1999 Volume 12 Issue 3 Pages 356-362
From 1994 to 1998, implant installation was done in 15 cases of guided bone regeneration (GBR) combined with autobone graft.
Materials and methods: Fifteen patients, 12 females and three males, age 18 to 65 years old. The patterns of bone defects of the alveolar ridge were divided into a narrow type (ten cases) and a concave type (five cases). The extent of the GBR treatment area was distributed from two-teeth to five-teeth in width.
Surgical procedure:
1. One or two pieces of cortical bone fragment and some chips of cancellous bone were gathered from the mentum or the anterior region of the mandibular ramus.
2. The bone surface of the alveolar ridge was exposed and several small holes were made on the lateral surface by a small drill.
3. The cortical bone was fixed to the lateral wall of the alveolar ridge by a mini-screw.
4. The e-PTFE membrane was fixed to the top of the alveolar ridge by two mini-screws for covering with grafted bone.
5. The space around cortical bone was filled with pieces of cancellous bone and the lower end of the membrane was fixed to the alveolar ridge by mim-screws.
6. Fixtures were installed about six months after the initial GBR surgery.
Evaluation of bone formation was classified into three grades. If enough bone formation beneath the membrane was found, it was evaluated as “ excellent.” If the bone volume was almost the same as that of grafted bone, it was evaluated as “not good.” If absorption or reduction of grafted bone was observed, it was evaluated as “poor.”
Results: In five of 15 cases, no trouble occurred during the entire treatment course until implant installation. In the other ten cases, mucus wounds ruptured and the e-PTFE membrane was exposed after surgery; therefore, the membrane was partially cut and the mucus wound was resutured. In four of ten cases, preimplant surgery rerupture did not occur, but in the other six cases, the membrane was reexposed. Therefore, in four cases, the whole membrane was removed and in two, the whole membrane and a part of the grafted bone, which partially necrosed, were removed. In the concave type to which this GBR method was applied, the incidence of membrane exposure was higher than in the narrow type.
In ten of 15 cases, bone formation was evaluated as “ excellent, ” in three it was “not good,” and in two “poor.” Fixtures could be installed in all of the cases.
