The results of this meta- analysis showed no significant changes in enamel microhardness when using the 10 % carbamide peroxide bleaching gel over periods of 7 , 14 and 21 days
Several studies have investigated the effect of bleaching on dental tissues .
The evaluation of the effect of home bleaching with 10 % carbamide peroxide is important for assessing alterations in enamel microhardness that may affect dental health in terms of resistance to masticatory forces .
This meta- analysis was performed in order to determine scientific evidence regarding the effects of home vital bleaching with 10 % carbamide peroxide gel on the microhardness of human dental enamel .
In situ effect of 10% carbamide peroxide on microhardness of human enamel: function of time.
PURPOSE This study evaluated the effect of two home bleaching regimens ( 1 h/day versus 7 h/day for a total of 21 days ) on the microhardness of superficial enamel treated with 10 % carbamide peroxide gel . MATERIAL S AND METHODS Rectangular enamel specimens ( 2.5 x 2.5 x 1 mm ) were obtained from human third molars and mounted on the palatal aspect of removable orthodontic retainers . Nine enamel specimens were mounted in each of 10 retainers , used by 10 volunteers during the active phase of the study . Modified 0.089 cm thick bleaching trays were fabricated for each participant . Each bleaching tray fit a participant 's arch and the retainer containing the enamel specimens . Enamel specimens were treated with a 10 % carbamide peroxide bleaching gel ( Nite White Excel 2Z , Discus Dental , Culver City , CA , USA ) for either 1 h/day ( n = 30 ) or 7 h/day ( n = 30 ) , both for 21 days . Three enamel specimens in each retainer were never treated and served as controls . The retainers were worn by the participants whether or not they underwent bleaching . This simulated the natural action of the saliva/oral fluids on the enamel specimens . Enamel specimens were subjected to pre- and post-treatment microhardness measurements . Post-treatment Knoop hardness numbers were compared with baseline values and analyzed statistically . RESULTS Bleaching treatment result ed in a nonsignificant reduction in microhardness values when compared with values of the control nontreated specimens ( 1.7 % and 2.5 % reduction in hardness for 1 h/day and 7 h/day , respectively ) . There was no difference in microhardness between the different treatment regimens . CONCLUSION Home bleaching with 10 % carbamide peroxide for up to 7 h/day for 21 days does not significantly affect enamel microhardness . CLINICAL SIGNIFICANCE Bleaching with 10 % carbamide peroxide for 1 h/day or 7 h/day for a total of 21 days is safe for human enamel
The results of this meta- analysis showed no significant changes in enamel microhardness when using the 10 % carbamide peroxide bleaching gel over periods of 7 , 14 and 21 days
Several studies have investigated the effect of bleaching on dental tissues .
The evaluation of the effect of home bleaching with 10 % carbamide peroxide is important for assessing alterations in enamel microhardness that may affect dental health in terms of resistance to masticatory forces .
This meta- analysis was performed in order to determine scientific evidence regarding the effects of home vital bleaching with 10 % carbamide peroxide gel on the microhardness of human dental enamel .