sp14_-_occlusion_20141210195236 Flashcards
What is the definition of occlude?
to close tight, as to bring the mandibular teeth into contact with the teeth in the maxilla
What are the functions of the masticatory system?
- mastication- swallowing- speech- respiration and expression
What is the central pattern generator (CPG)?
a pool or neurons that controls rhythmic muscle activities and is responsible for the precise timing of activity between antagonistic muscles so that specific functions can be carried out
What is the chewing stroke?
rhythmic control of the separation and closure of teeth
What is the shape of the movement pattern of the chewing stroke?
tear-shaped
What are the 2 phases of the closing movement during mastication?
- crushing- grinding
Which condyle is the working condyle? Which is the nonworking condyle?
- working condyle = rotating condyle- nonworking condyle = orbiting or translating condyle
True or false: In the chewing stroke, as the teeth approach each other, the lateral displacement is lessened.
true
True or false: The mandible moves backward during incising.
FALSE. The mandible moves forward during incising.
When is there greater lateral movement: when the food is first introduced to the mouth or when the food has been chewed?
when the food is first introduced
True or false: The amount of lateral movement is always constant.
FALSE. The amount of lateral movement varies according to food consistency.
Does chewing hard food create a narrower or broader chewing stroke?
broader
Does chewing gum produce a narrower or broader chewing stroke?
broader
Is there an increase or decrease in tooth contact as food is broken down?
increase
What is maximum intercuspation?
maximum condyle position determined when the teeth are clenched
What type of contact occurs as cuspal inclines pass each other during opening and grinding?
gliding contact
What type of contact occurs in maximum intercuspal position?
single contact
What is centric relation?
where you can put the jaw in place so that the condyle is in the correct position
True or false: Usually centric relation and maximum intercuspation do not coincide in people.
true
What type of chewing stroke is promoted by tall cusps and deep fossae?
predominantly vertical chewing strokes
What type of chewing stroke is promoted by flattened or worn teeth?
broad chewing stroke
How many more times more force can molars handle as oppose to incisors?
3x as much force
True or false: Biting forces increase with age up to adolescence.
true
Where is the greatest amount of force placed during mastication?
the 2nd premolar and the 1st molar
What is the role of lips in mastication?
guide and control the intake of food and seal the oral cavity
What is the role of the tongue in mastication?
used to taste and maneuver the food within the oral cavity; also sweeps the teeth
What is the role of the muscles (like the buccinator) in mastication?
help position the bolus of food in the surfaces of the teeth
What are the two types of swallowing? Describe each.
- somatic swallow - during swallowing, teeth come together into maximum intercuspation position to stabilize the mandible in order of the suprahyoid and infrahyoid to contract and control the proper movement of the hyoid in order to swallow- visceral swallow - occurse in infants and adults with no teeth; mandible is braced by placing the tongue forward and between the dental arches or gum pads
Which force is stronger on the teeth: the force during mastication or the force during swallowing?
the force during swallowing
What are the 3 stages of swallowing?
- first stage - voluntary; selective parting of the masticated food into bolus by the tongue; bolus on dorsum of tongue and pressed lightly against hard palate; lips are sealed and teeth brought together; reflex wave is initiated and bolus is pushed backwards into the pharynx- second stage - when bolus is in pharynx, peristaltic wave carries it down the esophagus; soft palate rises to posterior pharyngeal wall to seal off nasopharynx; epiglottis blocks the trachea; pharyngeal orifices of the eustachian tube are openned- third stage - pass the bolus through the length of the esophagus and into the stomach carried by peristaltic waves; the cardiac sphincter relaxes as bolus reaches it; the upper section of the esophagus has voluntary muscles while the lower section is involuntary
What is the significance of the āMā sound?
a relaxed rest position between āMā sounds repeated at slow intervals are used to evaluate the amount of incisal display at rest
What is the significance of the āFā or āVā sounds?
length of central incisors and lingual tilt of the incisal third
What is the significance of the āSā sound?
closest speaking space where the incisal and occlusal surfaces of the teeth donāt touch
What are the objectives of the additive wax technique?
provides meaning and purpose to:- ridge and groove direction- cusp height and fossa depth- the lingual concavity of the maxillary anterior teeth
To what degree should the condylar path be set to on the articulator?
25 degrees
What are the 2 movements of the mandible?
rotation and translation
What motion is created by the ginglymoid joint?
hinging
What motion is created by the arthodial joint?
gliding
What are the 3 parts of the TMJ compound joint?
- mandibular condyle- articular fossa and eminence (of temporal bone)- articular disc
Which dimension of the mandibular condyle is larger?
mesiodistal