dental occlusion sagittal determinants

Sagittal dimension

forward and back

(cannot measure right to left)

which head is biggest, superior or inferior head of lateral pterygoid muscle

inferior head

inferior head of LP

pulls condyle forward

superior head of LP

pulls disc forward

maximum opening of mouth

50-60 mm

hinge opening

20-25 mm

excursive movements

-anterior teeth protect posterior teeth

mutually protected occlusion (MI)

posterior teeth protect anterior teeth

nutcracker theory

-posterior teeth more subjected to more force in excursive movement

-closer to the joint the more force

excursive contacts

-lingual slope of the canines and incisors

anterior guidance

canine guidance + incisal guidance

incisal guidance

-combination of horizontal and vertical overlap of incisors

-steeper than condylar guidance

-dentist controlled

-protrusive movement

what can dentists not control

posterior teeth (can control anterior teeth)

canine guidance

-positional relationship of the maxillary to mandibular canines

-right to left movement (lateral movement)

group function occurs when

-canines are malposed

-canines are small and weak

balanced occlusion

The bilateral, simultaneous, anterior, and posterior occlusal contact of teeth in centric and eccentric positions.

sagittal determinant principles

-A determinant that increases disclusion of the posterior teeth allows (may) variation in the cuspal and anterior lingual concavity morphology

-A determinant that decreases disclusion of the posterior teeth restricts (must) cuspal and lingual concavity morphology

relationship b/w curve of spee and cusp height

-steeper cure of spee= shorter the cusps must be

-less curved= sharper/longer cusps may be (teeth hit less)

angle of eminence

condylar guidance

horizontal and vertical overlap

incisal guidance

Angle of Eminentia

angle between condylar path and Frankfort plane

Smaller the angle of eminentia

-less separation of posterior teeth

-cusp of posterior teeth must be shorter

-lingual concavity must be greater

The larger angle of eminentia, the

-more separation of posterior teeth

-cusps of posterior teeth may be longer

-less lingual concavity of maxillary incisors

Steep horizontal condylar guidance

-cusps of posterior teeth must be longer

shallow horizontal condylar guidance

-cusps of posterior teeth must be shorter

horizontal overlap

overjet

vertical overlap

overbite

lesser the horizontal overlap

-more separation of posterior teeth

-longer the posterior cusps may be

greater the horizontal overlap

-less separation of the posterior teeth

-shorter the posterior teeth must be

greater the vertical overlap

-more separation of posterior teeth

-longer the posterior cusp may be

lesser vertical overlap

-less separation of posterior teeth

-shorter the posterior cusps must be

more horizontal, less vertical

less separation of jaw