Brånemark implants in the posterior maxilla : Clinical study of 660 implants followed up for 5 to 12 years

Aim of the study

To determine the possible causes of loss of implants in this risk area.

Materials and methods

660 implants that were placed in the maxillary posterior segments between November 1986 and December 1994 in 202 patients aged between 18 and 81 years. If an implant was not immovable on placement to a force of 40 Ncm, it was removed.

Results

13 implants (2 %) failed between the time of placement and subsequent loading, 12 within the first year of loading and 10 later on (2 fractured between 3 and 4 years). This gives a cumulative success rate of 94.4 % and 93.4 % at 5 and 12 years respectively. According to the author, the quantity and quality of bone had little influence on the failure rate and he prefers to accord greater importance to planning and to surgical technique (implants ≥3.75 mm, if possible and to place them in the axis of the prosthesis).

Commentaries

The study provides no further details in connection with other studies (Jemt and Lekholm, 1995). Amongst the 30 patients who lost implants, 5 of them accounted for 58 % of the failed implants. Were these problems of bone quality or purely infection problems ? In conclusion, this study provided no new information of the causes of implant failure in the posterior segments of the maxilla.