Lecture 4: Alignment and Occlusion Part 2

Question 1

Interarch tooth alignment describes the relationship between_______?

Answer 1

the teeth in one arch to those in the other, both anterior and posterior
OCCLUSAL RELATIONSHIP OF THE TEETH IS ESTABLISHED

Question 2

What are Centric Cusps?

Answer 2

They are the functional, working cusps that are also used for support.
Maxillary Lingual cusps & Mandibular Buccal Cusps
THEY HOLD THE VERTICAL DIMENSION OF OCCLUSION

Question 3

What are Non-Centric Cusps?

Answer 3

Also known as GUIDING CUSPS, used for shearing (nonworking)

Maxillary Buccal cusps & Mandibular Lingual cusps

Question 4

What are Interocclusal Contacts?

Answer 4

The occlusal contacts that occur when the centric (working) cusps contact the opposing Central Fossa Line

Contact can be in the CFL or in the marginal ridge and embrasure areas

Question 5

What is the normal Interocclusal contact seen in posterior teeth?

Answer 5

Mandibular teeth occlude with its maxillary counterpart and the adjacent mesial tooth.
Maxillary tooth occludes with its counterpart and the adjacent Distal Tooth
Contact occurs btwn cusp tips AND fossa btwn cusp tips and marginal ridges.

Question 6

Describe Normal Buccolingual Arch relationship and function.

Answer 6

Mandibular buccal cusps occlude along the central fossa of the maxillary teeth, and the maxillary lingual cusps occlude in the central fossa areas of the mandibular teeth.
this PROTECTS THE SURROUNDING SOFT TISSUE
Max teeth protect buccal mucosa from getting bit and mand teeth protect the tongue.

Question 7

What are the 3 main cuspal positions of the Normal Buccolingual Arch Relationship?

VISUALIZE

Answer 7

1. Outer incline of the mandibular buccal cusp opposes the inner incline of the maxillary buccal cusp
2. Outer incline of the maxillary lingual cusp opposes the inner incline of the mandibular lingual cusp
3. Inner incline of the mandibular buccal cusp opposes the inner incline of the maxillary lingual cusp

Question 8

What makes up the Functional Outer Aspect (FOA) of the Normal Buccolingual Arch Relationship?

Answer 8

The only area of an outer incline with functional significance: Mandibular buccal outer incline & Maxillary lingual outer incline

Question 9

Describe the occlusion of a Posterior Crossbite.

Answer 9

Mandibular lingual cusps occlude in the central fossa area of the maxillary teeth and the maxillary buccal cusps occlude in the central fossa area of the mandibular teeth… (this is the opposite of what it should be, normal is max out and mand in)

Question 10

Where do we find the proximal contact areas between the posterior teeth in relation to the central fossa (CF) line?

Answer 10

BUCCAL! :D

Question 11

In normal occlusion, each tooth occludes with ______ opposing teeth. What are the exceptions to this rule?

Answer 11

Two teeth.

Mandibular central incisors & Maxillary 3rd molars

Question 12

Angle’s Classification describes the relationship of teeth centered around which tooth?

Answer 12

1st Molar

Question 13

Class I of Angle’s Classification includes what occlusal relationship?

Answer 13

Class I of Angle’s Classification is normal occlusion. Since Angle’s Classification is based off the relationship of the first molar know that:

• the mesiobuccal cusp of the mandibular first molar occludes in the occlusal embrasure btwn the maxillary second premolar and first molar
• the mesiobuccal cusp of the maxillary first molar is aligned directly over the buccal groove of the mandibular first molar.
• the distobuccal cusp of the mandibular first molar occludes in the central fossa of the maxillary first molar
• the mesiolingula cusp of the maxillary first molar is situated in the central fossa area of the mandibular first molar
• the distolingual cusp of the maxillary first molar occludes in the central fossa of the mandibular first and second molars

Question 14

What variations can occur with a Class I relationship?

Answer 14

1. Cusp tip contacts embrasure area and both marginal ridges resulting in two contacts on the cusp tip.
2. Cusp tip is positioned such that it contacts only one contact on the cusp tip.

Question 15

What’s a Class II?

Answer 15

Div 1: Large Overbite and Large Overjet
- The Mesiobuccal cusp of the mandibular first molar occludes in the central fossa of the maxillary first molar.
- The mesiobuccal cusp of the mandibular first molar is aligned with the buccal groove of the maxillary first molar
- The distolingual cusp of the maxillary occludes in the central fossa of the mandibular first molar
Div 2:?

Question 16

What’s a Class III?

Answer 16

Underbite

• The distobuccal cusp of the mandibular first molar occludes in the embrasure btwn the maxillary second premolar and first molar
• the mesiobuccal cusp of the maxillary first molar is aligned with the buccal embrasure btwn the mandibular first and second molar
• the mesiolingual cusp of the maxillary first molar occludes in the mesial triangular fossa of the mandibular second molar

Question 17

What is the normal range of angulation form the vertical reference line for anterior teeth?

Answer 17

12-28 degrees

Question 18

T/F. Anterior teeth are able to sustain heavy vertical forces when in normal occlusion. T/F. Maxillary incisors are always in contact with mandibular incisors in normal occlusion.

Answer 18

DOUBLE FALSE. They are NOT resistant to heavy vertical forces.

“Light or no occlusal contact is not uncommon.”

Question 19

How far from the incisal edge do mandibular incisal edges contact the lingual surfaces of maxillary teeth?

Answer 19

~4mm.

Question 20

What factors determine the amount or degree of posterior tooth separation during tooth movements?

Answer 20

The lingual concavity of the maxillary anterior teeth and the amount of vertical and horizontal overbite.

Question 21

What is a Horizontal Overlap?

Answer 21

Horizontal overlap (aka overjet) refers to the occlusal relationship where the distance between the labial incisal edge of the maxillary incisor and the labial surface of the mandibular incisor in intercuspal position. (idk if there is a numeric value for this distance or just a space)

Question 22

What is a Vertical Overlap?

Answer 22

Also called OVERBITE. noted by the distance btween the incisal edges of the opposing anterior teeth.
Normal occlusion has approximately 3-5 mm overlap

Question 23

Which teeth are used in Anterior Guidance?

Answer 23

opposing maxillary and mandibular incisors and canines. (DUH). These teeth produce disclusion of the posterior teeth when the mandible protrudes and moves to either side.
Formed by the guiding inclines of maxillary teeth

Question 24

What is Eccentric Movement? Name 3 types.

Answer 24

Any movement of the mandible fmor the intercuspal position that results in tooth contact.

1. Protrusive
2. Laterotrusive
3. Retrotrusive

Question 25

How does the occlusal contact change during Protrusive Mandibular Movement?

Answer 25

Contact occur between the incisal and labial edges of the mandibular incisors against the lingual fossa of the maxillary incisors.
Posterior occlusal contacts occur between the distal inclines of the maxillary lingual cusps and the mesial inclines of the opposing fossae and marginal ridges. Also between the mesial inclines of the mandibular buccal cusps and the distal inclines of the opposing fossae and marginal edges.

Question 26

How does the occlusal contact change during Laterotrusive Mandibular Movement?

Answer 26

RIght and left mandibular posterior teeth move across their opposing teeth in different directions. The side to which the mandible moves is the “working side”.. WORKING CONTACTS are

• the inner inclines of the maxillary buccal cusps against the outer inclines of the mandibular buccal cusps
• the outer inclines of the maxillary lingual cusps against the inner inclines of the mandibular lingual cusps (lingual-to-lingual laterotrusive)

Question 27

What is the “nonworking” side of Laterotrusive Mandibular Movements?

Answer 27

the side from which the mandible moves is referred to as the nonworking side, and the mandibular posterior teeth on that side are passing in medial direction across their opposing teeth.
– NONWORKING CONTACTS ARE MEDIOTRUSIVE CONTACTS.
the potential sites for occlusal contacts are between the inner inclines of the maxillary lingual cusps and the inner inclines of the mandibular buccal cusps.

Question 28

What are the “guiding inclines” of Laterotrusive Mandibular Movements?

Answer 28

the maxillary and mandibular canines contacts during right and left lateral movement between the labial surfaces and incisal edges of the mandibular canines and the lingual fossae and incisal edges of the maxillary canines. —-> those are considered the guiding inclines…. bitches

Question 29

What are Retrusive Mandibular Movements?

Answer 29

Posterior movement of the mandible from intercuspal position
small compared to other movements (2 mm)
Restricted by LIGAMENTS!
Mandibular buccal cusps move distally across the occlusal surface of their opposing maxillary teeth

Question 30

How does the occlusal contact change during Retrusive Mandibular Movement?

Answer 30

In the mandibular arch, retrusive contacts occur btwn the distal inclines of the mandibular buccal cusps and the mesial inclines of the opposing fossae and marginal ridges.
In the maxillary arch, contacts occur between the mesial inclines of the opposing central fossae and and marginal ridges
*occur on the reverse inclines of protrusive contacts

Question 31

Describe the contacts of the PREMOLARS in a Class I Occlusion.

Answer 31

• the buccal cusp of the mandibular first premolar occludes in the occlusal embrasure btwn the maxillary canine and first premolar
• the buccal cusp of the mandibular second premolar occludes in the occlusal embrasure btwn the maxillary first and second premolars
• the lingual cusp of the maxillary first premolar opposed the distal fossa of the mandibular first premolar
• the lingual cusp of the maxillary second premolar occludes in the distal fossa of the mandibular second premolar

Question 32

Describe the contacts of the 2nd MOLARS in a Class I Occlusion.

Answer 32

• the mesiobuccal cusp of the mandibular second molar occludes in the occlusal embrasure btwn the maxillary first and second molar
• the distobuccal cusp of the mandibular second molar occludes in the central fossa of the maxillary second molar
• the mesiolingual cusp of the maxillary second molar occludes in the central fossa of the mandibular second molar
• the distolingual cusp of the maxillary second molar opposes the distal fossa of the mandibular second molar