The Effect of Implant Neck Design on the Crestal Bone Levels that Support the Tissue Around the Implant –Restoration

This research aims to evaluate the impact of the shape of the implant neck on the level of crestal bone surrounding it. Dental implant surgeries were performed, and prosthesis were placed over (28) implants in six jaws for five patients (5 upper jaws and 1 lower jaw). These dental implant surgeries were performed on the jaws such that one of the sides received 2 or 3 implants from the BICON system with beveled neck, while the opposite side received the same number of implants from the ONB system from IDI with non-beveled neck. The implant-restorations were then performed following complete osseointegration. The patients were observed via periodic panoramic radiographs starting from the day the prosthesis were placed, then 3 months after the restoration, 6 months after the restoration and 18 months after the restoration. The distance between the implant neck and the point of contact of the crestal bone with the implant neck (mesial and distal) was measured for each implant using periodic panoramic radiographs taken for every patient. The results revealed the occurrence of peri-implant crestal bone loss, known as the saucerization phenomenon. Independent samples T-test was conducted to compare the mean bone loss with both types of implants mentioned above. The results of the study did not show any statistically significant differences in the early stages of the restoration/prosthesis. Yet, after 6 months and up to 18 months post restoration, statistically significant differences emerged verifying that the peri-implant bone loss occurring in implants with a beveled neck was less than that occurring around implants with a non-beveled neck, confirming the incidence of an initial bone loss following the restoration in all cases. This research revealed that the design of the implant yields better esthetic results in the presence of a bevel in the implant neck, taking into consideration the occurrence of a definite bone loss.