Occlusion Flashcards
what elevates and retracts the mandible
temporalis
what protrudes and depresses the mandible and causes lateral movement
lateral pterygoid
what elevates and protracts the mandible
masseter
what elevates the mandible and aids in lateral movement and protrusion
medial pterygoid
what are three types of mandibular movements
rotation
translation
lateral translation
what is rotational movement
small amount of mouth opening (RCP)
condyle and disc remain in the articular fossa
no forward or downwards movement
known as a hinge movement
what is the terminal hinge axis
imaginary line via which the condyles rotate
what is translation movement
lateral pterygoid contracts and causes articular disc and condyle to move
travels downwards and forwards
what three planes are border movements viewed at
horizontal
sagittal
frontal
what is posselts envelop
extremes of mandibular movement
what is ICP
tooth position regardless of condyle position
most comfortable bite
what is edge-edge position
condyle moves forwards in translation and teeth are contacting at incisal edges
what is protrusion
past edge-edge
condyle moves forwards and downwards on articular eminence
what is maximum opening
no tooth contact
mouth wide open
full translation of the condyle over articular eminence
what is the retruded axis position
no tooth contact
most superior anterior position of the condylar head in the fossa
what is RCP
first tooth contact in the retruded axis position
what is lateral translation
result of contraction of only one lateral pterygoid muscle
what is the working side
the side the mandible moves towwards
what is the bennet movement
another term for lateral translation - a bodily movement
what is the bennett angle
the angle formed by the sagittal plane and path of mandibular condyle during lateral movement when viewed from a horizontal plane
what side do you take the bennet angle from
the non working side
how do you mark tooth contacts
articulating paper
millers forceps to hold the paper
when do you mark tooth contacts
preparing a tooth
removing a restoration
placement of a crown
placement of a restoration
what is static occlusion
incisor relationship
molar relationship
overjets/ bites
what are functional cusps
cusps that occlude with opposing teeth in the ICP
what problems occur in static occlusion
angles classification
overbite / overjet
crossbite
AOBs
what are examples of dynamic occlusion
canine guidance
group function
protrusion
what are occlusal interferences
undesirable tooth contacts that produce mandibular deviation during closure to ICP
what are examples of occlusal interference
working side
non-working side
protrusive
what is a working side contact
usually a posterior tooth when the mandible is moved laterally that is in contact with the upper arch
what is a non working side contact
tooth contacts on the non-working side where there shouldnt be any
what is protrusive interference
any posterior contact during protrusion
why do we need to avoid posterior contacts
molars arent designed to absorb heavy forces in the direction of long axis of the tooth
what is eccentric bruxism
parafunctional grinding of teeth side to side
what is centric bruxism
clenching
what are clinical signs of bruxism
tooth wear
fractured restoration
tooth migration
muscle pain and fatigue
what is occlusal trauma
injury resulting in changes in the attachment apparatus including PDL, supporting alveolar bone and cementum as a result of occlusal forces
what are the three types of articulator
ARCON
average value
semi-adjustable
what are the average values for the Bennet Angle and Condylar Guidance angle on an average value articulator
bennet angle -15 degrees
condylar guidance angle -30 degrees
how can you mount a maxillary cast onto an articulator
facebow transfer
what is the first step in recording facebow occlusion
mark anterior reference point
how do you mark an anterior reference point for using a facebow
use patients right side
43mm apical to the incisal edge of the 12 ideally
position of this dot should be approximately position of infra-orbital foramen
what is the second step in using a facebow
apply registration paste to the bite fork and firmly seat on maxillary teeth
what do you need to do with the locating notch on the bitefork
have it at the midline
what should the facebow be parallel to
inter-pupillary line
what do you need to mount the lower cast against the maxillary cast taken by using facebow
ICP
or RCP
what can you use when ICP is not obvious to technician
wax wafer
silicone past which sets quickly
what is a conformative approach
the provision of restorations in harmony with the existing jaw positions
when is the conformative approach not used
an increase in vertical height is needed
teeth are out of position
a slight change in appearance is wanted
what are factors of copying existing guidance
simple
conformative
most often
