The Effect of Simplifying Dental Implant Drilling Sequence on Osseointegration: An Experimental Study in Dogs

Objectives. To test the hypothesis that there would be no differences in osseointegration by reducing the number of drills for site preparation relative to conventional drilling sequence. Methods. Seventy-two implants were bilaterally placed in the tibia of 18 beagle dogs and remained for 1, 3, and 5 weeks. Thirty-six implants were 3.75？mm in diameter and the other 36 were 4.2？mm. Half of the implants of each diameter were placed under a simplified technique (pilot drill？+？final diameter drill) and the other half were placed under conventional drilling where multiple drills of increasing diameter were utilized. After euthanisation, the bone-implant samples were processed and referred to histological analysis. Bone-to-implant contact (BIC) and bone-area-fraction occupancy (BAFO) were assessed. Statistical analyses were performed by GLM ANOVA at 95% level of significance considering implant diameter, time in vivo, and drilling procedure as independent variables and BIC and BAFO as the dependent variables. Results. Both techniques led to implant integration. No differences in BIC and BAFO were observed between drilling procedures as time elapsed in vivo. Conclusions. The simplified drilling protocol presented comparable osseointegration outcomes to the conventional protocol, which proved the initial hypothesis. 1. Introduction Osseointegration has been defined as the intimate contact between bone tissue and implanted biomaterial in the optical microscopy level, and such phenomenon has rendered dental implantology as one of the most successful treatment modalities in both dentistry and medicine [1, 2]. However, while high success rates have been reported (often higher than 90% over a decade), the early failure of the osseointegration has been associated with endogenous factors such as quantity and quality of bone, smoking habits, and host systemic impairment, as well as nutritional status and osteometabolic disorders that may impair bone healing or affect the maintenance of osseointegration. On the other hand, especially in cases where endogenous factors are not present, failure of dental implants has also been attributed to exogenous factors such as implant design (including macro- and microgeometry), surgical technique (excessive surgical trauma), overload, misfit of suprastructures, or surgical site infection [3, 4]. Albrektsson et al. (1981) suggested that there are 6 factors that determine the success of osseointegration, that is, biocompatibility, design, surface, state of the host bed, surgical technique, and loading conditions [5]. Needless to say,