Longitudinal Methods in Orthognathic Surgery Studies

This letter provides a methodological comment on the recent study by Kim et al., which evaluated soft tissue canting at preoperative, postoperative, and post-debonding stages in the same group of patients. The correspondence highlights that these measurements represent dependent observations and therefore require appropriate repeated-measures statistical methods. It emphasizes that one-way analysis of variance is designed for independent groups and is not suitable for longitudinal data. The aim of this letter is to encourage accurate statistical practice in studies involving repeated measurements in orthognathic and orthodontic research.