Efficacy Evaluation Of Different Bleaching Methods On Different Types Of Natural Teeth

Objective: To investigate the efficacy of different bleaching methods on the different types of natural teeth in aesthetic area.Methods: Forty patients undergoing natural tooth bleaching from November 2018 to January 2019 were prospective enrolled in this study.According to the random number table method,they were randomly divided into in-office bleaching group and combined bleaching group(n=20 for each group).The patients from the former group received an in-office treatment only once,and those from the latter group received a take-home bleaching treatment(with custom-made tray,8h/d)for 2 weeks after an in-office treatment.Materialise 3-matic modeling software and 3D printing technology were used to manufacture the individualized guides for tooth color measurement.Using the spectrophotometer VITA easyshade and the individualized guides,the color difference was calculated.We compared the ΔE(color difference),ΔL*(lightness difference),Δa*(red-green difference),Δb*(yellow-blue difference)values of incisors,canines and premolars between the two groups before and after treatment.Results: Significant differences were observed in ΔE,ΔL*,Δa*,Δb*values between the 2 different bleaching methods(P<0.05).There were significant differences in ΔE,Δa*,Δb* among different types of natural teeth(P<0.05).Mutual effect on Δ a* value was seen in bleaching methods and tooth types(P<0.05).The Δ a* values of 3 types of natural teeth treated by a combined in-office and at-home bleaching treatment were lower than their corresponding teeth treated by in-office bleaching treatment(P<0.05).In a combined in-office and at-home bleaching group,the Δa* values of canines and premolars were lower than that of central incisors(P<0.05).Conclusion: Different bleaching methods and types of teeth affected the treatment effect.In the comparison among three types of natural teeth on the red fading effect under two bleaching methods,the treatment effects of all types of natural teeth treated by a combined in-office and at-home bleaching therapy were better than that of all types of natural teeth treated by in-office therapy,the treatment effects of canines and premolars in a combined in-office and at-home bleaching group were better than that of central incisors.