Influence of maxillary first molar rotation on the severity of dental class II malocclusion: A cross-sectional study

The aim of the study was to evaluate and assess the influence of maxillary molar rotation on severity of dental class II malocclusion.

The study comprised of 4 different groups namely, 1/4th class II malocclusion, 2/4th class II malocclusion, 3/4th class II malocclusion and full class II malocclusion involving sample size of 20,15,16 and 12. The samples were subjected to digital evaluation of maxillary 1st permanent molar rotation using 4 parameters namely angle of Friel, Ricketts E-Line, angle of Henry and Premolar angle.

The results were subjected to statistical analysis using one way ANOVA wherein group IV (Full class II malocclusion) exhibited a greater rotational value. On evaluation, angle of Friel exhibited a mean of 59.6±1.61 degrees, Ricketts E-Line was found to be 12.3±1.77mm while angle of Henry showed a mean of 19±3.19 degrees and premolar angle was 12.5±5.83 degrees.

On evaluating molar rotation using angle of Friel, Ricketts E-Line, angle of Henry and premolar angle, full cusp class II malocclusion presented higher degree of mesiopalatal rotation maxillary molar rotation. With increasing mesiopalatal rotation, the severity of molar relation also increased from 1/4th to full class II. Hence the maxillary molar spatial position along the long axis majorly influences the molar relation wherein a full cusp class II molar relation exhibits higher degree of molar rotation.