Date of Award

Summer 2014

Document Type


Degree Name

Master of Science (MS)



First Advisor

Liu, Dawei

Second Advisor

Lobb, William

Third Advisor

Bradley, Thomas G.


Objective: To determine the effects of mechanical vibrations produced from electric tooth brushes and a commercially available device called AcceleDent, on the resistance to sliding at the bracket-arch wire interface. Materials and Methods: All as-received wires and brackets were cleaned with 95% ethanol prior to testing. An individual metal bracket was mounted on a custom metal fixture. The custom metal fixture had a polyurethane material that resembled the mechanical feature of the human periodontal ligament. The test metal bracket was aligned and bonded passively with 4 other non-movable brackets using a straight piece of .0215" X .025" SS wire. Another test bracket was then bonded at a 2 mm offset from the other test bracket. A new wire (7 cm straight piece of .016" X .022" NiTi) was ligated to the brackets using a conventional ligature tie. Resistance to sliding was measured over a 7 mm sliding distance using the mini-Instron universal testing machine with a 50 Newton load cell and a crosshead speed of 5 mm/min. Initial control testing of static and kinetic friction were performed. After baseline tests (control) were established, mechanical vibration was introduced to the testing both with electric tooth brushes and an AcceleDent device. During each test run, new test brackets and test wire were used and bonded in the same fashion as stated above. The effects of mechanical vibration on the static and kinetic friction were recorded and analyzed using one-way ANOVA with Tukey Post Hoc comparison. Statistical significance was considered when p value was less than 0.05. Results: Compared to the control (no vibration), the AcceleDent static and dynamic resistances to sliding were reduced by 8.5 % and 22.26 %, respectively. The Oral B side test group showed reductions of 14.6 % and 22.46 %. The Sonicare side test group showed reductions of 11.46% and 28.51%. The Oral B front test group showed reductions of 12.73 % and 30.3 %. The Sonicare front test group showed reductions 11.18 % and 28.84 %. All these changes were statistically significant (p = 0.000), with no significant differences found between vibration sources. Conclusions: Mechanical vibration from AcceleDent and electric tooth brushes significantly reduce the resistance to sliding in the orthodontic bracket-wire interface.