sp14_-_occlusion_20141210195236 Flashcards
1
Q
What is the definition of occlude?
A
to close tight, as to bring the mandibular teeth into contact with the teeth in the maxilla
2
Q
What are the functions of the masticatory system?
A
- mastication- swallowing- speech- respiration and expression
3
Q
What is the central pattern generator (CPG)?
A
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
4
Q
What is the chewing stroke?
A
rhythmic control of the separation and closure of teeth
5
Q
What is the shape of the movement pattern of the chewing stroke?
A
tear-shaped
6
Q
What are the 2 phases of the closing movement during mastication?
A
- crushing- grinding
7
Q
Which condyle is the working condyle? Which is the nonworking condyle?
A
- working condyle = rotating condyle- nonworking condyle = orbiting or translating condyle
8
Q
True or false: In the chewing stroke, as the teeth approach each other, the lateral displacement is lessened.
A
true
9
Q
True or false: The mandible moves backward during incising.
A
FALSE. The mandible moves forward during incising.
10
Q
When is there greater lateral movement: when the food is first introduced to the mouth or when the food has been chewed?
A
when the food is first introduced
11
Q
True or false: The amount of lateral movement is always constant.
A
FALSE. The amount of lateral movement varies according to food consistency.
12
Q
Does chewing hard food create a narrower or broader chewing stroke?
A
broader
13
Q
Does chewing gum produce a narrower or broader chewing stroke?
A
broader
14
Q
Is there an increase or decrease in tooth contact as food is broken down?
A
increase
15
Q
What is maximum intercuspation?
A
maximum condyle position determined when the teeth are clenched
16
Q
What type of contact occurs as cuspal inclines pass each other during opening and grinding?
A
gliding contact
17
Q
What type of contact occurs in maximum intercuspal position?
A
single contact
18
Q
What is centric relation?
A
where you can put the jaw in place so that the condyle is in the correct position
19
Q
True or false: Usually centric relation and maximum intercuspation do not coincide in people.
A
true
20
Q
What type of chewing stroke is promoted by tall cusps and deep fossae?
A
predominantly vertical chewing strokes
21
Q
What type of chewing stroke is promoted by flattened or worn teeth?
A
broad chewing stroke
22
Q
How many more times more force can molars handle as oppose to incisors?
A
3x as much force
23
Q
True or false: Biting forces increase with age up to adolescence.
A
true
24
Q
Where is the greatest amount of force placed during mastication?
A
the 2nd premolar and the 1st molar
25
What is the role of lips in mastication?
guide and control the intake of food and seal the oral cavity
26
What is the role of the tongue in mastication?
used to taste and maneuver the food within the oral cavity; also sweeps the teeth
27
What is the role of the muscles (like the buccinator) in mastication?
help position the bolus of food in the surfaces of the teeth
28
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
29
Which force is stronger on the teeth: the force during mastication or the force during swallowing?
the force during swallowing
30
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
31
What is the significance of the "M" sound?
a relaxed rest position between "M" sounds repeated at slow intervals are used to evaluate the amount of incisal display at rest
32
What is the significance of the "F" or "V" sounds?
length of central incisors and lingual tilt of the incisal third
33
What is the significance of the "S" sound?
closest speaking space where the incisal and occlusal surfaces of the teeth don't touch
34
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
35
To what degree should the condylar path be set to on the articulator?
25 degrees
36
What are the 2 movements of the mandible?
rotation and translation
37
What motion is created by the ginglymoid joint?
hinging
38
What motion is created by the arthodial joint?
gliding
39
What are the 3 parts of the TMJ compound joint?
- mandibular condyle- articular fossa and eminence (of temporal bone)- articular disc
40
Which dimension of the mandibular condyle is larger?
mesiodistal
41
Which articular (fossa or eminence) is the functioning portion? Which is the nonfunctioning portion?
- articular fossa - non-functioning portion- articular eminence - function portion
42
What makes up the articular disc?
fibrous connective tissue
43
True or false: The articular disc is vascularized.
true; the disc is vascularized except in the middle
44
What are the purposes of ligaments?
support the joint and limit movement; they do NOT move the joint
45
Name the ligaments of the TMJ.
- fibrous capsule- lateral ligament- stylomandibular ligament- sphenomandibular ligament- discal ligament
46
What is the purpose of the discal ligament?
collateral ligament that prevents excessive rotation
47
What is the purpose of the stylomandibular ligament?
prevents excessive protrusion
48
What is the purpose of the sphenomandibular ligament?
prevents excessive opening
49
What are the 2 parts of the lateral ligament? What are the purposes of each portion?
- internal horizontal portion - prevents condyle from moving too far back and helps lateral pterygoid- outer oblique portion - prevents excessive rotation; establishes first arch of opening
50
How many arches of opening are there?
2
51
What are the muscles of mastication?
- masseter muscles- temporalis muscles- medial pterygoid muscles- lateral pterygoid muscles
52
What is the function of the masseter?
to elevate the mandible (close teeth together)
53
What is the origin and insertion of the masseter muscle?
- origin - zygomatic arch (inferior and medial)- insertion - lateral surface of rami and angle of mandible
54
What are the functions of each of the 3 portions of the temporalis muscle?
- anterior - fibers elevate mandible and teeth contract- middle - fibers elevate and retrude- posterior - fibers retrude the mandible
55
What is the origin and insertion of the temporalis muscle?
- origin - temporal fossa on cranium- insertion - coronoid process, anterior border of ramus and temporal crest
56
What is the function of the medial pterygoid muscle?
to elevate mandible, close teeth together
57
What is the origin and insertion of the medial pterygoid muscle?
- origin - pterygoid fossae (sphenoid)- insertion - medial angle mandible
58
What is the function of the lateral pterygoid muscle?
one alone moves mandible laterally; together they prodtrude and depress the mandible
59
What is the origin and insertion of the lateral pterygoid muscle?
- origin - lateral pterygoid plate (sphenoid) and greater wing- insertion - pterygoid fovea (condylar process) and anterior part of articular disc
60
What are the suprahyoid muscles?
- geniohyoid- mylohyoid- diagastric
61
What are the infrahyoid muscles?
- omohyoid- sternohyoid
62
What is the function of the infrahyoid muscles?
working together, all can open mouth and depress mandible
63
What is the origin and insertion of the posterior belly of the hyoid?
- origin - mastoid notch- insertion - hyoid
64
What is the origin and insertion of the anterior belly of the hyoid?
- origin - medial and inferior surface of the mandible- insertion - hyoid
65
Other than the muscles of mastication, what other factors affect position or movement of the TMJ?
- ligaments- fascia- muscles of facial expression
66
Name the muscles that elevate the mandible.
- masseter- medial pterygoid- temporalis (anterior and middle fibers)
67
Name the muscles that depress the mandible.
- supra and infrahyoid muscles- both lateral pterygoids
68
Name the muscles that retrude the mandible.
- temporalis- suprahyoids (with help of infrahyoids)
69
Name the muscles that protrude the mandible.
- both lateral pterygoids simultaneously- masseter and medial pterygoid
70
Name the muscle responsible for the lateral excursion of the mandible.
right lateral pterygoid moves mandible to the left; left one moves mandible to the right
71
What is the innervation of the muscles of mastication?
mandibular branch of the trigeminal nerve (CN V3)
72
What is the innervation of the TMJ?
auriculotemporal and additionally by masseteric and deep temporal
73
What arteries supply the TMJ?
- superficial temporal artery- middle meningeal artery- internal maxillary artery
74
What are the 3 orthopedic principles that are followed by the biomechanics of the TMJ?
- ligaments do not participate actively in function of the TMJ; they just restrict some movements and permit others- ligaments do not stretch; they elongate if traction force is applied, causing normal joint functions to be compromised- the articular surfaces of TMJ must maintain contact (this is achieved by the elevator muscles)
75
What are the functions of biological contours?
- stimulate natural, healthy teeth- protect the supporting tissues- maintain the health of the gingiva and attachments- minimize trauma and irritation to bony tissues
76
What can improper contours lead to?
- often induce early breakdown of supportive structures- result in early loss of teeth
77
What is the definition of the crest of curvature (height of contour)?
the greatest convexity or bulge on the axial surface of the crown
78
What will occur if the curvature is too great?
the gingiva is protected too much and loses gingival tone; food and debris may pack under this area and result in chronic inflammation of the gingiva
79
In which third is the facial height of contour located?
cervical third no more than 0.5 mm facially beyond CEJ
80
Where is the lingual height of contour located in the posterior teeth? What teeth are an exception?
- height of contour located in middle third no more than 0.5 mm lingually beyond CEJ- mandibular 2nd premolar and mandibular molars are exceptions because of the lingual tilt (0.75-1.0 mm lingual of CEJ)
81
What is the definition of the emergence profile?
tooth surface that is gingival to the height of contour and above the gingival crest; the profile of the gingival third of a restoration as it emerges from the gingival crevice
82
What is the shape of the proximal surfaces between the contact area and the CEJ?
proximal surfaces are always flat or slightly concave between the contact area and the CEJ
83
What is the definition of the contact area?
the area of the mesial or distal surface of a tooth which touches its neighbors
84
What are the basic functions of contact areas?
- aids in proper development of the arches- prevents food from packing between teeth- allows the teeth to be self-cleaning (to some extent)- prevents injury to the interproximal tissues
85
How do the posterior teeth contacts change as the teeth age?
the contacts become worn and go from being points to areas (contacts get broader)
86
True or false: The contact becomes located in a different area as teeth age.
FALSE. The contacts are still located in the same area, just with a broader contact.
87
Where are the contact areas of posterior teeth located? What are the exceptions
- buccal to the central fossa and in the occlusal third- exceptions: between maxillary molars: contacts between occlusal and middle thirds or just in middle third and in the middle third rather than being just buccal to the midline (because lingual does not taper)
88
Are the distal contacts of posterior teeth more cervical or occlusal? What are the exceptions?
- distal contacts are more cervical- exceptions: mandibular first premolars
89
Why is it necessary to establish contact between teeth when restoring them?
- develop arch integrity (stability)- prevent food retention- protect interdental papillae
90
What are transitional line angles?
- surface between the faciolingual convexities and proximal concavities- contours should blend the convexities and concavities
91
Transitional line angles extend from what to what?
transitional line angles are straight between the proximal contact point and the cementoenamel junction
92
What depressions surround a marginal ridge?
- occlusal embrasure- proximal fossa
93
What shape are marginal ridges mesiodistally and faciolingually?
- mesiodistally: convex- faciolingually: concave
94
Marginal ridges are all at the same height except between what teeth?
canines and premolars
95
Marginal ridges converge in what direction?
from buccal to lingual
96
What is the definition of an embrasure?
a "V" shaped space extending outward fromt eh contact areas of the teeth
97
What are the functions of embrasures?
- it is a spillway for the escape of food during function- it helps to maintain the cleanliness of the tooth
98
Are lingual or buccal embrasures bigger?
lingual
99
What is the typical biologic width between the margin and bone?
1.5-2.0 mm
100
For subginigival margins, what type of restoration margin should be used? Why?
metal margin because it is easily tolerated by the tissues
