Denture teeth shade modification using metal oxide tints and composites

It is often a challenge for clinicians to match the shades of partial denture teeth to remaining natural dentations. Objective: We conducted an experimental study in vitro to test the feasibility of denture teeth shade modification using metal oxide tints and composite resins. Methods: We used 15 extracted human maxillary incisors and 45 selected denture teeth (Heraeus Kulzer Artic) with best matching shades. The L*a*b* values of the teeth were measured with a dental colorimeter (ShadeVision). The denture teeth were divided into 3 groups of 15 each: DT1 – denture teeth with no modification; DT2 – denture teeth modified with metal oxide tints; DT3–denture teeth modified with tints and covered with microfilled composite resins (Renamel). The L*a*b* values of the teeth were measured again. The teeth were then subjected to 1000 cycles of thermal cycling (5oC and 55oC), followed by brushing under 150g load for 1000 cycles in a brushing machine. The L*a*b* values of the teeth were measured for the third time and compared to the previous values using t-tests and ANOVA. Results: Denture teeth stained with metal oxide tints improved the perceptual shade matching between the denture and nature teeth. Tinting of denture teeth, with or without composite resins, altered the color characteristics as shown by changes in L*a*b* values (p<0.05). Thermal cycling and tooth brush abrasion tests did not significantly change the effects of tinting in both DT2 and DT3 groups (p>0.05), indicating color stability even without a composite coverage layer. There were 3 teeth with composite coverage showed degradation of the composites after thermal cycling and brushing abrasion. Conclusions: Metal oxide tinting of denture teeth may improve their shade matching with natural teeth. Tinted denture teeth showed color stability after thermal and mechanical challenges.