インプラント埋入と同時GBRの臨床経過観察

抄録

So-called osseointegrated implants, such as Brånemark^®, ITI^®, and IMZ^®, introduced in the 1980s, induced more predictable implantology, and eventually the survival rate went up high. However, the position of the implant socket used to be absolutely governed by the condition of the residual alveolar ridge. Guided bone regeneration(GBR) challenged this common knowledge and extended the indication of implant surgery.
There are two approaches for GBR: a staged approach,and a simultaneous approach that is performed when the implant is placed. But the latter has limited indication.
Buser classified the residual alveolar ridge into 4 classes, and advised that the simultaneous approach is contraindicated for a class 4 type of alveolar ridge,which has crator-like bone resorption,leaving about 5.00 mm ridge in bucco-lingual width.
However, the operator encounters many patients who demand less time-consumming implant service. The author has tried to answer their demands and challenged this difficulty by executing the simultaneous approach in class 4 alveolar ridge in daily clinic.
In simultaneous GBR, Goretex Ti-reinforced GTAM^® was used to cover autografted bone chips, which were harvested from the implant socket and the other part of the alveolar ridge. The applied implants were all TPS ITT screw type.The periodentological observation of the postoperative progresses of 6 cases was performed for 3 years postoperatively. Probing attachment level (PAL) and probing pocket depth (PPD), using a WHO probe,were measured chronologically at the insertion of prostheses, 1 year later, 2 years later, and 3 years later, respectively.
As for PAL, the average values were 2.7 mm, 2.7 mm, 2.5 mm, and 2.5 mm at insertion time, 1 year later, 2 years later,and 3 years later, respectively. The total average of measurement of PAL was 2.6 mm. As for PPD, the average values were 1.3 mm, 1.4 mm, 1.4 mm, and 1.4 mm at the insertion of prostheses, 1 year later, 2 years later, and 3 years Iater, respectively. The total average was 1.4 mm.
These values of the measurements indicated that the peri-implant pocket was kept in shallow, healthy condition for 3 years postoperatively. And the author expects this healthy-condition will continue, like other approach. From the result, the author concluded that simultaneous GBR can be indicated in the so-called class 4 type of residual alveolar ridge.