Employment of Reservoirs in At-Home Whitening Trays: Efficacy and Efficiency in Tooth Whitening

This study aimed to determine the efficacy of trays made with and without reservoirs, in conjunction with time and cost evaluations, by measuring color change with home whitening procedures. Extracted human maxillary teeth (central incisors n = 20; canines n = 20; molars n = 20) and 60 artificial teeth (lateral n = 20; premolar n = 40) were mounted into ten typodonts. Tray fabrication was completed such that a block-out resin reservoir was placed on half of the buccal surface of the tray, while the other half remained without a reservoir. Whitening with custom fabricated trays was performed based on two different whitening regimens, where each regimen was assigned to five typodonts: Night-time: Opalescence PF 10% carbamide peroxide for 8 hours daily and Day-time: Philips DayWhite 9.5% hydrogen peroxide for 30 minutes, twice daily. Both systems were applied for 1 week. To evaluate tooth shade, the VITA Easyshade® Advance 4.0 spectrophotometer was used. Color measurements were obtained at baseline (T1), 1-day post-whitening (T2), and 1 month post-whitening (T3). One-way ANOVA, followed by post-hoc Tukey's HSD test, was used to detect significant difference in the overall color change (ΔE*) among the four groups at T2 and T3. Additionally, paired-sample t-test was used to assess difference in ΔE* between T2 and T3 treatment within each of four techniques of tray fabrication. No significant difference in ΔE* was found among the four groups at T2 and T3 (p > 0.05 in each instance). There were significant differences in mean ΔE* between T2 and T3 treatment for the day white treatment groups without reservoir (6.96 vs 10.19 respectively; p = 0.0026) and with reservoirs (6.23 vs 9.79 respectively; p = 0.0031). The use of reservoirs does not have a significant effect on whitening efficacy, regardless of type of whitening material and regimen. The use of custom fabricated trays with or without reservoirs were equally effective in whitening teeth.