ABSTRACT
Objective:To study the characters of perioral muscle p re ssure of the adult patients with skeletal crossbite. Methods:20 patients were diagnosed to be with skeletal crossbite. The perioral muscle press ures on upper and lower central incisors, first molars and cuspids were measured buccally and lingually at rest position. 10 health adults were served as the co ntrols. Results:The perioral force in skeletal crossbite group was larger than that in the control group on the correspondence area(P0.05). In the skeletal cross bite group, the perioral force on the mandibular area was larger than that on th e correspondence maxillary area(P0.05). The muscle pressure on the labial side was larger than that on t he lingual correspondence side in both groups(P
ABSTRACT
Objective: To investigate the effect of orthodontic and surgical treatments of skeletal crossbite on the electromyographic activity of human masticatory muscles. Methods: Electromyogram was used to test the changes of the electromyographic activity of masseter muscles, temporal anterior and diagastric anterior in 20 patients with skeletal crossbite before and after treatments. Results: Orthodontic and surgical treatments showed different effect on the activity of masseter muscle, temporal anterior and diagastric anterior. The change of the activity of the masseter muscle was the most significant among them. But, during chewing the masseter muscle was less active after treatments. Conclusion: Abnormal activity of the masticatory muscles can be partly corrected by the orthodontic and surgical treatments. The treatments cannot fully recover the function of the masseter muscle.
ABSTRACT
Objective:To examine the soft tissue changes of early skeletal Class III malocclusion patients after maxillary protraction treatment. Methods:60 skeletal anterior crossbite patients, 27 males, 33 females in the late mixed dentition were selected. The age ranged from 8 to 11 years. Mean age was 9.3 years. The patients were divided into treatment group and control group. Average treatment time was 12.1 months. Pre- and post-treatment lateral cephalograms of both groups were traced and analyzed. Difference between pre- and post-treatment was analyzed with paired t-tests. Results:After treatment, Ns-Sn-Pos, Ns-Prn-Pos, Sn-S-Si and Cm-Sn-UL decreased significantly,while Sn-Ns-Si and UL-E increased significantly. No significant change was found in S-Ns-Sn and LL-E. Conclusion:Soft tissue profiles are significantly improved by maxillary protraction treatment in the late mixed dentition. The concave profiles were changed to straight or nearly normal profiles. The relationship among nose, upper lip, lower lip and chin become harmonious. The curve of the lips tends to be smooth and harmonious.