Date of Graduation

2000

Document Type

Thesis

Degree Type

MS

Committee Chair

Kavita Kohli

Abstract

A new generation of resin-modified glass ionomer adhesive (RMGI) which has fluoride releasing and recharging properties may be effective in prevention of white spot lesions around orthodontic brackets. The objectives of this study were to compare 1) the amount of fluoride release in vitro, 2) the amount of decalcification around brackets among a resin-modified glass ionomer (Fuji Ortho LC), a fluoride releasing composite resin (Light Bond), and a non-fluoride releasing composite resin (Resilience L3) in vitro and in vivo. Five samples of each bonding material were made by injecting the materials into a small circular polyvinylsiloxane template. Fluoride release over a 5 month period was measured using a fluoride probe. For enamel decalcification experiment, orthodontic brackets were bonded to human third molars (n= 30) and subjected to in vitro demineralization treatment. Lesion depths and areas on serial sections were measured using polarized light microscopy. Data were analysed using ANOVA. The results showed significant differences in fluoride release over the 5 month period among the three materials (p< .001) with significantly higher concentrations of fluoride release by Fuji and Light Bond as compared with Resilience. Significant differences were also found in lesion depth and area among the three materials (p< .001) with smaller lesion depth and area found in the RMGI product (Fuji = 13.7 µm and 6.7 µm2) as compared to Light Bond (41.2 µm and 20.7 µm2), and to Resilience (70.2 µm and 35.2 µm2). Results in vivo showed no significant differences in percentage increase in decalcification around brackets among the three materials. These results suggest that fluoride releasing properties of RMGI may be effective in preventing enamel decalcification around orthodontic brackets in vitro. However, there was no difference in the clinical performance of the RMGI when compared to conventional resins.

Download

Share

COinS