Assessment of the relationship between fractal analysis of mandibular bone and orthodontic treatment duration

This retrospective study aimed to determine whether a correlation exists between the fractal dimension value and overall orthodontic treatment duration in children and young adults.

The study included a total of 643 patients (age: 10–25 years) who received orthodontic treatment between January 2015 and March 2020. Patient records and pretreatment panoramic radiographs were evaluated. The regions of interest selected for calculating fractal dimension were the bilateral mental foramen regions of the mandible. Fractal dimension was set in relation to orthodontic treatment duration using a linear regression model which was also adjusted for potential confounding variables. Total treatment duration was the outcome variable of interest used as a continuous variable. The predictor variables of interest included age, gender, type of dental and skeletal malocclusion, vertical growth pattern, extraction type, and fractal dimension.

The mean age, treatment duration, and fractal dimension were 14.56 years, 27.01 months, and 1.23 mm, respectively. Multiple linear regression analysis showed that the fractal dimension had a significant influence on overall treatment duration (P < 0.001). From the other variables, Angle class II malocclusion significantly influenced treatment duration (P < 0.01), age showed a significant negative correlation with treatment duration (P < 0.01), and treatment duration significantly increased for patients with tooth extractions (P < 0.001).

There was a negative correlation between fractal dimensions at the mandibular mental region and total orthodontic treatment duration. Fractal dimension analysis may help to understand physiologic features of alveolar bone and predict orthodontic tooth movement.