Effect of white strip bleaching on enamel surface roughness (In vitro study)

Increased enamel surface roughness is a problem associated with bleaching of teeth. Bleaching treatment can also result in unwanted side effects such as decreased enamel microhardness، increased staining and greater caries vulnerability. The aim of this study was to evaluate the enamel surface roughness exposed to white strip bleaching and a home bleaching system. In this Experimental study، 30 enamel blocks obtained from 15 newly extracted human third molars were divided into two groups The samples were exposed to bleaching agents for 14 (group 1) and 21 (group 2) days، twice a day for 30 minutes. Group one received Day White ACP (9. 5% H2O2) and group 2 was exposed to Crest White Strip supreme (14% H2O2). The surface roughness of each specimen was analyzed initially and after treatment with a profile meter. The paired sample t - test was used for data comparison before and after in each group and independent sample t test was used for data comparing between two groups. Surface roughness in white strip group and home bleaching were 4. 06±1. 42 and 3. 3 ±0. 73 respectively which indicated an increase in comparison to baseline figures: 2. 22 ± 0. 67 and 3. 01±0. 16. The increase in surface roughness was significant within in each group. (p<0. 05). However، no significant difference existed between the two groups and bleaching agents. (p>0. 05) The results confirm that enamel surface roughness increases after bleaching and there is not any difference between two groups.