Objectives: to analyze the frontal chewing patterns in posterior crossbite.
Material and Methods: The sample was composed of 55 posterior crossbite subjects aged 12-35 years and 22 normal occlusion subjects aged 16-30 years. The chewing patterns were classified into 8 chewing types according to the shape of frontal incisor point movement. The posterior crossbite subjects were further grouping by different sides. The Mann-Whitney U test was performed to compare the frequency of each chewing type in posterior crossbite group with normal occlusion and between posterior crossbite groups.
Results: It showed that normal occlusion has a simple and stable chewing type. In posterior crossbite group, reverse type, reverse crossing type and superimposition type was higher (P<0.001, 0.05, 0.05 respectively), the normal type was lower (p<0.001) in frequency in comparison with normal occlusion group. When accompanied by mandibular shift, mandibuar protrusion, arch crossbite, in the crossbite side or shift side, reverse type and reverse crossing type occurred higher than contralateral side.
Conclusions: In frontal plane, posterior crossbite may contribute to the high frequency of reverse and reverse crossing chewing type, especially when accompanied by mandibular shift, mandibuar protrusion and arch crossbite.