Association of Bolton Discrepancy with Arch form and Sagittal Molar Relationship

Background: The Bolton analysis evaluates tooth size discrepancies to ensure optimal occlusion, with its influence across sagittal molar classes and arch forms remaining unclear.Objective: To compare anterior and overall Bolton ratios across different sagittal molar classes (Class I, II, III) and arch forms (ovoid, square, tapered) in orthodontic patients aged 13 to 35 yearsMaterials and Methods: This cross-sectional comparative study was conducted on 90 cases, using consecutive, non-probability sampling techniques. Inclusion criteria included dental cases of both genders aged 13 to 35 years with all anterior permanent teeth erupted and in good quality study casts. Exclusion criteria included mesiodistal loss or excess of tooth material due to caries or restorations, prosthetic replacements of teeth, previous orthodontic treatment, or transverse discrepancies such as crossbite or scissors bite. Measurements of the mesiodistal width of twelve teeth in each arch were taken using a digital vernier caliper. ANOVA test was run to compare ratios among different classes and arch forms. Results: The mean age of participants was 20.59±5.59 years. Gender distribution was 51.11% females and 48.89% males. The comparison of anterior and overall Bolton ratios among different sagittal molar classes revealed no significant differences: class I had ratios of 91.41±2.21 (overall) and 77.41±2.21 (anterior), class II had ratios of 91.54±2.37 (overall) and 77.54±2.37 (anterior), and class III had ratios of 91.79±1.69 (overall) and 77.79±1.69 (anterior). The comparison among different arch forms also showed no significant differences: ovoid arch form had ratios of 91.95±1.92 (overall) and 77.95±1.92 (anterior), square arch form had ratios of 91.35±2.41 (overall) and 77.35±2.41 (anterior), and tapered arch form had ratios of 91.12±1.79 (overall) and 77.12±1.79 (anterior).Conclusion: Bolton discrepancy is not influenced by sagittal molar class or arch form, regardless of gender. Keywords: Angle's classification, Arch forms, Bolton ratio, Dental discrepancies, Orthodontics, Sagittal molar classes.