Influence of interimplant distance on bone resorption : A radiological and histological study in beagle dogs

Lee, Su Youn; Lee, Jae Wook; Kim, Jin Wook; Lee, Sang Han

Abstract

INTRODUCTION: Possible etiologic factors associated with bone loss around implants after implantation are surgical trauma, occlusal overload, peri-implantitis, presence of micro gap and the formation of biologic distances. Tarnow et al. observed that the crestal bone loss was greater when the distance between the implants was <3mm than when the implants were > or =3mm apart. The aim of this study was to evaluate the influence of different interimplant distance on marginal bone and crestal bone resorption in the beagle dogs.
MATERIALS AND METHODS
The mandibular premolars of 5 dogs were extracted bilaterally. After 12 weeks of healing, each dog received 7 implants. On each side, implants were separated by 2mm (Group 1) and by 5mm (Group 2). After 16 weeks of healing, the dogs were sacrificed. Marginal bone loss was determined through linear measurements made between the implant-abutment junctions and the most coronal portions of the bone in contact with the implant surface. A line was drawn uniting the implant-abutment junctions of the adjacent implants, and a linear measurement was made at the midpoint in the direction of the most coronal peak of the interimplant bone crest to determine the crestal bone loss. Both of them was measured radiologically and histologically. RESULT AND CONCLUSION: In radiological analysis, the mean of marginal bone loss was 1.26+/-0.14mm for group 1 and 1.23+/-0.34mm for group 2, the mean of crestal bone loss was 1.10+/-0.14mm for group 1 and 1.02+/-0.30mm for group 2. The results were not statistically significant between 2 groups. In histological analysis, the mean of marginal bone loss was 1.63+/-0.48mm for group 1 and 1.62+/-0.50mm for group 2, the mean of crestal bone loss was 1.23+/-0.35mm for group 1 and 1.15+/-0.39mm for group 2. The differences were also not statistically significant. The clinical significance of this result is that the increase in the crestal bone loss results in the increase in the distance between the base of the interproximal contact of the crowns and the bone crest, and this determines if papilla will be present or absent between implants. Considering this fact, keeping up sufficient interimplant distance is important to minimize crestal bone loss.