SHEAR BOND STRENGTH OF ORTHODONTIC BRACKETS BETWEEN HEALTHY AND MILD FLUOROSED ENAMEL

Objective: To  evaluate  the  influence of  dental  fluorosis on  the  shear  bond  strengths  of orthodontic brackets bonded to enamel.
 
Materials and methods: Twenty extracted human maxillary central incisors, extracted for periodontal reasons were used. The sample was divided into two experimental groups. Group A with healthy teeth and group B with mild fluorosed teeth. Etching enamel then the adhesives were applied to entire enamel surface then light cured for 10 seconds with LED. The base ceramic orthodontic brackets were filled by nano-filled composite and placed on the tooth and cured by LED for 40 seconds. The specimens were then thermocycled (5–55˚C, 500 cycles) and tested in Lloyd universal testing machine. The recorded values of bond strengths in (MPa) were collected, tabulated and statistically analyzed. One way analysis of variance (ANOVA) and Tukey’s tests were used for testing the significance between the means of tested groups which are statistically significant when the P value ≤ 0.05.
Results: The mean shear bond strength of ceramic brackets bonded to non-fluorosed enamel (Group A) was significantly higher than shear bond strength of ceramic brackets bonded to fluorosed enamel (group B).