Implants versus tooth-implant supported protheses in the posterior maxilla : a 2 year report

Aim of the study

To compare the mechanical and biological reactions to implants placed in the posterior maxilla whilst connected to teeth or only to each other.

Materials and methods

Two types of prosthetic reconstruction were undertaken in the posterior maxillae of 26 patients with bilateral tooth loss. On one side a natural tooth was attached to a more distal implant (Group TISP). On the other side the reconstruction was purely implant-supported (Group ISP). Clinical and radiographic assessments were carried out at 3, 6, 12 and 24 months and the results analysed statistically.

Results

The success rate for the implants (88 %) was the same for the two groups. The peri-implant bone loss at 2 years was significantly greater for the posterior implants (in the position of the 2^nd premolar or molar) in the ISP group.

Conclusion

Where the sinus prevents the placement of more than one implant in the maxilla, connection to a natural tooth is a reliable and predictable procedure. The absence of intrusion is related to the use of rigid attachments between teeth and implants. As far as the differences between the two groups in peri-implant bone loss after 2 years is concerned, the authors advance a biomechanical hypothesis that needs to be clarified.

Commentary

This study is interesting because of the split mouth protocol. This permits the exclusion of factors inherent to the individual that could bias the comparison. In addition, it involves the maxilla where, because of the proximity of the sinus, the need to connect implants to teeth is often observed. There is often a drawback, prosthetic complications frequently occur after two years.