Week 12 Flashcards
what is an anteriorly, superiorly braced position along the articular eminence of the glenoid fossa, with the articular disc interposed between the condyle and eminence
centric relation
is CR a joint related position?
YES
T/F: CR has NOTHING to do with the teeth, and EVERYTHING to do with the joint (TMJ)
TRUE
components of the TMJ
- articular eminence
- condyle
- external auditory meatus
- superior and inferior lateral pterygoids
- retrodiscal tissue
- thin superior wall of glenoid fossa
centric relation is the most stable position ___ and ___.
orthopedically and musculoskeletally
what has been highly debated for years
centric relation
what is a good place to start when planning major restorative work?
centric relation
what is the difference between a healthy and unhealthy joint in centric relation?
healthy: condyle is anterior and superior
unhealthy: anteriorly displaced disc (internal derangement)
angle and length of condylar rotation (mm)
10-13 degrees
20-25 mm
fundamentals of occlusion Wilcox vs. Shil
Wilcox: broad stable posterior support and effective anterior guidance
Shil: create posterior contacts that stabilize mandibular position
what is purely hinge movement and is also termed the kinematic axis?
horizontal axis of mandibular movement
what creates a rotating condyle and orbiting condyle?
vertical axis of mandibular movement
e.g. if moving left, you rotate left and orbit right
what axis moves down and forward
sagittal axis
if mandible is moved to the left, the left side is the [nonworking or working] and the right side is the [nonworking or working]
left side is working
right side is nonworking
what is the bodily shift of the mandible in the direction of the working side?
immediate side shift or Bennett angle
what is a gradual shifting of the mandible during the working side movement?
progressive side shift
what is the continuation of the Bennett angle as it continues movement
progressive side shift
what is the posterior determinant of mandibular movementt
condyles
what is the anterior determinant of mandibular movement
contacting teeth:
- posterior teeth provide vertical stops and guide mandible into MI
- anterior teeth provide guidance (canines and Class III lever system)
T/F: the closer a tooth is to the determinant, the more it will be influenced by that determinant
TRUE
what are undesirable contacts that may produce mandibular deviation or may hinder smooth passage to and from intercuspal position?
occlusal interferences
what is the most destructive occlusal interference?
nonworking
What occurs when condyles are in the most superoanterior position, posterior teeth in solid and even contact, anterior light contact
closure
occlusal forces are along what axis of teeth
long axis
what occurs when working side contacts and disocclude nonworking teeth instantly?
lateral excursions
what occurs when anterior contacts disocclude posteriors
protrusive
in ___ posture, posterior contacts are heavier than anterior
upright posture
what are the 3 occlusal schemes?
- bilateral balanced
- unilateral balance
- mutually protects (canine protected)
what is the maximum number of teeth in contact in all positions, and excessive wear only used now only with dentures prevent tipping
bilateral balanced occlusal scheme for dentures
what occlusal scheme is where only working side contacts
unilateral balance (group function)
what occlusal scheme is when posterior disocclusion is in eccentric movements, most accepted, usually used in large restorative cases and requires good anterior perio?
mutually protected occlusal schemes (canine guidance taught at creighton)
the angle between the working and nonworking path is greater on teeth located ___ from the condyle.
FARTHER
what burs to use for proximal reduction
888 (gradoville choice) or 169
clearance from the adjacent teeth should be what?
at lest >0.8 mm (width of explorer)
how many mm of occlusal clearance should one have?
1-1.5 mm (aim for 1.3 mm bc that’s the length of the ball burnisher
what bur to use for Chamfer
876 proximally
856 or 876 for everything else
