Effect of implant surface and grafting on implants placed into simulated extraction sockets: a histologic study in dogs.

PURPOSE: To study bone healing at implant sites in simulated extraction sockets with 1-mm marginal defects and compare healing around a turned surface (T) to that around a porous oxide surface prepared by anodic oxidation (AO) with or without the use of an autogenous bone graft. MATERIALS AND METHODS: All mandibular premolars and first molars were extracted from 10 mongrel dogs. After 9 weeks, four sites were prepared on both sides of all mandibles. Each osteotomy was widened in the coronal 5 mm to create a marginal defect of 1 mm around the implants. Autogenous bone was collected during the drilling procedure. The sites were randomized to receive implants with a T or an AO surface, with or without bone grafting. The animals were sacrificed 4 months after implant placement for histologic analysis. RESULTS: Clinically, all sites healed with complete bone fill. The combination of an AO implant and a bone graft resulted in a significantly greater percentage of bone-to-implant contact (BIC) (P < .05) versus all other groups. The highest point of BIC was achieved with the AO group, which was significantly greater than the lowest group (T). No significant differences between groups were found when the apical 4 mm (non-gap areas) were compared (P = .65). CONCLUSIONS: Studies have demonstrated that bone can fill in a marginal defect around a titanium implant with varied histologic BIC, depending on implant surface type and defect dimensions. Based upon this animal study using 10 mongrel dogs, marginal circumferential defects of 1 mm showed significantly higher BIC values for implants that were prepared by AO compared to implants with a turned surface. The addition of autogenous bone grafts further enhanced the degree of BIC.

Clinical application of spiral tomography in anterior implant placement: case report.

BACKGROUND: Placement of endosseous dental implants in edentulous areas of the anterior maxilla poses a unique challenge due to variations in the amount of residual alveolar bone. Implant position becomes crucial in cases demanding high esthetic results but possessing minimal ridge width or in cases requiring augmentation. Recent advances in spiral tomography have allowed for more precise planning and placement of endosseous implants in these challenging areas. METHODS: The purpose of this report is to describe a series of clinical cases in which spiral tomography was utilized in the planning and placement of endosseous dental implants. Two cases will be described utilizing initial spiral tomographic radiographs for implant planning and surgical guide fabrication, followed by post-insertion tomography to evaluate the results of implant position and inclination. RESULTS: Preimplant spiral tomograms revealed that the initial prosthetic trajectory through the proposed incisal edge of each tooth replacement would result in a final osteotomy site that would compromise the overall thickness of the facial cortical plate. After adjusting for magnification and distortion factors, new prosthetic/surgical trajectories were fabricated into the surgical guide, and this information was utilized to prepare the final implant osteotomy site. This adjustment resulted in 2 mm of residual crestal facial bone postimplant insertion, which became wider at more apical measurements. These findings were verified in the postimplant serial tomograms. CONCLUSIONS: Spiral tomography was a valuable adjunct in the treatment planning phases of endosseous dental implant placement especially in cases with minimal crestal width, high esthetic demands, or where exact implant placement is critical for successful treatment outcomes.

Histologic comparison of a thermal dual-etched implant surface to machined, TPS, and HA surfaces: bone contact in vivo in rabbits.

PURPOSE: To evaluate the bone contact percentage around a proprietary high-temperature dual-etched (DE) implant surface (Osseotite) versus implants with machined, hydroxyapatite (HA), and titanium plasma-sprayed (TPS) surfaces. MATERIALS AND METHODS: Each implant type was placed in rabbit tibiae of the same animal and assessed at 1 to 8 weeks. Histologic sections were prepared and analyzed histomorphometrically. RESULTS: The DE implant surface achieved higher levels of bone contact percentage than the other surfaces. This enhanced contact level was apparent by 3 weeks and seen at all time intervals except 2 weeks, at which machined exceeded the DE mean. In evaluating which surface outscored the others in each individual rabbit, there was a statistically significant confidence for the DE surface (P < .001). The other 3 surfaces failed to show significance, although the numeric scores for the TPS surfaces were below random expectations and the machined scores were slightly above. There was no correlation between degree of roughness and bone contact percentage. DISCUSSION: Arbitrarily roughening the implant surface may not result in a large change in bone conductivity. The specific texture of the DE process yielded more contact, possibly as the result of better fibrin clot retention and growth factor enhancement. CONCLUSIONS: There was no advantage demonstrated in this model to an HA surface over titanium. The bone contact to the rough HA surface scored similarly to that for the TPS surface of similar roughness, and well below that for the DE titanium surface. The DE surface appeared to have an advantage in bone contact percentage, particularly in early healing in a rabbit tibia model.