Each tooth opposes two teeth in occlusion, except …… & ……..
Mandibular central incisor & Maxillary 3rd molar
Each tooth in the Max. arch occludes with …….
its counterpart & the one distal to it
Each tooth in the Mand. arch occludes with …..
its counterpart & the one mesial to it
When the arches come together, the posterior teeth contact, and the anterior are …..
just out of contact
* There is overbite & overjet
The Max. canine occludes in …….
The Mand. canine occludes in …..
- The buccal embrasure between the Mand. canine & first premolar
- The lingual embrasure between the Max. canine & lateral incisor
- Note that: occlude here doesn’t mean contact
Define:
- Supporting cusp
2. Guiding cusp
- The cusps that occlude in the opposing fossae or marginal ridges. Responsible for supporting forces of occlusion
- The cusps that are not in contact, but outside the occluding area
The guiding inclines are …….
the inclines of the guiding cusps, from the cusp tip towards the center of the tooth (e.g the lingual incline of the buccal cusps of the Max. molars)
* They make contact with the Functional outer Aspect (FOA) of the opposing functional cusps
What are the areas of contact in a posterior tooth in occlusion??
- FOA of the holding cusp contacting the guiding incline of the opposing guiding cusp
- Occlusal slope of the holding cusp contacting the occlusal slope of the opposing holding cusp
- The guiding incline of the guiding cusp contacting the FOA of the holding cusp in the opposing
The Max. posterior tooth holding cusp occludes in ………., except for the ML cusp of Molars which occlude in …….
- the distal marginal ridge of the counterpart, and the mesial marginal ridge of the one distal to it
- ML occludes in the central fossa of the coutnerpart
- Reverse the order for the Mand. teeth
- see p. 742 if not clear
The distal cusp of the Mand. molar occludes in ……… of the counterpart
distal triangular fossa of the counterpart
* Note that: the DB cusp of the Mand. molars occlude in the central fossa of the counterpart
The gliding cusps of the Max. posterior teeth oppose the facial embrasure between …… & …… except for MB of molars which oppose …… & the DB cusp of the 1st molar which oppose …….
the counterpart & the one distal to it
- buccal groove of the counterpart
- DB groove of the Mand. 1st molar
The DB cusp of the Max. 2nd molar opposes ……
the facial embrasure between the second & third Mand. molars
The gliding cusps of the Mand. posterior teeth oppose the lingual embrasure between …… & …… except for the DL cusp of molars which oppose ……..
counterpart & the tooth mesial to it
* the lingual groove of the Max. counterpart
The lingual surface of the Max. incisors is like …….. & the incisal 2 mm of the labial surface of Mand. incisors is like ……..
gliding slope
FOA
The Mand. central incisor labioincisal angle opposes ……..
the mesial marginal ridge of the Max. central & its lingual fossa
The Mand. lateral incisor labioincisal angle opposes …..
the distal marginal ridge of the Max. central & the mesial of Max. lateral, plus the lingual fossa
The Max. central opposes ………., the lateral opposes ….., while the canine opposes ……
The Mand. central & lateral
The Mand. lateral & canine
The embrasure between the Mand. canine & 1st premolar
What is Angle classification of occlusion?
- Class I: MB cusp of Max. 1st molar is in MB groove of Mand. 1st molar. Max. canine is in facial embrasure between Mand. canine and 1st premolar
- Class II: MB cusp of Max. 1st molar is anterior to MB groove of Mand. 1st molar. Same for Canine. Called Distocclusion
- Class III: MB cusp of Max. 1st molar is posterior to the MB groove of the Mand. 1st molar. Same for the canine. Called Mesiocclusion
Angle class I is considered malocclusion. T/F?
True
- Anterior crowding may be present. Normal occlusion is not classified by Angle. Class I also called neutrocclusion
- In Class II, the Mandible is micrognathic, while in Class III, it is prognathic
The side, to which the mandible moves during function is called ……., while the other side is called …….
working side (functional side) non working side (balancing side)
- Note that: functional cusp is called supporting/holding/occluding cusp
- Remember: Mand. is moving, the Max. is stationary! see note p. 745 for cusp pathways
Protrusion of the Mandible is caused by the coordinated function of ……
lateral pterygoid muscle
* The condyles move forward & downward on the articular eminence
Movement of the mandible laterally to the left is caused by contraction of ……..
right lateral pterygoid muscle
Describe the condyle movement during lateral excursion
- The condyle rotates on the working side. During this movement, the gliding and holding cusps move through the embrasures & grooves of the opposing teeth, and cusps don’t become tip to tip
- On the non working side, the condyle moves forward, downward & medially on the eminence, hence, the cusps move anterior & lateral (diagonally). Teeth on this side don’t contact (due to downward movement) p. 746
Describe the condyle movement during the lateral protrusive movement
- Working side: condyle rotates with forward & downward movement.
- Non working side: condyle moves anteriorly, downward & medially. Cusp movement similar to pure lateral movement, except the oblique line points more anteriorly (i.e less angle from the central area of the arch)
* see p. 747 if not clear
