Evaluation of staining value of teeth after bleaching by at-home and in-office technique

Abstract

Introduction: Nowadays, people value their beauty and many individuals care about whiteness of their teeth or suffer from their teeth color. Human knowledge has reached a level that easily by methods such as bleaching make their teeth white. White teeth create a special effect on individual beauty and increase self-esteem. The bleaching is actually brightening the tooth color through the use of chemicals to oxidize organic pigments. In general, there are two methods of bleaching for the teeth: home bleaching and bleaching in the office, both of them have the same purpose and their results have been proven. However, the variables affecting the bleaching process are still unknown. One factor that changes the final bleaching effect is exposure to the colored materials in foods and beverages. Long-term exposure to this material can cause a change in the color of the teeth that has recently been applied to the bleaching process. However, foods and beverages are not the only color factors, but tobacco and some drugs can also change the color of the teeth. In addition, it has been observed that the sensitivity of the staining of the teeth increases after the tooth whitening processes. The aim of this research was to examine the degree of dental staining after bleaching at home and office. Materials and Methods: In this study, 40 teeth were collected and disinfected in thymol solution and the teeth were randomly divided into five groups of eight. The teeth in the first and second groups and two bleaching groups were bleached in the office and the teeth in the third and fourth groups were bleach at home. After bleaching, staining was performed on all teeth. Determination of the color of the teeth was done with the aid of a spectrophotometer. All specimens were immersed in this colorless solution for 20 consecutive days (24 hours every other day) for 20 consecutive days in order to be similar to the clinical condition. After completion of the process, the samples were washed and distilled into water. In first and second groups, bleaching processes of the dental samples were taken in the office using hydrogen peroxide (Opalescence® Boost HP 40% Ultradent, USA) and carbamide peroxide (Opalescence® Quick PF 45% kit, Ultradent, USA) according to the manufacturer instructions. In the third and fourth groups, bleaching process of the dental specimens were prepared according to the manufacturer’s instruction with 20% carbamide peroxide (Opalescence® PF 20% Ultradent, USA) and carbamide peroxide 15% (Opalescence® PF 15% Ultradent, USA) respectively. The fifth group was our control group and no bleaching was done on the samples during the bleaching process. Determination of the color of the specimens was done in both bleaching groups immediately after the bleaching process and after the staining process and using a spectrophotometer (SpectroShade®, MHT , Verona, Italy) with the help of indicators (L, a, b) on a white background. The mean of teeth color difference was calculated in different stages and using ANOVA test with a significant level of p <0.05 were evaluated. Statistical analysis was performed using SPSS17 software. Results: Finally, according to the results of evaluation of the data, the general results of this study can be summarized as follows: 1- There is a significant difference between the mean change in two methods of bleaching and the average color change at home bleaching method is higher than the average in the office bleaching method (P-value <0.05). 2- There is no significant difference between the means of color change in the two substances used in bleaching (P value> 0.05). 3- There is no interaction between the bleaching method and the type of material used in bleaching, in other words, the effect of the substance used in bleaching on the mean color change is the same in both bleaching methods (P value> 0.05).