Immediate implantation in fresh extraction sockets. A controlled clinical and histological study in man

Aim of the study

This controlled histological study compares the osseointegration of implants inserted immediately after tooth extraction with those fitted according to a traditional protocol.

Materials and methods

Forty-eight patients needing bilateral implants were included in this study. The main criterion for inclusion was the presence of a site suitable for an immediate post-extraction implant on one side of the mouth (test site) and a healed site suitable for a conventional implant (control site), symmetrically placed on the other side. At the test sites, the implant was placed at the level of the crest of the ridge, leaving a space no greater than 2 mm between the bony walls and the implant and without the insertion of any material or the use of a regenerative membrane. Twenty-four test implants were placed in the maxilla and 24 in the mandible were compared with the same number of control implants. Healing posts were in place for 6 months. Six months later, after taking plaque and inflammation indices, the test and control implants were removed using a trephine.

Results

The clinical indices showed no difference between the test and control implants. The percentage of bone-implant contact was 64.8 % and 62.3 % respectively in the maxilla and 70.6 % and 67.9 % in the mandible. However, three test fixtures showed the interposition of a limited amount of dense, non-inflamed connective tissue at the coronal part of the implant (1-1.5 mm).

Conclusion

These results show that in cases of immediate implantation, at sites where all four bony walls are within 2 mm of the implant, a regenerative membrane is not needed in order to allow a degree of osseointegration equivalent to that achieved with a traditional protocol.

Commentary

This study, with its unique protocol, confirms the data obtained from earlier animal experiments.