151 terms

Dental Anatomy Occlusion

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What is occlusion?
Contact between teeth.
Relationship between the max and mand teeth when they approach each other.
What is intercuspation?
-The cusp-to-fossa relationship of the upper and lower posterior teeth to one another.
-The interlocking/fitting together of the cusps of opposing teeth.
What is interdigitation?
Another name for intercuspation (interlocking/fitting together of cusps of opposing teeth)
As a general rule, each tooth interdigitates with (1/2/3) opposing teeth.
2
Why do teeth interdigitate with 2 opposing teeth?
To provide stability to the dental arches.
Interdigitation is most distinct in the (anterior/premolar/molar) regions of the mouth.
Anterior and premolar.
Interdigitation is least distinct in the (anterior/premolar/molar) regions of the mouth.
molar
A mandibular tooth interdigitates with which teeth in the maxillary arch?
The same tooth and the tooth mesial to it.
A maxillary tooth interdigitates with which teeth in the mandibular arch?
The same tooth and the tooth distal to it.
Which teeth only interdigitate with one opposing tooth?
-Mandibular central incisors
-Maxillary third molars.
What is centric occlusion?
The occlusion of opposing teeth when the mandible is in centric relation.
T/F: Centric occlusion always coincides with maximum intercuspation.
False
What is maximum intercuspation?
The occlusal position of the mandible in which the cusps of the teeth of both arches fully interpose themselves with the cusps of the teeth of the opposing arch..
Basically when you bite down the furthest you can.
Maxillary buccal cusps are in line with opposing (buccal/lingual) embrasures and developmental grooves.
Buccal
Mandibular lingual cusps are in line with opposing (buccal/lingual) embrasures and developmental grooves.
lingual
What is centric relation?
The maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective disks with the complex in the anterior-superior position against the shapes of the articular eminencies.
T/F: Centric relation depends on tooth contact.
False, it is independent of tooth contact.
When is centric relation clinically discernible?
When the mandible is directed superior and anteriorly.
Centric relation is restricted to a purely rotary movement about the transverse (horizontal/vertical) axis.
horizontal
How is centric relation useful when treating edentulous patients?
Since they don't have teeth as landmarks, you can use centric relation as landmarks for restorative/prosthetic procedures.
Which position of the condyl would be considered centric relation (see photo)?
When the upside down U shaped condyl is located at the highest part in the socket.

(most superoanterior position resting on the posterior slopes of the articular eminences with the disks properly interposed)
Centric (relation/occlusion) has been described as a tooth-to-tooth relationship.
Occlusion
Centric (relation/occlusion) has been described as a bone-to-bone relationship.
Relation
Centric (relation/occlusion) has been described as a bone-to-disk-to-bone relationship.
Relation
What is centric stop?
Opposing cuspal/fossae contacts that maintain the occlusal vertical dimension between the opposing arches.
What are a few examples of centric stop?
Cusp-marginal ridge
Cusp-fossa
Cusp-occlusal embrasure
What is the line of the central groove?
Rolling in of the outer inclines of the supporting cusps that places them under/over the line of the central groove of the opposing arch.
The (anterior/posterior) teeth act as "closure stoppers".
posterior
Ideally, the only excursive contacts should be on the (anterior/posterior) teeth.
anterior
In mutually protected occlusion, the (anterior/posterior) teeth protect the (anterior/posterior) teeth to prevent excess loading to the TMJs.
posterior, anterior
In mutually protected occlusion, the incisors protect the canines and posterior teeth in (lateral/protrusive movement).
protrusive
In mutually protected occlusion, the canines protect the incisors and posterior teeth in (lateral/protrusive) movement.
lateral
In the maxillary arch, the supporting cusps are the (buccal/lingual) cusps.
lingual
In the mandibular arch, the supporting cusps are the (buccal/lingual) cusps.
buccal
In the maxillary arch, the non-supporting cusps are the (buccal/lingual) cusps.
buccal
In the mandibular arch, the non-supporting cusps are the (buccal/lingual) cusps.
lingual.
In centric occlusion, there is a ___-___ mm space between the supporting and non-supporting cusps.
0.5-1.0
The (maxillary/mandibular) buccal cusps help keep the cheeks out of the way during mastication.
maxillary
The (maxillary/mandibular) lingual cusps help keep the tongue out of the way during mastication.
mandibular
What is anterior guidance?
The functional relationships of the maxillary and mandibular anterior teeth during excursive movements (movements away from centric occlusion).
During posterior disclusion, _____ _____ protects the posterior teeth.
anterior guidance
Where are the effects of anterior guidance greater?
a. incisors
b. canines
c. premolars
d. molars
c. premolars
Where are the effects of condylar guidance greater?
a. incisors
b. canines
c. premolars
d. molars
molars
How does anterior guidance protect the TMJs?
Helps prevent excessive range of motion.
The forces in the teeth closer to the TMJ are (smaller/greater).
greater
What is canine protected articulation (aka canine guidance/cuspid rise)?
A form of mutually protected articulation in which the vertical and horizontal overlap of the canine teeth disengage the posterior teeth in excursive movements of the mandible.
What are the canine eminences?
Thick facial plates of bone that provide additional protection from the forces on the canines.
During lateral excursion, the (incisors/canines/premolars/molars) are the only teeth to touch on the working side.
canines
What is group function?
Multiple contact relations between the max and mand teeth in lateral movements on the working side whereby simultaneous contact of several teeth acts as a group to distribute occlusal forces.
In group function, which inclines of the mandibular teeth and maxillary teeth contact each other?
The outer inclines of mandibular buccal cusps contact the inner inclines of maxillary buccal cusps.
When a patient has group function, the restorative dentist may need to give special consideration to the (anterior/condylar) guidance.
condylar
On large restorative cases with group function, some clinicians want no working contacts on the distobuccal cusps of the (first/second/third) molars and the buccal cusps of the (first/second/third) molars.
first, second
Which teeth are described as the steering wheel of occlusion?
The anterior teeth.
What is the hinge axis?
The axis that runs through each condyle. The condyles hinge and rotate about this fixed axis.
In Posselts diagram, which line represents hinge opening?
The line between B to CR (but may vary)
Hinge or rotary opening occurs for the first ____-_____ mm
20-25
What is translatory opening?
Condyles translate or slide down and forward on the articular eminences.
What can occur at maximum opening of the condyles?
They may slide over the crests of the articulator eminences. (The part where the arrows are)
In Posselts diagram, which line represents translatory opening?
B to E
Translation of the condyles normally continues until there has been ____ to _____ mm of total opening.
40-60
During right lateral excursion, the right sides is the (working/non-working) side and the left side is the (working/non-working) side.
working, non-working
What is another name for the non-working side?
The balancing side
What are the two condyles doing during lateral excursion?
On the working side, (mesiobuccal/ distobuccal/ mesiolingual/ distolingual) cusps of maxillary molars track out the lingual grooves of mandibular molars.
mesiolingual
On the working side, the (mesiobuccal/distobuccal/mesiolingual/distolingual) cusps of mandibular molars track out the buccal grooves of maxillary molars.
distobuccal
On the non-working or balancing side, the (mesiobuccal/distobuccal/mesiolingual/distolingual) cusp of the maxillary first molar tracks over the disto-buccal groove of the mandibular first molar. The cusp tracks in a (mesiobuccal/distobuccal/mesiolingual/distolingual) direction.
mesiolingual, distobuccal
The (mesiodistal/occlusocervical/buccolingual) position of the non-supporting cusps accommodates working movements.
mesiodistal
T/F: The nonsupporting cusps are aligned with opposing embrasures and developmental grooves in the working position.
True
The orbiting condyle is the condyle on the (working/non-working) side.
non-working
The rotating condyle is the condyle on the (working/non-working) side.
working
The orbiting condyle moves
a. upward
b. downward
c. forward
d. backward
e. medially
f. laterally
b, c, e
Downward, forward, and medially
The rotating condyle moves
a. upward
b. downward
c. forward
d. backward
e. medially
f. laterally
a, b, c, d, and f
Upward, downward, forward, backward, and laterally
What is protrusive movement?
When the condyles slide forward and downward on the articular eminences.
What is condylar guidance?
The functional relation of the hard & soft tissues of the temporomandibular joints which control mandibular movements.
The flatter the articular eminence, the (taller/shorter) the cusps must be.
shorter
(left is normal, middle is shallow, right is steep).
The steeper the articular eminence, the (taller/shorter) the cusps may be.
taller
The anterior guidance should be (smaller/equal/greater) than the condylar guidance.
equal or greater
What can distraction of the condyles due to centric relation or excursive interference do?
Harm the temporomandibular joints.
What are the determinants of occlusion?
-the right and left temporomandibular joints
-the occlusion of the permanent dentition
-the neuromusculature
For the occlusion determinant, we may want to consider the (anterior/posterior) teeth as active determinants and the (anterior/posterior) teeth as passive determinants.
anterior, posterior
What is the physiologic rest position (aka postural rest position or clinical rest position)?
The postural position of the mandible when the head is in an upright position and the associated muscles are in a state of minimal contraction.
What is freeway space?
The distance between the occluding surfaces of the maxillary & mandibular teeth when the mandible is in the physiological rest position.
The normal amount of freeway space in a dentulous dentition in ___ to _____ mm.
2-4
What is malocclusion?
Any deviation from a physiologically acceptable contact between the opposing dental arches.
What is occlusal prematurity
Any contact of opposing teeth that occurs before the planned intercuspation.
Occlusal splint
An artificial occlusal appliance used to modify the occlusion on a temporary basis
What is the number one sign of occlusal traumatism?
mobility
What is primary occlusal traumatism?
Abnormal forces on normal supporting structures. When the prematurity & interferences are removed, the tooth can stabilize in several days.
What is fremitus?
functional mobility
When premature contact occurs, what does the brain do?
It instructs the muscles of mastication to bring the teeth into a new maximum intercuspation
What is occlusal interference?
Any tooth contact that inhibits the remaining occluding surfaces from achieving stable & harmonious contacts.
What can occlusal interference cause?
Disclusion of the anterior guidance.
What is occlusal adjustment?
Any change in the occlusion intended to alter the occluding relation.
What is an articulator?
A mechanical instrument that represents the temporomandibular joints and jaws, to which maxillary and mandibular casts may be attached to simulate some oralmandibularmovements. -
What is a facebow?
A device that helps mount the articulator model in a way as close as possible to the patients occlusion.
Deglutition
the act or process of swallowing food.
The mandible is stabilized by bringing teeth into (CR/CO) during deglutition.
CO
Diagnostic casts
A positive likeness of a part or parts of the oral cavity for the purpose of study and treatment planning. (Basically impressions?)
Dynamic Occlusion
The movement/force involved when one chews, bites, holds objects, or clenches the teeth.
Freeway space
The distance between the occluding surfaces of the max and mand teeth when the mandible is in its physiological rest position.
What is the normal amount of freeway space?
2-4 mm
Occlusal interference
An occlusal contact which alters or restricts mandibular movement
Static occlusion
When the teeth touch lightly together in centric occlusion with the jaws slightly relaxed so that there is neither force nor movement
Centric cusps
Another name for supporting cusps
Non-centric cusps
Another name for non-supporting cusps
The buccal cusps of the mandibular premolars contact which area on the opposing maxillary teeth?
Mesial marginal ridge
The mesiobuccal cusps of the mandibular molars contact which area on the opposing maxillary teeth?
Mesial marginal ridge
What is the alternate centric stop for the buccal cusp of the mandibular premolars and the mesiobuccal cusps of the mand molars?
Distal marginal ridge
What is a cusp-marginal ridge type of occlusion?
When the buccal/mesiobuccal cusps of the mandibular posterior teeth contact the marginal ridges of the opposing maxillary teeth.
The distobuccal cusps of the mandibular molars contact which area on the opposing maxillary molars? What is this arrangement called?
The central fossae. Cusp-fossae arrangement
The lingual cusps of the maxillary premolars contact which area on the opposing mandibular teeth?
The distal marginal ridge
The distolingual cusp of the maxillary molars contact which area on the opposing mandibular teeth?
The distal marginal ridge
The mesiolingual cusps of the maxillary molars contact which area of the opposing mandibular molars?
The central fossae
Which cusps are maxillary centric cusps?
All lingual cusps of the maxillary posterior teeth
Which non-supporting cusps are the only ones that do not overlap the opposing non-supporting cusp?
The mandibular 1st premolars
Where are the lingual cusps of the 1st mandibular premolar positioned?
In alignment w/ opposing embrasures of developmental grooves
The central groove line can be used as a landmark indication for what?
1. The beginning of the facio-lingual taper
2. The beginning of the lingual embrasure
3. The end of proximal contact towards the lingual
4. The buccolingual position for centric stops
The central grooves of which teeth are not centered on the occlusal surface? Are they located more buccal or lingual?
-Mandibular 1st premolar
-Y-shaped mandibular 2nd premolar
-More lingual
On the mandibular 1st molar, how is the distal marginal ridge centric stop location different than usual?
It's located more lingual because of the presence of the distal third buccal cusp
T/F: The centric stops are often in the triangular fossae.
False
The centric stops are related to the (marginal ridges/embrasure surfaces).
Marginal ridges
Where is the distobuccal cusp of the mandibular 1st molar located in relation to the opposing maxillary molar?
Distal fossa, but no contact
The anterior teeth should (not contact/contact/contact lightly) the opposing teeth.
Either not contact, or contact lightly
T/F: The space between the non-supporting cusps and the supporting cusps acts to reduce lateral forces and helps prevent interferences.
True
In the working position, where are the non-supporting cusps positioned in relation to the opposing teeth?
Centered mesiodistally in the opposing embrasures (buccal or lingual) or the developmental grooves (buccal or lingual)
The relationship of which two teeth provides the basis for the morphological classification of occlusion and malocclusion?
Max 1st molar and mand 1st molar
In class 1 ideal occlusion, the mesiobuccal cusp of the maxillary 1st molar opposes which portion of the mandibular 1st molar?
The mesiobuccal developmental groove
What are the 7 requirements for Class 1 ideal occlusion?
1. Ideal interdigitiation
2. Ideal skeletal relationship
3. Ideal overjet
4. Ideal overbite
5. No impactions
6. No missing teeth
7. No supernumerary teeth
When is an occlusion considered Class 1 malocclusion?
When the mesiobuccal cusp of the max 1st molar opposes the mesiobuccal developmental groove of the mand 1st molar, but not all of the 7 requirements are met.
In class II malocclusion , the mesiobuccal cusp of the max 1st molar is (anterior/posterior) to the mesiobuccal developmental groove of the mand 1st molar.
Anterior
What is the difference between division 1 and division 2 Class II malocclusion?
-In division 1, there is excessive overjet of the anterior teeth.
-In division 2, there is an excessive lingual inclination of the max central incisors and an excessive labial inclination of the max lateral incisors.
In a class III malocclusion, the mesiobuccal cusp of the max 1st molar is (anterior/posterior) to the mesiobuccal developmental groove of the mand 1st molar.
Posterior
Which types of malocclusion lack or are deficient in anterior guidance?
a. Class II division 1
b. Class II dividion 2
c. Class III
b and c
Which articular model do we use?
Hanau Modular model 190
If the anterior teeth do not contact in centric occlusion, there should be (non-uniform/uniform) movement of the mandible until the anterior teeth contact.
uniform
What is incisal edge position?
As the mandible moves forward, the mandibular anterior teeth assume an edge-to-edge position w/ maxillary anterior teeth.
What is right lateral excursion?
As the mandible moves to the right, the buccal cusps of the mandibular right posterior teeth move into buccolingual alignment with the buccal cusps of the maxillary right posterior teeth
What is left lateral excursion?
As the mandible moves to the left, the left side assumes the working position and the right side becomes the balancing side.
What are lateral protrusive movements?
Movements between a straight protrusive movement and a pure lateral movement.
What are border movements?
Movements of the mandible in right and left lateral excursions.
(apex of V is CR)
T/F: A purely protrusive movement represented by the line extending forward from centric relation is considered a border movement and is repeatable.
False, it is not a border movement and is not repeatable.
What does the drawing of border movements of the mandible look like from the frontal plane?
-A is CO
-AD is right lateral excursion
-AC is left lateral excursion
-BD and BC represent border movements from endpoint of a lateral excursion to maximum opening.
Which point represents maximum protrusion on Posselt's diagram?
F
Which point represents the incisal edge-to-edge position on Posselt's diagram?
Top horizontal line
Which point represents centric occlusion on Posselt's diagram?
CO
Which point represents centric relation on Posselt's diagram?
CR
Which line represents the masticatory cycle position on Posselt's diagram?
Which line represents hinge opening on Posselt's diagram?
Line between CR and B
Which line represents normal opening on Posselt's diagram?
Line between CO and E
Which point represents maximum opening on Posselt's diagram?
Point E
Which point represents postural rest position on Posselt's diagram?
Point R