Maximal Bite In Intercuspal Position Research Articles

A COMPARATIVE ELECTROMYOGRAPHIC STUDY OF TEMPORALAND MASSETER MUSCLE IN CLASS I AND CLASS II DIVISION I CASES

Aim- The purpose of this study was to record the electromyographic activity of the temporalis and masseter muscles in normal and Angle's class II division 1 cases in maximal biting in intercuspal position and during chewing and to compare the activities of the two muscles in class II division 1 cases with those of normal occlusion. Materials And Methods- 15 subjects of Angle's class II division 1 malocclusion with deep anterior overbite, skeletal class II pattern with ANB angle greater than 4° and normal mandibular plane angle were selected. The 15 normal occlusion subjects had normal overjet and overbite with class I dental arch and normal mandibular plane angle. All the subjects were male of 9-15 years of age, with full compliment of teeth particular for that age, were free of any temporomandibular joint disorder and had no history of previous orthodontic treatment. Electromyographic activity of the temporal and masseter muscles of both sides were recorded during maximal biting in intercuspal position and during chewing of peanuts. The peak to peak amplitude was obtained from the raw EMG data using the integrated software. The average peak to peak amplitude in uv were used for statistical analyses. Results And Conclusion-The results revealed that there was no statistically signicant differences in activity of the muscles of the right and left sides in both the groups. The activity of the masseter muscle in both maximal biting and chewing was signicantly higher in class I group. In class II division 1 group although the masseteric activity was higher, it was not statistically signicant. Comparison between the groups showed that the masseteric activity was signicantly higher in class 1 group for both chewing and maximal biting. The temporalis activity was also signicantly higher for class I group during chewing, but the difference in temporalis activity during maximal biting, although higher in class I group, was not statistically signicant.

Changes in electrical activity of masseter and temporal muscles after temporomandibular joint surgery: A one-year follow up

The functioning of the masseter and anterior temporal muscles was recorded by electromyography (EMG) in 15 patients with disc interference of the temporomandibular joints, before surgery and three months, six months and one year afterwards. EMG recordings were made during maximal bite in intercuspal position and while chewing. The mean electrical activity in the masseter and anterior temporal muscles, both on the operated and nonoperated sides, decreased markedly three months after surgery, especially during maximal bite in intercuspal position, but increased to above the preoperative values at the one-year recording in both functions. Statistically, significantly lower activities were seen on the operated side in patients with anterior dislocation of the disc without reduction, as compared to patients with reduction of the disc. The EMG activities of the masseter muscles on the nonoperated side were significantly lower in women and in older patients, as well as in patients with a longer duration of symptoms than in men and younger patients.

Changes in electric activity of masseter and temporal muscles after mandibular sagittal split osteotomy

The functioning of the masseter and anterior temporal muscles was assessed by electromyography in 18 patients before orthognathic surgery and 6 weeks, 3 months, 1 year, and 2 years afterwards. Electromyogram (EMG) recordings were made during maximal bite in intercuspal position and chewing. The mean electric activity in the masseter and anterior temporal muscles decreased markedly 6 weeks after surgery but increased clearly for 1 year in both functions. Only a slight further increase was observed at a 2-year follow-up during chewing, but not during maximal bite in intercuspidation. The mean changes in electric activity increased more clearly in patients with hyperplastic mandible than in patients with hypoplastic mandible and in those with long shift of the mandible. The same finding was also more visible in men and older patients than in women and younger patients.

Muscle activity in Class II, Division 1 malocclusions treated by bite jumping with the Herbst appliance: An electromyographic study

The effect of continuous bite jumping on masticatory muscle activity was investigated in ten growing boys with Class II, Division 1 malocclusion treated with the Herbst appliance. Integrated EMG recordings from the temporal and masseter muscles were analyzed quantitatively during maximal biting in intercuspal position and during chewing of peanuts. The results of the investigation revealed the following: (1) Before treatment the EMG activity from the masseter muscle was less than from the temporal muscle, especially during maximal biting in the intercuspal position. After treatment no difference in EMG activity was found between the two muscles, during either maximal biting or chewing. (2) During insertion of the Herbst appliance, the mandible was jumped anteriorly to an incisor edge-to-edge position with no occlusal contacts present in the posterior dental arch segments. The EMG activity from the two muscles during maximal biting and chewing was markedly reduced. (3) When the Herbst appliance was removed after 6 months of treatment, normal occlusal relations were found in all patients. The EMG activity in the two muscles exceeded pretreatment values. The increase in EMG activity seen was greater for the masseter than for the temporal muscle. The results of this investigation suggest that the increased muscle activity seen in the Class II, Division 1 cases during bite jumping with the Herbst appliance was due to an altered sagittal jaw base or dental relationship.

Activity of the temporal and masseter muscles in Class II, Division 1 malocclusions: An electromyographic investigation

A quantitative analysis of EMG activity in the masticatory muscles was performed in homogeneous groups of boys with Class II, Division 1 malocclusion and normal occlusion. Integrated EMG recordings from the temporal and masseter muscles were analyzed during maximal biting in the intercuspal position (centric occlusion) and during the chewing of peanuts. The results of the investigation revealed the following: (1) During maximal biting in intercuspal position the boys with Class II malocclusion exhibited less EMG activity in the masseter and temporal muscles than the boys with normal occlusion. In the Class II boys the reduction in EMG activity was most apparent for the masseter muscle. (2) During chewing the Class II subjects showed less EMG activity in the masseter muscle than the normal occlusion subjects. For the temporal muscle, no differences were found between the two occlusion groups. (3) High positive correlations were found between the EMG activity during maximal biting and chewing for both muscles in the two occlusion groups. The impaired muscle activity found in the Class II cases may be attributed to a diverging dentofacial morphology and unstable occlusal contact conditions.

Temporal and masseter muscle activity in children and adults with normal occlusion. An electromyographic investigation.

Temporal and masseter muscle activity was investigated in male subjects with normal occlusion, 11 years (n = 23) and 25 years (n = 21) of age. Integrated EMG recordings were analysed quantitatively during maximal biting in intercuspal position and during chewing of peanuts. The results of the investigation revealed the following: 1. Masseter muscle activity was greater in the older than in the younger age group. 2. Temporal muscle activity was the same in both age groups. 3. Masseter muscle activity was increased in relation to temporal muscle activity in the older subjects. In the younger subjects the same activity was found in the two muscles. 4. For the temporal muscle the chewing activity was positively correlated to maximal biting activity in both age groups. For the masseter muscle a clear correlation between chewing and biting activity was found in the younger age group only. The difference in EMG activity found between children and adults may be attributed to age changes and/or an exercising effect of the masseter muscle occurring during maturation.