Date of Graduation
2005
Document Type
Thesis
Degree Type
MS
Committee Chair
Peter W. Ngan
Committee Chair
Peter W. Ngan
Abstract
The in vitro portion of this study utilized 35 extracted human third molars. The third molars were sectioned into buccal and lingual halves. The enamel surfaces were pumiced, etched using self etching primer, and divided into five groups with various levels of exposure to argon laser irradiation (40, 80, 120, or 240 J/cm2 ) or no laser exposure (control group). In the first experiment, teeth were exposed to a demineralization solution (pH=4.46) for 48 hours and in the second experiment, teeth were exposed to the demineralization solution for 72 hours. Lesion depth, lesion area, and lesion fluorescence were measured using confocal microscopy. Results were analyzed using ANOVA and Tukey-Kramer analyses. For the in vivo study, 21 patients who received comprehensive orthodontic treatment participated in the study. The patients had orthodontic brackets bonded to maxillary and mandibular dentitions using a split arch bonding technique where half the teeth were bonded using conventional visible light and the other half with 40 J/cm2 of argon laser irradiation to the mesial and distal portions of the orthodontic brackets. All teeth were pumiced and etched using self etching primer prior to bonding. Results were analyzed using ANOVA, Chi-Squared, and Tukey-Kramer analyses. In the in vitro study, the results show that as the intensity of argon laser exposure increased, lesion depth and area decreased. For samples placed in a demineralizing solution for 48 hours and exposed to 120 J/cm2 or 240 J/cm2 , the lesion depth was reduced 30.9% and 42.4%, respectively, compared to the control group. Lesion area was reduced by 44.3% and 44.9%, respectively (p=0.01). No other significant differences were found. In the in vivo study, enamel surfaces exposed to 40 J/cm2 of argon laser irradiation had a mean decalcification score of 1.84, compared to 2.01 in the control group (p=0.05). These results suggest that exposing enamel surfaces to argon laser irradiation provides protection against enamel decalcification.
Recommended Citation
Shipley, Thomas S., "The effect of argon laser irradiation on reducing enamel decalcification during orthodontic treatment: An in vitro and in vivo study." (2005). Graduate Theses, Dissertations, and Problem Reports (ETD). 10870.
https://researchrepository.wvu.edu/etd/10870