Chapter 5 E: Dental Occlusion Flashcards
Occlusion vs functional occlusion?
- occlusion is static
- functional occlusion is dynamic
Functional balance:
MS PB
Mastication swallowing phonation breathing
Characteristics of an ideal occlusion?
- upper arch is larger
- all upper teeth buccally cover the lower ones
- palatal usps of upper teeth engage over middle pits of the lower teeth
- canine class I and molar class I
- all lower teeth are mesial to the upper ones
- overbite 2-4mm = 1/3
- over jet 2-3 mm
- compensation curves (Wilson frontal, spee sagittal)
All the lower teeth are in a mesial position with respect to their upper teeth, so that every tooth of an arch occludes with two teeth of the opposite arch except?
the lower central incisors and the last upper molars
Centric relation is?
Independent of tooth contact
- position in which the mandibular condyles are in the fossae in an anterosuperior position against the posterior slope of the articular eminence
- In CR, the muscles are in their most relaxed and least stressed state
Maximum intercuspation is?
Independent of condylar position
- There is a maximum number of contacts between the upper and lower teeth
Centric occlusion is
CR + MI= C0
Only 10% have this
Resting and occlusal position? Which is altered by orhto and which isnt?
Resting isnt
Occlusal is
The vertical space between the arches in resting position is?
2-3 mm
Difference in occlusion between dentitions? Incisors?
- primary: vertical incisors
- mixed: slight labial inclination
- permanent: buccally inclined
Difference in occlusion between dentitions? Overbite
- primary: minimum, almost edge to edge
- mixed: light overbite
- permanent: 1/3= 2-4mm
Difference in occlusion between dentitions? Spee and Wilson curves
- primary: almost flat
- mixed: light
- permanent: more marked
Difference in occlusion between dentitions? Glenoid cavity and TMJ
- primary: almost flat glenoid fossa and underdeveloped TMJ
- mixed: development of both
- permanent: fully developed
Difference in occlusion between dentitions? Primate spaces and inter-dentary diastemas
- primary: both present
- mixed: disappearance of both
- permanent: non existent
6 basic keys of Angle:
- Molar relationship
- Crown angulation
- Crown inclination
- Rotation
- Spaces
- Occlusal plane
Molar relationship:
- MB cusp of upper 1st molar in groove between mesial and middle cusps of lower 1st molar
- Distal surface of DB cusp of upper 1st molar occludes with the mesial surface of the MB cusp of 2nd lower molar
- Slight inclination of upper 1st molar contributes to the stability of the gear
Crown angulation:
- angulation of long axis of the tooth
- gingival portion was distal to the incisal portion
Crown inclination:
- buccolingual
- upper incisors: buccal inclination of the crown
- posterosuperior teeth: palatal inclination of the crowns, molars more inclined then PM and canines
- lower incisors: less declined to buccal almost straight
- posteroinferior teeth: lingual inclinations inc from canine to molars
Which tooth when rotated takes up less space?
Upper anterior teeth
Who included and suggested the importance of joint positions and the role of function?
Ronald Roth
5 main etiological factors related to TMD:
- occlusion
- trauma
- emotional stress
- deep pain input
- parafunction
Stable masticatory system=
Stable occlusal position + stable joint position
Orthodontic treatment goals:
- CR
- when the mandible moves into laterotrusive positions, there should be adequate tooth-guided contacts on the laterotrusive (working) side to immediately disclude the mediotrusice (nonworking) side
- when the mandible moves into a protrusive position, there should be adequate tooth-guided contact on the anterior teeth to immediately disclude all posterior teeth
- Posterior tooth contact should be heavier than the anterior tooth contacts
Ortho treatment goal:
to develop the maximum intercuspal position of the teeth in the musculoskeletally stable position
