Abstract
For long-term stability and favorable function of the endosseous dental implant, direct bone contact with the implant is highly recommended. From such a standpoint, the 2-stage implant procedure is more preferrable. However, in the 2-stage implant procedure, the problem of the gap between fixture and abutment still remains.
In this study, we developed a new 2-stage implant procedure in which the fixture and lower portion of the abutment were coated with hydroxylapatite (HA) to achieve bone sealing of the gap between fixture and abutment. Four monkeys were used. Eight newly designed HA-coated implants and eight uncoated implants as a control were inserted into the prepared edentulous area. After 3 months of insertion, the abutment with/without HA-coating was connected to the fixture by lock screw. Animals were sacrificed 5 and 10 weeks after abutment connection. Undecalcified ground sections were made and examined by light microscopy. Lock screws were loose in some implants. In these cases,severe inflammation was observed at the gingiva around the implant, and no bone formation was observed there. However, in other cases in which lock screws were not loose, the gap between fixture and abutment was completely sealed by newly formed bone tissue.
