Date of Award
Summer 2020
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Dentistry
First Advisor
Liu, Dawei
Second Advisor
Ahuja, Bhoomika
Third Advisor
Nimeri, Ghada
Abstract
Introduction: High-frequency vibration with low magnitude acceleration has varying effects on alveolar bone. The objectives of this study were to establish a murine model for periodontitis and to explore the best time window of this model to investigate the effects of high frequency, low magnitude mechanical vibration on alveolar bone following ligature-induced experimental periodontitis. Materials and Methods: Ninety-five 11-week-old inbred strain C57BL/67 male mice were randomly assigned into four groups: 1) healthy control (n = 9); 2) healthy + mechanical vibration (n = 8); 3) experimental periodontitis + no treatment (n=7); and 4) experimental periodontitis + vibration (n = 9). All mice in the disease groups had ligature‐induced experimental periodontitis induced for 8 days to generate localized alveolar bone loss. In mechanical vibration treatment groups, the mice received high frequency mechanical vibration (60 Hz, 0.3 g) for 5 min/day on the maxillary right 1st molar for consecutive 7 and 21 days, respectively to determine the effects on alveolar bone following experimental periodontitis. Micro computed tomography (micro-CT) was used to quantify new bone formation through bone volume fraction (BVF), tissue mineral density (TMD), and alveolar bone heights post treatment with or without mechanical vibration. Analysis of variance (ANOVA) was performed with Bonferroni post hoc tests to measure statistically significant differences between groups for volumetric and linear bone levels. P value less than 0.05 was considered significant. Results: Ligature-induced experimental periodontitis resulted in significant reductions in BVF, TMD and alveolar bone height compared to healthy controls. Treatment with mechanical vibration for 7 and 21 days led to a non-significant, local anabolic effect; however, decreases in BVF and TMD of alveolar bone were seen in areas adjacent to the site of application of mechanical vibration. Conclusion: Healing in ligature-induced experimental periodontitis is in progress at 7 days and completed by 21 days. Mechanical vibration (60 Hz, 0.3 g, 5 min/day) modestly increases bone volume and density of the tooth vibrated directly, indicating a potential clinical application for improving bone quantity and quality following periodontitis.