Exposure of Barriers Used in Guided Bone Regeneration: Rate, Timing, Managenent, and Effect on Grated Bone-A Retrospective Analysis

The purpose of this study is to compare the exposure rate of 3 different barrier types after a guided-bone regeneration procedure as well as to compare the percentage grafted bone dimensional loss with and without exposed barriers. Patient records from September 2007 to May 2015 were reviewed to identify subjects who had received a bone graft followed by implant placement procedure after the graft had completely healed. The subjects were divided into 3 groups: (1) resorbable barrier, (2) nonresorbable barrier, and (3) titanium-mesh barrier. Incidences of barrier exposure were recorded. Cone-beam computerized tomography images before treatment (T0), right after grafting (T1), and after healing (T2) were used to determine the percentage of grafted bone dimensional loss and am quantitative amount of grafted bone remaining (mm(2)). Three cross-sectioned areas, at 1-mm apart, of preplanned implant positions at the grafted site were measured using cone-beam computerized tomography to calculate the remaining grafted bone and grafted bone dimensional change. The exposure rate of all guided bone regeneration was 36.9%. The exposure rate of the resorbable barrier (233%) was significantly lower than titanium mesh (68.9%) and nonresorbable (72.7%; chi(2), P < .001). The results of this study revealed that barrier types have a significant effect on the exposure rate. There was also a significant difference in grafted bone dimensional loss between sites with barrier exposure (58.3%) and sites with no barrier exposure (44.1%) during the healing period (Mann-Whitney U test, P = .008).