Comparison Of The Fidget Grades Induced By Preseted Levels Of Clenching And Forearm Raising

The masticatory system is made up primarily of bones, joint, ligaments, teeth, and muscles, exercising important function of stomatognathic system, such as chewing, speaking, swallowing, and so on. All movement is regulated by an intricate neurologic control system composed of the brain, brainstem, and peripheral nervous system, and coordinated to maximize function while minimizing damage to any structure. The current aim is to investigate whether force level, visual feedback and maintenance effort displayed different effects on the grade of annoyance induced by the motivated clenching and forearm raising to target force levels using advanced detection means.The present purpose was to use the synchronized T-Scan III and BioEMG III systems to evaluate the interrelationships between occlusal force and jaw-closing muscles activity by simultaneously recording of occlusion and surface electromyographic(SEMG) activity of anterior temporalis(TA) and masseter(MM) muscles in asymptomatic volunteers. Twenty five healthy young female right-handed subjects were enrolled to clench or raise the left forearm with low, medium, and maximum force level with/without visual feedback and with/without maintenance effort. The force level was visually indicated and the surface electromyographic(SEMG) activity was simultaneously recorded from anterior temporalis(TA), masseter muscles(MM), and left biceps brachii muscle(Bic L). Annoyance level was evaluated via questionnaire survey with visual analog scale(VAS) immediately after completing each of the tasks.We get the results as the following:1. Factor of force level and maintenance effort contribute to the increasing of SEMG values in all the tested jaw muscles during clenching with an interaction of them. The contribution of factor of visual feedback to the SEMG values was only noticed in TAL and MMR. The factor of maintenance enhanced the SEMG activity during clenching with the maximum force, but not with the medium or low force.2. For Bic L, only factor of force level contributed to the elevation of SEMG activity. Neither the factor of visual feedback nor maintenance effort displayed the effect on SEMG activity during forearm raising. No any interaction was noticed.3. The annoyance VAS value is generally correlated with difficulty VAS value at all three tested force levels in all tasks of with or without visual feedback when efforts were maintained or not, except the forearm raising task at medium force level with maintenance but without visual feedback.4. A higher level of annoyance is not linked with a higher level of clenching force, the highest annoyance score elicited by clenching was at low force level with visual feedback but without maintenance effort.5. A higher level of annoyance is linked with a higher level of forearm raising force, the highest annoyance score elicited by forearm raising was at maximum force level with vision feedback and also with maintenance effort.6. The difficulty VAS value is higher when performing clenching than forearm raising task under the condition of low force with visual feedback but without maintenance effort. And the VAS values of difficulty and annoyance are both lower when performed clenching tasks than forearm raising tasks at large force level with maintenance effort and with or without visual feedback.The results indicated that:1. When performing a forced clenching in asymptomatic volunteers, the periodontal mechanoreceptors takes the role of feedback modification. This kind of peripheral feedback seems control the force level well, hence the SEMG activity, but probably elicit a higher level of annoyance at the meantime.2. The SEMG activity of all tested muscles was increased with force level. The SEMG activity was enhanced by maintenance effort at the maximum force level for jaw muscles, but not for BicL.3. Extensively, a poor occlusion which always requires an extra-modification to find a proper or effective contact or positional relation via periodontal feedback during chewing is potentially contribute to masticatory annoyance or emotional behavior, though not necessarily a high level of SEMG activity of the jaw muscles, yet requires a clarification. The factor of occlusion may be lead to psychological reaction and original reason of TMD.