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Physiologic activity formedwhen there is normalocclusion in a cyclicmovement a complex function thatuses not only the muscles,teeth, periodontal supportivestructures but also the lipscheeks tongue palate andsalivary glands it consists of a number ofchewing strokesMastication
MasticationPurposes:1. Physiologic transformation of food2. Enhances growth and development of the dento-alveolar structures through stimulation3. Stimulates salivary flow (which in turn maintainoral hygiene)4. Vitalization of food increase appetite5. Protection of food from undesirable foodcomponents6. Helps further develop or allow jaw bone to grow
It is the rhythmic and well-controlled separationand closure of the maxillary and mandibular teeth Each stroke has a tear-shaped movement pattern.Divided into:**OpeningCrushing Phase**ClosingGrinding Phase
Mandible dropsdown from theIntercuspalposition (ICP)to a pointwhere theincisal edges ofthe teeth areabout 16 to 18mm apart.It then moves laterally 5-6 mm from the midline.OPENING PHASE
The buccal cusps of the Md teeth are almostdirectly under the buccal cusps of the Mx teethon the side the mandible was shifted.Mandible isguided by the occlusalsurfaces back to theintercuspal positionwhich causes the cuspalinclines of the teeth topass across each other,permitting shearing andgrinding .CLOSING PHASE
When food is initially introduced into the mouth,amount of lateral movement is greater andbecomes lesser as food is broken down.The harder the food, the morelateral the closure strokesbecome and the more chewingstrokes neededChewing StrokeFRONTAL VIEW
1. GLIDING – occurs as the cuspal inclines pass byeach other during the opening and grindingphases of mastication2. SINGLE – occurs in the maximum intercuspation 194 ms – average length of time for tooth contactwhile during mastication
Maximum biting force varies from individual toindividual.MALE118 to142 lb (53.6 to 64.4 kg)FEMALE79 to 99 lb (35.8 to 44.9 kg)
Maximum amount of force applied to molar isusually several times that can be applied to anincisor.Central Incisor29 to 51 lb(13.2 to 23.1 kg)1st molar91 to 198 lb(41.3 to 89.8 kg)
With age up to adolescence With practice and exercise Persons with markeddivergence of the maxillaand mandible
LIPS guide, control intake and sealfood.TONGUE plays a major role in tasteand maneuvering the food inside theoral cavity. It also helps in dividingsoft foods and in sweeping the fooddebris after eating.CHEEKS (buccinator muscles)repositions the food on the buccalsides.
aka “Deglutition”; an innate function the series of coordinated muscle contractionthat moves a bolus of food from the oral cavitythrough the esophagus to the stomach.The decision to swallow depends on severalfactors:•Degree of fineness of the food•Intensity of the taste extracted•Degree of lubrication of the bolus
1. INFANTILE / VISCERALSWALLOWCharacterisitics:1. Lips are sealed and appear stiff2. Tongue is abnormally large and is caught betweenmaxillary and mandibular gumpads3. There is no harmonious relationship between the maxillaand the mandible4. Absence of normal seal5. There is no harmonious relationship between cranial andfacial structures
2. SOMATIC SWALLOWCharacterisitics:1. Presence of normal seal2. Presence of normal occlusion3. Tongue is inside oral cavity4. There is normal antero-posterior relationship betweeenmaxilla and mandible5. There is harmonious relationship between the cranial andfacial structure
OVERRETENTION OF INFANTILE SWALLOWCauses:1. Lack of tooth support due to poor tooth positionor arch relationship.2. Discomfort during tooth contact due to caries ortooth sensitivityEFFECTS:1. Labial displacement of the anterior teeth bypowerful tongue muscle (Anterior Open Bite)
Voluntary Begins with selective partingof the masticated foodInto mass or bolus bytongue Bolus placed on dorsum oftongue and pressed onthe hard palate while thetip of tongue rest on theIncisors. Lips are sealed, teeth broughttogether. Reflex wave of contraction inthe tongue caused byfood on palatal mucosapresses bolus backward.
Once the bolus reaches the pharynx, aperistaltic wave caused by contraction ofthe pharyngeal constrictor muscles carriesit down to esophagus. The soft palate touches the posteriorpharyngeal wall sealing off the nasalpassages. Phrayngeal orifices of the eustachiantubes openOral and Pharyngeal phases ofswallow together last for 1s.
Consists of passing of the bolusthrough the length of the esophagusto the stomach by Peristaltic waves(6-7s) The Cardiac sphincter relaxes asthe bolus approaches and let it entersthe stomach. Upper section of esophagus iscomposed of voluntary muscles whilelower portion is entirely withinvoluntary muscles.
According to Studies:590 cycles --- 24-hr period146 cycles --- eating394 cycles --- between meals while awake50 cycles --- sleep**Lower levels of salivary flow duringsleep result in less need to swallow
DYSPHAGIA – difficulty in swallowing ODYNOPHAGIA – painful swallowing APHAGIA – absence of swallowing due to paralysis of musclesof deglutition or mastication Abnormal growth of esophagus – cancer, tumor, outgrowthor overgroath
3rd major function of the stomatognathicsystem It occurs when a volume of air is forcedfrom the lungs by the diaphragm through thelarynx and the oral cavity. Controlled contraction and relaxation of thelarynx create a sound with desired PITCH. It occurs during the expiration stage ofrespiration
Afferent mechanism – those involved in hearing andsight Association areas – those involved in:A. seat of learning and memoryB. seat of habits and condition habitsC. cerebral cortex and molar centers Efferent mechanism – involves the nerves thatsupplies the muscles involved in speech
RESPIRATION –simultaneousbreathing to have streamof air from lungs isneeded to producesvibration PHONATION –actual productionof speech soundsRESONANCE –process by whichsound is intensified oramplified
ARTICULATION – breaking up of sound andmodification of sounds from lungs, this involves thecomplex conditioning movements of:a. Lipsb. Cheeksc. Palated. Tonguee. Posterior laryngeal wall
By varying the relationships of the lips and tongueto the palate and teeth, a variety of sounds can beproduced.M, B, P ---- formed by lipsS -------- by teeth( in close approximation)D -------- tongue and palateTH -------- tongue to maxillary incisorsF, V ------- lip to incisal edges of maxillary teethK, G ------- posterior portion of thee tongue tosoft palate
ARTICULATIONOF SOUNDSCreated byspecific positionsof the Lips,Tongue andTeeth
It is a continuous process closely associatedwith deglutition. This is also referred to as ventilation where inthere is an entrance of oxygen and release ofcarbon dioxide
External Respiration-exchange of airbetween blood andenvironmentInternal Respiration-exchange of airbetween blood and cells
1. Presence of normal seal2. Normal atmospheric pressure3. Normal TMJ4. Normal occlusion5. Normal antero-posterior relationship of maxillaand mandible6. Tongue is kept within the oral cavity7. Establishment of physiologic rest position
CAUSES:• chronic allergies• tonsil hypertrophy• nasal polyps• deviated nasal septum• constricted upper airways• a backward positioned lower jaw caused bythumb sucking• excessive pacifier use or insufficient sucklingas an infant