Cephalometric factors associated with orthodontic treatment initiation: a retrospective analysis

Background: While malocclusion prevalence and orthodontic treatment need have been widely described, the association between objectively quantified craniofacial morphology and actual orthodontic treatment initiation remains insufficiently characterised. This study aimed to identify cephalometric parameters associated with orthodontic treatment initiation in routine clinical practice. Methods: A retrospective observational study was conducted using clinical records from a private orthodontic centre in Poland. Consecutive patients aged ≥ 11 years who attended an initial orthodontic consultation between 2022 and 2024 and had a lateral cephalogram were included (n = 902). Orthodontic treatment initiation at the study centre was defined as a binary outcome (yes/no). Cephalometric variables derived from Segner–Hasund analysis were assessed, including sagittal and vertical skeletal parameters, dentoalveolar measurements, and soft-tissue indices. Comparisons between treated and untreated individuals were performed using non-parametric tests, with additional analyses stratified by gender and age. Also, the univariate and multivariable logistic regression modelling was conducted. Results: Of the 902 participants, 490 initiated orthodontic treatment and 412 did not. No significant differences were observed for sagittal skeletal parameters (SNA, SNB, ANB, Wits appraisal) or skeletal class distribution between groups. In contrast, significant differences were identified for vertical skeletal configuration (NSL–NL), maxillary incisor protrusion relative to NA (1+:NA, mm), and the lower facial height index. Gender-stratified analysis revealed that treatment initiation in females was associated primarily with maxillary incisor inclination and protrusion, whereas in males it was associated with vertical skeletal parameters and lower facial height. Age-stratified analyses indicated that vertical skeletal characteristics were more strongly associated with treatment initiation in adult and older individuals, while no clear cephalometric differentiators were identified in younger patients. In logistic regression analysis, increased NSL–NL angle was independently associated with a lower likelihood of undertaking orthodontic treatment, while greater upper incisor protrusion (1+:NA, mm) increased the probability of treatment initiation. Although several associations reached statistical significance, the majority of cephalometric variables showed no significant relationship with treatment initiation, and effect sizes for statistically significant predictors were small, with the largest odds ratio observed for 1+:NA (mm) (OR = 1.053). In the multivariable model, NSL–NL and SNA remained significant predictors, and the model demonstrated good fit. Conclusions: Associations between cephalometric parameters and orthodontic treatment initiation were selective and predominantly related to vertical skeletal configuration and maxillary incisor position. These findings suggest that cephalometric morphology alone has limited explanatory value for treatment uptake and should be interpreted within a broader multifactorial framework encompassing aesthetic perception, patient preferences, and contextual factors.