Cuspal Arrangement of Teeth and Occlusal Morphology Flashcards
5 determinants of tooth position
lips and cheeks tongue proximal contacts occlusal contacts oral habits
Forces of mastication normal? maximum where? dentures? \+ implications on gender
Male is greater than female
Molar - more force than incisor teeth
normal chewing is about 25% of maximum force
Dentures – only get 25% of force of natural dentition
- varies with age and diet
- as you get older chewing is not as efficient
definition of occlusal stability
equalization of contacts that prevents tooth movement after closure
stable = open and close in a repeatable pattern
inter-arch relationship of teeth
where the occluding surfaces of the teeth are intercuspated to resist the vertical and horizontal physiologic forces
part of maintaining stability
interarch relationships for dental stability - forces
relationship of the interarch articulation allows the forces to be transmitted to attachment apparatus ALONG THE LONG AXIS OF THE TOOTH
interarch relationships for dental stability - space
Opposing teeth should meet solidly from a vertical dimension of occlusion (VDO) vertical dimension of rest (VDR) to a point that is acceptable to allow for ADEQUATE INTEROCCLUSAL REST SPACE (freeway space = VDR-VDO)
free way space
VDR - VDO
space at rest usually about 3 mm and can be produced after patient says the word ‘Emma’
interarch relationships for dental stability - contacts
contacts during a working side movement of the mandible should DISARTICULATE THE TEETH ON THE NON-WORKING SIDE
interarch relationships for dental stability - excursions
anterior and lateral excursions should be compatible with the posterior cuspal anatomy to AVOID posterior interferences
condylar guidance
angle at which the condyles descend along the articular eminence
protrusive records are made in order to adjust?
angle at which the condyles descend along the articular eminence (condylar guidance)
shape of the articular disc
biconcave
function of plane of occlusion
arranged to permit maximum use of tooth contacts during function
occlusal plane in sagittal plane
curve of spee
occlusal plane in frontal plan
curve of wilson
curve of spee
definition
view
importance
posterior to anterior along the buccal cusp of the canine to the last molar
viewed in sagittal plane
helps maintain anatomy of teeth and function
curve of wilson
definition
view
importance
from buccal cusp to lingual cusp through the lingual and buccal acorss the arch
viewed from frontal
classification of cusps
Supporting = centric cusps or functional
Guiding = non-centric, guiding, shearing
supporting cusps
functions and characteristics
function/centric cusps
LINGUAL/palatal of upper
mandibular buccal cusps
- maintain VDO
- play major role in mastication
- rounded shape
guiding cusps
functions and characteristics
non-centric, guiding, shearing
maxillary buccal and mandibularl lingual
- assist in shearing food
- sharp tips
- minimize tissue impingement and to maintain the bolus of food on the occlusal table during mastication
posterior cuspal relationship
the mandibular buccal cusps occlude in the central fossae of the maxillary teeth
the maxillary lingual cusps occlude in the central fossae of the opposing
posterior crossbite
mandibular lingual cusps in central fossae
maxillary buccal in central fossa
opposite of normal
- the functional switch
Buccooclusal line
linguocclusal line
connects buccal cusps
connects lingual cusps in arch
outer functional cusp inclines
the functional OUTER ASPECT of the centric cusp is the only area of an outer incline with functional significance - it is GUIDING
GUIDE THE CUSP INTO THE MIP
functional cusp inclines (three)
supporting - INNER
guiding - OUTER SURFACE
guiding - INNER
Guiding inclines of maxillary
guiding inclines of the maxillary teeth are the surfaces responsible for the characteristics of anterior guidance
occlusal table
area of major forces of mastication
chewing surface
this is NOT cusp tip to cusp tip
- in the fossa
- could be 50-60% of occlusal table
four determinants of mandibular motion
- right condyle
- left condyle
- muscles
- dentition
Class I
Orgonathic Profile occurs 72% of time
MB cusp of the maxillary first molar is aligned directly over the buccal groove of mandibular 1st molar
Class II
Mesial buccal cusp of maxillary first molar is in the ebrasure area between the mandibular 2nd premolar and 1st manddibular molae
Protruded maxilla and retruded mandible
excessive overjet or horizontal overlap
Class II Division 1
proclined (flared out) maxillary anteriors - lower lip can be behind the maxillary anteriors and push them outward
class ii division ii implications
maxillary anteriors pushed lingual or straight
results in steep anterior guidance
what type of lever is our jaw?
Class III lever - like a stapler and have the effort BETWEEN the fulcrum (condyle) and the load
Class II occlusion
Distal occlusion
Class III occlusion
MB cusp of the maxillary first molar occludes in the embrasure area between the mandibular 1st and 2nd molar
Mesial occlusion with anterior crossbite
prognathic profile
what surfaces of the teeth are responsible for guiding the cusps in lateral movements?
outer surfaces of functional cusps
inner surfaces of the guiding
angles class i - anterior teeth
vertical overlap (2-3 mm) horizontal overlap (minimal)
responsible for anterior guidance (diocclusion of posterior teeth and interferences)
angles class iii - anteriors
edge to edge or anterior crossbite
