EFFECTS OF GUIDED BONE REGENERATION AROUND COMMERCIALLY PURE TITANIUMAND HYDROXYAPATITE-COATED DENTAL IMPLANTS .1. RADIOGRAPHIC ANALYSIS

THE PURPOSE OF THIS STUDY was to determine which treatment of a large osseous defect adjacent to an endosseous dental implant would produce the greatest regeneration of bone and degree of osseointegration: barr ier membrane therapy plus demineralized freeze-dried bone allograft (D FDBA), membrane therapy alone, or no treatment, The current study asse ssed radiographic density changes in bone within the healed peri-impla nt osseous defect, In a split-mouth design, 6 implants were placed in edentulous mandibular ridges of 10 mongrel dogs after preparation of 6 cylindrical mid-crestal defects, 5 mm in depth and 9.525 mm in diamet er. An implant site was then prepared in the center of each defect to a depth of 5 mm beyond the apical extent of the defect. One mandibular quadrant received three commercially pure titanium (Ti) screw implant s (3.75 x 10 mm), while the contralateral side received three hydroxya patite (HA) coated root-form implants (3.3 x 10 mm). Consequently, the coronal 5 mm of each implant was surrounded by a circumferential defe ct approximately 3 mm wide and 5 mm deep. The three dental implants in each quadrant received either DFDBA (canine source) and an expanded p olytetrafluoroethylene membrane (ePTFE), ePTFE membrane alone, or no t reatment (control). Standardized radiographs were taken at 1 week and 4 months post-implant placement. Computer-assisted densitometric image analysis (CADIA) was performed at 6 areas of interest (coronal, middl e, and apical defect areas mesial and distal to each implant) for each of the implant sites. Significantly greater increase in bone density was obtained using DFDBA/ePTFE compared to ePTFE alone or the controls ; likewise, ePTFE alone resulted in greater bone density change than t he controls. There were no significant differences in radiographic bon e density adjacent to Ti versus HA-coated implants. When 3 dogs having postoperative membrane complications were eliminated from the analysi s, the results were similar with the exception that defects adjacent t o Ti implants had significantly less density gain when compared to HA- coated implants. The results of this study indicate the use of DFDBA/e PTFE in large surgically-created defects promotes a denser healing of bone adjacent to implants when measured radiographically than either e PTFE alone or no treatment.