COMPARISON OF SHEAR BOND STRENGTH OF COMPOSITE TO DECIDUOUS TEETH ENAMEL FOLLOWING PHOSPBORIC ACID AND ND:YAG LASER ETCHING
Abstract
Introduction. Enamel acid etching prior to repair dental caries and fractures with composites has been quite satisfactory and economic, however, etching on deciduous dentition has shown less effective due to its resistance to acids. The purpose of this study was to evaluate composite bond strength on decidious teeth treated with laser instead of being acid etched.
Methods. Forty four deciduous molars without any restoration or buccal decay were chased and randomly divided in the four groups of 10. Four other teeth were prepared for SEM observation. Group 1: samples were treated with Nd: YA Glaser (20 pps, 1.6 w). Group 2: samples, treated with Nd: YA Glaser (10 pps, 0.8 w). Group 3: samples acid etched with 37% phosphoric acid. Group 4: samples in this group were taken as control with no treatment on enamel. Shear bond strength of the composite and teeth in all 4 groups were then measured with universal tast machine (Dartec).Data were analysed statistically using ANOVA test.
Results. The least mean amount of bond strength was related to group 4 (control), which was significantly different from other groups (P < 0.05). The most mean amount was related to group 3 (acid etched) with statistically significant difference from other groups (P < 0.05). Among the samples treated with laser, group 1 has greater amount of mean strength comparing to group 2, however this difference was not significant (P > 0.05).
Discussion. In order to obtain optimum bond strength for composite restorations, enamel surface should be prepared. Use of Nd: YAG laser for enamel etching under the condition of our study is not recommended on deciduous dentition.
Methods. Forty four deciduous molars without any restoration or buccal decay were chased and randomly divided in the four groups of 10. Four other teeth were prepared for SEM observation. Group 1: samples were treated with Nd: YA Glaser (20 pps, 1.6 w). Group 2: samples, treated with Nd: YA Glaser (10 pps, 0.8 w). Group 3: samples acid etched with 37% phosphoric acid. Group 4: samples in this group were taken as control with no treatment on enamel. Shear bond strength of the composite and teeth in all 4 groups were then measured with universal tast machine (Dartec).Data were analysed statistically using ANOVA test.
Results. The least mean amount of bond strength was related to group 4 (control), which was significantly different from other groups (P < 0.05). The most mean amount was related to group 3 (acid etched) with statistically significant difference from other groups (P < 0.05). Among the samples treated with laser, group 1 has greater amount of mean strength comparing to group 2, however this difference was not significant (P > 0.05).
Discussion. In order to obtain optimum bond strength for composite restorations, enamel surface should be prepared. Use of Nd: YAG laser for enamel etching under the condition of our study is not recommended on deciduous dentition.
Keywords
Shear Bond Strength; Nd: YAG Laser, Phosphoric; Acid; Acid Etching