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Marginal Bone Loss in Implants Placed in the Maxillary Sinus Grafted With Anorganic Bovine Bone: A Prospective Clinical and Radiographic Study
Abstract
Background:
Sinus elevation is a reliable and often used technique. The success of implants placed in such situations, even with bone substitutes alone, led us to strive for bone loss close to zero and to seek out variables that cause higher or lower rates of resorption. The objective of this study was twofold: to evaluate the survival rates and marginal bone loss (MBL) around implants installed in maxillary sinus augmentation using anorganic bovine bone, and to identify surgical and prosthetic prognostic variables.
Methods:
A total of 55 implants were placed in 30 grafted maxillary sinuses in 24 patients. Periapical radiographs were evaluated immediately after implant placement (at baseline), at 6 months, and at the most recent follow-up. MBL was calculated, taking into account the distortion rate for each radiograph as compared to the original implant measurements, from the difference between the initial and final measurements.
Results:
The survival rate was 98.2%, with only one implant lost (100% survival rate after loading) over a mean follow-up time of 2 ± 0.9 years. The MBL ranged from 0 to 2.85 mm: 75.9% of mesial sites and 83.4% of distal sites showed <1mm of MBL, while 35.2% of mesial sites and 37% of distal sites exhibited no bone loss. The MBL was significantly (p<0.05) greater in open flap as compared to flapless surgery.
Conclusion:
Within the limitations of this study, we concluded that maxillary sinus elevation with 100% anorganic bovine bone presents predictable results, and that flapless surgery results in less MBL as compared to traditional open flap surgery.
... This study was approved by the Malatya Clinical Research Ethics Committee (Protocol code 2018/ [8][9][10][11][12][13][14][15][16][17][18][19][20] and study was conducted according to the principles of the Declaration of Helsinki. Individuals selected in accordance with the study criteria were informed in detail about the purpose and method of study, and a written informed consent was obtained from each participant. ...
... The difference between marginal bone levels obtained from first and last digital panoramic radiographs was noted as bone loss (Figure 1). The mean bone level percentage for an implant was calculated by taking the mean value of the mesial and distal measurements ((M+D)/2) (15,16). ...
... Therefore, placement of longer implants by sinus lift surgery instead of short implants in the upper jaw posterior region clinically provides marginal bone preservation by providing an ideal crown/implant ratio (29). In several studies, marginal bone loss was measured from the mesial and distal sides of each implant (15)(16)(17). For this reason, marginal bone loss in our study was calculated by taking the mean bone loss in the mesial and distal parts of the radiographs. ...
... -Survival Rate The 95.16% implant survival rate presented in this study is lower than showed by studies assessing implants in sinus lift technique (23,24) and grafts with iliac crest or DBBM mixed with autogenous bone for atrophic maxilla (17), but it is in accordance Hellem et al. (25). Jensen and Terheyden (26) concluded that a high level of evidence has shown that the survival rates of implants placed in augmented bone are comparable to the rates of implants placed in native bone. ...
Background
Tooth loss and use of a complete denture is still a reality and results in bone loss. Adequate reconstruction of an extremely atrophic edentulous maxilla is a challenge, and different treatment methods have been described for its resolution.
Material and Methods
Patients seeking implant placement in edentulous upper jaw with atrophic maxilla were selected in a private clinic in Porto Alegre, Brazil. The bone graft was performed with bilateral sinus lift and horizontal bone graft in anterior region with 0,25-1mm particles of Bio-Oss (Geistlich) covered with a collagen membrane (Bio-Gide, Geistlich). CBCTs were evaluated to verify the need for bone graft, and 6-8 months after bone graft follow-up, to plan implant placement and assess horizontal bone gain.
Results
124 implants were placed in 19 patients, 76 of those in the sinus region. The survival rate was 95.2%, with six implants lost over a mean implants follow-up time of 47.68 months. The horizontal bone gain ranged from 0.00 to 6.86 mm, a mean gain of 2.85mm. An average of 5.5g of Bio-Oss was used per patient, and in 73.7 % of the cases, a flapless surgery was possible for implant placement, and in 92 implants an immediate loading was possible. Final rehabilitation was accomplished with fixed prosthodontics in 16 patients with a mean follow-up of 38.4 months.
Conclusions
Within the limitations of this study, it is possible to affirm that bone graft with 100% Bio-Oss in atrophic maxilla is a reliable treatment and allow rehabilitation with implants with a high survival rate and the higher the initial bone height, the greater the gain in bone width.
Key words:Bone Regeneration, Dental Implants, Prosthodontics, Dentistry.
... To overcome these disadvantages, a large number of biomaterials have been used alone or in combination with autografts in augmentation procedures [8][9][10][11][12][13][14][15][16][17][18][19]. Among the osteoconductive materials, allografts (fresh-frozen bone, freezedried bone, demineralized freeze-dried bone), xenografts (of bovine, equine, or porcine origin), and alloplastic materials (different combination of calcium-phosphate, bioactive glasses, polymers) were described in the dental literature as being able to enhance bone formation. ...
Objectives
To evaluate the performances of six different bone substitute materials used as graft in maxillary sinus augmentation by means of histological and histomorphometric analysis of bone biopsies retrieved from human subjects after a 6-month healing period.
Materials and Methods
Six consecutive patients (3 males, 3 females, aged 50-72 years), healthy, nonsmokers, and with good oral hygiene, presenting edentulous posterior maxilla with a residual bone crest measuring ≤ 4 mm in vertical height and 3 to 5 mm in horizontal thickness at radiographic examination, were selected to receive sinus augmentation and delayed implant placement. Under randomized conditions, sinus augmentation procedures were carried out using mineralized solvent-dehydrated bone allograft (MCBA), freeze-dried mineralized bone allograft (FDBA), anorganic bovine bone (ABB), equine-derived bone (EB), synthetic micro-macroporous biphasic calcium-phosphate block consisting of 70% beta-tricalcium phosphate and 30% hydroxyapatite (HA-β-TCP 30/70), or bioapatite-collagen (BC). After 6 months, bone core biopsies were retrieved and 13 implants were placed. Bone samples were processed for histological and histomorphometric analysis. CT scans were taken before and after surgery. After 4 months of healing, patients were restored with a provisional fixed acrylic resin prosthesis, as well as after further 2-4 months with a definitive cemented zirconia or porcelain-fused-to-metal crowns.
Results
There were no postoperative complications or implant failures. The histological examination showed that all biomaterials were in close contact with newly formed bone, surrounding the graft granules with a bridge-like network. No signs of acute inflammation were observed. The histomorphometry revealed 20.1% newly formed bone for MCBA, 32.1% for FDBA, 16.1% for ABB, 22.8% for EB, 20.3% for HA-β-TCP 30/70, and 21.4% for BC.
Conclusions
Within the limitations of the present investigation, all the six tested biomaterials showed good biocompatibility and osteoconductive properties when used in sinus augmentation procedures, although the FDBA seemed to have a better histomorphometric result in terms of newly formed bone and residual graft material. This trial is registered with ClinicalTrials.gov Identifier (Registration Number): NCT03496688.
... Alternatively there are various bone graft materials that have been studied on their own or in combination: xenografts, allografts, and synthetic grafts [9][10][11]. Despite disadvantages, such as causing an immune response by the host and slow degradation, xenografts have been used successfully in numerous studies, including guided bone regeneration (GBR) [12] and sinus augmentation [13]. In addition, the studies conducted on rat calvarial defects with Bio-Oss have also shown positive results on bone formation [14,15]. ...
Aim: The purpose of this study was to investigate the healing potential of local puerarin administration on xenograft in cranial bone defect treatment in rats. Material and Method: A critical-size defect of 5-mm diameter was created in the calvarium of twenty-four rats. The animals were divided into three groups: group C (passive control), group XBG (treated with Bio-Oss), and group P-XBG (treated with puerarin + Bio-Oss combination). All animals were euthanized at 28 days postoperative. Stereologic analyses were performed. New bone area and connective tissue volumes were measured. Results: Mean new bone volumes were 1.57 ± 0.13mm3, 1.24 ± 0.10 mm3, and 0.31 ± 0.09 mm3 in groups P-XBG, XBG and C respectively. The new bone volumes were statistically significant in groups P-XBG and XBG compared to group C (p ≤ 0.05). Moreover, the new bone formation in group P-XBG was statistically higher when compared to the XBG group (P<0.05). In the P-XBG group, mean connective tissue volume was 2.00 ± 0.12 mm3. The connective tissue volumes were statistically higher in groups P-XBG and XBG compared to group C (p<0.05). The difference between group P-XBG and group XBG was also statistically significant (p<0.05). Discussion: Puerarin had a positive effect on xenograft and increased new bone formation.
... Nonetheless, these bone substitutes have high rates of success with dental implants (range, 98.2 to 100%). 37,38 In conclusion, ChronOS combined with autogenous bone graft in a 1:1 ratio presented behavior similar to that of autogenous bone graft alone. However, the groups with Bio-Oss had histomorphometric and immuno-labeling scores for the proteins evaluated, indicating maturation of the grafted bone, thus allowing the placement of dental implants. ...
Purpose:
The aim of this study was to compare ChronOS (β-tricalcium phosphate), Bio-Oss, and their addition to an autogenous bone graft in a 1:1 ratio in human maxillary sinus bone augmentation.
Materials and methods:
Thirty maxillary sinuses were divided in 5 groups: group 1 included 6 maxillary sinuses grafted with autogenous bone graft alone; group 2 included 6 maxillary sinuses grafted with ChronOS; group 3 included 6 maxillary sinuses grafted with ChronOS and autogenous bone graft in a 1:1 ratio; group 4 included 6 maxillary sinuses grafted with Bio-Oss; and group 5 included 6 maxillary sinuses grafted with Bio-Oss and autogenous bone graft in a 1:1 ratio. The number of samples for each group was determined by the statistical power test.
Results:
The median areas of new bone formation in groups 1, 2, 3, 4, and 5 were 121,917.0, 83,787.0, 99,295.0, 65,717.0, and 56,230.0 μm(2), respectively. Statistically significant differences were found between groups 3 and 5, groups 1 and 4, and groups 1 and 5 (P < .05). The median areas of remaining biomaterial were 2,900.5, 5,291.0, 2,662.0, 56,258.5, and 64,753.5 μm(2) in groups 1, 2, 3, 4 and 5, respectively. Statistically significant differences occurred between groups 1 and 5, groups 3 and 5, and groups 2 and 5 (P < .05). Areas of connective tissue were 67,829.0 ± 22,984.6 μm(2) in group 1, 97,445.9 ± 18,983.3 μm(2) in group 2, 88,256.0 ± 21,820.5 μm(2) in group 3, 65,501.8 ± 6,297.6 in group 4, and 70,203.2 ± 13,421.3 μm(2) in group 5.
Conclusions:
ChronOS combined with autogenous bone graft presented a behavior similar to that of autogenous bone graft alone. However, the groups treated with Bio-Oss showed immuno-labeling results indicating maturation of grafted bone.
... Many different surgical reconstructive techniques have been introduced in order to reestablish an adequate bone volume and allow proper implant placement [9][10][11][12][13][14]: among these, alveolar ridge augmentation by means of onlay/inlay bone blocks [10,11], as well as GBR [9,28], maxillary sinus elevation [12,29], and split-crest [14] are the most popular. ...
Purpose . To present a computer-assisted-design/computer-assisted-manufacturing (CAD/CAM) technique for the design, fabrication, and clinical application of custom-made synthetic scaffolds, for alveolar ridge augmentation. Methods . The CAD/CAM procedure consisted of (1) virtual planning/design of the custom-made scaffold; (2) milling of the scaffold into the exact size/shape from a preformed synthetic bone block; (3) reconstructive surgery. The main clinical/radiographic outcomes were vertical/horizontal bone gain, any biological complication, and implant survival. Results . Fifteen patients were selected who had been treated with a custom-made synthetic scaffold for ridge augmentation. The scaffolds closely matched the shape of the defects: this reduced the operation time and contributed to good healing. A few patients experienced biological complications, such as pain/swelling (2/15: 13.3%) and exposure of the scaffold (3/15: 20.0%); one of these had infection and complete graft loss. In all other patients, 8 months after reconstruction, a well-integrated newly formed bone was clinically available, and the radiographic evaluation revealed a mean vertical and horizontal bone gain of 2.1±0.9 mm and 3.0±1.0 mm, respectively. Fourteen implants were placed and restored with single crowns. The implant survival rate was 100%. Conclusions . Although positive outcomes have been found with custom-made synthetic scaffolds in alveolar ridge augmentation, further studies are needed to validate this technique.
... Thus, this issue represents a gap in the knowledge of the longevity of the implant-prosthesis assembly (8,9). Although several aspects concerning implant survival rate and peri-implant bone loss have been reported, (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11) there is still lack of clinical investigations in humans considering the role of unsuitable occlusal factors on the establishment and maintenance of oral implant osseointegration (12)(13)(14), together with implant-prosthetic and periodontal parameters. ...
This study evaluated retrospectively the association among occlusal, periodontal and implant-prosthetic parameters and marginal bone loss (MBL) around implants and survival rate at 5.7 ±3.2 years of follow-up after prosthetic loading. Eighty-two patients received 164 external hexagon implants. After the standard healing period (3 to 6 months), the implants were restored with single-tooth or up to three splinted crowns. All patients were followed according to a strict maintenance program with regular recalls and clinically evaluated by a calibrated examiner. The MBL measurements taken from standardized radiographs made at permanent crown placement (baseline) and after the last evaluation were calculated considering occlusal, periodontal and implant-prosthetic parameters. Veneer fractures and abutment loosening were not considered failure. Two implants failed during the follow-up period, resulting in a survival rate of 98.8%. Cox regression analyses showed MBL associated with non-working side contacts (p=0.047), inadequate anterior guidance (p=0.001), lateral group guidance involving teeth and implants (p=0.015), periimplant plaque index (p=0.035), prosthetic design (p=0.030) and retention (p=0.006). Inadequate occlusal pattern guide, presence of visible plaque, and cemented and splinted implant-supported restoration were associated with greater MBL around the implant.
Bu çalışmanın amacı; implant yuvasının preparasyonunda düşük devirli irrigasyonsuz frezlemenin implant etrafındaki marjinal kemik kaybına ve implantların kaybedilme oranına etkilerinin değerlendirilmesidir. Çalışmaya parsiyel ve total dişsizliğe sahip toplam 23 hasta dahil edildi. Çalışma grubundaki 44 implantın frezlemesi 50rpm düşük devirli irrigasyonsuz şekilde yapılırken, kontrol grubundaki 30 implantın frezlemesi 600rpm devirli ve irrigasyonlu bir şekilde yapıldı. Marjinal kemik seviyelerini belirlemek için tüm implantlardan, yerleştirildikten hemen sonra ve postoperatif 3. ayda periapikal radyografiler alındı. Ayrıca, çalışmada implantların kaybedilme oranı, yerleştirme tork değerleri, implant yerleştirilen bölgedeki kemik kalitesi, frezleme ve toplam ameliyat süreleri kaydedildi. Bu çalışmada; düşük devirli irrigasyonsuz frezleme (DDİF) ile standart frezleme (SF) protokolü arasında mesial, distal ve ortalama marjinal kemik kaybı düzeyleri açısından istatistiksel olarak anlamlı bir farklılık görülmedi (p>0.05). İmplantların kaybedilme oranları da gruplar arasında benzerdi (p>0.05). Ayrıca, implant yerleştirme tork değerleri, frezleme ve toplam ameliyat sürelerinde de gruplar arasında farklılık gözlenmedi (p>0.05). Bu çalışmanın bulguları, DDİF’nin cerrahi sonrası iyileşme dönemindeki marjinal kemik kaybı, implant kaybı ve başlangıç tork değerlerine etkilerinin SF ile benzer olduğunu işaret etmektedir. Ancak, tekniğin güvenilirliği açısından daha ileri ve uzun hasta takipli çalışmalara ihtiyaç vardır.
Statement of problem:
Because of market demand for innovation, new restoration materials have been introduced without adequate testing; clinical failure may be the consequence, and clinical studies are needed.
Purpose:
The purpose of this clinical study was to evaluate the biological and mechanical clinical behavior of implant-supported resin-modified ceramic crowns compared with that of metal-ceramic crowns.
Material and methods:
Forty-two participants aged between 35 and 65 years received single implants in posterior edentulous sites. After the osseointegration period, half of the implants (selected randomly) (n=25) were restored with metal-ceramic crowns (MC group) and the other half with resin-modified ceramic crowns (RMC group) bonded with dual-polymerized resin cement onto titanium abutments. The biomechanical state of the restorations and implants was analyzed.
Results:
Mean peri-implant bone loss after 5 years of functional life was 0.3 ±0.6 mm. The implant clinical survival rate was 98%. RMC crowns had a survival rate of 70%, whereas MC crowns had a 100% survival rate. RMC crowns had more mechanical complications than the MC group (P<.001). Peri-implant bone loss showed no significant differences between crown type (P=.175).
Conclusions:
All peri-implant bone loss values were within the range considered acceptable. Metal-ceramic crowns showed better mechanical behavior than resin-modified ceramic crowns. Biological responses of peri-implant tissue would appear to be independent of the type of cemented crown.
Purpose:
To perform a systematic review and individual- and aggregate-data meta-analysis of observational studies to determine the success rate of the lateral sinus floor elevation with simultaneous implant placement and without grafting materials.
Material and methods:
We included prospective and retrospective observational studies analyzing survival rate of implants in patients who underwent graftless lateral sinus floor elevation. Secondary outcomes included increase of bone height, marginal bone loss (MBL), implant stability, and adverse events such as sinus membrane perforation and signs of infection in the maxillary sinuses. Survival rate and proportion of adverse outcomes were calculated using the variance-stabilizing Freeman-Tukey double-arcsine transformation. Meta-analyses of bone gain and MBL were performed based on changes from baseline and sampling variance. Implant stability was analyzed at follow-up. Individual participant data were modeled using a one-step approach. The survival probability was determined using the Kaplan-Meier method, and the Cox proportional-hazards regression was applied to investigate the association between survival time of implants and covariates.
Results:
11 observational studies were included in the study. The meta-analysis based on 660 implants and 17 failures showed a pooled survival rate of 97.5% (CI 95% 95.8 to 98.9). Pooled analysis also showed an increase in mean bone height of 5.7 mm (CI 95% 4.78 to 6.56), MBL of 1.2 mm (CI 95% 0.84 to 1.51), and implant stability quotient of 70.5 (CI 95% 64.2 to 76.9). A pooled rate of 20.0% (CI 95% 10.9 to 30.6) and 3.0% (CI 95% 0.5 to 6.8), respectively, for membrane perforations and sinus infection was found. Individual-data meta-analysis showed an overall 5-year survival of 93.1% (SE 2.67%) with a mean survival time of 6.7 years (SE 0.08). Longer implants were associated with a decreased hazard ratio (0.64; CI 95% 0.41 to 0.99).
Conclusions:
Current available evidence based on aggregate and individual patient data meta-analysis suggests that lateral maxillary sinus floor elevation without grafting, and simultaneous implant placement, is a safe and effective technique with high survival rates, especially for implants with more than 13 mm in length.
In this study, we analyzed the influence of prosthetic abutment height on marginal bone loss (MBL) around implants in the posterior maxilla. In this retrospective cohort study, the radiographically determined MBL was related to the height of the abutments of internal conical connection implants at 6 and 18 months post-loading. Data were gathered on age, sex, bone substratum, smoking habit, history of periodontitis, and prosthetic features, among other variables. A linear mixed model was used for statistical analysis. The study included 131 patients receiving 315 implants. MBL rates at 6 and 18 months were mainly affected by the abutment height but were also significantly influenced by the bone substratum, periodontitis, and smoking habit. MBL rates were higher for prosthetic abutment < 2 mm vs. ≥ 2 mm, for periodontal vs. non-periodontal patients, for grafted vs. pristine bone, and for a heavier smoking habit. The abutment height is a key factor in MBL. MBL rates followed a non-linear trend, with a greater MBL rate during the first 6 months post-loading than during the next 12 months.
This 1-year prospective study evaluated the implant success rate and marginal bone response of non-submerged implants with platform and non-platform switching abutments in posterior healed sites.
Nineteen patients (9 male, 10 female) with posterior partially edentulous spaces, between the ages of 23 and 76 (mean = 55.4 years), were included in this study. A total of 30 implants (15 implants restored with platform switching [PS] abutments [control] and 15 implants restored with non-platform switching [NPS] abutments [test]) were assigned between two groups using a randomization procedure. The definitive abutments with conical connections were placed at the time of surgery, and the definitive restorations were placed at 3 months. All patients were evaluated clinically and radiographically using standardized radiographs at time of implant placement (0), 3, 6 and 12 months after implant placement. Data were analyzed using Friedman test with post hoc pairwise comparisons, Mann-Whitney U-test, and Pearson's chi-square test at the significance level of α = 0.05.
At 12 months, all 30 implants remained osseointegrated corresponding to a 100% success rate. The overall mean marginal bone level change at 12 months was -0.04 ± 0.08 mm for PS group and -0.19 ± 0.16 mm for NPS group. Statistically significant difference in the marginal bone level change was observed between groups at 0 to 12 months and 3 to 12 months (P < 0.05).
This 1-year randomized control study suggests that when a conical implant-abutment connection is present, similar peri-implant tissue responses can be achieved with platform switching and non-platform switching abutments.
The aim of this study was to determine the influence of patient-related systemic risk factors (systemic disease, genetic traits, chronic drug or alcohol consumption, and smoking status) on peri-implant bone loss at least 1 year after implant installation and prosthetic loading. An electronic search was performed of MEDLINE, EMBASE, and The Cochrane Central Register of Controlled Trials up to January 2012. One thousand seven hundred and sixty-three studies were identified. After applying a three-stage screening process, 17 articles were included in the qualitative analysis, but only 13 in the quantitative analysis, since smoking was a common exposure. The meta-analysis of these 13 studies (478 smokers and 1207 non-smokers) revealed a high level of heterogeneity and that smoking increases the annual rate of bone loss by 0.164mm/year. Exposure to smoking had a harmful effect on peri-implant bone loss. However, the level of evidence for oral implant therapy in patients with systemic conditions is very low. Future studies should be improved in order to provide more robust data for clinical application.
To evaluate how bone-level implants maintain crestal bone stability after thickening of thin mucosal tissues with allogenic membrane.
Ninety-seven bone-level implants of 4.1 mm diameter (Institute Straumann AG, Switzerland) were evaluated in 97 patients (28 men and 69 women, mean age 47.3 ± 1.2 years). According to vertical gingival thickness, patients were assigned into test T1 (thin, 2 mm or less, n = 33), test T2 (thin thickened with allogenic membrane, n = 32) and control C groups (thick, more than 2 mm, n = 32). Implants were placed in posterior mandible in one-stage approach and after integration were restored with single screw-retained metal-ceramic restorations. Radiographic examination was performed after implant placement, 2 months after healing, after prosthetic restoration and after 1-year follow-up. Crestal bone loss was calculated mesially and distally. Mann-Whitney U-test was applied and significance was set to 0.05.
After 2 months, implants in group T1 had 0.75 ± 0.11 mm bone loss mesially and 0.73 ± 0.10 mm distally. Implants in group T2 had 0.16 ± 0.06 mm mesially and 0.20 ± 0.06 mm distally. C group implants lost 0.17 ± 0.05 mm mesially and 0.18 ± 0.03 mm distally. Differences between T1/T2, and T1/C were statistically significant (P = 0.000) both mesially and distally, while between T2 and C was not significant mesially (P = 0.861) and distally (P = 0.827). After 1-year follow-up implants in group T1 had 1.22 ± 0.08 mm bone loss mesially and 1.14 ± 0.07 mm distally. Implants in group T2 had 0.24 ± 0.06 mm mesially and 0.19 ± 0.06 mm distally. C group implants lost 0.22 ± 0.06 mm mesially and 0.20 ± 0.06 mm distally. Differences between T1/T2, and T1/C were statistically significant (P = 0.000) both mesially and distally, while between T2 and C was not significant mesially (P = 0.909) and distally (P = 0.312).
Significantly less bone loss can occur around bone-level implants placed in naturally thick mucosal tissues, in comparison with thin biotype. Augmentation of thin soft tissues with allogenic membrane during implant placement could be way to reduce crestal bone loss.
Background:
The clinical outcomes of implants placed using the flapless approach have not yet been systematically investigated. Hence, the present systematic review and meta-analysis aims to study the effect of the flapless technique on implant survival rates (SRs) and marginal bone levels (MBLs) compared with the conventional flap approach.
Methods:
An electronic search of five databases (from 1990 to March 2013), including PubMed, Ovid (MEDLINE), EMBASE, Web of Science, and Cochrane Central, and a hand search of peer-reviewed journals for relevant articles were performed. Human clinical trials with data on comparison of SR and changes in MBL between the flapless and conventional flap procedures, with at least five implants in each study group and a follow-up period of at least 6 months, were included.
Results:
Twelve studies, including seven randomized controlled trials (RCTs), one cohort study, one pilot study, and three retrospective case-controlled trials (CCTs), were included. The SR of each study was recorded, weighted mean difference (WMD) and confidence interval (CI) were calculated, and meta-analyses were performed for changes in MBL. The average SR is 97.0% (range, 90% to 100%) for the flapless procedure and 98.6% (range, 91.67% to 100%) for the flap procedure. Meta-analysis for the comparison of SR among selected studies presented a similar outcome (risk ratio = 0.99, 95% CI = 0.97 to 1.01, P = 0.30) for both interventions. Mean differences of MBL were retrieved from five RCTs and two retrospective CCTs and subsequently pooled into meta-analyses; however, none of the comparisons showed statistical significance. For RCTs, the WMD was 0.07, with a 95% CI of -0.05 to 0.20 (P = 0.26). For retrospective CCTs, the WMD was 0.23, with a 95% CI of -0.58 to 1.05 (P = 0.58). For the combined analysis, the WMD was 0.03, with a 95% CI of -0.11 to 0.18 (P = 0.67). The comparison of SR presented a low to moderate heterogeneity, but MBL presented a considerable heterogeneity among studies.
Conclusion:
This systematic review revealed that the SRs and radiographic marginal bone loss of flapless intervention were comparable with the flap surgery approach.
It has been shown that thin mucosal tissues may be an important factor in crestal bone loss etiology. Thus, it is possible that mucosal tissue thickening with allogenic membrane might reduce crestal bone loss.
The purpose of this study was to evaluate how implants with traditional connection maintain crestal bone level after soft tissue thickening with allogenic membrane.
One hundred three patients received 103 internal hex implants of 4.6 mm diameter with regular connection. According to gingiva thickness, patients were assigned into A (thin tissues, n = 34), B (thin, thickened with allogenic membrane, n = 35), and C group (thick tissues, n = 34). Groups A and C had one-stage approach, and in group B, implants were placed in two stages. Radiographic examination was performed after implant placement, 2 months after healing, after restoration, and after 1-year follow-up. Crestal bone loss was calculated medially and distally. Significance was set to 0.05.
After 1-year follow-up, implants in group A had 1.65 ± 0.08-mm bone loss mesially and 1.81 ± 0.06 mm distally. Group B had 0.31 ± 0.05 mm mesially and 0.34 ± 0.05 mm distally. C group implants experienced bone loss of 0.44 ± 0.06 mm mesially and 0.47 ± 0.07 mm distally. Differences between A and B, and A and C were significant (p = .000) both mesially and distally, whereas differences between B and C were not significant mesially (p = .166) and distally (p = .255).
It can be concluded that thin mucosal tissues may cause early crestal bone loss, but their thickening with allogenic membrane may significantly reduce bone resorption. Implants in naturally thick soft tissues experienced minor bone remodeling.
The aim of this study was to evaluate 3.5 years-cumulative survival rate of implants placed on augmented sinus using Osteon, a bone graft material, and to assess the height of the grafted material through radiographic evaluation.
Twenty patients were treated with maxillary sinus augmentation and 45 implant fixtures were installed simultaneously or after 6 months healing period. The height of the augmented sinus and the loss of marginal bone were measured by panoramic and intraoral radiographs immediately after augmentation and up to 42 months (mean, 19.4 months) subsequently. Changes in the height of the sinus graft material were calculated radiographically.
The cumulative survival rate was 95.56% in all 45 implants. Additionally, normal healing process without any complication was observed in all patients. The original sinus height was mean 4.3 mm and the augmented sinus height was mean 13.4 mm after the surgery. The mean marginal bone loss till 42 months was 0.52±0.56 mm. The reduced height of Osteon was 0.83±0.38 mm and it did not show significant correlation with the follow up periods (P=0.102). There were no statistically significant differences in reduced height of Osteon according to the simultaneous/delayed implantation (P=0.299) and particle size of Osteon (P=0.644).
It can be suggested that Osteon may have predictable result when it was used as a grafting material for sinus floor augmentation.
The aim of the present study is to evaluate the use of anorganic bovine bone (ABB) associated with a collagen membrane (CM) for a sinus graft by means of clinical, histologic, and radiographic parameters in cases with bone availability < or =7 mm. A preliminary evaluation consisted of a clinical examination, computed tomography (CT), and a panoramic x-ray.
Ninety-two patients requiring bilateral sinus grafts and 222 requiring unilateral procedures (total: 406 sinuses) participated in this study. A total of 1,025 implants were placed in the grafted sinuses. A total of 118 implants were placed simultaneously with the sinus graft (one stage), and 907 implants were placed in a subsequent surgery (two stages), 6 to 12 months after the graft was performed. In seven cases, a biopsy was harvested for histomorphometric analysis. Recall appointments were scheduled every 6 months, and panoramic and periapical x-rays were required every year for 3 years.
Among 1,025 implants, 19 were lost (survival rate: 98.1%). The difference in survival rates for implants placed in native bone < or =3 mm (98.1%), >3 to < or =5 mm (98.6%), and >5 to < or =7 mm (97.0%) was not statistically significant (P = 0.3408). The survival rates for implants with rough and machined surfaces (98.6% and 97.0%, respectively) were not statistically significant (P = 0.0840). The histomorphometric analysis showed new bone formation (39.0% +/- 12%), marrow space (52.9% +/- 9.3%), and residual ABB (8% +/- 2.7%).
Our results indicated that 1,025 implants placed in sinuses grafted exclusively with ABB combined with CM led to an excellent and predictable survival rate of 98.1%.
Anorganic bovine bone (ABB) has been shown to have osteoconductive properties and no inflammatory or adverse responses as grafting materials used in sinus augmentation procedures. Despite these successful results, histologic data in humans over the long-term period are scarce. The purpose of this study was to analyze the histomorphometric data 9 years after surgery in a case of maxillary sinus augmentation using ABB.
The histologic evaluation was performed in five different thin sections of the specimen, comparing histomorphometric measures for newly formed bone, marrow spaces, biomaterial particles remnants, and number of osteocytes embedded in both trabecular bone and bone tissue near the ABB. The investigation was carried out by means of scanning electron microscopy and brightfield and circularly polarized light microscopy.
We observed a mean amount of newly formed bone of 46.0% +/- 4.67%, ABB remnants of 16.0% +/- 5.89%, and marrow spaces of 38.0% +/- 8.93%. The osteocyte index was 4.43 for bone around ABB and 3.27 in the trabecular bone at a distance from the particles.
After 9 years, the tissue pattern appeared composed by residual ABB particles in close contact to the newly formed bone. The bone mineralized matrix around the ABB had collagen fibers randomly oriented and more osteocytes embedded. The results demonstrate both a high level of osteoconductivity and a "biomimetic" behavior over the long term.
Fourteen Swedish teams outside the University of Gothenburg, each with minimally three years' experience in the Nobelpharma osseointegrated implant participated in a retrospective multiclinic study. The total number of consecutively inserted implants at the 14 clinics was 8139. The outcome of every implant was reported and all implant failures, irrespective of when they occurred, were published. The success criteria included absence of implant mobility, absence of radiolucent zones on x-rays, and an annual bone loss after the first year of less than 0.2 mm. In the mandible 334 implants were followed for five to eight years, with only three failures, for a success rate of 99.1 %. In the maxilla 106 implants were followed for five to seven years, with a success rate of 84.9%. In irradiated and grafted mandibles, 56 implants were inserted and none was lost during a follow-up of up to five years. In the irradiated maxilla there were 16 implants inserted with three reported failures and in the grafted upper ja...
Insufficient bone volume is a common problem encountered in the rehabilitation of the edentulous posterior maxillae with implant-supported prostheses. Bone volume is limited by the presence of the maxillary sinus together with loss of alveolar bone height. Sinus lift procedures increase bone volume by augmenting the sinus cavity with autogenous bone or commercially available biomaterials, or both. This is an update of a Cochrane review first published in 2010.
To assess the beneficial or harmful effects of bone augmentation compared to no augmentation when undertaking a sinus lift procedure. Secondly, to compare the benefits and harms of different maxillary sinus lift techniques for dental implant rehabilitation.
We searched the Cochrane Oral Health Group's Trials Register (to 17 January 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 12), MEDLINE via OVID (1946 to 17 January 2014) and EMBASE via OVID (1980 to 17 January 2014). There were no language or date restrictions on the searches of the electronic databases.
Randomised controlled trials (RCTs) of different techniques and materials for augmenting the maxillary sinus for rehabilitation with dental implants that report the outcome of implant success or failure at least to four months after initial loading.
Screening of eligible studies, assessment of the risk of bias of the trials, and data extraction were conducted independently and in duplicate. Authors were contacted for any missing information. Results were expressed using fixed-effect models as there were either less than four studies or we used Peto odds ratios (ORs) for dichotomous data when there were zero cells in either the treatment or control or both arms and the number of trials was small. The statistical unit of the analysis was the patient.
Eighteen RCTs out of 64 potentially eligible study reports met the inclusion criteria. They compared undertaking a sinus lift with not doing so, and the use of different sinus lift techniques. There were 650 patients providing data for the outcomes evaluated. Five studies were assessed as low risk of bias, 11 were assessed as high risk of bias, and in two the risk was unclear. Sinus lift versus no sinus lift Four trials of moderate quality (three trials at low and one at high risk of bias) with 102 participants evaluated short implants (5 to 8.5 mm long) as an alternative to sinus lift in bone with residual height between 4 and 9 mm. One year after loading there was insufficient evidence to claim differences between the two procedures for prosthesis failure (OR (Peto) 0.37, 95% confidence interval (CI) 0.05 to 2.68; three trials) or implant failure (OR (Peto) 0.44, 95% CI 0.10 to 1.99; four trials). There was however an increase in complications at treated sites when undertaking the sinus lift (OR (Peto) 4.77, 95% CI 1.79 to 12.71, P value = 0.002; four trials). Different sinus lift techniques Fourteen trials with 548 participants compared different sinus lift techniques. Only three comparisons included more than one trial (two trials for each). These were bone graft versus no bone graft, autogenous bone versus bone substitute, bone graft with or without platelet-rich plasma (PRP). There was insufficient evidence to claim a benefit for any of these techniques for the primary outcomes of prosthesis and implant failure. For the other reported outcomes, in a single study at high risk of bias, only bone gain was greater for the bone graft site than the site without a graft six months after augmentation, however this was not significant at 18 or 30 months.The other comparisons with single studies were rotary versus piezosurgery to open a lateral sinus window, two different bone substitutes, use or not of a membrane to seal the lateral window, one- versus two-stage lateral sinus lift, two-stage granular bone versus one-stage autogenous bone blocks, and crestal versus lateral sinus lift; two trials compared three different crestal sinus lifting techniques: rotatory versus hand malleting (patients preferred rotatory instruments over hand malleting) and hand versus electric malleting. There was no evidence of a benefit for any sinus lift procedure compared to any other for the primary outcomes prosthesis or implant failure.
There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 8.5 mm) in reducing prosthesis or implant failure up to one year after loading. However, there are more complications at sites treated with sinus lift procedures. Many trials compared different sinus lift procedures and none of these indicated that one procedure reduced prosthetic or implant failures when compared to the other. Based on low quality evidence, patients may prefer rotary instruments over hand malleting for crestal sinus lift.
Purpose:
The aim of this study was to investigate the influence of interimplant distance of internal connection implants with platform switching on crestal bone loss using radiographic evaluation.
Materials and methods:
The present study included patients missing two consecutive teeth in the posterior quadrant and receiving internal connection implants. Digital periapical radiographs were taken at the time of superstructure connection and at the time of more than 1 year of loading. Bone level change was measured on the modified image using a digital subtraction program. The crestal bone loss between implants and the horizontal and vertical loss of peri-implant marginal bone were evaluated, and the influence of interimplant distance on crestal bone loss was analyzed at α = .05.
Results:
A total of 10 pairs of implants having ≤ 3 mm of interimplant distance was included in this study (group 1). The other 15 pairs of implants having > 3 mm of interimplant distance were selected as a control group (group 2). After the mean 19.3 months of observation, the mean crestal bone loss between implants was -0.26 ± 0.14 mm in group 1 and -0.23 ± 0.29 mm in group 2 (P > .05). There was no significant difference between the interimplant distance and the crestal bone loss according to the regression analysis (P = .765). The mean horizontal and vertical marginal bone loss was -0.18 ± 0.25 mm and -0.15 ± 0.18 mm, respectively, in group 1 and -0.17 ± 0.31 mm and -0.11 ± 0.33 mm, respectively, in group 2. There were no significant differences between outside and inside bone loss of implants in horizontal and vertical change (P > .05).
Conclusions:
Within the limitations of the short-term study, the interimplant distance did not affect the crestal bone loss with internal connection implants with platform switching. The horizontal and vertical marginal bone loss was found to be too small to result in overlapping loss of the interimplant crestal bone.
The aim of this study was to analyze marginal bone loss (MBL) rates around implants to establish the difference between physiological bone loss and bone loss due to peri-implantitis.
Five hundred and eight implants were placed in the posterior maxilla in 208 patients. Data were gathered on age, gender, bone substratum (grafted or pristine), prosthetic connection, smoking and alcohol habits, and previous periodontitis. MBL was radiographically analyzed in three time frames (5 months post-surgery and at 6 and 18 months post-loading). Nonparametric receiver operating curve (ROC) analysis and mixed linear model analysis were used to determine whether implants could be classified as high or low bone loser type (BLT) and to establish the influence of this factor on MBL rates.
Marginal bone loss rates were significantly affected by BLT, connection type, bone substratum, and smoking. Bone loss rates at 18 months were associated with initial bone loss rates: 96% of implants with an MBL of >2 mm at 18 months had lost 0.44 mm or more at 6 months post-loading.
Implants with increased MBL rates at early stages (healing and immediate post-loading periods) are likely to reach MBL values that compromise their final outcome. Initial (healing, immediate post-loading) MBL rates around an implant of more than 0.44 mm/year are an indication of peri-implant bone loss progression.
The aim of this systematic review was to evaluate the outcomes of flapless surgery for implants placed using either free-hand or guided (with or without 3D navigation) surgical methods. Literature searches were conducted to collect information on survival rate, marginal bone loss, and complications of implants placed with such surgeries. Twenty-three clinical studies with a minimum of 1year follow-up time were finally selected and reviewed. Free-hand flapless surgery demonstrated survival rates between 98.3% and 100% and mean marginal bone loss between 0.09 and 1.40mm at 1-4 years after implant insertion. Flapless guided surgery without 3D navigation showed survival rates between 91% and 100% and mean marginal bone loss of 0.89mm after an observation period of 2-10 years. The survival rates and mean marginal bone loss for implants placed with 3D guided flapless surgery were 89-100% and 0.55-2.6mm, respectively, at 1-5 years after implant insertion. In 17 studies, surgical and technical complications such as bone perforation, fracture of the surgical guide, and fracture of the provisional prosthesis were reported. However, none of the identified methods has demonstrated advantages over the others. Further studies are needed to confirm the predictability and effectiveness of 3D navigation techniques.
This study evaluates whether or not, among other factors, membrane-coverage of antrostomy defects improves implant survival in sinus augmentation procedures.
We performed a two-arm and split-mouth randomized controlled clinical trial on 104 and 5 patients respectively. In the two-arm study, antrostomy defects were membrane-covered in 66 procedures and uncovered in 69, before placing a total of 265 implants that were followed up for 1 year. In the split-mouth study, following bilateral sinus augmentation, antrostomy defects were membrane-covered on one side and left uncovered on the contra-lateral. Bone biopsies from each sinus were histologically analysed 6 months later.
In the two-arm study, implant survival rates were similar (p = 0.08) in the membrane-covered (96.1%) and uncovered (94.2%) groups. In the split-mouth study, bone augmentation was similar in both groups (p = 0.52). Delayed implant placement (p = 0.04), thick Schneider's membrane (≥2 mm) (p < 0.01), treatment for hypertension (p = 0.04) and non-smoking (p = 0.01) seemed to be associated with lower risk of implant failure.
Implant survival in sinus lifting procedures could be influenced significantly by timing of implant placement, Schneider's membrane thickness, antihypertensive treatment and smoking habits, but not by antrostomy membrane coverage.
To identify risk factors for failure and bone loss of implants in a large study sample on the basis of multivariate analyses.
Patient files of all patients referred for implant treatment from November 2004 to December 2007 were scrutinized, and information on implant- and patient-related factors was collected. The study sample in this retrospective cohort study consisted of both partially dentate and fully edentulous patients referred for various indications. The only inclusion criterion was a follow-up of at least 2 years. Implant survival and bone loss were assessed by an external investigator (SV) comparing digital periapical radiographs taken during recall visits with the postoperative ones. Univariate and multivariate tests were adopted to identify possible risk indicators for implant failure and peri-implant bone loss.
Twenty-one of 1,320 (1.6%) implants were lost in 19 of 376 (5.1%) patients (210 female, 166 male; mean age 56, range 17-82) after a mean follow-up of 32 months (range 24-62). Based on multivariate analysis, only smoking (p = .001) and recall compliance (p = .010) had a significant influence on implant failure, with smokers more prone to failure. The overall mean bone loss was 0.36 mm (SD 0.68, range 0.00-7.10). Smoking (p = .001) and jaw of treatment (p = .001) affected peri-implant bone loss. More peri-implant bone loss was observed in smokers and in the maxilla. A clear discrepancy was found between univariate and multivariate analysis with regard to identification of risk factors.
Multivariate analysis demonstrated that implant-related factors did not affect the clinical outcome, but smoking was identified as a predictor for implant failure. Predictors for peri-implant bone loss were smoking and jaw of treatment.
Deproteinized bovine bone mineral (DBBM) is one of the best-documented bone substitute materials for sinus floor elevation (SFE).
DBBM is available in two particle sizes. Large particles are believed to facilitate improved neoangiogenesis compared with small ones. However, their impact on the rate of new bone formation, osteoconduction, and DBBM degradation has never been reported. In addition, the implant stability quotient (ISQ) has never been correlated to bone-to-implant contact (BIC) after SFE with simultaneous implant placement.
Bilateral SFE with simultaneous implant placement was performed in 10 Göttingen minipigs. The two sides were randomized to receive large or small particle size DBBM. Two groups of 5 minipigs healed for 6 and 12 weeks, respectively. ISQ was recorded immediately after implant placement and at sacrifice. Qualitative histological differences were described and bone formation, DBBM degradation, BIC and bone-to-DBBM contact (osteoconduction) were quantified histomorphometrically.
DBBM particle size had no qualitative or quantitative impact on the amount of newly formed bone, DBBM degradation, or BIC for either of the healing periods (p > 0.05). Small-size DBBM showed higher osteoconduction after 6 weeks than large-size DBBM (p < 0.001). After 12 weeks this difference was compensated. There was no significant correlation between BIC and ISQ.
Small and large particle sizes were equally predictable when DBBM was used for SFE with simultaneous implant placement.
PurposeThe purpose of this study is to evaluate the vertical and horizontal graft bone resorption (GR) in grafted maxillary sinuses and the marginal bone loss (MBL) around implants placed in the sinuses with different prosthetic connections and to determine the effect of other clinical factors on these tissue responses at 6 and 18 months postloading.Material and MethodA total of 254 implants were placed in 150 grafted maxillary sinuses of 101 patients (51.5% female) with mean age of 52.2 years (range, 32–82 years). GR and MBL measurements were made in implants placed with two different prosthetic connections (internal and external) at 6 and 18 months postloading. The complex samples general linear model was used to analyze the influence of patient age, gender, smoking habit, history of periodontal disease, implantation timing (simultaneous vs deferred), and prosthetic abutment length on radiographic GR and MBL values.ResultsAt 18 months postloading, the MBL ranged from 0 mm to 5.89 mm; less than 1 mm was lost around 49.0% (mesial) and 44.3% (distal) of the implants, while no bone was lost around 32.9% (mesial) and 26.7% (distal). The GR was significantly affected by smoking, remnant alveolar bone height, graft length, graft height, gender, and age, and it significantly decreased over time. The MBL was influenced by the type of connection, implantation timing, and prosthetic abutment length. The MBL was greater with longer postloading interval and higher patient age and in smokers.Conclusion
Resorption of grafts that combine autogenous cortical bone with anorganic bovine bone is dependent on the anatomic features of the sinus and is not affected by the time elapsed after the first 6 months. The MBL in implants placed in these grafted areas is time dependent and mainly related to potentially modifiable clinical decisions and patient habits.
Objectives:
To assess differences in marginal bone loss around implants placed in maxillary pristine bone and implants placed following maxillary sinus augmentation over a period of 3 years after functional loading.
Material and methods:
Two cohorts of subjects (Group 1: Subjects who received sinus augmentation with simultaneous implant placement; Group 2: Subjects who underwent conventional implant placement in posterior maxillary pristine bone) were included in this retrospective study. Radiographic marginal bone loss was measured around one implant per patient on digitized panoramic radiographs that were obtained at the time of prosthesis delivery (baseline) and 12, 24, and 36 months later. The influence of age, gender, smoking habits, history of periodontal disease, and type of prosthetic connection (internal or external) on marginal bone loss was analyzed in function of the type of osseous support (previously grafted or pristine).
Results:
A total of 105 subjects were included in this study. Cumulative radiographic marginal bone loss ranged from 0 mm to 3.9 mm after 36 months of functional loading. There were statistically significant differences in marginal bone loss between implants placed in grafted and pristine bone at the 12-month assessment, but not in the subsequent progression rate. External prosthetic connection, smoking, and history of periodontitis negatively influenced peri-implant bone maintenance, regardless of the type of osseous substrate.
Conclusions:
Implants placed in sites that received maxillary sinus augmentation exhibited more marginal bone loss than implants placed in pristine bone, although marginal bone loss mainly occurred during the first 12 months after functional loading. Implants with external implant connection were strongly associated with increased marginal bone loss overtime.
Context:
The maxillary sinus elevation procedure has become an important pre-prosthetic surgical procedure for the creation of bone volume in the edentulous posterior maxilla for the placement of dental implants. Research and clinical experience over the past 30 years has increased the predictability of this procedure as well as reduced patient morbidity.
Evidence acquisition:
Data on grafting materials and implant survival rates comes from 10 published evidence-based reviews that include all relevant published data from 1980 to 2012. Supporting clinical material comes from the experience of the authors.
Evidence synthesis:
The evidence-based reviews report and compare the implant survival rates utilizing various grafting materials, implant surfaces, and the use or non-use of barrier membranes over the lateral window. Clinical studies report on complication rates utilizing piezoelectric surgery and compare them to complication rates with rotary instrumentation.
Conclusions:
The conclusions of all the evidence-based reviews indicate that the utilization of bone replacement grafts, rough-surfaced implants, and barrier membranes result in the most positive outcomes when considering implant survival. Further, the utilization of piezoelectric surgery, rather than rotary diamond burs, for lateral window preparation and membrane separation leads to a dramatic reduction in the occurrence of the intraoperative complications of bleeding and membrane perforation.
Aim:
To determine the influence of different local and systemic factors on histologic, histomorphometric, and radiographic outcomes after maxillary sinus augmentation.
Materials and methods:
Fifty-two sinus augmentation procedures were performed. Grafting material consisted of a mixture of anorganic bovine bone (ABB) and autogenous bone. After 6 months, bone core biopsies were harvested from implant sites for histologic and histomorphometric analyses. Data regarding age, gender, type of edentulism, alcohol consumption, smoking habits, and history of periodontal disease were recorded and statistically analyzed.
Results:
Histomorphometric analyses revealed the presence of 35.75% ± 16.42% of vital bone, 40.56% ± 16.23% of nonmineralized tissue, and 23.69% ± 18.23% of residual ABB particles. Radiographic vertical bone resorption inversely correlated with residual ABB. A significant difference in bone resorption patterns was observed for completely edentulous patients and for those with a history of periodontitis. Tobacco and alcohol negatively influenced vital bone formation after sinus augmentation. Implant and prostheses survival after 2 years of functional loading was not directly affected by patient's individual habits.
Conclusion:
Certain patient-related variables such as history of periodontitis, type of edentulism, or smoking/drinking habits play an important role in bone graft maturation after maxillary sinus floor elevation.
To systematically review the literature to compare implant survival (IS) and marginal bone loss (MBL) around platform-switched (PS) versus conventionally restored platform-matching dental implants.
Randomized, controlled human clinical trials (RCTs) comparing IS and MBL in PS and conventionally restored implants, with 12 months of follow-up and at least 10 implants were identified through electronic and manual search. Review and meta-analysis were performed according to PRISMA statement. Risk ratio (RR) for implant failure and mean difference (MD) for MBL, with 95% confidence interval (CI) were calculated. Sources of heterogeneity among studies were also investigated by subgroup analyses.
Ten RCTs involving 435 subjects and 993 implants contributed to this review. The cumulative estimated implant success rate revealed no statistically significant difference between the two groups. At a patient level, a smaller amount of MBL [MD -0.55 mm, 95%CI (-0.86; -0.24), p = 0.0006] was noted around PS implants. Subgroup analyses performed at implant level suggested less MBL when platform switching showed a larger mismatching.
PS technique appeared to be useful in limiting bone resorption. Nevertheless, these data should be interpreted cautiously as significant heterogeneity and possible publication bias were noted. Further research is needed to identify the factors most associated with successful outcomes.
This article reviews the literature on the outcome of flapless surgery for dental implants in the posterior maxilla. The literature search was carried out in using the keywords: flapless, dental implants and maxilla. A hand search and Medline search were carried out on studies published between 1971 and 2011. The authors included research involving a minimum of 15 dental implants with a follow-up period of 1 year, an outcome measurement of implant survival, but excluded studies involving multiple simultaneous interventions, and studies with missing data. The Cochrane approach for cohort studies and Oxford Centre for Evidence-Based Medicine were applied. Of the 56 published papers selected, 14 papers on the flapless technique showed high overall implant survival rates. The prospective studies yielded 97.01% (95% CI: 90.72-99.0) while retrospective studies or case series illustrated 95.08% (95% CI: 91.0-97.93) survival. The average of intraoperative complications was 6.55% using the flapless procedure. The limited data obtained showed that flapless surgery in posterior maxilla areas could be a viable and predictable treatment method for implant placement. Flapless surgery tends to be more applicable in this area of the mouth. Further long-term clinical controlled studies are needed.
Aim : To elucidate the influence of initial soft tissue thickness on peri-implant bone remodeling. The research hypothesis was that implants installed in patients or at sites with thin mucosal tissues would show increased peri-implant bone loss.
Material and Methods : 79 edentulous patients were consecutively treated with two non-splinted implants supporting an overdenture in the mandible. During recall-visits, peri-implant health was determined by means of probing pocket depth and the modified plaque/bleeding index. Digital peri-apical radiographs were taken from individual implants. Bone level changes were measured from a reference point (lower border of the smooth implant collar) to the marginal bone-to-implant contact level. The linear mixed-effect model analysis was adopted to analyze the influence of clinical parameters and transmucosal abutment height on peri-implant bone loss.
Results : 67 patients attended the 1-year and 66 the 2-year recall-visit. Mean bone level changes were 0.89 mm (SD 0.62) and 0.90 mm (SD 0.66), plaque scores 0.82 (SD 0.94) and 0.87 (SD 0.92), bleeding scores 0.46 (SD 0.68) and 0.56 (SD 0.72) and PPD 1.65 mm (SD 0.60) and 1.78 mm (SD 0.59) after 1 year and 2 years respectively. The linear mixed-effect model revealed increasing bone level changes with decreasing abutment heights. Peri-implant bone level changes were significantly higher for implants with abutments of = 4 mm-abutments (bone level changes set to zero as reference value) both after 1 year and 2 years and bone level changes were significantly influenced by probing pocket depth (p < .01, p < .01), but not by plaque (p = .31, p = .09) and bleeding scores (p = .30, p = .40).
Conclusion : The present study suggests that implants with lower abutments, reflecting the initial gingival thickness, lose more peri-implant bone, possibly by a re-establishment of the biological width.
Purpose This study evaluated 17 edentulous cadavers for bone quantity and quality of the alveolar process of the maxilla for the purpose of dental implant placement.
Materials and Methods The maxillary arch was divided into four anatomically defined regions for measurements of bone quantity. Bone quality was assessed histologically and described by trabecular bone patterns and tissue composition.
Results Average bone height with a minimum thickness of 4 mm was as follows: region 1, 12.1 ± 4.9 mm; region 2, 14.1 ± 7.2 mm; region 3, 6.1 ± 2.8 mm; and region 4, 8.5 ± 2.2 mm. Histological evaluation showed increased trabeculation and thicker cortex in the maxillary anterior area, regions 1 and 2. Region 3, the floor of the maxillary sinus area, had the least amount of bone; however, the quality of bone was superior to that of region 4, the maxillary tuberosity area. Trabecular distance or marrow spaces ranged from 40 μm to 2 mm with larger spaces associated with the posterior maxilla.
Conclusions Maxillary tuberosity is the least desirable site for the placement of implants in the maxilla. The area corresponding to the first and second molars had the least bone thickness. All measures of bone preservation need to be considered, especially in this area.
Objectives:
The objective of this study was to compare the placement of flapped vs. flapless dental implants utilizing clinical, radiographic, microbiological, and immunological parameters.
Material and methods:
A total of 20 patients received 30 dental implants following a one-stage protocol. The patients were randomly assigned into two study groups: control group with 15 flapped implants and test group with 15 flapless implants. Follow-up examinations were carried out after 1, 2, 6, and 12 weeks. Clinical recordings, sulcular fluid sampling, microbiological analysis, and digital subtraction radiography were utilized to compare the two surgical approaches.
Results:
Peri-implant sulcus depth was significantly greater in flapped implants at both 6 and 12 postsurgical weeks (P < 0.001). Flapped implants showed crestal bone loss (0.29 ± 0.06 mm), whereas no bone resorption was detected around flapless implants. Matrix metalloproteinase-8 values were higher to a statistically significant level in the control group at 1 (P = 0.003) and 6 weeks (P = 0.007) after placement. In the test group, the presence of Porphyromonas gingivalis was significantly higher at the 2nd postoperative week (P = 0.005), whereas the counts of Tannerella forsythia were significantly elevated at the 1st (P = 0.005), 2nd (P = 0.001), and 12th (P = 0.002) postoperative weeks, possibly indicating an earlier formation and maturation of the peri-implant sulcus. Patients reported more pain after flapped implant placement.
Conclusions:
Flapless implant placement yielded improved clinical, radiographic, and immunological outcomes compared with flapped implantation. In addition, patients seem to better withstand flapless implant placement.
The aim of the present cross-sectional retrospective study was to determine bone loss in a sample of subjects restored with implant-supported prostheses and the prevalence and severity of peri-implantitis in a sub-sample.
A total of 139 patients who had attended a follow-up visit in 2007 were considered for inclusion. Subjects with implants that had been in function for less than 3 years or had poor quality radiographs were excluded. The final study population comprised 133 subjects with a total of 407 implants. Radiographic measurements identified subjects who had ≥1 implant site exhibiting marginal bone loss of >0.5 mm; 40 subjects met this criterion and were recalled for a clinical examination. Of the 40 subjects that were recalled for the clinical examination, 30 attended. The following parameters were recorded at mesial, distal, buccal, and lingual/palatal aspects of all implants: oral hygiene standard (plaque), bleeding on probing, probing pocket depth (PPD).
The mean interval between the baseline (1-year post-loading) and the follow-up radiographs was 4.8 ± 2.3 years. In the total subject sample (133 subjects and 407 implants), the mean amount of marginal bone loss that had occurred was 0.2 ± 1.2 mm. Ninety-three subjects with 246 implant sites exhibited no bone level alteration (group A), whereas 40 subjects with 161 implant sites (group B) displayed marginal bone loss of >0.5 mm at ≥1 implant (loser site). Sixty-eight implant sites in group B exhibited bone loss of >0.5 mm. However, only 20% of subjects and 11% of sites had lost >1 mm marginal bone, and 8% of subjects and 4% of sites had lost >2 mm bone. The total amount of bone loss that had occurred in group B was (i) 0.88 ± 1.5 mm and (ii) among the loser sites 2.1 ± 1.4 mm. Thirty subjects from group B were exposed to a clinical examination; out of 37 sites with bone loss >0.5 mm in this subgroup, 29 sites had a PPD value of ≥4 mm.
Marginal bone loss (>0.5 mm) at implants was observed in 30% of subjects and 16% of implant sites. More advanced loss of marginal bone occurred in much fewer subjects and sites. Sites with marginal bone loss was in the sub-sample characterized by bleeding on probing, but only occasionally with deep (≥6 mm) pockets.
Deproteinized bovine bone mineral (DBBM) and human freeze-dried bone allograft (FDBA) were compared in five patients undergoing bilateral maxillary sinus floor augmentation using DBBM on one side and FDBA on the contralateral side. After 9 months, core biopsy specimens were harvested. Mean newly formed bone values were 31.8% and 27.2% at FDBA and DBBM sites, respectively (P = .451); mean residual graft particle values were 21.5% and 24.2%, respectively (P = .619); and mean connective tissue values were 46.7% and 48.6%, respectively (P = .566). Within the limits of the present study, it is suggested that both graft materials are equally suitable for sinus augmentation.
The purpose of the present study was to compare the crestal bone loss around implants placed according to either a 1-stage or 2-stage implant installation procedure using a digital subtraction radiography technique.
In the present randomized clinical trial, screw-shaped tapered implants were inserted in the posterior mandible of patients needing fixed partial dentures. In each edentulous area, according to the randomization table, 1 implant was inserted using a 1-stage procedure (group 1) and 1 was placed using a 2-stage approach (group 2). The implants were temporized with the relined denture after 2 weeks. All implants were functionally loaded with fixed partial dentures after 3 months. Crestal bone loss (primary outcome variable) was measured using a digital subtraction radiography technique. Standardized radiovisiographs were taken after implant insertion, after fixed partial denture installation (3 months after surgery), and after 6 and 12 months of functional loading. The data were analyzed using the Wilcoxon signed ranks test (α = 0.05).
Eleven patients (mean age 46.9 years, 3 women and 8 men) were included in the study. A total of 34 implants were inserted, 17 using a 1-stage protocol and 17 using a 2-stage protocol. Three months after implant placement, the 2-stage implants showed significantly more crestal bone loss (0.65 ± 0.71 mm) than the 1-stage implants (0.41 ± 0.53 mm; P = .02). However, after 6 and 12 months of functional loading, both groups showed comparable changes in bone level (P > .05).
No differences were found between 1-stage and 2-stage implant placement in crestal bone loss after 1 year of functional loading.
The aim of this study was to evaluate short-term bone level and stability/mobility measurement alterations at platform switched (PS) and standard platform (SP) implants placed in mandibular premolar/molar regions using a single-stage protocol.
Sixteen PS and 16 SP implants restorated with fixed prosthesis were included. Standard implant dimensions were used for both implant systems. After 3 months of osseointegration, implants were connected to abutments and final restorations were performed. Marginal bone loss was measured by standardized periapical radiographs. Implant stability/mobility was determined by resonance frequency analysis (RFA) and mobility measuring (MM) device values. Peri-implant parameters were evaluated with clinical periodontal indices and all parameters were assessed at baseline, 1, 3, and 6 months after the surgery.
After 6 months, all implants showed uneventful healing. Radiographic evaluation showed a mean bone loss of 0.72 mm for PS and 0.56 mm for SP implants, and there were no significant differences between implant types. At 6 months, mean implant stability quotient (ISQ) values were 73.38 and 77 for PS and SP implants, respectively. Mean MM values were -4.75 for PS and -6.38 for SP implants. Mean MM values were lower for SP implants compared to PS implants at all time points. No significant differences were detected between implant types according to clinical peri-implant parameters.
The micro-gap at crestal level which immediately exposed to the oral cavity in non-submerged two part implants seems to have adverse influence on the marginal bone level.
Objective: The purpose of the present study was to histologically and histomorphometrically evaluate the long-term tissue response to deproteinized bovine bone (DPBB) particles used in association with autogenous bone and to compare particle size after 6 months and 11 years, in the same patients, in order to determine possible resorption.
Material and methods: Twenty consecutive patients (14 women and six men) with a mean age of 62 years (range 48–69 years) with severe atrophy of the posterior maxilla were included in this study. Thirty maxillary sinuses with <5 mm subantral alveolar bone were augmented with a mixture of 80% DPBB and 20% autogenous bone. Eleven years (mean 11.5 years) after augmentation, biopsies were taken from the grafted areas of the 11 patients who volunteered to participate in this new surgical intervention. The following histomorphometrical measurements were performed in these specimens: total bone area in percentage, total area of the DPBB, total area of marrow space, the degree of DPBB–bone contact (percentage of the total surface length for each particle), the length of all DPBB particles and the area of all DPBB particles. The length and the area of the particles were compared with samples harvested from the same patients at 6 months (nine samples) and pristine particles from the manufacturer.
Results: The biopsies consisted of 44.7±16.9% lamellar bone, 38±16.9% marrow space and 17.3±13.2% DPBB. The degree of DPBB to bone contact was 61.5±34%. There were no statistically significant differences between the length and area of the particles after 11 years compared with those measured after 6 months in the same patients or to pristine particles from the manufacturer.
Conclusion: DPBB particles were found to be well integrated in lamellar bone, after sinus floor augmentation in humans, showing no significant changes in particle size after 11 years.
To cite this article: Mordenfeld A, Hallman M, Johansson CB, Albrektsson T. Histological and histomorphometrical analyses of biopsies harvested 11 years after maxillary sinus floor augmentation with deproteinized bovine and autogenous bone. Clin. Oral Impl. Res. 21, 2010; 961–970. doi: 10.1111/j.1600-0501.2010.01939.x
Sufficient bone quantity is required for dental implant placement. Bone quantity towards the back of the upper jaw may be insufficient for dental implant placement because of the presence of the maxillary sinus, a natural cavity within the bone. This cavity may enlarge following tooth loss. There are a number of techniques, termed sinus lift procedures, aimed at increasing bone quantity prior to implant placement. These techniques utilise bone graft material, either the patients own bone (autogenous bone), a range of commercially available materials (biomaterials) or a combination of the two. Short implants (5 to 8 mm) may be as effective and cause fewer complications than longer implants placed using a more complex technique. It is not clear that bone graft materials are needed or whether some bone graft materials are more effective than others. Biomaterials might be used in place of autogenous bone. There is no evidence to suggest factors extracted from the patients blood improve bone healing.
Patients with severely atrophic posterior maxillae and increased pneumatization of the maxillary sinus may lack adequate bone height for endosteal implant placement. Grafting of the maxillary sinus via a sinus lift procedure augments the atrophic ridge and allows for such implants. Grafting with bone harvested from intraoral sites has distinct advantages over other previously described techniques.
Fourteen Swedish teams outside the University of Gothenburg, each with minimally three years' experience in the Nobelpharma osseointegrated implant participated in a retrospective multiclinic study. The total number of consecutively inserted implants at the 14 clinics was 8139. The outcome of every implant was reported and all implant failures, irrespective of when they occurred, were published. The success criteria included absence of implant mobility, absence of radiolucent zones on x-rays, and an annual bone loss after the first year of less than 0.2 mm. In the mandible 334 implants were followed for five to eight years, with only three failures, for a success rate of 99.1%. In the maxilla 106 implants were followed for five to seven years, with a success rate of 84.9%. In irradiated and grafted mandibles, 56 implants were inserted and none was lost during a follow-up of up to five years. In the irradiated maxilla there were 16 implants inserted with three reported failures and in the grafted upper jaw 71 implants were inserted with 12 failures. The proportions of mandibular and maxillary sleeping implants were 0.8 and 0.3%, of patient drop-out implants 0.3 and 0.6%, and of patient death implants 0.9 and 1.2%, respectively. It was concluded that the osseointegrated implant, if inserted according to the guidelines of Brånemark, results in a very high degree of clinical success, thereby meeting any published oral implant success criteria.
AND CONCLUSIONS
The root and sinus series of the Omnii system have been used extensively since 1981. They are very versatile in their ability to be used within edentulous areas of the maxilla. Their design attempts to maximize the use of the available bone, and placement techniques allow the manipulation of bone to form sockets in otherwise deficient areas of bone. The root implants can be used as free-standing implants or as multiple abutments. The sinus implant is always used as an abutment. It may be used in conjunction with other implants or with natural abutments. Maxillary implants are not loaded until a 6-month healing time has elapsed following placement. An understanding of the different qualities of bone found in the maxilla is important to achieving the successful loading of these implants. Different times are required to allow physiologic loading in different qualities of maxillary bone. Restorative treatment is normally done with fixed bridge work, and the use of any type of stress breaker attachments is not recommended.
The objective of the present study was to determine the dimension of the mucosal-implant attachment at sites with insufficient width of the ridge mucosa. 5 beagle dogs were used. Extractions of all mandibular premolars were performed and 3 months later, 3 fixtures of the Branemark System were installed in each side. Following 3 months of healing, abutment connection was carried out. On the right or left side of the mandible, abutment connection was performed according to the Branemark System manual (control side). On the contralateral side (test side), an incision not extending through the periosteum was made at the crest of the ridge. The soft tissue was dissected and a critical amount of connective tissue on the inside of the flap was excised. The periosteum was subsequently incised, abutment connection performed, and the trimmed flaps sutured. The sutures were removed after 10 days. After a 6-month period of plaque control, the animals were sacrificed, biopsies sampled and processed for light microscopy. The length of the junctional epithelium varied within a rather narrow range; 2.1 mm (control side) and 2.0 mm (test side). The height of the suprabony connective tissue in this model varied between 1.3+/-0.3 mm (test side) and 1.8+/-0.4 mm (control side). At sites where the ridge mucosa prior to abutment connection was made thin (< or = 2 mm), wound healing consistently included bone resorption. This implies that a certain minimum width of the periimplant mucosa may be required, and that bone resorption may take place to allow a stable soft tissue attachment to form.
In 1993 the Department of Implant Dentistry at New York University College of Dentistry began a long-term clinical, histologic, histomorphometric, and radiographic study of the sinus elevation procedure. One of the parameters under evaluation in this study is the effect of barrier membrane placement on the creation of vital bone in the grafted sinus cavity. This report presents a histologic and histomorphometric evaluation of healing with and without the placement of an expanded polytetrafluoroethylene (e-PTFE) barrier membrane over the lateral window at the time of sinus grafting. The data were collected from 12 patients who underwent bilateral sinus elevation surgery. In each of these 12 patients the same grafting material was used in both sinuses, making the presence or absence of an e-PTFE barrier membrane the only controlled variable. Under the conditions of this study, the results indicate that (1) placement of the barrier membrane tends to increase vital bone formation; (2) placement of a barrier membrane has a positive effect on implant survival; and (3) membrane placement should be considered for all sinus elevation procedures.
Based on a systematic review of the literature from 1986 to 2002, this study sought to determine the survival rate of root-form dental implants placed in the grafted maxillary sinus. Secondary goals were to determine the effects of graft material, implant surface characteristics, and simultaneous versus delayed placement on survival rate. A search of the main electronic databases was performed in addition to a hand search of the most relevant journals. All relevant articles were screened according to specific inclusion criteria. Selected papers were reviewed for data extraction. The search yielded 252 articles applicable to sinus grafts associated with implant treatment. Of these, 39 met the inclusion criteria for qualitative data analysis. Only 3 of the articles were randomized controlled trials. The overall implant survival rate for the 39 included studies was 91.49%. The database included 6,913 implants placed in 2,046 subjects with loaded follow-up time ranging from 12 to 75 months. Implant survival was 87.70% with grafts of 100% autogenous bone, 94.88% when combining autogenous bone with various bone substitutes, and 95.98% with bone grafts consisting of bone substitutes alone. The survival rate for implants having smooth and rough surfaces was 85.64% and 95.98%, respectively. Simultaneous and delayed procedures displayed similar survival rates of 92.17% and 92.93%, respectively. When implants are placed in grafted maxillary sinuses, the performance of rough implants is superior to that of smooth implants. Bone-substitute materials are as effective as autogenous bone when used alone or in combination with autogenous bone. Studies using a split-mouth design with one variable are needed to further validate the findings.
The aim of this study was to identify and measure postextraction maxillary sinus pneumatization using fixed reference lines on panoramic radiographs.
One hundred fifty-two panoramic radiographs, each of a different subject, were used to measure superoinferior differences of the sinus floor position in dentate sites in comparison with contralateral edentulous sites. Fifty-eight pairs of panoramic radiographs, each pair of the same subject, were used to measure superoinferior differences of the sinus floor position in the same site before and 6 to 67 months after extraction. All measurements were performed using an interorbital line and 2 zygomatic process lines as reference lines. Statistical correlations between the amount of expansion of the sinus and the root classification, projection length, duration after extraction, type, and number of the extracted teeth were examined.
Postextraction expansion of the sinus in an inferior direction occurred in both comparisons (2.18 +/- 2.89 mm for dentate versus contralateral sites and 1.83 +/- 2.46 mm for the same site pre- and postextraction). A considerable amount of expansion occurred after the extraction of teeth surrounded by a superiorly curving sinus floor (5.27 +/- 1.59 mm). A larger expansion was also measured after second molar extractions in comparison to first molars and in cases of extractions of 2 or more adjacent posterior teeth.
Posterior maxillary tooth extraction caused an inferior expansion of the maxillary sinus in relation to fixed anatomic landmarks, thus proving the pneumatization phenomenon after tooth loss.
Sinus pneumatization was identified after extraction of maxillary posterior teeth. The expansion of the sinus was larger following extraction of teeth enveloped by a superiorly curving sinus floor, extraction of several adjacent posterior teeth, and extraction of second molars (in comparison with first molars). If dental implant placement is planned in these cases, immediate implantation and/or immediate bone grafting should be considered to assist in preserving the 3-dimensional bony architecture of the sinus floor at the extraction site.
Marginal Bone Loss in Implants Placed in Grafted Maxillary Sinus
- P Galindo-Moreno
- A Fernández-Jiménez
- O Valle
Galindo-Moreno P, Fernández-Jiménez A, O'Valle F et al. Marginal Bone Loss in Implants Placed
in Grafted Maxillary Sinus. Clin Implant Dent Relat Res 2015;17:373-383.
Journal of Periodontology; Copyright 2016
DOI: 10.1902/jop.2016.150514