The Effect of Surface Topography of Dental Implants on the Resorption of the Inter-implant Bone Crest

Introduction : The purpose of this study was to assess whether differences in the surface topography of implants affect the bone resorption of adjacent inter-implants.Subjects and Methods : From the patients who underwent implant therapy at Meikai University PDI Tokyo Dental Clinic between 2004 and 2014, patients in which two or more implants with identical surface topography had been placed adjacently and who had the superstructure in place for 3 years or more were extracted. Subjects were divided into 2 groups according to the surface topography of the implants, and radiological measurements were performed. The different surface topographies that were compared were implants that were machined smooth for 3 mm from the platform and thereafter the surface was roughened as far as the tip (group A), and implants with a roughened surface all the way from the platform to the tip (group B). The inter-implant distance of the adjacent implants was also measured, and measurements were compared using Mann-Whitney U Test (p ＜ 0.01)Results : Among subjects with an inter-implant distance of 3 mm or more the amount of horizontal bone resorption and vertical bone resorption tended to be smaller in the group B. However, no differences were found between the group A and the group B among subjects with an inter-implant distance less than 3 mm.Discussion and Conclusion : In the present study, a statistically significant difference was found in the amount of bone resorption due to differences in implant surface topography. However, there were no effects due to differences in surface topography among subjects with an inter-implant distance less than 3 mm. Using implants which have the whole surface roughened and maintaining an appropriate distance between adjacent implants are likely to be useful in protecting against inter-implant bone resorption.