Postsurgical Bone Level and Density around Implant by Digital Radiographs

Objectives: Bone level and density around dental implant is important factor for prediction of the prognosis. The aim of the present study was to evaluate post-surgical bone level and density adjacent to submerged dental implant by digitized conventional radiographs and subtraction images. Methods: The radiographs taken for seventy-eight implants (32 implants of 3.25mm diameter, 46 implants of 4mm diameter; Spline, Zimmer dental) were used. The radiographs were obtained at three time periods; at the time immediately after first surgery, and 3 and 6 months after the surgery before the second surgery. The radiographs were digitized into a personal computer by a scanner. The images were manipulated by EMAGO/Advanced 5.x software (Oral Diagnostic system, Amsterdam, The Netherlands) and linear and logarithmic digital subtraction images were produced. The logarithmic subtraction was enhanced with the use of a filter. The bone level and density around implant was assessed in the subtraction images. The subtraction image was analyzed by NIH image. The data was analyzed using one-way ANOVA. Differences between experimental groups were considered statistically significant at the p<0.05 levels. Results: The bone loss was observed around the implants at 3 or 6 month after first surgery. The bone levels around the implants were significantly lower at 3 or 6 month after first surgery than at immediately after first surgery. The implants of 4mm diameter showed significantly higher bone levels than the implants of 3.25 mm diameter both at 3 and 6 months after the first surgery. Conclusions: The results indicate that the implant having a larger diameter may lose less amount of bone around the implant after the first surgery.