Effect of immediate functional loading on osseointegration of implants used for single tooth replacement. A human histological study

Abstract

To analyze hard tissue reactions to immediate functionally loaded single implants that were installed either with a conventional drill preparation procedure or with an osteotome preparation technique. Thirteen subjects with two sites requiring single tooth rehabilitation by means of implants volunteered for the study. Each subject received one test (immediate functionally loaded) and one control (non-loaded) implant. In six subjects (group 1) the implants were placed using a conventional drilling procedure, whereas in the remaining seven subjects (group 2) an osteotome preparation procedure was performed. Block biopsies containing test and control implants and peri-implant bone tissues were collected at 1month in four of the subjects in group 1 and in five subjects of group 2. The remaining implant sites were sampled at 3months after implant placement. The biopsies were prepared for histological examination. Two implants of the test-2 group (osteotome preparation) representing 1month of healing and another test-2 implant representing 3months of healing failed to integrate. A multilevel multivariate statistical analysis demonstrated that no differences in bone-to-implant contact (BIC)% were found in between test and control implants, the density of newly formed peri-implant bone was significantly higher around test than control implants at 1 and 3months of healing. Sections representing osteotome technique sites showed fractured trabeculae and large amounts of bone particles. It is suggested that immediate loading of implants does not influence the osseointegration process, whereas the density of newly formed peri-implant bone at such sites appears to be increased in relation to unloaded control implants. The use of an osteotome preparation technique during installation results in damage of peri-implant bone and enhances the risk for failure in osseointegration.