Bone regeneration and collagen fiber orientation around machined and rough surface of CaP-coated implants in circumferential defect : a histomorphometric study in dogs

Abstract

Objectives: The aim of this study was to compare the bone formation and tissue reactions around CaP-coated machined surface and CaP-coated rough surface implants (CPMS and CPRS) at the critical-sized circumferential ridge defects in dogs at 4 and 8 weeks of the observation period.Materials and methods: All mandibular premolars were extracted bilaterally in five male mongrel dogs. After eight weeks, circumferential marginal defects (2mm gap and 5mm depth) were created unilaterally using a customized drill and CPMS and CPRS implants were inserted. Four weeks later, the contralateral side was prepared using the same protocol. The dogs were then sacrificed four weeks after the last surgery. Specimens were analyzed histologically and histomorphometrically.Results: Both CPMS and CPRS implants showed successful osseointegration at the non-defect area, normal bone area regardless of the observation periods (4 and 8 weeks). All circumferential defects were incompletely filled and osseointegration was limited at the half lower area of the defect. In unfilled defect area, collagen fibers were arranged perpendicularly or obliquely onto the exposed implant surfaces, especially on CPRS implants. Conclusion: Within the limits of this study, it can be suggested that CPMS and CPRS implants show no difference in bone-to-implant contact and bone regeneration in the circumferential defects in 4 and 8 weeks healing period, and unique features of perpendicularly/obliquely arranged collagen fibers onto the exposed implant surfaces