Influence of early cover screw exposure on crestal bone loss around implants: intraindividual comparison of bone level at exposed and non-exposed implants.

BACKGROUND

The objective of this study was to evaluate the influence of early exposure of the cover screw on crestal bone loss around implants.

METHODS

The study population consisted of 19 patients who were treated with dental implants placed using a two-stage surgical protocol and had early exposed and non-exposed implants (20 early exposed and 20 non-exposed implants). The crestal bone loss at exposed and non-exposed implants in each patient was evaluated with a periapical radiograph taken at the first surgery and at suprastructure insertion using a computerized image-analysis system. The bone loss was compared using the Wilcoxon signed-rank test.

RESULTS

The mean crestal bone loss at exposed implants was 0.40 +/- 0.53 mm, and it was 0.18 +/- 0.26 mm at non-exposed implants. The Wilcoxon signed-rank test revealed a statistically significant difference in crestal bone loss between exposed and non-exposed implants in the same patient (P = 0.02).

CONCLUSIONS

The early exposure of the cover screw that results in breakdown of the mucosal seal seems to accelerate early peri-implant crestal bone loss. Periodic follow-up after the first surgery may be critical for minimizing the influence of early exposure.