Fracture of dental implants is a rare phenomenon with severe clinical results. In this article, the literature is reviewed and various causative factors that may lead to fracture are presented. Galvanic activity has not been mentioned before as a possible cause for implant fracture, yet, it can occur at the level of contact with the superstructure. This is illustrated by the case of a titanium implant restored with a nonprecious porcelain-fused-to-metal cemented crown that fractured 4 years after loading. The radiographs show alveolar bone resorption around the fixture. Metallurgical analysis of the implant indicated that the fracture was caused by metal fatigue and that the crown metal, a nickel-chromium-molybdenum alloy, exhibited corrosion. These findings suggest a new explanation for implant fractures; cytotoxic nickel ions, leaching from the base metal alloy may cause bone resorption. This in turn leads to increased mobility, facilitating washout of the luting cement. Contact of the base metal with titanium in the presence of oral fluids produces galvanic currents that hasten corrosion and leaching out of nickel ions, thus leading to further bone resorption. Loss of bone support allows lateral bending moments that cause metal fatigue, eventually leading to fracture. Therefore, good treatment planning and appropriate case selection might have prevented this fracture. Furthermore, the use of nonprecious metal alloy for the crown’s infrastructure had further contribution to the chain of events that led to the implant’s fracture.

Objective: To compare the use of autogenous iliac bone graft (ABG) alone with nonresorbable expanded polytetrafluoroethylene Gore-Tex TR membrane (GTM) and with ABG plus resorbable Resolut XT membrane barriers for the secondary closure of alveolar cleft defects. Study Design: Fifteen patients aged 9 to 17 years with unilateral cleft palate were included in this study. All patients had primary closure of the soft tissues at infancy. Presurgical orthodontics and scaling preceded the surgery. The patients were randomized to one of three surgical treatment groups: (1) ABG, (2) GTM, or (3) autogenous bone plus resorbable membrane (ABM). Periapical radiographs were taken pretreatment and 2 to 6 years later and were used to measure changes in size (linear and area) of the osseous defect. Results: Significant decreases were observed in mean initial defect width (9.8 to 6.7 mm; p = .0263), mean initial defect height (20.7 to 15.1 mm), and overall mean defect size (223.6 to 143.9 mm ² ). Greater improvement in mean defect width was observed for the ABM group (6.42 mm) compared with the ABG (1.22 mm) and GTM (1.38 mm) groups. The reduction in overall mean defect size was significantly greater in the ABM group (177 mm ² ) compared with the GTM (20.51 mm ² ) and ABG (41.69 mm ² ) groups. Conclusion: Guided bone regeneration was found potentially useful for the treatment of osseous cleft palate defects. The combined approach yielded significantly greater defect fill. If further substantiated in larger independent studies, the adjunctive use of barrier membranes could improve the management of secondary closure of cleft palate defects.

Aim: To assess the horizontal and vertical dimensional changes of the alveolar ridge when using a collagen matrix in combination with collagen embedded xenogenic bone substitute, in comparison with natural healing after tooth extraction.Methods: Patients that required extraction in non‐molars areas were included. Test group‐15 sockets were treated with deproteinized bovine bone mineral containing 10% collagen (DBBM‐C), covered by a procaine collagen membrane (CMXs). Control group‐15 sockets left for spontaneous healing. We used a custom‐made acrylic stent as a reference for alveolar ridge measurements. Six‐month postoperative, a single implant was placed in the experimental site. A core biopsy was taken from the site, using a trephine bur. Histomorphometric analysis assessed bone area, connective tissue, bone marrow, and residual bone graft.Results: Six months later, horizontal ridge width at −3 mm showed a significant (p < 0.05) reduction in both groups albeit smaller in the test group 1.19 ± 1.55 mm, compared with the control 2.27 ± 1.52 (p = 0.087). At −5 mm sub‐crestally, statistically non‐significant reduction was noted in both groups, 1.61 ± 1.53 and 1.96 ± 1.52 mm for the test and control groups, respectively (p = 0.542). Vertical changes were smaller in the test group (0.14 ± 1.84 mm) compared with control (0.98 ± 1.49 mm). Keratinized tissue (KT) width was 7.3 ± 2.13 and 7.5 ± 3.49 mm in the test and control groups, respectively. Newly formed bone occupied 33.79 ± 17.37% and 51.14 ± 23.04% in the test and control groups, respectively, (p = 0.11). Connective tissue volume was 33.74 ± 13.81% and 30.12 ± 18.32% in the test and control groups, respectively (p = 0.65). Bone marrow occupied 19.57 ± 10.26% and 18.74 ± 17.15% in the test and control groups, respectively (p = 0.91). Residual graft occupied 12.9 ± 9.88% in the test group.Conclusion: Alveolar ridge preservation using DBBM‐C resulted in reductions of the vertical and horizontal dimensions albeit not reaching statistical significance. The larger than anticipated standard deviation and smaller inter‐group differences might account for this phenomenon.