Background & Objectives: Fluoride releasing bonding agents can help the orthodontist to minimize enamel demineralization independent of patient cooperation. This in vivo study was conducted to evaluate the efficacy of resin modifi ed glass ionomer cement (RMGIC) on reducing enamel demineralization around orthodontic brackets and confirm the superior caries-preventive effect of RMGIC by assessing the mutans streptococci (S.mutans) in plaque samples in vitro.
Methods: 60 subjects (aged 14-20 years) scheduled to have premolar extractions as part of the orthodontic treatment plan were selected and randomly divided into 2 groups of 30 each (group 1: the brackets were bonded on the teeth using light cure composite resin and group 2: the brackets were bonded using RMGIC). Plaque scores (modification of plaque index by Silness and Loe) were recorded and plaque samples were collected before bonding, one week and one month after bonding. S.mutans colonies were recorded from the plaque samples inoculated on MSB agar plates, incubated under 95% N2 and 5% CO2 for 48 hours at 370C in a CO2 jar. After 1 month, the right maxillary and mandibular first premolars were debonded, extracted and depth of enamel demineralization area was estimated using polarized light microscope.
Results: After statistical analysis, a significantly higher mean depth of demineralized lesions was noticed in group 1 as compared to group 2. A significant difference between occlusal and gingival depth was seen only in group 2, thus illustrating a wedge effect. In group 1, a statistically significant increase in the mean colony forming units (CFU) of S.mutans has been noticed at different time intervals whereas in group2, a significant increase was observed only at 1month. Unlike at 1 month, a statistically significant difference in mean CFU between group 1 and group 2 has been observed at 1 week (P<0.05).
Conclusions: Enamel lesions adjacent to the bracket base on teeth bonded with the RMGIC were smaller than those on teeth bonded with a composite resin. The high “burst effect” of fluoride release for the first few days of RMGIC after bonding is confirmed by statistically significant reduction in CFU counts of S. mutans in plaque.