OSCE 1

3 tooth functions

eating, swallowing, speaking

Determination of tooth position

1. Forces applied by soft tissues

2. Impact of size

3. Forces applied by therapeutic modalities

4. Missing tooth

   1. Can lead to food impaction → caries

Curve of wilson

curve of spee

max teeth angulation: Anteriors are mesially inclined, while most posteior teeth become more distally inclined with reference to alveolar bone

angulation of the mandibular: anteriors and posteriors are inclined mesially

all max posteriors are slightly inclined bucally

all mandibular posteriors are slightly inclined lingually

With loss of proximal contact…

tooth distal to the extraction site will drift mesially

when a tooth is lost..

distal tooth moves mesially, unopposed tooth erupts seeking occlusal contact

anterior open bite

• Lingual force > than labial/buccal

• Labial flaring of anteiror teeth

• Bite is caused by constant resting of tongue NOT unusual swallowing

plane of occlusion

plane that would be established if line were drawn through all buccal cusp tips and incisal edges of mandibular teeth and broadened out to included lingual cusp tips and continuing across arch to include buccal and lingual of the opposing arch

Curve of spee: relationships seen where?

Teeth?

Planes of occlusion?

• MD axial relationships seen from lateral view

• Angulation of teeth w respect to alveolar bone

  • Max Anteriors: M inclination

  • Max Post: D inclination of most

  • Man Ant + Post: M inclination, 2nd and 3rd more inclined than premolars

• Maxilla: Convex

• Mandible: Concave

Curve of Wilson: Relationships seen where?

Teeth?

Planes of occlusion?

• BL axial relationships seen from frontal

• Max Posteriors: slight buccal inclination

• Mand Post: slight lingual inclination

• Maxilla: Convex

• Mandible Concave

Bonwill Triangle

triangle between condyles (mandible) + mesial contact areas of Mandibular central incisors

• Condyle - Condyle: 4 inches

  • Condyle - man cen incisor: 4 inches

Sphere of Monson

Based on bonwill triangle

• sphere w 4 inch radius, center equal distance from occlusal surfaces of posterior teeth + center of condyles

Occlusal surfaces divisions

occlusal table, outer aspect

Occlusal table

• Area of posterior teeth between B and L cusp tips

• Major forces applied here

• 50-60% total BL dimension of tooth

• Positioned over long axis of root structure

  • Considered inner aspect of tooth

Occlusal table, total BL width

Outer aspect

occlusal area of posterior teeth outside of cusp tips

Occlusal surface divisions are made up of inclines that extend?

outer incline: cusp tips to hight of contour on lingual/labial surface

Inner incline: cusp tips to central fossa area

mesially inclined surfaces face the __ portion of the tooth

mesial

outer incline

inner incline

arch length

line at the distal surface of 3rd molar, extends mesially thru all prox contracts around entire arch ending at distal of opposite 3rd molar

both arches approx same, but max 128 mm, man: 126 mm

the slight difference in arch length is from?

narrow mesialdistal distances of mandibular incisors vs maxillary

arch width

distance across arch

mandibular slightly less than max = each max tooth is more facially positioned than occluding mandibular tooth

since the maxillary teeth are more facially positioned (or facial inclination at leas) the normal occlusal relationship of posterior teeth enables?

mandibular buccal cusps to occlude along central fossa areas of max teeth

max lingual cusps occlude along central fossa of man teeth

protects surrounding soft tissue

cross bite

max buccal cusps contact central fossa of mandibular teeth

posterior cross bite

supporting/centric cusp: ?

supports what?

buccal cusps of mandibular posterior, lingual cusps of maxillary posterior teeth occlude with opposing central fossa area

these support distance between maxilla and mandible = vertical dimension of occlusion

the centric cusps are ___ and __

when viewed from occlusal, tips are located approx ___ distance into the buccolingual width of tooth

broad and rounded, 1/3

mandibular first molar: 1/3 = centric, 1/6 = guiding/noncentric

guiding, noncentric cusps

buccal cusps of maxillary posterior teeth and lingual cusps of mandibular posterior

guiding cusps are ___

located __ distance into total buccolingual width of the tooth

sharp, 1/6

functional outer aspect

inner incline of guiding cusp near central fossa and either contacts or is close to small portion of outer aspect of opposite centric cusp (1 mm small area)

shearing cusps

noncentric

noncentric cusps major role

minimize tissue impingement, maintain bolus of food on occlusal table, mandible stability, feedback to Neuromuscular system (controls chewing stroke)

posterior cross bite

If mandible moves laterally from ICP (intracuspsal position)

if mouth is open/closed..

noncentric cusp will contact and guide it

noncentric guides mandible back to ICP

BO line? represents?

occludes with?

buccoocclusal:

line extended thru all buccal cusp tips of mandibular posterior teeth, BO is established: represents demarcation (separation) of inner and outer aspects of buccal teeth

BO line occludes with CF line of maxillary

LO line? represents? occludes with?

lingual occlusal line

line extended thru all lingual cusps of max posterior teeth: demarcation between outer and inner aspects of centric cusps

LO line occludes with Mandibular teeth

LO line (maxillary)

BO line of mandibular

CF line

line thru all central developmental grooves of max and mand posterior teeth: normal arch this is continous

top is buccal embrasure area, bottom is lingual embrasure area

CF line: proximal relationships: ___ lingual embrasure area, __ buccal embrasure area

which acts a major spillway for food being masticated?

larger, smaller

lingual

centric cusps contacting opposing: contact in two areas? (from facial aspect)

1. CF areas

   1. grinding of pestle in mortar

   2. only certain areas contacting at one time, other areas are spillways

   3. as mandible shifts, new spillways = efficient

2. Marginal ridges/embrasures

   1. like cusp tip contacting flat surface

   2. Spillways in all directions

   3. circular area around true cusp tip with radius of 5 mm provides contact area with opposite tooth surface

marginal ridge

slightly raised convex areas at mesial and distal borders of occlusal surfaces that join with interproximal surface of teeth

when the normal interach tooth relationship is viewed lateral, each tooth occludes with ?

Two exceptions?

2 teeth

mandibular central incisors and and max 3rd molar

normal relationship, the mandibular teeth are positioned slightly ___ + __

lingual and mesial to counterparts