Demographic and clinical characteristics of patients who underwent clear aligner therapy: A multicenter cohort study

To investigate the demographic and clinical characteristics of patients who underwent clear aligner therapy in Korea.

This retrospective descriptive multicenter study included 1,068 patients who completed Invisalign treatment under four orthodontists. The variables included age, sex, region, problem list, previous orthodontic treatment, aligner option, extraction pattern, treatment duration, refinement number, and change interval.

Females outnumbered males (65.2% vs. 34.8%, P < 0.001). Only 10.8% had a history of previous orthodontic treatment. Skeletal Class I and II malocclusions were more common than Class III (45.2% and 41.8% vs. 13.0%, respectively). The First option was mainly used in children under 10, while among patients aged 10-19 years, 88.5% received the Comprehensive option. Adults (≥ 20 years) were treated with either the Lite or Comprehensive option. Nonextraction treatment was more frequent than extraction (86.0% vs. 14.0%). All extraction cases used the Comprehensive option. In First cases, girls had a shorter total treatment duration than boys (19.7 months vs. 21.6 months, P < 0.05). However, no significant sex differences were observed in Lite, Comprehensive-nonextraction, or Comprehensive-extraction cases. In males, the proportion of cases requiring no or only one refinement was lower in Comprehensive-extraction cases than in Comprehensive-nonextraction cases (32.7% vs. 54.0%, P < 0.01). The change interval tended to be longer in Lite and Comprehensive-extraction cases compared to First and Comprehensive-nonextraction cases (12.0 and 10.3 days vs. 8.3 and 8.8 days).

Treatment duration, refinement number, and aligner change interval showed variations according to treatment groups. Further studies using initial malocclusion severity indices, treatment outcome indices, and compliance evaluations are needed.