To carry out a comparative study of two implants with different neck features and prostheses platform connection (machined with external connection and rough-surfaced with switching platform) upon peri-implant marginal bone loss, before and after functional loading.

MATERIALS AND METHODS

A randomized, prospective radiological study was made. Eighteen totally edentulous patients were selected. Subjects were divided into two groups according to the type of implant neck used: (a) Osseous®, with machined surface, without microthreads, external connection, and without platform switching; and (b) Inhex®, with treated surface, microthreads, internal con- nection, and platform switching.

Fifteen patients that received 120 dental implants were included: 47% Osseous® group and 53% Inhex® group. Global mean marginal bone loss with Osseous® was 0.27 ± 0.43 mm and 0.38 ± 0.51 mm as determined 6 and 12 months after prosthetic loading, respectively, whereas in the case of Inhex® was 0.07 ± 0.13 and 0.12 ± 0.17 mm. These differences were statistically signifi- cant (P = 0.047). Difference between Osseous® and Inhex® in maxilla (P = 0.272) and mandibu- lar (P = 0.462) bone loss were not statistically significant.

Bone loss after 6 and 12 months proved statistically significant between two groups, with comparatively greater loss in the case of Osseous® implants vs. Inhex® implants. Regardless the heerogeneity of the two groups (neck shape, microthreads, surface texture), the implant– abutment connection appears to be a significant factor on peri-implant crestal bone levels. Anyway, in both groups, the values obtained were within normal ranges described in the lite- rature.