Comparison of Maxillary First Molar Rotation Among Class I, Class II, and Class III Malocclusions: A Cross-Sectional Comparative Study

Abstract

Objective: To compare the rotation of the maxillary permanent first molar among patients with Class I, Class II, and Class III malocclusions.

Study Design: Cross-sectional Comparative Study

Place and Duration: Armed Forces Institute of Dentistry, Rawalpindi, Pakistan, from Jan to Dec 2025

Methodology: This study used a non-probability consecutive sampling technique on 90 cases. Inclusion criteria were the availability of dental casts, cephalograms, and profile photographs, while participants with missing or restored upper first molars, posterior crossbite, excessive wear, or incomplete records were excluded. Age and gender were recorded, and permanent maxillary first molar rotation was measured on dental casts. One-way ANOVA and chi-square tests were used to compare the rotation of permanent maxillary first molars among classes.

Results: The mean age was 21.1±5.9 years. There were 54 females (60%) and 36 males (40%). Participants were equally distributed across skeletal classes, with 30 individuals (33.3%) in each of Classes I, II, and III. The mean permanent maxillary molar rotation differed significantly among classes, with Class II showing the highest rotation (78.7° ± 5.7) compared with Class III (73.4° ± 9.2) and Class I (71.6° ± 3.8) (p < 0.001). When categorized as rotation >73°, the proportion of rotated molars was highest in Class II (73%), followed by Class III (47%) and Class I (27%) (p = 0.0013).

Conclusion: Permanent Maxillary first molar rotation is significantly associated with sagittal skeletal pattern in untreated young adults. The most pronounced rotation occurs in individuals with skeletal Class II relationships, with a ..