The effect of interceptive treatment on bone loss caused by early coverscrew exposure : a comparative retrospective study

Abstract

[한글]

[영문]The aim of this study was to evaluate whether interceptive treatment of premature bone loss caused by early cover screw exposure is effective or not. Nineteen patients with a mean age of 53.8 years with either one exposed and one non-exposed dental implant (18 patients) or with two exposed and two non-exposed dental implants (one patient) were selected. When a cover screw exposure was observed between the first and the second surgeries, an uncovering surgery was performed immediately. The inflammatory tissue was excised and healing abutments were connected after the cover screws were removed without flap elevation. For the coverscrews non-exposed group, the second surgery was performed six months later for maxillary implants and three months later for mandibular implants. Bone loss around each implant was analyzed after one year of functional loading and gingival parameters (modified plaue index and modified sulcus bleeding index) of peri implant tissue were evaluated. Bone loss after loading and gingival parameters were compared using Wilcoxon signed-rank test.The mean crestal bone loss from fixture placement to prosthesis delivery was 0.41 ± 0.43 mm in exposed dental implants and 0.16 ± 0.22 mm in non-exposed dental implants. The differences in the changes in mean crestal bone loss from fixture placement to prosthesis delivery were statistically significant between exposed and non-exposed implants (p = 0.0034). The mean crestal bone loss from prosthesis delivery to one year of functional loading was 0.07 ± 0.08 mm in exposed dental implants and 0.06 ± 0.09 mm in non-exposed dental implants. The differences in the changes in mean crestal bone loss from prosthesis delivery to one year of functional loading were not statistically significant between exposed and non-exposed implants (p = 0.8603).Based on the present findings, the connection of a healing abutment as soon as a perforation is detected should allow peri-implant soft tissue to re-establish the dimension of the biologic width or a soft tissue barrier. Taken together, the results of this study show that once healthy fibrointegration is stabilized, premature bone loss caused by early cover screw exposure will no longer influence peri-implant bone levels.