A Retrospective Evaluation of 1381 Implant-Supported Single-Tooth Restorations

Objectives: The aim of the present study was to evaluate the overall survival rate and factors affecting this clinical outcome in 1381 consecutively placed implant-supported single crowns up to 6-year period. Methods: There were 1381 implants placed in 1215 subjects, during the past 6 years (1999-2005). Of these subjects, 1073 were males and 142 females, who required single-tooth replacement. The average time from implant placement was 2.7±4.27(SD) years. Most of the implants were placed in the maxillary premolar area (39.6%) followed by the premaxilla area (28.8%). Implant survival as well as implant location, need for bone augmentation, implant dimensions, and implant type were recorded and analyzed. Results: Ninety-five implants failed, resulting an overall survival rate of 93.1%. Bone augmentation was performed in 9.7% of the implants with 92.5% survival rate which was similar to the survival rate of non-augmented areas (93.2%; p=0.78). The average implant length was 13.3 ranging from 8 to 16mm. Longer implants (11mm or longer) showed similar survival rate as did implants shorter than 11mm (93.2% vs. 90.2% respectively; p=0.4). Implant width ranged between 3.25 to 5 mm. (mean 3.9) with no effect on implant survival (p=0.45). There was significant difference in implant survival according to the anatomical zone of implant placement (p=0.0075). The maxillary premolar area showed the highest survival rate (96.2%). Implant type was significantly correlated to implant survival (p<0.0001) ranging from 88.3% to 98% in the three implant types. Conclusion: Implant-supported single-tooth replacement is a predictable procedure with a very good survival rate up to 6-years.