Microcomputed Tomography and Histologic Analysis of a Maxillary Implant Retrieved 19 Months After Placement and Indirect Sinus Augmentation With Biphasic Calcium Phosphate: A Case Report

Introduction: Implant osseointegration in regenerated bone and the resorptive outcome of graft materials are major clinical concerns.Case Presentation: A 40-year-old female patient underwent an indirect maxillary sinus augmentation with biphasic calcium phosphate (BCP) in conjunction with implant placement. Because of implant fracture, the implant and adjacent tissues were excised with a trephine bur 19 months after placement. The biopsy with the implant in place was analyzed by microcomputed tomography (micro-CT) and histology. Marginal bone loss of the implant was evident, particularly on the fractured side. The graft particles were predominantly integrated in bone. Resorption lacunae were observed in the marginal bone area, but were not observed on the surface of the graft particles. Graft particles without contact to bone were observed coronal to the most coronal level of bone-to-implant contact, presumably exfoliated after marginal bone resorption. Of the total peri-implant volume, 20.5% was residual...