ABSTRACT
@#Introduction: Human teeth tend to stain from intrinsic and extrinsic factors with time. The study was aimed to assess colour change of stained enamel after the use of bleaching agents. Methods: 63 extracted human teeth were selected and soaked in the coffee solution for 7 days to stain the teeth. Then they were randomly divided into 3 groups (n = 21). The groups were divided as the control group (distilled water), group using 6% carbamide peroxide (CP6) and group using 9% carbamide peroxide (CP9). The groups of CP6 and CP9 were bleached with 0.2 ml of bleaching agent for 5 minutes daily until 14 days. Colour changes were visually recorded by using VITA Toothguide 3D-MASTER and Ocean Optics Spectrometer instrument. Results: CP6 started to show shade reduction on Day 3 (score 5), followed by a steady reduction until Day 10. Day 12 to 14 showed another steady reduction of CP6. CP9 had a larger shade reduction (scores of 2-5) from Day 1 to Day 4, followed by a steady reduction until Day 14. Spectrometer analysis shows that CP9 samples had lower absorbance unit compared to CP6 samples for both second-day and sixth-day groups. However, most changes can be observed on the CP9 samples from control to the second-day and sixth-day. Conclusion: Bleaching agent with low concentration can approach the efficacy of high concentration of bleaching agent with an extended treatment time.
ABSTRACT
@# Colour stability of the material is an essential factor that contributes to the selection of a flexible denture material. Staining effects on the denture may result in unattractive appearance, the dissatisfaction of the wearer, and limited usage period of the denture. This study aims to identify the colour stability of the Valplast flexible denture material using three types of beverages. Methods: A total of 32 disc-shaped flexible resin materials (20 +/- 0.1 mm in diameter and thickness 3 +/- 0.1 mm) were prepared based on the manufacturer instructions. The samples were randomly divided into 4 groups of immersion: distilled water (control), coffee solution, tea solution and red wine. The samples were left in the specified immersion solution for up to 60 days. Colour changes were measured after 1, 3, 7, 14, 21, 30, 45 and 60 days of immersion. Results: The samples immersed in coffee solution changed from S1 to S2, whereas samples in tea solution changed from S1 to S3. Additionally, samples in red wine changed from S1 to S4, as observed using the Valplast colour tone guide. The highest reflection measured using spectroscopy was 65.146 at 385.19 nm of the control samples, whereas the lowest reflection was 1.974 at the wavelength of 385.97 nm on the samples immersed in the red wine. Conclusion: The most significant difference can be observed in the red wine group, followed by samples in tea and coffee solutions. Moreover, increasing the immersion period causes increasing staining effect of the denture.