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occlusal forces reduced further forward tooth position is in contact in arch is what lever system:
Class III lever
If RCP-ICP slide and resistance from lateral pterygoid what occurs?
stretches lateral pterygoid
worn and flat occlusions result from which chewing movements?
horizontal and wide
custom incisal guidance table w/ self cure acrylic modled by incisal pin that copies the contact movements of stone cast crowns used for:
tranfer exact anterior guidance characteristics worked up in temp crowns in the mouth to articulator and final restoration.
patient: class I occlusion
crowns #5, 6 contribute to smile esthetics
#5 esthetically correct but laterotrusive interference w #28 in R lateral
What is best option?
Adjust, reshape or groove distal cusp ridge of #28 buccal cusp
#31 crown w/Class I
poor anterior guidance little posterior disclusion
How do you adjust opposing occlusion to accomodate ML of #2 which mediotrusion interference
DB groove in #31 by dividing DB into Distal and DB cusp
tooth movement in ICP or contact movements
clinical TMJ clicking
1mm RCP-ICP slide
what worsens a TM anterior disc displacement with reduction
performing bit adjustment to remove slide (ICP=RCP)
anterior teeth survive guidance without traumatic occlusion because:
- brief contacts
- not in every stroke-> program proprioception of chewing position when contact does occur
- disadvantagous or demagnified forces from masseter
progressive protrusion guidance
for pt w/ large overjet to avoid molar interferences in protrusion
1st guidance 2ND PREMOLARS-> 1st premolars -> canines
restoring 11-15 w/ extensive bruxing poor remaining group function guidance
What is most predictable occlusal guidance?
Place group function occlusion with gradual disclusion guidance
Most fundamental requirement for occlusion?
Stable and single end point of jaw closure
pt w no repeatable ICP
consider CR and RCP as alternative for multi unit bridge
CR and RCP will mean functinal position quite posterior to current functional position.
How do you test pt tolerance to CR and consequences of altering ICP to CRO as a functional position?
- 1. Test TMJ symptoms produced when manipulating joints in CR
- 2. Occlusal appliance (splint, orthotic, night guard adjust for CR to RCP) for 1-2 weeks
- 3. study articulated casts mounted in CR using CR interocclusal checkbite record and facebow and perform diagnostic (trial) coronoplasty (bite adjustment)
full crown, lower molar, fractured buccal cusp
very flattened by wear-> wide occlusal table with sharp square occluso-buccal and occluso-lingual line angles
- 1. Opposing worn tooth should be reshaped before constructing above restoration to reduce non-axial forces falling on tooth
- 2. Examine rest of arch and reshap and round off similarly worn flattened broadened occlusal surface edges to reduce risk of similar cusp fractures
TMJ what kind of model:
- NOT ball & socket
- spheroid held against and moving down an inclined plane
half arch non anatomic dental articulators
- used to construct 1-2 posterior crowns if sufficient teeth allow seating in ICP
- no error in ICP if working casts articulated in ICP on non-anatomic articulator and no facebow
- likely to be error in lateral and mediotrusive movements requiring clinical adjustments
- risk or lateral, medio contacts or interference is likely to occure when patient has MINIMAL anterior guidance
"close-packed" position for joint is
which jaw manipulation to CR is most consistent
Bimanual jaw manipulation (Peter Dawson)
co-axial translation of jaw along horzontal axis is
mandibular side shift
reflexive resists proper or full lateral contacts
best advice to make full range for accuracy?
night guard and retake in 4 weeks
Contraindication for crown reconstruction segmentally
if increasing VDO
good anterior guidance
disclusion of ICP contacts and separation of posterior teeth in protrusion
(T/F) unusual to find lack of molar ICP holding contact in jaw of normal functioning dentate patient
presence of jaw dysfunction related to Angle Class?
unusual for lack of ICP holding contacts at incisors for normal?
movement of mandibular supporting cusps on mediotrusive side
downward, forward, medial
notable mandibular side shift (1-2mm) is more likely to increase risk for interference in which types of contact movement, side
mediotrusion side in lateral jaw movement?
supporting cusp exit pathways observed on opposing occlusal surface make what kind of pathway in latertrusion movement viewed from horizontal plane
right angles to line of upper or lower arch in latertrusion side movements
arrow traced from ICP toward excursion pathway direction matched the read direction of actual jaw movement when:
mandibular cusp movements across upper occlusal surface
ICP, Class I
MB cusp of 15 aligns with?
B groove of 18
most frequent response to placing high filling or high cusp for single tooth restoration?
posturing of jaw to avoid interference
Increase curve of wilson increases what risk?
What determinant of occlusion is only testable clinically and not represented in articulator?
lingual cusp #13 occludes distal fossa of 20
what increases risk for intereference?
B. left laterotrusion
C. right lateral due to interference of ML #19 and Lingual #13
D. right lateral due to interference of MB#19 and Lingual #13
anterior guidance angle greatest influence on cusp angles the closer the teeth are to anterior guidance control
condyle guidance exerts greatest influence on teeth closer they are to TMJ
careful setting of condylar angles on articulator critical for
- 1. occlusion goal of balanced rather than posterior disclusion
- 2. when there is poor anterior guidance
protrusive and lateral cheek bite in occlusal records are:
100% correct in the location of the jaw position at which they were actually recorded.
pt discomfort in upper premolars
check w/ mylar find equal holding ICP in premolars and adjacent teeth
fremitus was detected #5 and propose occlusal reshaping.
- 1. steady tooth with finger and retest contacts
- 2. mark and adjust premature ICP contact
- 3. bring latertrusion guidance into group function to share eccentric contact loading
- DO NOT first adjust premature excursive contact on tooth #5 unless stablized
under-set protrusive condyle angle
what is the effect
more disclusion between crowns in patients mouth than seen when crowns were in articulator
when would you see most posterior tooth attrition?
- Class III
- Class II, div 2=least posterior wear
which pattern recruits the least jaw elevator muscle activity in voluntary clench or bruxing movement?
canine or canine segment guidance
natural deep bites displace mandible posteriorly and are associated with muscle pain and TMJ clicking
increased or increasing incisor overjet can be consequence of what disorder?
TMJ osteoarthritis or osteoarthritis
what way does steepness of occlusal plane affect ability to accomodate steeper cusp angles and deeper fossas?
- flatter and lower OP-> steeper Cusp inclination
- Condylar inclination * Incisal guidance/
- Occlusal Plane * Cuspal inclination * Compensating Curve
crowns for 12-15
12 and 14 are supported by implants
don't want to leave crowns high in contact and implants out of contace and vice versa
need to refine ICP because it is high
How do you instruct patient to close to properly mark and adjust occlusion
have patient clench more firmly so the supported teeth matches the occlusion on natural teeth when they are loaded and slightly intruded.
multifactor studies on chronic occlusal variation suggest that the contribution of dental occlusal variation to TMJ disorders is
only about 4% to 25%