Post-treatment stability after 5 years of retention with vacuum-formed and bonded retainers-a randomized controlled trial.

BACKGROUND: Retention after orthodontic treatment is still a challenge and more evidence about post-treatment stability and patients' perceptions of different retention strategies is needed. OBJECTIVES: This trial compares removable vacuum-formed retainers (VFR) with bonded cuspid-to-cuspid retainers (CTC) after 5 years of retention. TRIAL DESIGN: A single centre two-arm parallel-group randomized controlled trial. METHODS: This trial included 104 adolescent patients, randomized into two groups (computer-generated), using sequentially numbered, opaque, and sealed envelopes. All patients were treated with fixed appliances in both jaws with and without tooth extractions. Patients in the intervention group received a VFR in the mandible (n = 52), and patients in the active comparator group received a CTC (n = 52). Both groups had a VFR in the maxilla. Dental casts at debond (T1), after 6 months (T2), after 18 months (T3), and after 5 years (T4) were digitized and analysed regarding Little's Irregularity Index (LII), overbite, overjet, arch length, and intercanine and intermolar width. The patients completed questionnaires at T1, T2, T3, and T4. RESULTS: Post-treatment changes between T1 and T4 in both jaws were overall small. In the maxilla, LII increased significantly (median difference: 0.3 mm), equally in both groups. In the mandible, LII increased significantly in the group VFR/VFR (median difference: 0.6 mm) compared to group VFR/CTC (median difference: 0.1 mm). In both groups, overjet was stable, overbite increased, and arch lengths decreased continuously. Intercanine widths and intermolar width in the mandible remained stable, but intermolar width in the maxilla decreased significantly. No differences were found between groups. Regardless of retention strategy, patients were very satisfied with the treatment outcome and their retention appliances after 5 years. LIMITATIONS: It was not possible to perform blinded assessments of digital models at follow-up. CONCLUSIONS: Post-treatment changes in both jaws were small. Anterior alignment in the mandible was more stable with a bonded CTC retainer compared to a removable VFR after 5 years of retention. Patients were equally satisfied with fixed and removable retention appliances. TRIAL REGISTRATION: ClinicalTrials.gov (NCT03070444).

Vacuum-formed retainers and bonded retainers for dental stabilization-a randomized controlled trial. Part II: patients' perceptions 6 and 18 months after orthodontic treatment.

OBJECTIVE: To compare removable vacuum-formed Essix C retainers with bonded cuspid-to-cuspid retainers (CTCs) regarding patients' perceptions after debonding and 6 and 18 months of retention. TRIAL DESIGN: A single-centre two-arm parallel-group randomized controlled trial. METHODS: This trial included 104 adolescent patients, computer-generated randomized, with sequentially numbered, opaque and sealed envelopes, into two groups and stratified by gender. They were treated with fixed appliances with and without tooth extractions in both jaws and were ready for debond. Patients in the intervention arm received a vacuum-formed retainer (VFR) in the mandible (n = 52), and patients in the active comparator arm received a CTC (n = 52). Both groups had a VFR in the maxilla. Treatment outcome satisfaction, quality of care and attention, side-effects during the retention phase, and retainer acceptance and compliance were assessed with questionnaires at baseline (T1, 2 weeks after debond) and after 6 (T2) and 18 months (T3) of retention. Operator was blinded to group assignment during measurements. RESULTS: Ninety-five patients completed the questionnaires at all three time points. Patients were overall satisfied with treatment outcome, quality of care and attention, and how their retainers worked at all three time points, with no differences between groups. At T1 and T3, the VFR group reported significantly more pain and discomfort (T1: P = 0.005, T3: P < 0.0001) and soreness (T1: P = 0.001, T3: P = 0.011) in the mandible compared to the CTC group. The CTC group found it easier to get used to their retainers. After 18 months, 70.5 per cent in the VFR group and 73.9 per cent in the CTC group reported the recommended wear-time of the VFRs. Decreased wear-time was correlated to perceived pain and discomfort (rs = -0.421, P < 0.0001). LIMITATIONS: The results were limited by our retainer design and recommended wear regimen. CONCLUSIONS: Both groups reported high treatment outcome satisfaction and low levels of side-effects during the retention phase. Nevertheless, the VFR group reported more pain and discomfort at T1 and at T3. Self-reported compliance was the same in both groups. The VFR group was more concerned about relapse. TRIAL REGISTRATION: NCT03070444 (https://clinicaltrials.gov).

Histological and histomorphometrical outcome after lateral guided bone regeneration augmentation of the mandible with different ratios of deproteinized bovine bone mineral and autogenous bone. A preclinical in vivo study.

OBJECTIVE: To test the hypotheses of no differences in (I) percentage of bone (POB), non-mineralized tissue (NMT), and deproteinized bovine bone mineral (DBBM), and (II) ingrowth of mineralized bone after lateral guided bone regeneration (GBR) augmentation of the mandible with different ratios of DBBM and particulate autogenous bone (PAB) at different time points. MATERIAL AND METHODS: Twenty-four minipigs were randomly allocated into three groups. Lateral augmentation in 96 sites (4 in each animal) was performed unilaterally with a standardized quantity of grafting material in each animal with different ratios of DBBM and PAB (50:50, 75:25, 100:0) and autogenous bone block in combination with DBBM and covered with a collagen membrane. The percentage of different tissues in the graft and ingrowth of mineralized bone was assessed by histomorphometrical and histological analyses after 10, 20, and 30 weeks, respectively. RESULTS: The POB was 54% (50:50), 50% (75:25), and 48% (100:0) after 10 weeks, 60% (50:50), 61% (75:25), and 60% (100:0) after 20 weeks, and 63% (50:50), 62% (75:25), and 62% (100:0) after 30 weeks. There was no significant difference between the groups at any time points. There was a significant increase in POB and a significant decrease in NMT for 75:25 and 100:0 from 10 to 30 weeks. All ratios demonstrated a non-complete ingrowth of mineralized bone into the graft after 10 weeks and complete mineralization after 30 weeks. CONCLUSION: Within the limitations of the present study, it seems like addition of autogenous bone to DBBM for LRA did not affect the bone formation nor graft incorporation after 10-30 weeks of healing. However, a prolonged healing time seems to result in an increased POB for all ratios.

Comparison of a polyethylene glycol membrane and a collagen membrane for the treatment of bone dehiscence defects at bone level implants-A prospective, randomized, controlled, multicenter clinical trial.

OBJECTIVES: The aim of the present randomized, controlled clinical multicenter trial was to compare a polyethylene glycol (PEG) and a native collagen membrane (BG) for simultaneous guided bone regeneration at bony dehiscence-type defects around bone level titanium implants. MATERIAL AND METHODS: The study enrolled 117 patients requiring implant treatment in the posterior maxilla or mandible with expected buccal bony dehiscence-type defects at the placed titanium implants. According to a parallel groups design, defects were filled with a synthetic bone filler and randomly assigned to either PEG or BG membrane. As primary parameter, the relative vertical bone fill was assessed at baseline and at re-entry after 6 months of healing. As secondary parameters, the marginal bone level (MBL) was assessed radiographically and soft tissue conditions were recorded up to 18 months postloading. RESULTS: Both groups showed comparable vertical bone fill revealing a relative change in defect height of 59.7% (PEG) and 64.4% (BG). The absolute mean reduction in defect size was 2.5 mm in the PEG group and 3.2 mm in the BG group. Although both groups revealed a statistically significant mean defect reduction (p < .001), a comparison between the two groups did not show statistical significances. The non-inferiority test with inferiority limit of -5% could not be rejected, based on the 90% confidence interval of the differences of the two means with lower limit -15.4%. After 18 months, an MBL increase of 0.45 ± 0.43 mm in the PEG group and 0.41 ± 0.81 mm in the BG group was detected (p < .001). Soft tissue complications were observed in both groups without showing statistical significance. CONCLUSIONS: Both membranes supported bone regeneration at dehiscence-type defects and obtained vertical bone fill with a relative change in defect height of 59.7% (PEG) and 64.4% (BG); however, the non-inferiority of PEG could not be shown.

Vacuum-formed retainer versus bonded retainer for dental stabilization in the mandible-a randomized controlled trial. Part I: retentive capacity 6 and 18 months after orthodontic treatment.

BACKGROUND: Evidence concerning the most appropriate retention strategy after orthodontic treatment is still inconclusive. OBJECTIVE: This trial compares the retentive capacity of vacuum-formed Essix C-retainers (VFR) and bonded cuspid-to-cuspid retainers (CTC) in the mandible 6 and 18 months after orthodontic treatment. TRIAL DESIGN: A single-centre two-arm parallel-group randomized controlled trial. METHODS: This study included 104 adolescent patients, computer-generated randomized with sequentially numbered, opaque, and sealed envelopes into two groups and stratified by gender (52 females and 52 males). The patients were treated with fixed appliances with and without tooth extractions in both jaws and were ready for debond. In the intervention arm, patients received a VFR (n = 52); in the active comparator arm, patients received a CTC (n = 52). Dental casts were obtained at debond (T1), after 6 months (T2), and after 18 months (T3). The casts were digitized. The retentive capacity was evaluated on digital three-dimensional models using Little's Irregularity Index (LII), overbite, overjet, arch length, and intermolar and intercanine width. RESULTS: Baseline values were similar for both groups. Statistically significant increases were noted in LII and overbite, mainly between T1 and T2, but also between T1 and T3 in the VFR group (LII = 0.52 mm, P < 0.001, overbite = 0.51 mm, P < 0.001) and in the CTC group (LII = 0.45 mm P < 0.001, overbite = 0.36 mm, P < 0.001). There were no significant differences between groups. Overjet showed small variations during the observation periods but was overall stable within and between groups after 18 months. Arch length decreased slightly in both groups after 6 and 18 months. Intermolar and intercanine widths remained stable after debond. LIMITATIONS: Patients, operator, and outcome assessor could not be blinded due to the study design. CONCLUSIONS: VFR and CTC have the same retention capacity in the mandible after 6 and 18 months. Relapse mainly occurs during the first 6 months of retention, but the post-treatment changes are generally small. Shorter VFRs in the mandible do not cause negative vertical effects. Part-time wear regimen is not associated with increased relapse. TRIAL REGISTRATION: NCT03070444.

Osteotome-Mediated Sinus Floor Elevation With or Without a Grafting Material: A Systematic Review and Meta-analysis of Long-term Studies (≥5-Years).

OBJECTIVE: To test the hypothesis of no difference in the long-term treatment outcome after osteotome-mediated sinus floor elevation with or without a grafting material. MATERIALS AND METHODS: A MEDLINE/PubMed, Cochrane Library, and EMBASE search in combination with a hand-search of relevant journals was conducted, including human studies published in English from January 1, 1986 to December 1, 2017. RESULTS: One comparative and 7 noncomparative studies fulfilled the inclusion criteria. Survival of suprastructures had never been compared within the same study. Meta-analysis demonstrated an overall estimated patient-based implant survival of 94%. Gain in vertical alveolar bone height was similar with the 2 treatment modalities. Noncomparative studies demonstrated high long-term survival rate of suprastructures and implants with the 2 treatment modalities, as well as limited periimplant marginal bone loss. CONCLUSION: High long-term implant survival was demonstrated after osteotome-mediated sinus floor elevation with or without a grafting material. However, long-term randomized controlled trials comparing the 2 treatment modalities are sparse. Hence, conclusions drawn from this systematic review should be interpreted with caution.

Sinus floor elevation procedures to enable implant placement and integration: techniques, biological aspects and clinical outcomes.

Implant treatment in an atrophied edentulous posterior maxilla constitutes a challenge for the therapeutic team. The authors of the present study acknowledge that modern micro-rough surface implants in lengths of about 8-10 mm or longer and of different brands are similarly successful. Consequently, the authors propose that the use of different sinus floor elevation techniques should be considered when < 8 mm of bone is available below the maxillary sinus. The type of sinus floor elevation technique selected is mainly based on residual vertical bone height, marginal bone width, local intrasinus anatomy and the number of teeth to be replaced, although other factors (such as surgical training and surgical experience) may have an impact. It is proposed that a transcrestal sinus floor elevation approach can be considered as a first-choice method for single tooth gaps in situations with sufficient width for implant placement and a residual bone height of 5-8 mm, while lateral sinus floor elevation, with or without grafting materials, is indicated when < 5 mm of bone is available and when several teeth are to be replaced. With regard to time of implant placement, a one-stage procedure is preferred provided that high primary stability can be ensured.

A randomized and controlled clinical trial of two different compositions of deproteinized bovine bone and autogenous bone used for lateral ridge augmentation.

OBJECTIVE: The aim of the study was to radiologically and histologically evaluate the graft healing and volumetric changes after lateral augmentation with two different compositions of deproteinized bovine bone (DPBB) and autogenous bone (AB). MATERIAL AND METHODS: Thirteen patients with a mean age of 59.6 ± 12.1 years (six men and seven women) were included in this randomized and controlled trial, designed as a split-mouth study. Ten edentulous and four partially edentulous jaws with an alveolar ridge width of ≤4 mm were laterally augmented with a graft composition of 60 : 40 (DPBB/AB) on one side and 90 : 10 (DPBB/AB) on the contralateral side. Cone beam computed tomography (CB/CT) was obtained immediately postoperatively and after a healing period of 7.5 months. Width changes were measured on CB/CT scans. After a mean healing period of 8.1 months (range, 7.9-8.3), biopsies were retrieved perpendicular to the crest from each graft by means of a trephine bur. Histomorphometry was performed, and the following variables were recorded: Ingrowth of new bone (percentage of total graft width), percentage of DPBB, bone and soft tissue, and percentage of DPBB particles in contact with bone. RESULTS: The mean gained width of the alveolar crest after 7.5 months was significantly more for the 60 : 40 mixture compared with the 90 : 10 mixture, 3.5 (±1.3) mm and 2.9 (±1.3) mm, respectively. There was a significant difference in graft width reduction between 60 : 40 and 90 : 10 after 7.5 months, 37 (±19.9)% and 46.9 (±23.5)%, respectively. New bone ingrowth had occurred in 82.1 (±23.3)% and 82.3 (±26.6)% of the graft, respectively. There were no statistical differences between fractions of different tissues between the 90 : 10 and 60 : 40 compositions. However, there were significantly more soft tissue and less new bone formation closer to the periosteum compared with the graft portion closer to the residual bone in both 60 : 40 and 90 : 10 compositions. CONCLUSIONS: There was significantly less graft width reduction with a mixture of 60 : 40 (DPBB/AB) compared with a mixture of 90 : 10 composition, but the results from the histomorphometry showed no statistical differences comparing the groups.

Tissue reactions to subperiosteal onlays of demineralized xenogenous dentin blocks in rats.

OBJECTIVES: This study was undertaken to examine the influence of partial demineralization of xenogenous dentin on bone formation in an osteoconductive environment. MATERIALS AND METHODS: Sixty dentin blocks, 2-3 mm thick and 4 mm in diameter, were prepared from developing teeth of young pigs. Forty blocks were demineralized in 24% ethylenediaminetetraacetic acid (pH 7.0) for 1, 2, 6 or 12 h. Forty adult rats divided into eight groups with five rats in each group were used. A sagittal midcranial incision was made from the occipital to the frontal region. Through a subperiostal dissection, a pocket was created on each side of the skull. One demineralized block was placed on one side, and a non-demineralized block was placed on the contralateral side, or the pocket was left empty as controls. Thus, eight experimental groups with five rats in each were formed. RESULTS: Resorption increased significantly with increasing degree of demineralization while bone formation increased significantly with increasing degree of demineralization, provided inflammation was compensated for. This suggests an important role for inflammation or infection control during the healing period of osteogenic implants to optimize osseous integration in an osteoconductive environment. CONCLUSION: Partial demineralization of xenogenous dentin blocks may provide a method for optimizing the integration of dentin onlays in an osteoconductive environment, thus stabilizing the implant and slowing down replacement resorption.

Back-scattered electron imaging and elemental analysis of retrieved bone tissue following sinus augmentation with deproteinized bovine bone or biphasic calcium phosphate.

OBJECTIVES: To compare resorption of a synthetic biphasic calcium phosphate (BCP) bone-graft substitute with deproteinized bovine bone (DBB) used for human maxillary sinus augmentation. MATERIALS AND METHODS: Eleven patients underwent bilateral maxillary sinus floor augmentation with DBB in one side and a BCP (40%beta-tricalcium phosphate (beta-TCP) and 60% hydroxyapatite) in the contralateral side. Simultaneously, with the augmentation on each side a microimplant was placed vertically from the top of the alveolar crest penetrating the residual bone and the grafting material. Eight months after initial surgery the microimplants were retrieved with a surrounding bone core. The composition of residual graft material and surrounding bone was analysed by scanning electron microscopy and energy dispersive X-ray spectroscopy. RESULTS: Residual graft material of both types was present as 10-500 mum particles in direct contact with, or completely surrounded by, newly formed bone; smaller particles were also present in non-mineralized tissue. In the case of BCP the bone-graft substitute interface showed evidence of superficial disintegration of particles into individual grains. Median Ca/P ratios (at.%), determined from >200 discreet sites within residual graft particles and adjacent bone, were: DBB: 1.61 (confidence interval [CI] 1.59-1.64); BCP: 1.5 (CI 1.45-1.52); DBB-augmented bone: 1.62 (CI 1.59-1.66); BCP-augmented bone: 1.52 (CI 1.47-1.55); P=0.028 for DBB vs. BCP and DBB- vs. BCP-augmented bone. The reduction in Ca/P ratio for BCP over the healing period is consistent with the dissolution of beta-TCP and reprecipitation on the surface of calcium-deficient hydroxyapatite. CONCLUSION: The beta-TCP component of BCP may be gradually substituted by calcium-deficient hydroxyapatite over the healing period. This process and superficial degranulation of BCP particles may influence the progress of resorption and healing.

Histological and histomorphometrical analyses of biopsies harvested 11 years after maxillary sinus floor augmentation with deproteinized bovine and autogenous bone.

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.

Clinical histology of microimplants placed in two different biomaterials.

PURPOSE: This randomized, controlled study was designed to compare bone formation around microimplants with a sandblasted, acid-etched surface placed at the time of maxillary sinus floor augmentation with a synthetic biphasic calcium phosphate (BCP) or deproteinized bovine bone (DBB). MATERIALS AND METHODS: Nine completely edentulous patients and two partially edentulous patients (six women, five men) with a mean age of 67 years (range, 50 to 79 years) requiring bilateral sinus augmentation were included in the study. The patients were randomized for augmentation with BCP (test) in one side and DBB (control) in the contralateral side. At the time of augmentation, one microimplant on each side was placed vertically from the top of the alveolar crest, penetrating the residual bone and the grafting material. After 8 months of graft healing, at the time of ordinary implant placement, all 22 microimplants were retrieved with a surrounding bone core for histologic analyses. RESULTS: The bone-to-implant contact in the BCP group was 64.6% +/- 9.0%, versus 55.0% +/- 16.0% for the DBB group. The difference was not significant. The corresponding values for the area of newly formed bone in the biopsies were 41.1% +/- 9.8% and 41.6% +/- 14.0% for BCP and DBB, respectively. There were significantly more DBB particles in contact with newly formed bone than BCP particles (87.9 +/- 18.2% versus 53.9 +/- 26.1%; Wilcoxon rank sum test; P = .007). CONCLUSION: In this randomized, controlled clinical trial, new bone formation and bone-to-implant contact around microimplants with a sandblasted, acid-etched surface was found to be equivalent between sinuses augmented with BCP or DBB. Significantly more DBB particles than BCP particles were in contact with newly formed bone, but the clinical relevance of this has yet to be established.

Bone replacement following dental trauma prior to implant surgery--status.

Dento-alveolar trauma often leads to a need for reconstruction of the alveolar crest before an implant can be placed. Although autogenous bone grafts is considered the 'gold standard', this may be associated with patient morbidity and graft resorption. Consequently, the use of bone substitutes has increased. Today, a substantial number of biomaterials are available on the market, but only a few are well documented. The user should be aware that these biomaterials have different properties: resorbable or non-resorbable, time of resorption and resorption mechanism. The purpose of this review is to describe the function of various bone substitutes and indications for their use in reconstructive implant surgery and to give an overview of the current situation.

Back-scattered electron imaging and elemental microanalysis of retrieved bone tissue following maxillary sinus floor augmentation with calcium sulphate.

OBJECTIVES: To investigate the presence and composition of residual bone graft substitute material in bone biopsies from the maxillary sinus of human subjects, following augmentation with calcium sulphate (CaS). MATERIAL AND METHODS: Bone cores were harvested from the maxillary sinus of patients who had undergone a sinus lift procedure using CaS G170 granules 4 months after the initial surgery. Samples from seven patients, which contained residual biomaterial particles, were examined by field emission scanning electron microscopy and energy dispersive X-ray spectroscopy was used to determine the composition of the remaining bone graft substitute material. RESULTS: Residual graft material occurred in isolated areas surrounded by bone and consisted of individual particles up to 1 mm in length and smaller spherical granules. On the basis of 187 separate point analyses, the residual material was divided into three categories (A, B and C) consisting of: A, mainly CaS (S/P atomic% ratio > or =2.41); B, a heterogeneous mixture of CaS and calcium phosphate (S/P=0.11-2.4) and C, mainly calcium phosphate (S/P< or =0.11; C), which had a mean Ca : P ratio of 1.63+/-0.2, consistent with Ca-deficient hydroxyapatite. Linescans and elemental maps showed that type C material was present in areas which appeared dense and surrounded, or were adjacent to, more granular CaS-containing material, and also occurred as spherical particles. The latter could be disintegrating calcium phosphate in the final stages of the resorption process. CONCLUSIONS: CaS resorption in the human maxillary sinus is accompanied by CaP precipitation which may contribute to its biocompatibility and rapid replacement by bone.

Sinus Floor Augmentation Using Straumann® BoneCeramic™ and Bio-Oss® in a Split Mouth Design and Later Placement of Implants: A 5-Year Report from a Longitudinal Study.

BACKGROUND: Straumann® BoneCeramic™ is a synthetic biphasic calcium phosphate (BCP) aimed for sinus floor augmentation. Long-term follow-up of implants placed in BCP after sinus augmentation is still missing. PURPOSE: The primary aim of the study was to compare survival rates and marginal bone loss of Straumann SLActive implants placed in either BCP (test) or Bio-Oss® (DBB) (control) after sinus floor augmentation. The secondary aim was to calculate graft sinus height at different time points. MATERIALS AND METHODS: Bilateral sinus floor augmentation was performed in a split mouth model. Eleven patients (mean age 67 years) received 100% BCP on one side and 100% DBB on the contralateral side. After 8 months of graft healing, 62 Straumann SLActive implants were placed. After 5 years of functional loading (6 years after augmentation) of implants, marginal bone levels and grafted sinus height were measured, and implant survival and success rates were calculated. RESULTS: After 5 years of loading, all prosthetic constructions were in function although two implants were lost in each grafting material. The overall implant survival rate was 93.5% (91.7% for BCP, 91.3% for DBB, and 100% for residual bone). The success rates were 83.3% and 91.3% for BCP and DBB, respectively. There was no statistically significant difference in mean marginal bone level after 5 years between BCP (1.4 ± 1.2 mm) and DBB (1.0 ± 0.7 mm). Graft height reduction (GHR) after 6 years was limited to 6.6% for BCP and 5.8% for DBB. CONCLUSION: In this limited RCT study, the choice of biomaterial used for sinus floor augmentation did not seem to have any impact on survival rates and marginal bone level of the placed implants after 5 years of functional loading and GHR was minimal.

A retrospective 5-year follow-up study of two different titanium implant surfaces used after interpositional bone grafting for reconstruction of the atrophic edentulous maxilla.

BACKGROUND: Long-term comparative follow-up studies of dental implants placed in augmented bone are rare. Variations in design and surface roughness have been found to be important for bone integration of implants. However, there is no clinical evidence that such variations lead to an improved clinical outcome. PURPOSE: To compare two different implant systems used after interpositional bone grafting of the severely resorbed maxilla with a modified augmentation technique using fibrin glue. MATERIALS AND METHODS: Twenty-two consecutive patients presenting with severe maxillary atrophy underwent reconstruction with Le Fort I osteotomies and interpositional bone grafting. Before placement of bone blocks, the floors of the maxillary sinuses were packed with bone chips mixed with a fibrin glue, to stabilize the graft. After 6 months of graft healing, the first 11 consecutive patients received Brånemark System implants with a turned surface (Nobel Biocare AB, Göteborg, Sweden). The following 11 consecutive patients were treated with Astra Tech implants with a blasted titanium surface (Astra Tech AB, Mölndal, Sweden). All patients received fixed prostheses. Marginal bone resorption and donor and recipient site morbidity were evaluated. All patients were clinically and radiographically observed throughout 5 years of functional loading. RESULTS: In the Brånemark group, 11 (13%) of 84 placed implants were lost, compared to 4 (5.5%) of 72 placed implants in the Astra Tech group. The difference was not significant. All patients retained fixed constructions after 5 years of loading. The mean marginal bone loss was 2.3+/-0.8 mm (range, 0-5.0 mm) in the Brånemark group and 2.4+/-1.4 mm (range, 0-7.0 mm) in the Astra Tech group although again no statistical difference was found. A larger number of implants in the Astra Tech group had a marginal bone resorption of>or=3 mm, and implant success in that group was lower than in the Brånemark group (52% vs 70%). CONCLUSION: In this study, reconstruction of the severely resorbed maxilla with Le Fort I osteotomy, interpositional bone grafting, and delayed placement of dental implants was found to be a predictable long-term procedure. Although more implants with a turned surface were lost during the follow-up period, there were no statistically significant differences between turned and titanium blasted implants.

A 5-year prospective follow-up study of implant-supported fixed prostheses in patients subjected to maxillary sinus floor augmentation with an 80:20 mixture of bovine hydroxyapatite and autogenous bone.

BACKGROUND: Prospective long-term follow-up studies evaluating the use of bone substitutes to enable dental implant placement and integration are rare. PURPOSE: This study was undertaken to evaluate the survival rate of dental implants placed 6 months after maxillary sinus floor augmentation using a mixture of 80% bovine hydroxyapatite (BH) and 20% autogenous bone (AB). MATERIAL AND METHODS: Twenty patients subjected to 30 maxillary sinus floor grafting procedures using fibrin glue and an 80:20 mixture of BH and AB to enable placement of dental implants 6 months later were followed for 5 years of functional loading. Clinical and radiographic examinations of the grafts and implants were performed. RESULTS: After 5 years of functional loading with fixed bridges, 15 of 108 implants had been lost, giving a cumulative survival rate of 86%. The mean marginal bone loss after 5 years was 1.3 +/- 1.1 mm. CONCLUSION: Grafting of the maxillary sinus with a mixture of BH and AB and later placements of turned implants could be performed with predictable long-term results. All but one of the patients who were observed had functional fixed bridges after 5 years of functional loading.

Nonsubmerged and submerged implants in the treatment of the partially edentulous maxilla.

BACKGROUND: Dental implants vary in design and surfaces. In addition, different surgical techniques have been used for implant insertion. The ITI Dental Implant System (Straumann AG, Waldenburg, Switzerland) has always required a one-stage technique, whereas the Brånemark System (Nobel Biocare AB, Gothenburg, Sweden) requires a two-stage technique. PURPOSE: The aim of this study is to compare the outcome of fixed partial bridges in the maxilla supported by both ITI and Brånemark implants in a split-mouth design. MATERIALS AND METHODS: Twenty-eight patients with a residual anterior dentition in the maxilla were included in this split-mouth study. The Brånemark implants were used on one side and the ITI implants on the other side of the residual dentition according to a randomization procedure. A blocking size of four was used, giving equal probability of placing ITI or Brånemark implants in the right or left side of the jaw. The surgical and prosthetic procedures followed the guidelines given by the manufacturers. The prosthetic treatment with the two-implant systems was performed at the same time, and for that reason the healing period was 6 months for both systems. The observation period for all patients was 1 year after loading. RESULTS: Two Brånemark implants (in one patient) were lost before loading, and one ITI implant was lost 1 year after loading. There was no significant difference in survival rate. Radiographic examination of the bone level was performed at the time of delivery of the bridge and after 1 year. The mean marginal bone level at baseline was situated 1.9 mm from the reference point for the Brånemark implants and 1.5 mm for the ITI implants. With regard to the insertion depth used, these bone levels indicate that bone loss had taken place before baseline. However, between baseline and the 1-year examination, there was no significant change of the marginal bone (0.2 +/- 0.08 mm at the Brånemark implants and 0.1 +/- 0.11 mm at the ITI implants). The difference between results with the two implants was not statistically significant. Crater-form bone destructions were seen at some ITI implants, indicating periimplantitis. However, at only two implants were there clinical signs of periimplantitis. CONCLUSIONS: No significant difference in survival rate or in marginal bone change could be demonstrated between the two systems. At some ITI implants (18%), crater-form bone loss was observed.

A three-year follow-up report of a comparative study of ITI Dental Implants and Brånemark System implants in the treatment of the partially edentulous maxilla.

BACKGROUND: Many longitudinal studies of different implant systems have been published but few controlled randomized investigations have been reported. A 1-year report of a comparative study of ITI Dental Implant System implants (Straumann AG, Waldenburg, Switzerland) and Brånemark System implants (Nobel Biocare AB, Gothenburg, Sweden) has been published by the present authors. This paper is a 3-year follow-up of that randomized study. PURPOSE: The aim of the study was to compare the outcome of fixed partial prostheses supported by ITI or Brånemark implants. The outcome was evaluated primarily in terms of survival rates and changes in marginal bone level. MATERIAL AND METHODS: The study group comprised 28 patients with anterior residual dentition in the maxilla. The patients were provided with two to four implants on each side of the dentition and were randomly allocated to Brånemark implants or ITI implants; 77 ITI implants and 73 Brånemark implants were inserted. After 6 months abutment connections were made to both ITI and Brånemark implants. All patients were provided with fixed partial prostheses of gold-ceramic. The patients were followed up annually with clinical and radiographic examinations for 3 years RESULTS: Two Brånemark implants and two ITI implants were lost. The Brånemark implants were lost before loading whereas the ITI implants were lost because of periimplantitis. The survival rate for both groups was 97.3%. The mean marginal bone level of the Brånemark implants was situated 1.8 mm from the reference point at both the baseline and the 3-year examinations. The corresponding values for the ITI implants were 1.4 mm at baseline and 1.3 mm after 3 years. There was no significant difference between the implant systems with regard to bone level or bone level change. A steady state of the marginal bone level was calculated to have been reached after 3 years for 95.5% of the Brånemark implants and 87.1% of the ITI implants. Periimplantitis (infection including pus and bone loss) was observed with seven ITI implants but with none of the Brånemark implants. This difference was statistically significant. CONCLUSIONS: No statistically significant differences were found between the implants studied, except for the frequency of periimplantitis, which was higher for the ITI implants. The survival rates were high, and the marginal bone loss was small for both systems.

Sinus floor augmentation with bovine hydroxyapatite mixed with fibrin glue and later placement of nonsubmerged implants: a retrospective study in 50 patients.

PURPOSE: The aim of the present study was to evaluate retrospectively both the results of using a mixture of bovine hydroxyapatite (BHA) and fibrin glue as the only grafting material in the floor of the maxillary sinus and the outcome of nonsubmerged implants placed later. MATERIALS AND METHODS: A total of 50 consecutive patients (71 maxillary sinuses) were augmented with a mixture of BHA and fibrin glue. The grafts were allowed to heal for a mean of 8 months prior to implant placement. A total of 218 solid titanium screw-type implants were placed in a nonsubmerged fashion and allowed to heal for a mean of 10 weeks before loading (range, 10 days to 10 months). The outcome of the placed dental implants was evaluated retrospectively. RESULTS: Twelve implants were lost, giving a cumulative survival rate of 94.5% after a mean loading time of 20 months (range, 6 to 42 months). DISCUSSION: This study shows that augmentation of the maxillary sinus with a BHA/fibrin glue mixture and later placement of nonsubmerged implants with short healing times preceding functional loading can be a predictable concept. However, the use of autogenous bone and placement of submerged implants in the grafts with long healing times is routine in many clinics. This article discusses the evidence on which this protocol is based. CONCLUSION: The short-term results from this retrospective clinical study indicated that BHA/fibrin glue can be used as a grafting material without autogenous bone in the maxillary sinus to produce a high survival rate for later placement of nonsubmerged implants.