[An assessment of different crown-to-implant ratio for implant teeth in the posterior region over 5 years].

Purpose: To evaluate the influence of crown-to-implant ratio (C/I ratio) on the results of restoration in the posterior region.

Methods: From January 2007 to January 2012,119 patients with 208 ITI implants in the posterior region were followed up for 6-66 months. Implant restorations were divided into three groups according to their respective clinical C/I ratios after noble porcelain-fused-to-mental crown restoration: C/I ≤1,11.5. Cumulative survival rate was calculated by life-table analysis. SPSS 13.0 software package was used for statistical analysis.

Results: The mean clinical C/I ratio of 208 implants was 1.07±0.24, with maximum C/I of 1.8 and C/I of 0.6, 9.6 percent; of 208 implants had biomechanical complications. Differences among three groups were not statistically significant in annual crestal bone loss and biomechanical complications. In addition,implant cumulative survival rate in C/I ratio>1 was 97.6 percent;,and 98.8 percent; in C/I≤ 1.

Conclusions: Clinical C/I ratio does not significantly influence peri-implant crestal bone loss and biomechanical complications, implant restorations with C/I ratios>1 is successfully used in the posterior areas in this study.