Opening Start from static intercuspal position muscle activity begins in the ipsilateral inferior head of the lateral pterygoid muscle approximately half way through the period of tooth contact. Follow closely by the action of the contralateral inferior lateral pterygoid muscles. Both superior and inferior head of th lateral pterygoid muscle are active during the opening phase.
Opening Early in the opening phase, digastric muscles become active and remain until maximum opening position During the opening phase, masseter, temporalis, medial pterygoid, and superior head of lateral pterygoid muscles are inactive.
Closing initiation of jaw closing the inferior heads of the lateral pterygoid muscle ceases their functioning and activity initiated in the contralateral medial pterygoid muscle
Closing Contralateral medial pterygoid controls the upward and lateral positions of the mandible Activity increases in the anterior and posterior temporalis muscle, in the deep and superficial masseter muscles, and in the ipsilateral medial pterygoid muscle anterior and posterior temporalis muscle, in the deep and superficial masseter muscles, and in the ipsilateral medial pterygoid muscle activity declines in activity at the onset of intercuspation. There appears to be reciprocal action between the inferior head of the lateral pterygoid muscle and the medial pterygoid muscle in same subject
Tooth contact during mastication Gliding contacts Single contact Average time for tooth contact is 194 minutes 60% Gliding contacts seen during grinding 56% gliding contacts seen during opening
Forces of mastication Maximum biting force in females 70 to 99 pounds Males 118 to 142 pounds Maximum bite force for molar 91 to 198 pounds Central incisors 29 to 51 pounds
Swallowing Series of coordinated muscle movements that moves bolus from oral cavity through esophagus to stomach
Frequency of swallowing 590 times in 24 hours 146 cycles during eating 394 in between meals 50 cycles during sleep
Speech Important sounds formed by the lip are m,band p Teeth are important in saying s Tongue and palate are essential in forming d Tongue touches maxillary incisors to form th Lower lip touches maxillary incisors to form f and v
Pain Unpleasant sensation perceived in the cortex as a result of incoming nociceptive input.
Modulation of pain Non painful cutaneous nerve stimulation Intermittent painful stimulation Psychological modulation
Types of pain Central pain Projected pain Referred pain
Central excitatory effect Explains the mechanism of referred pain