CH16: Occlusion

Occlusion

relationship between the 1st molars helps classify; the relationship of the teeth in the mandibular arch to those in the maxillary arch as they are brought together

Centric occlusion

maximum intercuspation or contact between the teeth 

Maxillary is stationary, the mandibular is the one that moves (true/false)

true

Alignment and occlusion of teeth helps

-masticatory

-functionality

-speech

-esthetics

Normal occlusion

-Facial profile-mesognathic

-slightly protruded jaws; flat face appearance

-straight profile

What type of Class?

Molar relationship:

• Mesiobuccal cusp of the maxillary 1st molar occluded with the buccal groove of the mandibular 1st molar; When you can’t use the permanent 1st molars to determine occlusion use the canines. 

Canine relationship:

• Maxillary canine occludes with the distal half of the mandibular canine and mesial half of the mandibular 1st premolar 

Class I: mesognathic

Malocclusion

any deviation from the physiologic acceptable relationship of the maxillary arch and/or teeth to the mandibular arch/teeth

-Class II

-Class III

What class?

Molar relationship

• The buccal groove of the mandibular molar is distal to the mesiobuccal cusp of the maxillary molar by at least the width of a premolar 

Canine relationship

• The distal surface of the mandibular canine is distal to the mesial surface of the maxillary canine by at least the width of a premolar

Class II: retrognathic

Something is referred to class tendency if it’s ___ than the width of a premolar

less

In class II, division 1 the maxillary incisors are _____; in division 2 the maxillary incisors are _____

protruded, retruded

What Class?

Molar relationship:

• The buccal groove of the mandibular 1st molar is mesial to the mesiobuccal cusp of the maxillary 1st molar by at least the width of a premolar

Canine relationship: 

• The distal surface of the mandibular canine is mesial to the mesial surface of the maxillary canine by at least the width of a premolar 

Class III: prognathic

Class I=normal occlusion, ideal occlusion, neutrocclusion, mesognathic, straight profile

Class II=distoocclusion, retrognathic, convex profile, deep overbite 

Class III=mesiooclusion, prognathic, concave profile, underdite 

Okie dokie

Malocclusions/malrelationships of dental arches include

-posterior cross bite

-anterior cross bite

-edge to edge bite

-end to end bite

-open bite

-overjet

-underjet

-overbite

Misalignment of teeth include

-labioversion

-linguoversion

-buccoversion

-supraversion

-toriversion

-infraversion

Posterior crossbite

maxillary or mandibular posterior teeth are either facial or lingual to their normal positions (unilateral or bilateral)

Anterior crossbite

Maxillary incisors are lingual to the mandibular incisors

Edge to edge bite

anterior teeth-incisal surfaces occlude instead of overlap

End to end bite

posterior teeth occlude

Open bite

lack of occlusal or incisal contact

Overjet

horizontal distance between labioincisal surfaces of the mandibular incisors and the linguoincisal surfaces of the maxillary incisors

Underjet

Maxillary teeth are lingual to the mandibular teeth

Overbite

vertical overlap by which the maxillary incisors overlap the mandibular incisors

Slight overbite

maxillary teeth fall on incisal third

moderate overbite

maxillary teeth fall on middle 3rd

severe overbite

maxillary fall on cervical 3rd

labioversion

tooth position toward lip

linguoversion

tooth positioned toward tongue

buccoversion

tooth positioned toward the cheek

supraversion

elongated, above the line of occlusion

toriversion

tooth twisted or rotated or turned

infraversion

depression/below line of occlusion

parafunctional activity

abnormal or deviated function

etiology of parafunctional activity

-clenching

-bruxism

-nail biting

-biting on objets

-lip or cheek biting

consequences of parafunctional habits

-accelerated tooth wear (wear facets, attrition

-pulpal involvement

-tooth movement

Occlusal trauma

trauma to the periodontium by dynamic or parafunctional forces that exceed the adaptive and reparative capacities

Primary occlusal trauma

excessive occlusal force on a tooth with normal bone support

Secondary occlusal trauma

normal or abnormal occlusal forces placed on a tooth with bone loss or inadequate alveolar bone support 

Effects of occlusal trauma (clinical + radiographic)

Clinical-progressive change in tooth mobility, fremitus, sensitivity to pressure, chewing, percussion, tooth drifting, fractured teeth

Radiographic-widening of PDL space, root resorption, thickening of the lamina dura