Comparison of Pre and Post-Orthodontic Treatment Condylar Distraction in Class II Patients with Extraction of Upper and Lower First Premolars

The role of occlusion and its relationship with functional disorders of the masticatory system remain relevant topics in clinical dentistry. Scientific evidence is divided, with some studies supporting a correlation between occlusal factors and temporomandibular disorders (TMD), while others refute such association. One key parameter in diagnosis and orthodontic treatment planning is the position of the mandibular condyle within the glenoid fossa, especially considering that achieving post-treatment stability is a primary therapeutic goal. The aim of this study was to analyze the magnitude of condylar displacement before and after orthodontic treatment in Class II patients indicated for extraction of the upper and lower first premolars. A sample of patients was selected through simple random sampling from the Orthodontics Postgraduate Clinic at Universidad del Desarrollo, regardless of age or sex. Condylar displacement was evaluated pre- and post-treatment using articulator- mounted casts, maximum intercuspation (MIC) records, and daily centric relation (CR) records. The Condylar Position Indicator (CPI) was employed to quantify displacement in the sagittal, vertical, and transverse dimensions. The data were processed using Microsoft Excel, applying descriptive statistics and Student’s t-test for comparative analysis. The results revealed no statistically significant differences in condylar position before and after orthodontic treatment. However, clinical relevance was noted in some cases. Although the findings are consistent with existing literature, they are not generalizable to the broader Chilean population due to the limited sample size.

KEY WORDS: Occlusion, Dental, temporomandibular joint disorders, mandibular condyle, glenoid fossa, malocclusion Angle Class II; condylar displacement, centric relation, tooth extraction.