Comparison of the success rate of bone level and tissue level implants placed in autogenous onlay bone block grafted...

The present study aims to compare the success rate of bone level implants and tissue level implants placed in previously reconstructed ridges using autogenous onlay bone block grafts.

This study included 53 patients presenting alveolar bone defects and treated with autogenous onlay bone block grafts. After 6 months of healing, implant placements were performed in augmented areas. 31 bone level implants and 48 tissue level implants were placed with the standard surgical protocol. Follow-up data (pain, mobility, exudation from peri-implant space, success rate, marginal bone loss) were retrospectively collected after five years of prosthetic loading.

The overall implant success rate at the 5-year examination was 95,8% for the tissue level implant group and 87% for bone level implant group. No tissue level implants were removed during the follow-up period however, there were four failed implants in the bone level group. Tissue level implants have a significantly higher success rate than bone level implants (p = 0.022). The average marginal bone loss was 1.37 ± 0.60 mm for tissue level implants and 1.59 ± 0.72 mm for bone level implants. No statistically significant differences for the peri-implant bone loss was found between groups (p = 0.263).

Tissue level implants present better long-term results in terms of success rate, as compared with bone level implants, when placed in reconstructed areas. No significant differences were found between the two types of implants as far as peri-implant bone maintenance is concerned.