Dimensional changes of buccal bone in the edentulous maxilla with telescopic-retained implant-supported fixed dental prostheses.

Abstract Statement of problem The buccal bone in an edentulous maxilla loses thickness over time because of physiological changes. However, the dimensional changes of the buccal bone in an edentulous maxilla with an implant-supported fixed dental prosthesis are unknown. Purpose The purpose of this retrospective clinical study was to evaluate cone beam computed tomography (CBCT) images of the dimensional changes of the buccal bone in edentulous maxillae with complete-arch telescopic-retained implant-supported fixed dental prostheses (CTI-FDPs) after 6 years by using a professional retrieval system. Material and methods This study included 17 participants with edentulous maxillae who had been provided with CTI-FDP with 121 taper joint implants. A three-dimensional radiographic analysis by using CBCT was performed at implant insertion (0 years) and after 6 years. Vertical and horizontal bone measurement values were evaluated. During horizontal bone thickness measurement, 4 different levels, 0, 2, 4, and 6 mm apical to the implant shoulder, were evaluated as bone value (BV)0mm, BV2mm, BV4mm, and BV6mm, respectively. The BVs were compared with the Wilcoxon signed-rank test and Kruskal-Wallis test (α=.05). In addition, the Spearman rank correlation coefficient was used to identify 0yBV factors that influence the 6yBVs. A nonlinear regression analysis was used to clarify the slopes of 0yBVs and 6yBV0mm. Results Significant decreases in vertical and horizontal BVs were found between 0 years and 6 years (P Conclusions The buccal bone in an edentulous maxilla with fixed implant-supported prostheses lost significant vertical and horizontal bone thicknesses after 6 years. At implant insertion, both a 0.58-mm buccal bone on the platform and a 0.78-mm buccal bone at 2 mm apical to the implant shoulder are necessary for longer term maintenance of bone on the platform of implants specifically supporting CTI-FDPs.