(13) The Effects of Clockwise and Counterclockwise conventional and Osseodensifying Drilling on Bone Dimensions and Biomechanical Properties

Introduction: Alveolar bone dimension and density are important factors affecting the success of dental implants. Osseodensification techniques have been used for osteotomy preparation to increase the dimension and bone density with counterclockwise (CCW) drilling motion. However, the effects of conventional drills with CCW have not been tested compared to the osseodensification burs. The aim of this study is to compare the effects of regular implant drills with osseodensifying drills used in clockwise and CCW motions on bone dimension change and implant primary stability.

Methods: A total of 40 bone models were created (20 x 15 x 4 mm) from porcine tibia to represent implants placed in soft bone. Implant osteotomies were prepared in the bone models, using one of the following techniques: 1. Regular implant drills in a clockwise direction (group A), 2. Regular implant drills in a counterclockwise direction (group B), 3. Osseodensifying drills in clockwise direction (group C), and 4. Osseodensifying drills in a counterclockwise direction (group D). Bone level tapered shape titanium alloy implants (4.1x10 mm) were placed following osteotomy creation. Implant stability quotient (ISQ) was measured after implant placement. Each bone model was scanned with an optical scanner to convert to Standard Tessellation Language (STL) files before and after the osteotomy creation. Pre and post-surgical STL files were superimposed and the dimensional changes were measured at 1, 3, and 7 mm from the crestal bone. Histomorphometric analysis were done and bone-implant-contact percentage (BIC%) was calculated.

Results: There were no significant differences in ISQ values (p=0.239) between any of the groups. Histomorphometric analysis showed implants in group D had significantly higher BIC than group A (p=0.020) and group B (p=0.009). The amount of bone expansion decreased with distance from the crest (p < 0.001). Group B (p=0.039) and group D (p=0.001) showed significant expansions at all levels compared to group A. No other statistically significant differences in dimensional change were found between groups.

Conclusions: : Both the regular or the osseodensification burs used in a CCW motion contributes to expansion of the bone dimension compared to conventional drilling methods.

Lead Author’s Contributions to the Research Project: The Lead Author was responsible for data collection and performing all the experiments, and composition of the abstract and paper.