Radiographic Analysis of Bone Levels around Teeth that Oppose Implants

Objectives: Although the bone levels around natural teeth that oppose an implant may be altered, little information has been reported. The aim of the present study was to evaluate the bone levels around natural teeth that oppose an implant using digitized conventional radiographs and subtraction images. Methods: Radiographs taken for 80 natural molars that oppose an implant were used. The radiographs were obtained at 6, 9 and 12 months after the implant crowns were fixed (HA coated implants of 4mm diameter, Spline, Zimmer Dental). Contralateral molars in the same jaw that did not oppose an implant were used as controls. The radiographs were digitized into a personal computer using 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 levels around natural teeth that oppose an implant and around control teeth were assessed in the subtraction images. The subtraction image was analyzed using NIH image. The statistical difference between the bone levels was analyzed using F-test. Differences between the group of teeth that oppose implants and the control group were considered statistically significant at p<0.05 levels. Results: Significant bone loss or gain was often observed around the teeth that oppose implants at 6, 9 or 12 months after the implant crown was fixed. Little bone loss was observed around the control teeth. The variance of the data in the group of teeth that oppose an implant was significantly greater than that in the control group. Conclusions: Our results suggest that the bone levels around teeth that oppose implants may be altered when compared to bone levels around teeth that do not oppose an implant.