the effect of chlorhexidine mouth rinse on the colour stability of porcelain with three different surface treatments: an in vitro study

statement of problem: the effect of mouth washes on discolouration of dental ceramics with different surface preparations is not well documented. objectives: this in-vitro study has been conducted to evaluate the effect of chlorhexidine (chx) mouth rinse on colour stability of overglazed (op), autoglazed, (ap) or polished porcelain (pop) specimens. materials and methods: the restorative material investigated in this study was overglazed, autoglazed, or polished feldspathic porcelain. a total of 48 cylandrical specimens were prepared, (n=16 per each group). after baseline colour measurements, for a period of14 days 8 specimens of each group were immersed in 15 ml of 0.2% chlorhexidine mouth rinse twice daily for 2 min. after each immersion, the specimens were washed and stored in artificial saliva. half of the specimens from each group were selected randomly as controls and stored in artificial saliva that was changed daily. the colour change (δe) of the specimens was measured by a spectrophotometer device. data were statistically analyzed using 2-way anova followed by tukey test results: all the specimens displayed colour changes after immersion in chlorhexidine mouth rinse. pop specimens exhibited more colour change compared to ap and op specimens (p=0.001). ap and op specimens showed relatively the same colour change which was not significant compared to the control groups (p=0.9). conclusion: auto-glazed and over-glazed porcelain can tolerate chlorhexidine mouth rinse better than polished porcelain. however the colour changes of the ceramic with three different surface preparations were not perceivable clinically.