Hard and soft tissue integration of immediate and delayed implants with a modified coronal macrodesign: Histological, micro-CT and volumetric soft tissue changes from a pre-clinical in vivo study.

Abstract

To study the healing of peri-implant tissues around implants with a triangular coronal third (test) or cylindrical (control). In eight beagle dogs, immediate and delayed implants were placed. Test and control implants were randomly assigned and the hard and soft tissue healing was evaluated with histology and micro-CT analysis at 4 and 12weeks. The soft tissue contour changes were assessed by image analysis software. When measured at the implant shoulder level, the buccal crestal width (primary outcome assessed in mm) attained similar values in test and control implants. More apically (3mm) test implants had greater buccal crestal width in delayed and immediate sites. For vertical soft and hard tissue measurements, no significant differences were found between Test and Control. Micro-CT evaluation of the buccal volume of interest showed less volume of implant component in T implants in all sites, although bone volume was not significantly different between T/C. Soft tissue contours were similar around T/C implants. Triangular implants showed similar percentage of osseointegration, buccal bone volume and soft tissue contours, although attaining greater buccal crestal bone width. No differences were found in regard to soft tissue dimensions and the position of the first bone-to-implant contact.