An Observational Study on the Association Between the Curve of Spee and Sagittal Condylar Guidance in Different Skeletal Malocclusions

Introduction The Curve of Spee (COS) is integral to occlusal function and esthetics. Its depth and relationship with sagittal condylar guidance (CG) across various malocclusion classes remain underexplored, especially within the Indian demographic. Objective To evaluate and correlate the depth of the COS with CG and other craniofacial parameters in Class I, II, and III malocclusions. Methods An observational analytical study was conducted on 74 patients aged 18-25 years undergoing orthodontic treatment. Subjects were categorized into Class I (n=50), Class II (n=16), and Class III (n=8) based on the ANB angle. Assessed parameters included COS, CG angle (via orthopantomogram), cephalometric variables (SNA, SNB, ANB, FMA, FH-OP), and dental measures (overjet, overbite). Statistical analyses encompassed analysis of variance (ANOVA), Pearson's correlation, and post hoc Tukey tests. Results COS differed significantly among malocclusion groups (p<0.001), being highest in Class II (2.98±0.95 mm) and lowest in Class III (1.75±0.4 mm). No significant difference was observed in CG across groups (p=0.464). A weak negative correlation existed between COS and CG in Class I and III, and a weak positive correlation in Class II, though not statistically significant. Conclusion COS significantly varies with sagittal malocclusion type. While condylar guidance does not significantly differ among groups, its weak correlation with COS suggests a potential but inconclusive relationship. Further research with larger samples and the inclusion of vertical growth patterns is warranted.