Comparison of occlusal settling, patient compliance, and retention ability between hawley’s and van der linden retainers – A randomized controlled trial

Abstract

To compare occlusal settling, patient compliance, and retention ability between Hawley’s and Van Der Linden retainers. Randomized, Parallel-Group, Active Controlled Trial. Randomization and allocation to the particular trial group was done through a lottery system. A total of 72 subjects were randomly assigned in both the groups- Hawley's retainer group (HL) (n = 36) and Van Der Linden group (VL) (n = 36). Each subject was given a removable maxillary retainer and a fixed bonded lingual mandibular retainer. Impressions were recorded on three different time spans i.e. at the time of retainer delivery (T0), 3 months later (T1), and post 6 months of retention (T2). Bite registration records and questionnaire evaluation were taken at time intervals T1 and T2. Each time assessments were performed from the cast by Little's Irregularity Index (LII), Inter Canine Width (ICW), and Inter Molar Width (IMW). Patient compliance was gauged with the help of a Questionnaire. The occlusal settling, patient compliance, and retention ability were evaluated and compared between the two groups. Both groups showed a rise in the number of total contacts (5.39 in HL and 2.42 in VL), and true contacts (6.89 in HL and 4.64 in VL), whereas near contacts declined (-1.53 in HL and 2.22 in VL) at T2. Post 6 months, the difference in LII, ICW, and IMW were slightly higher for VL than HL. This proved the better retention ability of the HL group. Patient compliance determined with the questionnaire showed that overall compliance was greater with HL than with VL. In the course of 6 months of retention, the total near contacts were reduced in both retainers but the total (True + near) contacts elevated, which suggests both retainers facilitated occlusal settling. Changes in values of LII, ICW, and IMW were not significantly different for both groups during T2, which proved the retention ability of both retainers. Patient compliance increased as patients wore either of the retainers, but they were more comfortable with HL.