The clinical effectiveness of 6 mm diameter implants.

BACKGROUND

Five- and 6 mm diameter screw-type endosseous implants have been used for the last decade. While some studies have reported very promising results (94% to 98% success rate), others have demonstrated survival rates below those clinically acceptable (75% to 87%). Moreover, such implants have been associated with increased cervical bone resorption and thread exposure.

METHODS

Between June 1999 and July 2003, 43 patients received treatment with 6 mm diameter tapered hydroxyapatite (HA)-coated implants. A total of 45 implants were placed. All patients were recalled annually after implant exposure. One patient was lost to follow-up after 1 year. Forty-four implants were evaluated at the recall examinations. All implants supported a fixed prosthesis; in the majority of patients (35 implants), it was a single-tooth fixed prosthesis. The mean loading time was 23.4 months (range, 1 to 54 months).

RESULTS

No implants were lost during the loading period. The overall survival rate was 100%. Crestal bone remodeling was examined using periapical radiographs. After a mean of 23.4 months in function, only one implant presented bone loss beyond the first thread.

CONCLUSIONS

This study showed that high survival rates can be obtained after prosthetic treatment with 6 mm-wide tapered HA-coated implants. Long-term prospective studies are needed to confirm these results.