Healing of Bio-Oss® grafted marginal gaps at implants placed into fresh extraction sockets of incisor teeth in dogs: a study on the effect of submerged vs. non-submerged healing.

Abstract

To evaluate the effect of submerged vs. non-submerged (NS) protocols in healing outcomes of grafted marginal defects of immediate implants. The second maxillary incisors were extracted bilaterally in six greyhound dogs. Bone level reduced diameter implants were installed into the extraction sockets leaving orofacial gaps of 2 mm wide. Defects were filled with Bio-Oss(®) and covered with Bio-Gide(®). On the one side, the flap was advanced to fully submerge the implant, and on the other, the flap was sutured to allow NS healing. After 3 months of healing, the dogs were sacrificed and block biopsies were obtained to perform histological and morphometric analysis. All implants were clinically healthy and well integrated into bone. In the majority of the specimens, the original bone in the coronal 2-3 mm of the buccal crest had completely resorbed and was replaced by a regenerated bone wall consisting of Bio-Oss(®) particles surrounded by newly formed bone. Horizontal and vertical resorption of the buccal bone resulted in ≥1 mm exposure of the implant surface in one-third of implants. Minor differences existed in some aspects of hard tissue healing between submerged and NS. There was very little difference in healing outcomes as well as modelling of the facial bone wall between the submerged and NS protocols in relation to immediate implant placement in this dog model.