Optimal Functional Occlusion Flashcards
What type of position is the optimal occlusion?
stationary
What are the occlusal philosphies during excursive movements?
- canine guidance (anterior guidance)
- group function
- balanced occlusion
What three things should you evaluate for the patient’s occlusion?
- teeth
- TMJ
- musculature
(the entire masticatory system)
True/False: If a patient has orthodontically ideal angles of class I occlusion this means that the patient has optimal occlusal contacts, mandibular position, etc.
false
Does not mean this
True/False: Someone with a class II or class III occlusion is not orthodontically ideal but may have an acceptable, functional occlusion.
True
If a patient has less tha ideal occlusion it may still be a…
functionally acceptable occlusion
or
physiologically acceptable occlusion
How do you know if the patient’s occlusion requires treatment?
- asses the masticatory system for evidence of pathology (tooth wear, tooth mobility, TMJ, dysfunction, muscle dysfunction)
The TM joints are in an optimum, orthopedically stable jiont position when the mandible is in…
centric relation
What is centric relation?
the condyles are in the most anterosuperior position in the glenoid fossa, braced up on the intermediate zone of the disc and the mandible is free to rotate about the terminal hinge axis
What term refers to only the joints and does not involve the teeth?
CR
Why is CR the optimal position to view optimal functional occlusion?
- musculature in CR
- TMJs in CR
The muscles that stabilize the TMJs are mainly…
masseter and medial pterygoid
Contraction of the masseter and medial pterygoid result in…
antero-superior vector of force (stability)
The lateral pterygoid muscles are msot relaxed in what position?
centric relation
The condyles in centric relation rest against the ______ sloep of the articular eminence
posterior (tolerate higher stresses since avascular and non-innervated)
What are excursive movements?
lateral
protrusive
Is CR jaw or teeth position?
jaw
How do the condyles move when the anterior teeth open 20-25 mm?
rotation
What is the axis of rotation in CR called?
terminal hinge axis
What does we restore in CR?
- completely edentulous patients
- partially edentulous patients (not a stable MIP)
- dentate patients who are going to receive extensive restorations that will alter their occlusion completely
Optimal functional occlusion involves?
- TMJ
- Teeth
- excursive movements
What is the most desirable position of the posterior teeth for optimal funtional occlusion?
- multiple, even, bilateral, and simultaneous occlusal contacts with the mandible in CR position
The posterior teeth are loaded mainly along the ______________
long axis of the tooth (axial loading)
Why is it important for mulitple posterior teeth to contact in occlusion?
more teeth that contact, the more stress is distributed throughout the arch
Why is it imporant that the posterior teeth are even in occlusion?
ALL posterior teeth should contact evently. This distributes the stress over all the teeth
Why is it important for posterior teeth to be bilateral in occlusion?
For stability. If not then the mandible can pivto around and place increased pressure on the opposite TMJ
How should the teeth be loaded?
axially loaded through the long axis of the tooth
Anterior teeth should have ________ occlusal contact when the posterior teeth are in occlusion
lighter
Anterior teeth are not loaded axially so they will not be able to withstand…
high loads
What is important during excursive movements?
canine guidance (anterior guidance)
What is canine guidance (canine disclusion/canine rise)?
mandible moves laterally, the canines on the working side guide the movement, causing all other teeth to disclude
What guide is important during protrusive movement?
anterior guidance
What teeth disclude the posterior teeth when the mandible moves in protrusion?
canines, central, and lateral incisors
Contacts between posterior teeth during excursive movements are considered…
interferences (can create damaging effects on teeth and periodontium)
WHY IS CANINE GUIDANCE/ANTERIOR GUIDANCE THE OPTIMAL OCCLUSAL SCHEME?
- canine has the longest root and best bone support
- most anterior and has a lesser impact
The anterior teeth exhibit lighter occlusal contacts as compared to posterior teeth in…
MIP
What teeth are axially loaded in MIP?
posterior teeth
What is another name for optimal functional occlusion?
mutually protected occlusion
What teeth can tolerate lateral foces in excursive movements (off-axial loading)?
anterior teeth
What are the three occlusal schemes/philosophies in excursive movements?
- canine guidance
- group function
- balanced occlusion
What is group function?
- when the mandible moves laterally, the mandible is guided by the outer inclines of the mandibular buccal cusps sliding along the inner inclines of the buccal cusps of the maxillary posterior teeth
What is the most desirable group function?
canine, premolars, and mesiobuccal cusp of the first molar
On the working side during group function only the buccal cusps of the ________ teeth guide along the inner inclines of the _______ teeth
mandibular
maxillary
What are the contacts on the non working side during group function?
no contacts
Group function is acceptable but…
not ideal
Group function is the only option for patients who…
- no anterior vertical overlap
- very large anterior horizontal overlap (class II)
- reverse overlap (class III)
What is balance occlusion?
simultaneous contacts on both sides (working and non-working) during lateral excursive movments
If the mandible moves to the right during balanced occlusion…
- the right side (working) has outer inclines of mandiblar buccal cusps contact inner inclines of maxillary buccal cusps at the same time
- the left side (NWS) has inner inclines of mandibular buccal cusps contact inner inclines of maxillary lingual cusps
In protrusion during balance occlusion that contacts are between…
posterior and anterior teeth
What is bad about balanced occlusion?
- not acceptable for dentate patients
- promotes tooth wear on dentate patients
- non-working side contacts are extremely destructive and must be avoided
Balanced occlusion is an acceptable form of occlusion for…
complete dentures