A retrospective analysis of 125 single molar crowns supported by two implants: long-term follow-up from 3 to 12 years.

PURPOSE: The purpose of this study was to analyze retrospectively the survival rate of implants used in pairs to support a single molar crown over a long-term follow-up period and to compare the efficacy of this technique to other existing methods of treatment.

MATERIALS AND

METHODS

The charts and radiographs of 105 patients who each received two implants to support a screw-retained single molar were examined according to the following criteria: age, gender, location of implant, time of loading (delayed versus immediate), opposing dentition, and the existence of adjacent implants.

RESULTS

Patients with follow-up between 3 and 12 years were selected to illustrate the long-term outcomes of the two-implant replacement procedure. Two hundred fifty implants were placed in 125 molar sites in 105 patients. Five of the 250 implants failed, resulting in a cumulative survival rate of 98.0%. Seven of 125 restorations experienced porcelain fracture (5.6%), seven prosthetic screws loosened (5.6%), and one abutment screw loosened (< 1.0%).

DISCUSSION: The placement of two implants to support a screw-retained single molar successfully reduces rotational forces that create stress on the implant. A single regular-diameter or even a wide-diameter implant is susceptible to these forces, which may lead to fatigue over the long term.

CONCLUSIONS

Two implants for the replacement of a single molar represent an effective method that provides a high survival rate over a long-term follow-up period. This approach produced a cumulative survival rate higher than that usually seen in studies of single implants used for molar replacement. The two implant-supported molar crown showed fewer complications than single implant-supported molar crowns.