Oral Anatomy: Function/Occlusion Flashcards
T/F: A compensating curve is used to create balanced occlusion for artificial teeth.
True
Describe a working side (laterotrusive) movement.
The side of the mouth that the mandible moves to
Descibe a nonworking side (mediotrusive) contact.
Contacts on the side away from which the mandible has moved
_________ is the vertical overlapping of mandibular incisors by maxillary incisors.
Overbite
_________ is the horizontal overlapping of mandibular incisors by maxillary incisors.
Overjet
T/F: Angle’s classification is based on molars only.
False
Molars and canines
What is the molar relationship that defines Class I occlusion?
MB cusp of max M1 occludes with MB groove of mand M1
Where is the max canine occluding in a Class I relationship?
Max canine occludes between mand canine and PM1
What is the difference between Division I and Division II Class II occlusion?
Division I - all max incisors proclined
Division II - max centrals retroclined, laterals proclined
In Class II occlusion, the MB cusp of max M1 occludes _________ to the MB groove of mand M1.
mesially
canine also occludes more mesially
In class III occlsuion, the MB cusp of M1 occludes _______ to the MB groove of mand M1.
distally
canine also occludes more distally
What are the working cusps of maxillary and mandibular teeth?
Max lingual and mand buccal
functional cusps
What do working cusps oppose?
central fossae and marginal ridges
T/F: Working cusps are sharper than nonworking cusps.
False
Broader and rounder
T/F: Nonworking cusps support the vertical dimension of the face.
False
Working cusps
What do nonworking cusps oppose?
Embrasure spaces and grooves
In ideal CO, every tooth in one arch contacts two teeth in the opposite arch except for which teeth?
Max 3rd molars and mand central incisors
Where do the ML cusps of max molars teeth occlude?
In the central fossa of their counterpart
Where do the DL cusps of max molars and the lingual cusps of max premolars occlude?
Distal marginal ridge of counterpart and mesial marginal ridge of distal tooth
The mandible acts as a _______ lever.
class III
Although there are a couple exceptions, where do most buccal cusps of mandibular posterior teeth occlude?
Mesial marginal ridge of maxillary counterpart and distal marginal ridge of mesial tooth
Which cusp of mand molars occludes in the central fossa of their counterparts?
DB cusps
Where does the distal cusp of mand M1 occlude?
Triangular fossa of max M1
Where does the MB cusp of max molars occlude?
Buccal groove of counterpart
Where does the DB cusp and oblique ridge of the max M1 occlude?
DB groove of mand M1
Because of the distal cusp of mand M1
Where do the DL cusps of mand molars occlude?
Lingual groove of counterpart
Which nonworking cusp in the mandible opposes nothing?
L cusp of PM1
_________ is the most anterior and superior position of the condyles.
Centric relation
What is the terminal hinge position?
Position of the condyles in CR
______ is a tooth-guided position. ______ is a ligament-guided position.
CO; CR
T/F: During swallowing, the mandible meets the maxilla in centric occlusion.
True
Posselt’s envelope of motion illustrates the mandible’s motion in which planes?
Sagittal, horizontal, frontal
T/F: The side that the mandible moves to is the working side.
True
The ____________ occurs during lateral excursive movements in which the working side condyle shifts laterally.
Bennett movement
Protrusive movements are caused by contraction of _______________.
Both lateral pterygoids
What muscle causes a lateral excursive movement?
Contraction of the lateral pterygoid on the non working side
In which directions does the non working condyle move during a lateral excursive?
Anteriorly and medially
Which muscles of mastication work for retrusion of the mandible? Protrusion?
Retrusion - temporalis and masseter
Protrusion - Medial and lateral pterygoid
Which is the only MoM that depresses the mandible?
Lateral Pterygoid
All MoM are innervated by ______.
V3
Which are the 5 suprahyoid muscles and how are they innervated?
- Anterior digastric - V3
- Posterior digastric - VII
- Mylohyoid - V3
- Geniohyoid - C1 via XII
- Stylohyoid - VII
T/F: Both the suprahyoid and infrahyoid muscles assist in depression of the mandible.
True
The ___________ elevate the hyoid, especially during swallowing.
suprahyoid
_____________ muscles depress the hyoid and larynx, especially after swallowing.
Infrahyoid
What are the four infrahyoid muscles and their innervation?
- Omohyoid - ansa cervicalis
- Sternohyoid - a.c.
- Sternothyroid - a.c.
- Thyrohyoid - C1 via XII
Which infrahyoid muscle is not innervated by the ansa cervicalis?
Thyrohyoid
T/F: If the hypoglossal nerve is injured, the tongue will deviate towards the side of the injury.
True
What are the four extrinsic muscles of the tongue?
Genioglossus - protrusion
Hyoglossus - depression
Styloglossus - elevation, retrusion
Palatoglossus - elevation
Which is the only tongue muscle not innervated by CN XII?
Palatoglossus - CN X (pharyngeal plexus)
Which ligament prevents posterior and inferior displacement of the condyles and provides direct support to the TMJ capsule?
Temporomandibular (lateral) ligament
