Evaluation of malocclusion in MPDS.

Introduction: Myofascial pain dysfunction syndrome (MPDS) is a disorder which is characterized by facial pain and limited mandibular function because of the complex nature of this disease. Malocclusion was never evaluated in MPDS patients to know its role. Electromyographic silent period durations of masseter were used for objective assessment of MPDS patients.

Aim: To evaluation of role of malocclusion in MPDS patients and also to study the EMG masseteric silent period pattern in MPDS patients in different malocclusions.

Materials And Methods: Two groups, groups I and II of 75 subjects each, were included in this study. Groups I and II constituted the normal subjects and MPDS patients respectively. All these subjects in both the groups were again subdivided based on Angle's class I, II and III malocclusion. Electromyographic (EMG) silent period of masseteric muscle on both sides was measured for all the subjects in both the groups to know whether it differs according to the type of malocclusion.

Results: The silent period was more in group II (MPDS patients). There was no signifcant difference in the silent periods in Angle's class I, II and III malocclusion in group I, whereas in group II, there was a signifcant difference in the silent period in Angle's class II compared to Angle's class I and III. There was no signifcant difference between males and females.

Conclusion: MPDS patients are more in Angle's class I malocclusion. Silent period is more in Angle's class II malocclusion of MPDS group. CLINICAL SIGNIFCANCE: The EMG masseter silent period duration can be advantageously utilized as an adjunct to clinical examination for diagnosis of myofascial pain dysfunction syndrome. It is enough if one side masseter muscle is measured for silent period duration.