Factors affecting duration of post-surgical orthodontics in the Surgery First/Early Approach: a retrospective study

Background: Surgery First Approach (SFA) and Surgery Early (SE) are considered promising alternatives, compared to the conventional three-stages orthodontic-surgical approach, for treatment of dento-maxillofacial deformities. However, many features need further study, like the role of the orthodontist. Aim of the study was to analyse the clinical characteristics of patients who underwent SFA and SE, and if differences in duration of orthodontics could be influenced by clinical features. Methods: A retrospective research was performed on patients who met the inclusion criteria for SFA (31) and SE (12), of the total of patients affected by dento-facial deformities in our Unit (191) in the period 2012-2017. After collection of clinical data, duration of orthodontics, age, pre-treatment PAR Index, ANB angle, amount of the curve of Spee were compared. A regression analysis evaluated if these clinical parameters, together with type of bracket and type of intervention, could influence the duration of post-surgical orthodontics. Results: All patients who performed the SFA/SE were affected by class III, II and active Unilateral Condylar Hyperplasia (22% of total population). Pre-treatment mean differences of age (p = 0.0518), PAR Index (p = 0.0916), curve of Spee (p = 0.1006) between groups were not statistically significant. A statically significant difference was found for the overall duration of therapy, for the significant shorter duration of pre-surgical orthodontics, while the difference of post-surgical orthodontics duration was not significant (p = 0.4753). Type of bracket (rho=-0.19039, p = 0.266) and intervention performed (rho=-0.11522, p = 0.5034) were not correlated with duration of post-surgical orthodontics, as well as pre-treatment PAR Index, ANB angle and depth of the curve of Spee. Conclusions: Surgery First/Early Approach is a therapeutic choice that could be performed only in patients affected by specific malocclusions and who exactly meet indications. Protocol and post-surgical occlusal stability are factors that should influence the duration of therapy more than clinical characteristics.