A COMPARATIVE EVALUATION OF TOOTH STRUCTURE LOSS WHILE REMOVAL OF OLD COMPOSITE MATERIAL WITH AND WITHOUT USING METHYLENE BLUE DYE: AN IN-VITRO STUDY.

Aims: A comparative evaluation of tooth structure loss while removal of old composite material with and without using methylene blue dye. Materials and Methods: 50 sound, non-carious permanent molar teeth extracted for periodontal reasons were collected and standard class II cavities (two-thirds of facio-lingual width, 1.5 mm pulpal depth and 0.5 mm inside the DEJ) were prepared and teeth were subjected to rehydration and dehydration. Tooth mass were recorded using digital analytical balance. Teeth were restored with composite resin and stored in distilled water at 37°C and thermocycled for simulating ageing process (5°C-55°C/5000 cycles). Samples were then assigned into 2 groups: Removal of composite restoration was carried out without and with using methylene blue dye in respective groups. Tooth mass was recorded again. Teeth were dissolved in 65% nitric acid for 6 days and weight of remaining composite material was assessed. Results: Loss of tooth structure was calculated using a structured formula. Loss of tooth structure was higher in GROUP A group with a t value of 1.408 but statistically not significant with a p value of 0.172. Comparison of the Remaining composite between the two groups showed that Remaining composite was higher in GROUP A group with a t value of 2.221 and is statistically significant with a p value of 0.039. Conclusion: loss of tooth structure and remaining composite was lower when methylene blue dye was used. This can help in preserving the natural tooth structure during replacement of failed composite restoration.