Removal torque of immediately loaded transitional endosseous implants in human subjects

Transitional implants were designed to support provisional restorations and to allow for load-free osseointegration of conventional implants while a patient was provided with immediate esthetics and function. The purpose of this study was to evaluate the removal torque values of immediately loaded transitional implants in human subjects.

Thirty-one 1.8-mm-diameter transitional implants were placed in 4 patients to support provisional restorations and were subjected to immediate loading. Removal torque values were recorded using a modified ITI torque driver, which was calibrated on an Instron test machine. Torque values were subjected to analysis of variance and post hoc comparisons of means (P < .05).

Twenty-six implants were removed intact with torque values between 10.5 and 22.9 Ncm, while 5 fractured at the bone crest at values between 27.1 and 35.4 Ncm. Mean torque values increased with time in function. These values were significantly lower in the maxilla (16.1 +/- 4.8 Ncm) than in the mandible (24.0 +/- 7.3 Ncm).

Results suggest that these transitional implants may be safely removed from the maxilla after 7 to 15 months, but there is a risk of implant fracture during removal from the mandible after 10 months.

Removal torque levels for these implants indicate varying degrees of integration even though they were subjected to immediate loading.