Color Stability of Monocrystalline and Polycrystalline Ceramic Orthodontic Brackets Immersed in Coffee Solution: An In Vitro Comparative Study.

Abstract

Context: Appearance of orthodontic appliances significantly influences patients' decisions to undergo orthodontic therapy. As the consumption of coffee stains the orthodontic brackets, an idea to understand the extent of staining between monocrystalline and polycrystalline ceramic orthodontic brackets can be useful in making a better choice.

Aim: To compare the color stability of monocrystalline and polycrystalline ceramic brackets on immersion in coffee solution at different time intervals.

Settings and design: This interventional comparative study included total of 40 brackets with 20 brackets monocrystalline and polycrystalline each. All the brackets were immersed in a coffee solution, and ∆E values were recorded at 1-hour, 24-hours, 7-days, and 14-days.

Statistical analysis: It was performed using SPSS (Statistical Package for Social Sciences) 25.0 version. Between group comparison was done using one-way ANOVA, within group was done using repeated measures ANOVA, and interaction effect of type of bracket and duration of exposure was done using two-way ANOVA.

Results: The ∆E was significantly higher for polycrystalline brackets than monocrystalline brackets at all time intervals (1-hour, 24-hours, 7-days, and 14-days). For both monocrystalline and polycrystalline brackets, the ∆E values increased significantly at each subsequent time interval compared to the previous one. Two-way ANOVA revealed that interaction between the effects of type (monocrystalline vs. polycrystalline) of ceramic brackets and duration of exposure had a significant effect on the ∆E.

Conclusions: Monocrystalline ceramic brackets exhibit significantly greater color stability. Duration of exposure to coffee has a direct influence on the degree of color change in both types of brackets.