The objective of the study was to evaluate the immediate and delayed effect of in office tooth bleaching on mineral profile ,surface roughness and microhardness of human enamel in vivo.
Methods:
19 patients scheduled for extraction of the anterior teeth for periodontal reasons participated in the study after written consent. Each participant had at least two anterior teeth scheduled for extraction . All the participants were subjected to professional oral hygiene. 38% hydrogen peroxide(Opalescence Xtra Boost) were used according to manufacturer 's instructions. For each patient One tooth was immediately extracted after bleaching(immediate group) while the other tooth after 21 days(delayed group). A total of 36 teeth were divided accordingly into two groups(n=18). The lingual surface of each tooth was used as a control. Each group was subdivided into three subgroups(n=6) according to the test carried out. Energy dispersive x-ray microanalysis(EDX) was used to evaluate the intensity of elements in enamel. Surface roughness was assessed with a profilometer and microhardness was assessed using microhardness testing machine.
Results:
The results of this study were statistically analysed(ANOVA,Tukey's test,p<0.05).EDX analysis revealed statistically significant highest mean weight% of oxygen while the calcium and phosphorus showed statistically significantly lowest mean weight% for immediate group although the control group for both of them showed the statistically significantly highest mean weight %.
The results of surface roughness showed statistically significantly highest mean surface roughness for immediate group followed by delayed group.
While the results of surface microhardness showed the statistically significant highest mean hardness for delayed group.
Conclusions:
1- In office bleaching negatively affect mineral tooth profile, surface roughness and microhardness of enamel tooth surface.
2- Post bleaching period in oral cavity resulted in an increase in values of all tested parameters although baseline values was not reached for mineral profile and surface roughness.