A Prospective Randomized Clinical Trial to Evaluate the Slot Size on Pain and Oral Health-Related Quality of Life (OHRQoL) in Orthodontics during the First Month of Treatment with Conventional and Low-Friction Brackets

The aim of this research project was to analyze the influence of slot size and low-friction on pain and the oral health-related quality of life (OHRQoL) of subjects receiving fixed appliances. A group of 120 patients (61 male, 59 female) were chosen for this randomized clinical trial. Participants were classified into four groups (30 patients in each). We compared conventional (C group) and low-friction (LF group) brackets and 0.018″ and 0.022″ slots. Pain was assessed at 4 (T0), 8 (T1), and 24 (T2) hours, and 2 (T3), 3 (T4), 4 (T5), 5 (T6), 6 (T7), and 7 (T8) days after the start of treatment by using the visual analogue scale (VAS). OHRQoL was assessed at 1 month using the Oral Health Impact Profile (OHIP-14). Data was analyzed using the analysis of variance (ANOVA) test with post-hoc Bonferroni correction. For pain on the visual analogue scale, statistically significant differences (p < 0.05) were found for T0 and T3. For OHRQoL, statistically significant differences (p < 0.01) were found in the domains of physical pain, psychological discomfort, psychological disability, and overall OHIP. The group with 0.022″ low-friction brackets showed a lower pain score and less impact on OHRQoL. The type of bracket system used and bracket slot size influenced patients’ perceptions of pain and their OHRQoL.