Relationship between masseter muscle thickness and maxillofacial morphology in pre-orthodontic treatment patients.

This study investigated the relationship between masseter muscle thickness and cephalometric facial parameters in pre-orthodontic treatment patients. Participants were grouped according to their vertical facial patterns into low, normal, and high angle facial patterns using standardised lateral cephalometric radiograph. Associations between the masseter muscle thickness (measured using ultrasonography) and different vertical facial patterns were analysed. Masseter muscle thickness in low angle subjects were significantly higher than the normal and high angle cases during both relaxation and contraction phases (P<0.001). Masseter muscle thickness correlated positively with Jarabak ratio and ramus thickness (R1/R2) during both phases, and negatively with LAFH, FMA, MMPA and gonial angle.