Using a 3-mm extended tray during at-home nightguard vital bleaching (NGVB) may increase the risk of gum irritation, according to a clinical trial published on November 18 in the Journal of Prosthetic Dentistry.
Additionally, participants who experienced tooth sensitivity reported greater intensity with an extended tray, the authors wrote.
"The use of a nonextended tray is recommended to reduce adverse reactions," wrote the authors, led by Dr. Patricia Pereira-Lores of the University of Santiago de Compostela School of Medicine and Dentistry in Spain.
The randomized clinical trial was conducted from March to April 2023 at the University of Santiago de Compostela. The study included 72 adult participants randomly assigned to two groups: a 3-mm extended bleaching tray and a 1-mm nonextended bleaching tray. Over three weeks, participants underwent nightly dental bleaching using 16% carbamide peroxide gel.
Gingival irritation was assessed daily by participants and at visits by clinicians, tooth sensitivity was recorded daily on a five-point scale, and tooth color was measured using a dental spectrophotometer. Statistical analysis included the Pearson chi-squared test, the Fisher exact test, and Student's t-test (α = .05), they wrote.
The extended tray group had a 66.7% risk of gingival irritation reported subjectively compared to 47.2% in the nonextended group, with no statistically significant difference (p > .05). However, gingival irritation was significantly higher in the extended group (88.9%) than in the nonextended group (63.9%) (p = .01; 95% confidence interval [CI], 1.06-1.83).
Furthermore, tooth sensitivity intensity was significantly greater in the extended tray group (p < .001), but the tray design did not significantly affect the overall risk of sensitivity (p > .05). Both groups showed no significant differences in color change (p > .05), they wrote.
The study had imitations. The findings, based on a specific bleaching agent and two tray designs, highlight the need for future research exploring different agents and intermediate sizes to better balance efficacy and side effects, the authors added.
"The use of an extended bleaching tray design is associated with an increased risk of gingival irritation and higher intensity of tooth sensitivity," Pereira-Lores concluded.
