introduction to occlusion ;) Flashcards
definitions of occlustion
the manner in which the teeth come together when closing the jaw
the relationship between the teeth when moving the mandible
how should the teeth work on closign
posteror teeth contact
anterior have light contact only
why should posterior teeth contact on closing
molars have a large root SA, 2/3 roots which can take the load and distribute it evenly
intercuspal postion
relationship between the maxilla and mandible when the teeth are in maximum intercuspation (when teeth are together)
centric relation
the most anterior superior position of the condyle disc assembly within the glenoid fossa
(when the condyle is sitting comfortable in the fossa)
- relationship between mandible and maxilla, nothing to do with teeth
centric realtion movment
range of movement within centric realtion
- as long as condyle is within the cavity
retruded contact position
first point of contact when the mouth is closing (at the back on the molars)
centric relation and ICP
retruded contact position in most people first
then squeeze down further, condyle is pulled forward to enter intercuspal posotion
(discrepancy between ICP and centric relation)
how should teeth work on forward movement/protrusion
anterior teeth disclude (separate) the posterior teeth by anterior guidance
- palatal surfaces of the upper anterior teeth dictate the movement of the mandible
what happens to the teeth during sideways movement
posterior teeth separate
canine dictates the movement
canine guidance in sideways movement
resist sideways forces due to shape
root much bigger than crown
Caine is highly innervated so uses proprioception to prevent load on anterior teeth
class one occlusion
lower incision occludes at of below the upper incisorycingulum plateau
class one occlusion molar
the mesiobuccal cusp of the permanent maxillary first molar occluded in the buccal groove of the permanent mandibular first molar
class two occlusions
lower incisor occludes behind the upper incisor cingulum plateau
class two occlusion molar
mesiobuccal cusps of the permanent maxillary first molar occlides medial to the buccal groove of the permanent mandibular first molar (i.e. lower molar tooth is further back)
incisors in the class two
correct inclination or proclined (overjet is increased)
or retroclined
divisions of class 2
divison 1 - overjet, proclaimed or correct inclinaition division 2 - upper incisors are retroclined - overbite
overbite vs overjet
overbite is the vertical distance of how the upper incisors cover the lower incisors
overreact
- horizontal distance between the incisors
class 3 occlision
lower incisors occlude in front of the upper incisors cingulum plateau or edge to edge
class 3 molar occlusion
mesiobuccal cusp of the permanent maxillary first molar occludes distal to the buccal groove of permanent mandibular first molar
anterior open bite
only in contact with back teeth
large amount of space between the anterior teeth
- all movement based on the back teeth
what is the movement of the mandible dictated by
position of the condyle in the fossae
condylar pathway along the articular eminence
teeth interfering with this border movement
protrusive eccursion
condole move forwards and downwards
what is the working side
where there is contact between the occlusal surfaces of teeth and where the lower teeth are moving to that side
e.g. think about chewing gum
what would be the ideal occlustion
ICP = CR forces directed through the long axis of the teeth anterior guidance in protrusion canine guidance in lateral excursion mutual protection
when would we be able to make an ideal occlusion
when making entire set of dentures
Occlusal schemes
ideal occlusion
group occlusion
balanced occlusion
group occlusion
all of the teeth are contacting we move to the working side, group of teeth functioning rather than canine guided when moving sideways
balanced occlusion
artificial, used in dentures to keep them stable by attempting to make the sids balance and for teeth to mesh together in each excursion
