A multicenter randomized controlled trial using a novel collagen membrane for guided bone regeneration at dehisced single implant sites: Outcome at prosthetic delivery and at 1-year follow-up.

OBJECTIVES: To compare clinical performance of a novel resorbable non-cross-linked collagen membrane (CXP) with a reference membrane (non-cross-linked resorbable membrane; BG) for simultaneous implant placement and guided bone regeneration (GBR) at dehisced single implant sites. MATERIALS AND METHODS: Preliminary data from this randomized controlled trial were reported previously; this is the 12-month report. The primary outcome measure was defected height at 6 months post-GBR. Secondary outcomes included implant cumulative survival rate (CSR) and success rate since placement; bone level changes, pink esthetic score (PES), and patient satisfaction since definitive prosthesis delivery; patient quality of life since pretreatment; and the 1-year bleeding index. Non-parametric statistical analyses were performed. RESULTS: Among patients, 24 were treated with CXP and 25 with BG. The 1-year implant CSR and success rate were 100% (n = 42). Bone level change between definitive prosthetic delivery and 1 year was not significantly different between the CXP and BG groups (BG + 0.42 mm, CXP + 0.01 mm). The PES increased from 7.55 to 8.10 for the CXP group and from 6.48 to 7.48 for the BG group; 1-year bleeding indices were 0 (16 CXP, 18 BG) and 1 (4 CXP, 2 BG). Patient quality of life changed from an OHIP-14 score of 6.5 at pretreatment to 1.9 at 1 year. Overall satisfaction (visual analogue score) with function and esthetics was 9.9 and 9.7, respectively. Inter-group differences were not significant for assessed outcomes. No device-related adverse events were reported. CONCLUSIONS: The use of CXP and BG for simultaneous implant placement and GBR at dehisced implant sites similarly reduced defect height and improved secondary measures, indicating non-inferiority.

A 5-year prospective clinical trial on short implants (6 mm) for single tooth replacement in the posterior maxilla: immediate versus delayed loading.

The aim of this paper was to demonstrate the treatment outcomes following immediate functional loading concept of short implants inserted for single tooth replacement in the posterior maxilla. The study was performed on 63 patients who received short (6 mm) implants for single tooth replacement in the posterior maxilla. Forty-eight patients underwent immediate functional concept, whereas 15 of the implants were loaded 3 months after insertion. The patients were evaluated for up to 5 years after prosthesis completion. The endpoints included the evaluation of implant survival rate, crown length, bone resorption, plaque accumulation (PI), bleeding on probing (BOP), periodontal probing depth (PPD) and assessment of oral health impact profile (OHIP). At the end of the follow-up period of 5 years, three implants (6.3%) from the immediate loading group have failed during the observation period. Bone loss was significantly lower in the delayed loading group compared to the immediately loaded implants. At the end of the second year, BOP values were higher in the immediately loaded group. Throughout the observation period, PI values in the group with immediate loading were higher. PPD increased consistently and during the first 3 years in the immediate loading group. As a conclusion, short implants inserted for single tooth replacement at the posterior maxilla presented with satisfactory clinical outcomes in both immediate and delayed loading concepts. However, immediately loaded implants presented with an increased bone loss and higher BOP values. As assessed by the OHIP score, a subjective improvement was observed in both groups without significant differences.

A multicenter randomized controlled clinical trial using a new resorbable non-cross-linked collagen membrane for guided bone regeneration at dehisced single implant sites: interim results of a bone augmentation procedure.

OBJECTIVE: To compare clinical performance of a new resorbable non-cross-linked collagen membrane, creos xenoprotect (CXP), with a reference membrane (BG) for guided bone regeneration at dehisced implant sites. MATERIALS AND METHODS: This randomized controlled clinical trial enrolled patients with expected dehiscence defects following implant placement to restore single teeth in the maxillary and mandibular esthetic zone and premolar area. Implants were placed using a two-stage surgical protocol with delayed loading. Bone augmentation material placed at the implant surface was immobilized with CXP or BG membrane. Soft tissue health was followed during the healing period, and the defect size was measured at reentry and 6 months after implant placement. RESULTS: Of the 49 included patients, 24 were treated with CXP and 25 with BG. Patient characteristics did not differ between the two arms. In the CXP arm, the defect height at implant insertion was (mean ± SD) 5.1 ± 2.1 mm (n = 24) and reduced at reentry by 81% to 1.0 ± 1.3 mm (n = 23). In the BG arm, the defect height at implant insertion was 4.9 ± 1.9 mm (n = 25) and reduced at reentry by 62% to 1.7 ± 2.1 mm (n = 24). Assuming a margin of non-inferiority of 1 mm, CXP was non-inferior to BG. Membrane exposure rate was highest at week 3 in both arms, reaching 16.7% for BG and 8.7% for CXP. CONCLUSIONS: The new resorbable non-cross-linked collagen membrane facilitates bone gain to support implant placement in expected dehiscence defects. The observed trend toward higher mean bone gain and lower exposure rate with CXP compared to BG should be further investigated.

Differences in degradation behavior of two non-cross-linked collagen barrier membranes: an in vitro and in vivo study.

OBJECTIVES: Collagen barrier membranes are used in guided bone regeneration/guided tissue regeneration because of their excellent bio- and cytocompatibility. However, they are considered to have limitations in clinical outcome because of rapid and unpredictable degradation profiles. The aim of this study was to investigate the degradation behavior of two porcine-based, non-cross-linked collagen membranes in vitro and in vivo. MATERIALS AND METHODS: Remaix™ (RX; Matricel GmbH, Herzogenrath, Germany) and Bio-Gide® (BG; Geistlich Pharma AG, Wolhusen, Switzerland) membranes were characterized by testing mechanical strength, denaturation temperature, enzymatic degradation and hydroxyproline content in vitro (n = 5 up to 16). Thereafter, both membranes were implanted subcutaneously in rats (n = 20) for up to 20 weeks to investigate tissue compatibility with respect to membrane thickness. RESULTS: BG contained a significant higher hydroxyproline content compared with RX, but RX showed a higher stress at break (dry: 11.4 (SD 2.9) vs. 5.5 (SD 1.5) N/mm(2)), higher suture retention (wet: 5.6 (SD 1.3) vs. 2.7 (SD 0.7) N), increased denaturation temperature (55.1 (SD 1) vs. 49.4 (SD 0.6)°C) and an almost twofold reduction in degradation rate (15.6% (SEM 1.3)/h vs. 24.8% (SEM 2.9)/h) in vitro. In the rat model, both membranes showed excellent tissue compatibility without signs of inflammatory reactions. Shortly after implantation, RX and BG showed moderate infiltration of mononuclear cells that appeared not to be influenced by the surface texture of the membranes. In the histomorphometric analysis, both membranes showed significant different thickness over the 20 weeks period (P = 0.0002). Although the thickness remained almost stable during the first 9 weeks after implantation, after 20 weeks, the thickness of RX decreased only slightly, whereas BG showed a thickness loss of around 50% and stronger degradation than RX. Therefore, the higher stability of RX against biodegradation found in vitro was confirmed in the animal study. CONCLUSION: This study shows differences in the biodegradation characteristics of two non-cross-linked collagen membranes in vitro and in vivo. Whether the higher stability of RX is of clinical relevance should be analyzed in future clinical investigations.

Guided Bone Regeneration with Collagen Membranes and Particulate Graft Materials: A Systematic Review and Meta-Analysis.

PURPOSE: The aim of this meta-analysis was to evaluate different methods for guided bone regeneration using collagen membranes and particulate grafting materials in implant dentistry. MATERIALS AND METHODS: An electronic database search and hand search were performed for all relevant articles dealing with guided bone regeneration in implant dentistry published between 1980 and 2014. Only randomized clinical trials and prospective controlled studies were included. The primary outcomes of interest were survival rates, membrane exposure rates, bone gain/defect reduction, and vertical bone loss at follow-up. A meta-analysis was performed to determine the effects of presence of membrane cross-linking, timing of implant placement, membrane fixation, and decortication. RESULTS: Twenty studies met the inclusion criteria. Implant survival rates were similar between simultaneous and subsequent implant placement. The membrane exposure rate of cross-linked membranes was approximately 30% higher than that of non-cross-linked membranes. The use of anorganic bovine bone mineral led to sufficient newly regenerated bone and high implant survival rates. Membrane fixation was weakly associated with increased vertical bone gain, and decortication led to higher horizontal bone gain (defect depth). CONCLUSION: Guided bone regeneration with particulate graft materials and resorbable collagen membranes is an effective technique for lateral alveolar ridge augmentation. Because implant survival rates for simultaneous and subsequent implant placement were similar, simultaneous implant placement is recommended when possible. Additional techniques like membrane fixation and decortication may represent beneficial implications for the practice.

Horizontal Ridge Augmentation with a Novel Resorbable Collagen Membrane: A Retrospective Analysis of 36 Consecutive Patients.

The aim of this investigation was to evaluate a new resorbable, monolayer, noncross-linked collagen barrier membrane for immobilizing bone augmentation material during horizontal guided bone regeneration (GBR) procedures. GBR was performed on 36 consecutive patients in 49 sites, with 103 implants placed either simultaneously or after a healing period. Healing time, suture retention, postoperative complications, and functional outcome after GBR, implant placement, and prosthesis loading were assessed. A wound dehiscence rate of only 12% and a graft failure rate of 4% occurred. Mean healing time was 5.8 months for simultaneous placement and 7.9 + 4.8 months for two-stage procedures. The implant survival rate was 100% after a mean follow-up of 18.3 months from implantation. These early data demonstrate a low dehiscence rate and excellent potential of this new noncross-linked collagen membrane for use with horizontal ridge augmentation.

Vertical Bone Grafting and Periosteal Vertical Mattress Suture for the Fixation of Resorbable Membranes and Stabilization of Particulate Grafts in Horizontal Guided Bone Regeneration to Achieve More Predictable Results: A Technical Report.

Osteosynthesis screws and titanium or resorbable pins have been recommended for fixing guided bone regeneration (GBR) membranes and stabilizing the graft. However, the removal of fixation screws or pins often requires an additional surgical procedure. This article presents a periosteal suturing technique with resorbable sutures for the fixation of grafts and membranes in GBR in single implant sites. This technique avoids potential complications of using fixation screws or pins, such as perforation of the roots when inserting the pins, and eliminates the need for a second retrieval surgery.