Objectives: The present study was conducted to evaluate clinically the effect of conventional etching and the self etch
primer on the change in enamel color before and after orthodontic treatment. Materialand Methods: The study was conducted on 24 patients treated with fixed orthodonticappliances. Metal brackets were bonded to the teeth mesial to first molars. The bracketswere bonded utilizing Transbond XT adhesiveafter application of either conventional etching (%37 phosphoric acid etch and Transbond XT primer) or Transbond XT self etch primer (splitmouth design). Teeth which showed bracket bond failure were excluded from the study. Therefore, the final number of teeth which were included in the conventional etch and self etch groups were 164 and 160 respectively. The color of the labial and buccal surfaces of the teeth mesial to the first molars was evaluated before bracket bonding and after orthodontic treatment. This step was done with the aid of spectrophotometer Vita Easyshade (Vita Zahnfabri, Germany). The evaluation of the color depended on the color space system of CIELAB (Commission Internationale de l›Eclairage L*, a* and b*). Three parameters were measured (L*, a*, b*). Also, color change
(ΔE) was calculated. Then the collected data was statistically analyzed using Paired t-test.
Results: All color measurements (L*, a*, b*) were significantly decreased after orthodontic treatment
(P<0.05). Conventional etching provided significantly higher ΔE value than the self etch primer (P<0.05).
Conclusion: The utilization of conventional etching or self etch primer have a significant negative effect on
tooth color after orthodontic treatment. However, the conventional etching has higher pronounced effects.