, GRH = gain in ridge height, AA = surface of the augmented area (mm²), MT⁺ = mineralized tissue, and NMT* = non-mineralized tissue within AA
Histological landmarks defined for the histomorphometrical analysis: BC = most coronal extension of the bone crest, BD = bottom of the bone defect, GRH = gain in ridge height, AA = surface of the augmented area (mm²), MT⁺ = mineralized tissue, and NMT* = non-mineralized tissue within AA
… 
Representative histological views of the crestal aspect of the alveolar bone in both groups (HE stain, blue line = BD). a The outer contour of AA was commonly characterized by cortical bone structures. b One experimental site of the TR-A groups revealed a residual graft (asterisk), which was clearly separated from the host bone. c TR-A specimen revealing a less pronounced maturation of MT (i.e., network of parallel-fibered woven bone) within the former defect area. d TR-C specimen exhibiting a more mature MT within the central aspect of AA
Representative histological views of the crestal aspect of the alveolar bone in both groups (HE stain, blue line = BD). a The outer contour of AA was commonly characterized by cortical bone structures. b One experimental site of the TR-A groups revealed a residual graft (asterisk), which was clearly separated from the host bone. c TR-A specimen revealing a less pronounced maturation of MT (i.e., network of parallel-fibered woven bone) within the former defect area. d TR-C specimen exhibiting a more mature MT within the central aspect of AA
… 
Linear regression plots to depict the relationship between MT/NMT and AA values. a MT, b NMT
Linear regression plots to depict the relationship between MT/NMT and AA values. a MT, b NMT
… 
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ORIGINAL ARTICLE
Histomorphometricalassessmentofverticalalveolarridge
augmentation using extracted tooth roots in the canine
Puria Parvini
1
&Carla Schliephake
1
&Sarah Al-Maawi
2
&Katrin Schwarz
3
&Robert Sader
2
&Shahram Ghanaati
2
&
Frank Schwarz
1,3
Received: 4 February 2019 /Accepted: 9 May 2019 / Published online: 17 May 2019
#Springer-Verlag GmbH Germany, part of Springer Nature 2019
Abstract
Objectives To histomorphometrically evaluate the influence of autoclavation on the efficacy of extracted tooth roots (TR) used
for vertical alveolar ridge augmentation.
Materials and methods Upper premolars were randomly assigned to either autoclavation (TR-A) or an untreated control group
(TR-C) and used as block grafts for vertical alveolar ridge augmentation in both lower quadrants (n= 4 beagle dogs). Tissue
biopsies were obtained after 15 weeks of submerged healing. Histological analyses considered gain in ridge height (GRH),
augmented area (AA), and the proportion of mineralized (MT) and non-mineralized tissue (NMT).
Results TR-C and TR-A grafts were commonly associated with a complete replacement resorption and a marked gain in ridge
height. Significant differencesbetween groups were noted for mean GRH [TR-C: 2.35 ± 0.55 vs. TR-A: 2.46 ± 0.21 mm] and AA
[TR-C: 11.88 ± 4.31 vs. TR-A: 8.65 ± 1.59 mm
2
] values. Within AA, both groups revealed a comparable distribution of mean
MT and NMT values. The linear regression analysis pointed to a significant correlation between NMT and AA values.
Conclusions Both TR-C and TR-A grafts supported vertical alveolar ridge augmentation; however, GRH was improved in the
TR-A group.
Clinical relevance TR grafts may serve as a potential alternative for vertical alveolar ridge augmentation.
Keywords Animal experiment .Alveolar ridge augmentation .Tooth tr ansplan ta tion .Histological technique
Introduction
The regeneration of alveolar ridge defects to allow for a prosthet-
ically driven implant placement is a frequently used approach in
contemporary dentistry. These procedures mainly encompass lat-
eral and vertical bone augmentation as well as sinus grafting.
While their overall efficacy in treating alveolar ridge/subantral
bone deficiencies and supporting implant survival was reported
to be high, there were also distinct differences noted among the
procedures with regards to associated complications [1–3]. In
particular, vertical grafting procedures were reported to be asso-
ciated with a weighted mean complication rate of 16.9%, mainly
including graft/membrane exposures, postoperative infections,
and loss of graft material [1].
A recent series of preclinical studies performed in a canine
model have demonstrated that extracted tooth roots (TR) may
be successfully used as an alternative autograft for lateral al-
veolar ridge augmentation and two-stage implant placement
[4,5]. TR were separated from either healthy, endodontically
treated, or periodontally infected premolars and histologically
involved in a replacement resorption, thus resulting in a com-
parable gain in ridge width as autogenous cortical bone blocks
(AB) [4–7]. These results were recently confirmed in a pro-
spective controlled clinical study, reporting on a mean lateral
gain of 10.06 ± 1.85 mm (median: 11.0) in the TR and 9.20 ±
2.09 mm (median: 8.50) in the AB group, respectively. Even
though these differences did not reach statistical significance,
the TR group was associated with a significantly lower
amount of graft resorption than the AB group [8]. The latter
*Frank Schwarz
f.schwarz@med.uni-frankfurt.de
1
Department of Oral Surgery and Implantology, Carolinum, Goethe
University, Frankfurt, Germany
2
Department for Oral, Cranio-Maxillofacial and Facial Plastic
Surgery, Medical Center of the Goethe University Frankfurt,
Frankfurt am Main, Germany
3
Department of Oral Surgery, Universitätsklinikum Düsseldorf,
Düsseldorf, Germany
Clinical Oral Investigations (2020) 24:317–323
https://doi.org/10.1007/s00784-019-02960-7
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... First support for this approach came from preclinical studies [2][3][4] and case reports [4] followed by radiological analysis [5,6]. Preclinical research continues to better understand the process of graft consolidation [7,8] and acellular tooth root may even be used as allografts [9]. Clinical studies were performed supporting the use of autogenous tooth roots for augmentation of the alveolar bone [10] and before placing the implant [11]. ...
... There is a growing evidence in using dentin for extraction socket augmentation and staged implant placement [2][3][4][5][6][7][8]10,11,30]. Graft consolidation is a result of both resorption and formation of the graft [31], thus the release of growth factors from dentin is expected to occur [32]. ...
Acid Dentin Lysate Modulates Macrophage Polarization and Osteoclastogenesis In Vitro
Article
Full-text available
  • Nov 2021
Dentin prepared from extracted teeth is used as autograft for alveolar bone augmentation. Graft consolidation involves the acid lysis of dentin thereby generating a characteristic paracrine environment. Acid lysate of dentin is mimicking this environment. Acid dentin lysate (ADL) potentially targets hematopoietic cells thereby affecting their differentiation towards macrophages and osteoclasts; however, the question remains if ADL controls macrophage polarization and osteoclastogenesis. Here, we show that ADL reduced lipopolysaccharide (LPS)-induced macrophage polarization of the pro-inflammatory (M1) phenotype, indicated by attenuated Interleukin 1 (IL1), Interleukine 6 (IL6)and cyclooxygenase 2 (COX2) expression. This decrease in M1 macrophages was confirmed by the reduced phosphorylation and nuclear translocation of p65 in the LPS-exposed RAW 264.7 macrophages. Similarly, when RAW 264.7 macrophages were incubated with other agonists of Toll-like receptor (TLR) signaling e.g., FSL1, Polyinosinic-polycytidylic acid High Molecular Weight (Poly (1:C) HMW), Pam3CSK4, and imiquimod, ADL reduced the IL6 expression. We further show herein that ADL decreased osteoclastogenesis indicated by the reduced formation of multinucleated cell expressing cathepsin K and tartrate-resistant acid phosphatase in murine bone marrow cultures. Overall, our results suggest that acid dentin lysate can affect the differentiation of hematopoietic cells to M1 macrophage polarization and a decrease in osteoclastogenesis in bone marrow cultures.
... Those studies demonstrated that calcium phosphate promoted the osteoconduction of BMP-2 to the upper part of the bone block. Several studies have investigated autogenous tooth roots (with or without autoclavation) (67) as block grafts for vertical bone augmentation by means of micro-CT (68) and histomorphometrical (69) analyses in the mandible of beagles. Both autogenous tooth roots were gradually replaced by newly formed bone. ...
... The protocol used to create a canine mandible model, as reported by Parvini et al (69), is reviewed below. Adult healthy beagles are used as the experimental subjects. ...
Animal models of vertical bone augmentation (Review)
Article
Full-text available
  • Jun 2021
Vertical bone augmentation is an important challenge in dental implantology. Existing vertical bone augmentation techniques, along with bone grafting materials, have achieved certain clinical progress but continue to have numerous limitations. In order to evaluate the possibility of using biomaterials to develop bone substitutes, medical devices and/or new bone grafting techniques for vertical bone augmentation, it is essential to establish clinically relevant animal models to investigate their biocompatibility, mechanical properties, applicability and safety. The present review discusses recent animal experiments related to vertical bone augmentation. In addition, surgical protocols for establishing relevant preclinical models with various animal species were reviewed. The present study aims to provide guidance for selecting experimental animal models of vertical bone augmentation.
... In vivo studies of beagle's vertical alveolar ridge augmentation show equally augmented bone of autoclaved tooth and natural tooth. But bone-to-implant contact of the natural tooth is much higher than autoclaved teeth [37,38]. Unlike other studies with the re-entry of 24 to 26 weeks [14,15,20], re-entry at the 4th month in our study also witnessed a sufficient bone gain, and TS had integrated with recipient's bone. ...
Bone augmentation with autologous tooth shell in the esthetic zone for dental implant restoration: a pilot study
Article
Full-text available
  • Dec 2021
Objectives To investigate the outcome and short-term follow-up of autogenous tooth shell (TS) grafting for bone augmentation in the esthetic zone, as well as stability and esthetics of implant-supported restoration. Materials and methods A total of 8 patients with 11 implants in 11 sites were enrolled in this study. All the horizontal and/or vertical bone defects in the esthetic zone were augmented by tooth shells, which were fixed laterally to the residual bone with osteosynthesis screws. The gap between the shell and residual bone was filled with Bio-Oss® granules. Four months after bone augmentation, dimensionally sufficient dental implants were inserted and implants-supported prostheses were made 3 months later. The esthetic outcome was evaluated by pink esthetic score (PES) and white esthetic score (WES) one year after prosthetic restoration. Horizontal ridge width (HRW) was assessed before and immediately after bone augmentation, as well as 4 and 19 months post-augmentation by radiography. The stability and absorption of TS grafts were evaluated at the 4th and 19th months post-augmentation. Results Though wound dehiscences occurred in 3 cases, secondary healings were obtained after TS modification and irrigation. The other 5 cases went through uneventful healing during the whole observation period. Radiographic examination showed that HRW was 8.01 ± 0.93 mm (median: 7.80, 95% CI 7.38, 8.64) 4 months after TS augmentation, which was statistically different compared to HRW (2.72 ± 1.73 mm) at the baseline. Mean HRW gain was 5.29 ± 2.03 mm (median: 4.60, 95% CI 3.92, 6.66). Three-dimensional bone volume in all the augmented sites was sufficient for dental implants insertion and prosthetic restoration. Follow-up of one year showed stable marginal bone around dental implants. The implant survival rate was 100%. HRW losses were 0.65 ± 0.43 mm (the 4th month) and 1.05 ± 0.54 mm (the 19th month) compared to HRW immediately after augmentation. The PES and WES of final prosthetic restorations were 8.09 ± 0.70 and 8.91 ± 0.54, respectively. Conclusions Autogenous tooth shell grafting is a reliable approach for bone augmentation in the esthetic zone for dental implant treatment, allowing for favorable stability and esthetic outcome of implant-supported prosthesis within the one-year follow-up period.
... In particular, histological and immunohistochemical analyses indicated that TR grafts were gradually replaced by newly formed bone and resulted in a significant horizontal and vertical bone gain. [3][4][5][6] Second stage implant placement was associated with a comparable formation of a new bone to implant contact (BIC) as noted at AB grafted sites. 3,5 To account for a potential contamination of grafts separated from potentially nonretainable, infected teeth, TR's were autoclaved and proven to exhibit a similar biological potential as nonautoclaved specimens. ...
Microstructural volumetric analysis of vertical alveolar ridge augmentation using autogenous tooth roots
Article
Full-text available
Background: To volumetrically assess the bone microstructure following vertical alveolar ridge augmentation using differently conditioned autogenous tooth roots (TR) and second-stage implant placement. Materials and methods: The upper premolars were bilaterally extracted in n = 4 beagle dogs and randomly assigned to either autoclavation (TR-A) or no additional treatment (TR-C). Subsequently, TR were used as block grafts for vertical alveolar ridge augmentation in both lower quadrants. At 12 weeks, titanium implants were inserted and left to heal 3 weeks. Microcomputed tomography was used to quantify bone volume per tissue volume (BV/TV), trabecular thickness (Tb.Th), and trabecular spacing (Tb.Sp) at vestibular (v) and oral (o) aspects along the implant and in the augmented upper half of the implant, respectively. Results: Median BV/TV [TR-C: 51.33% (v) and 70.42% (o) vs TR-A: 44.05% (v) and 64.46% (o)], Tb.th [TR-C: 0.22 mm (v) and 0.27 mm (o) vs TR-A: 0.23 mm (v) and 0.29 mm (o)] and Tb.Sp [TR-C: 0.26 mm (v) and 0.13 mm (o) vs TR-A: 0.29 μm (v) and 0.15 mm (o)] values were comparable in both groups. Conclusion: Both TR-C and TR-A grafts were associated with a comparable bone microstructure within the grafted area.
Autogenous dentin block versus bone block for horizontal alveolar ridge augmentation and staged implant placement: A randomized controlled clinical trial including histologic assessment
Article
  • May 2022
Objectives: This study aimed to compare the dentin block (D-group) harvested from impacted wisdom teeth with autogenous ramus bone block (A-group) for horizontal alveolar ridge augmentation. Materials and methods: Forty-two patients with anterior missing teeth and horizontal ridge defect were randomly assigned to two groups (n = 21 per group) to receive either dentin block group or autogenous bone block. Six months after the augmentation, dental implants were placed in all patients, and a core biopsy was performed for histological evaluation in addition to clinical and radiographic evaluation using cone beam computed tomography. The primary outcome was the mean overall clinical ridge width gain (CRWG) after 6 months of augmentation. Secondary outcomes were the overall radiographic ridge width gain (RRWG) after 6 months of augmentation and descriptive histological analysis with histomorphometric assessment of bone fraction %. Results: All sites healed uneventfully, and the mean overall CRWG 6 months after augmentation was 3.52 ± 0.56 mm and 2.24 ± 0.86 mm in the D and A groups, respectively, with statistically significant difference between them (P ≤ .001). The overall mean RRWG was 3.61 ± 0.61 mm and 3.41 ± 1.15 mm in D and A groups, respectively, without any statistically significant difference between them (p = .062). The histomorphometric analysis of the bone area fraction was 42.6% and 41.3% in D and A groups, respectively, without any statistically significant difference between the two values (p = .89, Student's t-test). Histological evaluation in the D-group revealed new bone formation, viable cells, and matrix formation on the dentin block periphery, in addition to well-organized woven bone that suggests dentin block remodeling and supports new bone deposition. Conclusion: The present clinical study revealed that dentin block may serve as an alternative graft to support horizontal alveolar ridge augmentation. Dentin blocks showed less resorption than autogenous bone blocks.
Efficacy of autogenous tooth roots for a combined vertical and horizontal alveolar ridge augmentation and staged implant placement. A prospective controlled clinical study
Article
  • Mar 2022
Objectives: To assess and compare the efficacy and safety of autogenous tooth roots (TRs) and autogenous bone blocks (ABs) for combined vertical and horizontal alveolar ridge augmentation and two-stage implant placement. Materials and methods: A total of 28 patients in need of implant therapy and vertical ridge augmentation were allocated to parallel groups receiving either healthy autogenous tooth roots (e.g., retained wisdom teeth) (n = 14, n = 15 defects) or cortical autogenous bone blocks harvested from the retromolar area (n = 14, n = 17 defects). After 26 weeks of submerged healing, the clinical reduction in ridge height (RH) deficiency was defined as the primary outcome. Results: Both surgical procedures were associated with a similar mean reduction in RH deficiency values, amounting to 4.48 ± 2.42 mm (median: 4.25; 95% CI: 3.08-5.88) in the TR group and 4.46 ± 3.31 mm (median: 3.00; 95% CI: 2.54-6.38) in the AB group (p = .60, Mann-Whitney U-test). In all patients investigated, the reduction in RH deficiency values allowed for an adequate implant placement at the respective sites. The frequency of complications (e.g., soft tissue dehiscences) was low (TR: n = 4; AB: n = 0). Conclusions: Up to staged-implant placement, both TR and AB grafts appeared to be associated with comparable efficacy and safety for combined vertical and horizontal alveolar ridge augmentation.
Clinical performance of tooth root blocks for alveolar ridge reconstruction
Article
This systematic literature review set out to investigate the clinical outcomes of autogenous tooth root blocks used for ridge augmentation: survival rates, block resorption, implant survival, post-surgical complications, and histology findings. This review followed PRISMA guidelines. An automated search was made in four databases, supplemented by a manual search for relevant articles published before December 2020. The quality of evidence provided was assessed with the Newcastle–Ottawa Quality Assessment Scale and the Joanna Briggs Institute Critical Appraisal tool. Seven articles fulfilled the inclusion criteria and underwent analysis. The articles included a total of 136 patients, who received 118 autogenous tooth root blocks and 26 autogenous bone blocks showing block survival rates of 99.15% and 100%, respectively. Tooth root blocks presented a mean bone gain that was similar to autologous bone blocks but showed less resorption. The implant survival rate was 98.32% for autogenous tooth root blocks. Reconstruction of alveolar crests by means of autogenous tooth root blocks appears to be a satisfactory option for single-tooth gaps and low grades of bone atrophy in terms of the survival of the bone block and the implants placed subsequently. More research providing long-term data is needed to confirm these findings.
Manufacture and preliminary evaluation of acellular tooth roots as allografts for alveolar ridge augmentation
Article
  • Jul 2021
Alveolar ridge augmentation can be used to obtain appropriate alveolar ridge for dental implantation. A variety of bone graft materials including autogenous bone, allograft, xenograft, and alloplastic material are used in alveolar ridge augmentation. Autogenous tooth-derived bone graft material has received much attention for the past few years, because the structure and physicochemical characteristics of tooth are similar to those of bones. Compared to autogenous tooth, allogenic tooth has the advantage of extensive resources. However, the problem of cell-derived immunological rejection of allogenic tooth remains unresolved. In the present study, acellular tooth root (ATR) is obtained by an innovative combination procedure. The biocompatibility of ATR is assessed using cytotoxicity test, hemolysis test, intracutaneous reactivity test, and acute systemic toxicity test. Osseointegration is evaluated in vivo by implanting ATR into the rat tibia defect as an allograft material. The results show that the ATR has fine biocompatibility, and there is an osseointegration between ATR and bone bed at 8 weeks post operation. This study demonstrates that the ATR could be used in alveolar ridge augmentation as a kind of new tooth-derived bone graft material.
Autogenous Dentin Block of A Non Restorable Wisdom Tooth for Localized Horizontal Ridge Augmentation: Radiographic and Histological Analysis: A Preliminary Case Report
Article
  • Nov 2020
Introduction: Tooth roots proved in different studies clinically and radiographically to be an alternative to autogenous bone. However, the histological evaluation of the tooth block following ridge augmentation is still missing. The aim of this case report was to evaluate histologically and radiographically the effect of autogenous dentin block (DB) to restore a horizontal ridge deficiency at a single tooth gap. Case presentation: A healthy 36-year-old female patient presented with a missing lower first molar (30), after clinical and radiographic examination, the site showed a class III defect horizontal atrophy. The procedure performed was the surgical removal of the wisdom tooth (32), shaping and fixation of a separated DB at the defect site using an osteosynthesis screw. A cone beam computed tomography was performed immediately and 6 month following the surgery. During implant placement, a core biopsy specimen was retrieved, stored and prepared for histological evaluation. The radiographic analysis showed a horizontal width gain of about 4 mm. The histologic assessment revealed cortical bone formation at the buccal and lingual aspects between the tooth and the bone. During implant placement, the core biopsy exhibited a slight separation upon removal from the grafted side, at 6 month following implant placement, the implant was successfully osteointegrated. Conclusion: DB was successfully used for horizontal alveolar ridge augmentation, thus allowing a prosthetically driven implant placement. More cases assessing implant survival and success are needed to confirm the results of this case report.
Efficacy of autogenous teeth for the reconstruction of alveolar ridge deficiencies: a systematic review
Article
Full-text available
Aim The aim of this systematic review was to critically evaluate the currently existing clinical evidence on the efficacy of autogenous teeth (AT) for the reconstruction of alveolar ridge deficiencies. Materials and methods A search protocol was developed to answer the focused question: “In patients exhibiting alveolar ridge deficiencies and being in need of an implant retained restoration, what is the efficacy of reconstructive procedures employing AT on changes in ridge dimensions compared with control measures?” Uncontrolled studies were also included to assess the overall efficacy of AT for specific procedures. Results A total of six studies (one randomized, one non-randomized controlled, two observational, one controlled case series, one retrospective) were identified. Two studies used AT for staged lateral augmentation, whereas four studies used AT as a demineralized dentin matrix (AutoBT) for the simultaneous grafting of dehiscence-type defects, vertical augmentation of post-extraction sockets, and lateral/transcrestal sinus floor elevation. The reported clinical outcomes following the application of either AT or AutoBT were within the range of those data noted in the respective control groups. Adverse events were commonly not observed. Conclusions The available limited studies involved relatively small patient samples and short follow-up periods but pointed to the potential of AT to serve as an alternative material for the reconstruction of alveolar ridge deficiencies. Clinical relevance AT appear to be effective in reconstructing alveolar ridge deficiencies.
Microstructural volumetric analysis of lateral ridge augmentation using differently conditioned tooth roots
Article
Full-text available
Objectives Previous research revealed that autogenous tooth roots may be biologically equivalent to conventional bone grafts for lateral ridge augmentation. However, these analyses were limited to two dimensions, whereas healing is a volumetric process. The present study aimed at volumetrically assessing the microstructure following lateral ridge augmentation using extracted tooth roots. Material and methods The roots of differently conditioned maxillary premolars (i.e., healthy: PM-C; endodontically treated: PM-E; ligature-induced periodontitis: PM-P) and retromolar cortical autogenous bone (AB) blocks were used for lateral ridge augmentation at chronic-type defects in the lower quadrants of n = 16 foxhounds. At 12 weeks, titanium implants were inserted and left to heal for another 3 weeks. Tissue biopsies were scanned using microcomputed tomography (μCT), and volumes of interest were separated at the buccal and oral aspects to measure bone volume per tissue volume (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), and connectivity density (Conn.D). Results All groups investigated revealed comparable BV/TV, Tb.Th, Tb.Sp, and Conn.D values at either the augmented buccal or pristine oral aspects, respectively. A gradual but heterogeneous replacement of grafts was observed in all groups, but residual PM fragments were particularly noted in PM-C and PM-P groups. Conclusions Differently conditioned PM and AB grafts were associated with a comparable bone microstructure within the grafted area. The duration of replacement resorption may vary considerably among the subjects. Clinical relevance Autogenous tooth roots may serve as potential alternative to AB for localized alveolar ridge augmentation.
Effect of Different Disinfection/Sterilization Methods on Risk of Fracture of Teeth Used in Preclinical Dental Education
Article
Full-text available
  • Jan 2018
The aim of this in vitro study was to determine whether different disinfection/sterilization methods affected the risk of fracture of extracted teeth used for preclinical dental education. Freshly extracted intact mandibular incisors were assigned to different groups according to the processing method used. In the autoclave group (n=20), teeth were autoclaved for 40 min at 240°F under a pressure of 20 psi; in the formalin group (n=20), teeth were immersed in 10% formalin for two weeks; and in the control group (n=10), teeth were not processed. Teeth were then stored at 4°C in distilled water until use. Endodontic procedures were performed, and the fracture strength of the specimen was subsequently tested under compressive force along the long axis of the teeth using an Instron universal testing machine. The results showed that none of the specimens fractured during endodontic procedures. However, the compressive load needed to fracture the teeth was significantly less for the autoclaved teeth than the teeth stored in formalin or the control teeth (p<0.001). The disinfection/sterilization method used affected the fracture resistance of extracted teeth: autoclaved teeth were less resistant to fracture than teeth that were not sterilized or teeth that were chemically disinfected. However, fracture resistance was not reduced enough to lead to tooth fracture during preclinical endodontic procedures. Therefore, either processing method may be appropriate for teeth to be used for preclinical endodontic training.
Influence of autoclavation on the efficacy of extracted tooth roots used for vertical alveolar ridge augmentation
Article
  • Feb 2019
Objectives To assess the influence of autoclavation on the efficacy of extracted tooth roots (TR) used for vertical alveolar ridge augmentation and two‐stage osseointegration. Material & Methods Maxillary premolars were randomly assigned to either autoclavation (TR‐A) or were left untreated (TR‐C) and used as block grafts for vertical alveolar ridge augmentation in both lower quadrants (n=4 beagle dogs). At 12 weeks, titanium implants were inserted and left to heal for 3 weeks. Histological analyses considered vertical bone gain (BD‐BC); augmented area (AA) and bone‐to‐implant contact (BIC) at vestibular (v) and oral (o) aspects. Results Both TR‐C and TR‐A (exposures n=3) grafts were associated with a replacement resorption and marked vertical bone gain. Median BD‐BC [TR‐C: 1.45 (v) to 1.62 mm (o) vs. TR‐A: 0.97 (v) to 1.79 mm (o)] and AA [TR‐C: 0.64 (v) to 2.36 mm² (o) vs. TR‐A: 0.22 (v) to 2.36 mm² (o) ] values were comparable in both groups. V BIC [TR‐C: 49.32 (v) to 52.97% (o) vs. TR‐A: 25.34 (v) to 46.11% (o)] values were significantly higher in the TR‐C group. Conclusions Both TR‐C and TR‐A grafts equally supported vertical alveolar ridge augmentation, however, osseointegration was partially facilitated in the TR‐C group. This article is protected by copyright. All rights reserved.
Effectiveness of vertical ridge augmentation interventions. A systematic review and meta-analysis
Article
  • Jan 2019
AIM: The primary aim of this systematic review was to evaluate the effect of various techniques used for vertical ridge augmentation on clinical vertical bone gain. MATERIAL AND METHODS: A protocol was developed to answer the following focused question: "In patients with vertical alveolar ridge deficiencies, how effective are different augmentation procedures for clinical alveolar ridge gain?" Randomized and controlled clinical trials and prospective and retrospective case series were included, and meta-analyses were performed to evaluate vertical bone gain based on the type of procedure and to compare bone gains in controlled studies. RESULTS: Thirty-six publications were included. Results demonstrated a significant vertical bone gain for all treatment approaches [n=33; weighted mean effect = 4.16 mm; 95% CI 3.72-4.61; p<0.001]. Clinical vertical bone gain and complications rate varied among the different procedures, with a weighted mean gain of 8.04 mm and complications rate of 47.3% for distraction osteogenesis, 4.18 mm and 12.1% for guided bone regeneration (GBR) and 3.46 mm and 23.9% for bone blocks. In comparative studies, GBR achieved a significant greater bone gain when compared to bone blocks [n=3; weighted mean difference=1.34 mm; 95% CI 0.76-1.91; p<0.001]. CONCLUSIONS: Vertical ridge augmentation is a feasible and effective therapy for the reconstruction of deficient alveolar ridges, although complications are common.
Long-term effectiveness of maxillary sinus floor augmentation A systematic review and meta-analysis
Article
  • Jan 2019
Aim: To assess the long-term effectiveness (≥5 years) of maxillary sinus floor augmentation (MSFA) procedures applying the lateral window technique and to determine possible differences in outcome between simultaneous and delayed implant placement, partially and fully edentulous patients and grafting procedures. Materials and methods: MEDLINE (1950-May 2018), EMBASE (1966-May 2018) and Cochrane Central Register of Controlled Trials (1800-May 2018) were searched. Inclusion criteria were prospective studies with follow-up ≥5 years and a residual bone height ≤6 mm. Outcome measures included implant loss, peri-implant bone level change, suprastructure survival, patient-reported outcome measures and overall complications. Data were pooled and analysed using a random effects model. Results: Out of 2,873 selected articles, 11 studies fulfilled all inclusion criteria. Meta-analysis revealed a weighted annual implant loss of 0.43% (95% CI: 0.37%-0.49%). Meta-regression analysis did not reveal significant differences in implant loss neither between edentulous and dentate patients nor implants placed simultaneously with or delayed after MSFA, nor implants placed in MSFA using solely autologous bone or bone substitutes. The results of the other outcome measures were favourable, and overall complications were low. Conclusion: MSFA is a reliable procedure in the partially and fully edentulous maxilla for support of dental implants.
Efficacy of lateral bone augmentation prior to implant placement: A systematic review and meta-analysis
Article
  • Jan 2019
Aim The aim of the current systematic review was to critically appraise evidence from randomized and prospective non‐randomized comparative clinical trials about the efficacy of lateral bone augmentation prior to implant placement and their outcome regarding bone‐width gain. Material and Methods Eight databases were searched until May 2018 for randomized and prospective non‐randomized comparative trials on lateral bone augmentation prior to implant placement. After elimination of duplicate studies, data extraction and risk‐of‐bias assessment according to the Cochrane guidelines, random‐effects meta‐analyses of Mean Differences (MD) or Relative Risks (RR) and their 95% CIs were performed, followed by subgroup, meta‐regression, and sensitivity analyses. Results A total of 25 trials (16 randomized / 9 non‐randomized) were identified, which included a total of 553 patients (42.2% male; mean age of 43.9 years). In these included studies and populations, various modalities for primary lateral bone augmentation rendered implant placement feasible. Bone width gain was significantly inversely associated with baseline bone width (pooled effect: ‐0.35 mm/mm; 95% CI: ‐0.63 to ‐0.07 mm; p=0.01). % graft resorption demonstrated a correlation with patient age (36% /year, 95% CI: ‐0.62 to ‐0.11 mm; p=0.01). The presence of xenograft added to autogenous graft led to less resorption compared to autograft alone (MD: 1.06 mm; 95% CI: 0.21 to 1.92 mm; p=0.01). Barrier membrane did not yield significant difference in terms of bone width gain (MD: ‐0.33 mm; 95% CI: ‐2.24 to 1.58 mm; p>0.05) and graft resorption (MD: 0.84 mm; 95% CI: ‐1.42 to 3.09 mm; p>0.05). Conclusions Initially smaller bone dimension favors larger bone width gain, which indicates that a severe lateral bone deficiency can be effectively augmented applying primary lateral bone augmentation. Patients’ age and recipient site (maxilla or mandible) seems to influence graft resorption. The addition of a xenograft can be helpful for reducing graft resorption.This article is protected by copyright. All rights reserved.
Efficacy of autogenous tooth roots for lateral alveolar ridge augmentation and staged implant placement. A prospective controlled clinical study
Article
  • Jul 2018
Objectives To assess and compare the efficacy and safety of autogenous tooth roots (TR) and autogenous bone blocks (AB) for lateral alveolar ridge augmentation and two‐stage implant placement. Material & Methods A total of 30 patients in need of implant therapy and lateral ridge augmentation were allocated to parallel groups receiving either 1) healthy autogenous tooth roots (e.g. retained wisdom or impacted teeth) (n=15), or 2) cortical autogenous bone blocks harvested from the retromolar area. After 26 weeks of submerged healing, the primary endpoint was defined as the crestal ridge width (mm) (CW26) being sufficient to place an adequately dimensioned titanium implant at the respective sites. Results Soft tissue healing was uneventful in both groups. CW26 at visit 6 allowed for a successful implant placement in all patients of both TR (15/15) and AB groups (15/15). Mean CW26 values amounted to 10.06±1.85 mm (median: 11.0) in the TR and 9.20±2.09 mm (median: 8.50) in the AB group, respectively. The difference between both groups did not reach statistical significance (P=0.241). Conclusions TR may serve as an alternative graft to support lateral alveolar ridge augmentation and two‐stage implant placement. This article is protected by copyright. All rights reserved.
Periodontally diseased tooth roots used for lateral alveolar ridge augmentation. A proof-of-concept study
Article
Objectives: To assess the efficacy of periodontally diseased tooth roots used as autografts for lateral ridge augmentation and two-stage early osseointegration of titanium implants. Material & methods: Ligature-induced periodontitis lesions were established at the maxillary premolars in n=8 foxhounds. Extracted, scaled and root planned premolar roots (PM-P) as well as retromolar cortical autogenous bone (AB) blocks were used for horizontal ridge augmentation of mandibular chronic-type defects. At 12 weeks, titanium implants were inserted and left to heal for another 3 weeks. Histological analyses included crestal ridge width - CW; augmented area - AA and bone-to-implant contact - BIC. Results: Both PM-P and AB grafts were gradually organized and replaced by newly formed bone. Median CW (PM-P: 3.83 vs. AB: 3.67 mm), AA (PM-P: 10.18 vs. AB: 9.82 mm(2) ) and BIC (PM-P: 50.00 vs. AB: 35.21%) values did not reach statistical significance between groups (p>0.05, respectively). Histologically, PM-P grafts were not associated with any inflammatory cell infiltrates. Conclusions: PM-P autografts may reveal a structural and biological potential to serve as an alternative autograft to AB. This article is protected by copyright. All rights reserved.
Biomechanical, micro-computed tomographic and immunohistochemical analysis of early osseous integration at titanium implants placed following lateral ridge augmentation using extracted tooth roots
Article
Objectives: To assess biomechanical, micro-computed tomographic (micro CT) and immunohistochemical characteristics of early osseous integration at titanium implants placed following lateral ridge augmentation using autogenous extracted tooth roots. Material & methods: The roots of healthy maxillary premolars (PM) and retromolar cortical autogenous bone (AB) blocks were used for lateral ridge augmentation at chronic-type defects in the lower quadrants of n = 16 foxhounds. At 12 weeks, titanium implants were inserted and left to heal for another 3 weeks. Osteocalcin (OC) antigen reactivity, removal torque values (RT) and the bone volume per tissue volume (micro CT- BV/TV) along the implants were assessed. Results: Median OC (PM: 6.71 vs. AB: 2.73%), RT (PM: 61.97 vs. AB: 44.8 Ncm) and BV/TV (PM: 0.34 vs. AB: 0.21) values were comparable in both PM and AB groups. Conclusions: PM and AB grafted sites equally supported the early stages of osseointegration.