Static Factors of Occlusion

Question 1

What are the factors and forces that determine tooth position?

Answer 1

• labiolingual alignment
• mesiodistal alignment
• vertical position

Question 2

What affects tooth position?

Answer 2

• muscles
• genetics
• habits

Question 3

What is the intra-arch tooth alignment?

Answer 3

the relationship of the teeth to each other within the dental arch

Question 4

What is the plane of occlusion?

Answer 4

the plane that curves to fit the occlusal surfaces and incisla edges of all the teeth

Question 5

What are the characteristics of the plane of occlusion?

Answer 5

• not flat
• concave on mandible
• convex on maxilla
• teeth positioned in the arches at varying degrees of inclination

Question 6

What is the angulation of the anterior mandibular teeth in the sagittal plane?

Answer 6

labially inclined
- 20 degrees

Question 7

What is the angulation of the premolar mandibular teeth in the sagittal plane?

Answer 7

mesially inclined
- 6 degrees

Question 8

What is the angulation of the molar mandibular teeth in the sagittal plane?

Answer 8

mesially inclined
- 10-15 degrees

Question 9

What is the angulation of the anterior maxillary teeth in the sagittal plane?

Answer 9

• labially inclined
• central incisor the greatest
• 28 degrees

Question 10

What is the angulation of the premolar maxillary teeth in the sagittal plane?

Answer 10

mesially inclined
- 9 degrees

Question 11

What is the angulation of the molar maxillary teeth in the sagittal plane?

Answer 11

mesially inclined
- 12 degrees
- crowns of maxillary molars are tilted distally and labially

Question 12

What is the angulation of the anterior mandibular teeth in the frontal plane?

Answer 12

vertical inclination
- 0 degrees

Question 13

What is the angulation of the premolar mandibular teeth in the frontal plane?

Answer 13

• 1st premolar: labial inclination (9 degrees)
• 2nd premolar: lingual inclination (9 degrees)

Question 14

What is the angulation of the molar mandibular teeth in the frontal plane?

Answer 14

lingual inclination
- 20 degrees

Question 15

What is the angulation of the anterior maxillary teeth in the frontal plane?

Answer 15

• incisors: distal inclination (2-6 degrees)
• canines: mesial inclination (17 degrees)

Question 16

What is the angulation of the premolar maxillary teeth in the frontal plane?

Answer 16

slight buccal inclincation
- 5 degrees

Question 17

What is the angulation of the molar maxillary teeth in the frontal plane?

Answer 17

buccal inclination
- 20 degrees

Question 18

What is the curve of spee?

Answer 18

• antero-posterior curvature of the occlusal plane
• concave in mandible
• convex in maxilla

Question 19

What is the curve of wilson?

Answer 19

• medio-lateral curvature of the occlusal plane
• concave in mandibe
• convex in maxilla

Question 20

What is this?

Answer 20

curve of spee

Question 21

What is this?

Answer 21

curve of Wilson

Question 22

When posterior teeth are occluded they are loaded…

Answer 22

axially

Question 23

Why are posterior teeth loaded axially?

Answer 23

designed to take heavy loads and support the occlusal vertical dimension

Question 24

When anterior teeth are occluded they are not loaded through…

Answer 24

their long axis

Question 25

Why are anterior teeth not loaded through their long axis?

Answer 25

not designed for loading

Question 26

What is the occlusal table?

Answer 26

the area defined by the cusp tips and the mesial and distal cups ridges/arms

Question 27

Occlusal table is _______% of the buccolingual width of the tooth

Answer 27

50-60%

Question 28

What does the occlusal table facilitate?

Answer 28

axial loading

Question 29

Whcih inclines are inside the buccal and lingual cusp ridges and which inclines are outside?

Answer 29

inner inclines - inside outer inclines - outside

Question 30

What is the inter-arch tooth alignment?

Answer 30

the relationship of the teeth in one arch to those in the other arch

Question 31

Which arch is longer?

Answer 31

maxillary arch is longer

Question 32

Which arch is wider?

Answer 32

maxillary arch is wider

Question 33

What is the bucco-occlusal (BO) line?

Answer 33

an imaginary line drawn through the buccal cusp tips of the mandibular teeth

Question 34

What is the linguo-occlusal (LO) line?

Answer 34

- imaginary line defined by joining the lingual cusp tips of the maxillary teeth

Question 35

What is the central fossa (CF) line?

Answer 35

- imaginary line that follows the central grooves and fossa of all the posterior teeth

Question 36

The _______ line of the mandible occludes in the central fossa (CF) line of the maxilla

Answer 36

bucco-occlusal (BO)

Question 37

The ______ line of the maxilla occludes in the central fossa (CF) line of the mandible

Answer 37

linguo-occlusal (LO)

Question 38

What is the opposite of the ideal inter-arch relationship?

Answer 38

crossbite

Question 39

What line of the maxilla does the CF line occlude with in the mandible during crossbite?

Answer 39

(BO) bucco-occlusal

Question 40

What line of the mandible does the CF line occlude with in the maxilla during crossbite?

Answer 40

LO linguo-occlusal

Question 41

What angles class is ideal occlusion from an orthodontic perspective?

Answer 41

class I

Question 42

What is a class I molar relationship?

Answer 42

- MB cups of the maxillary 1st molar is alinged over the buccal groove of the mandibular 1st molar - MB cups of the mandibular 1st molar occludes in the embrasure area between the maxillary second premolar and first molar - ML cups of the maxillary 1st molar occludes in the central fossa area of the mandibular first molar

Question 43

What is a class II molar relationship?

Answer 43

- MB cups of the maxillary 1st molar is situated over the embrasure between the mandibular 2nd premolar and 1st molar - MB cups of the mandibular 1st molar occludes in the central fossa of the maxillary 1st molar - DL cusp of the maxillary 1st molar occludes in the central fossa of the mandibular 1st molar

Question 44

What is a class III molar relationship?

Answer 44

- MB cups of the maxillary 1st molar is situated over the embrasure between the mandibular 1st and 2nd molar - DB cusp of the mandibular 1st molar occludes in the embrasure between distal marginal ridge of the maxillary 2nd premolar and mesial marginal ridge of the maxillary 1st molar - ML cusp of the maxillary 1st molar is situated in the mesial pit of the mandibular second molar

Question 45

What is the vertical overlap in class I?

Answer 45

2-4 mm

Question 46

What is the horizontal overlap in class I?

Answer 46

2-4 mm

Question 47

What are the two divisions of the class II anterior teeth?

Answer 47

D1: great vertical overlap, mandibular teeth contact the gingival third of the maxillary anterior teeth (Deep bite) D2: maxillary incisors are lingually inclined (lateral overlap the centrals labially)

Question 48

What are the two types of class III tooth relationships?

Answer 48

* end-to-end relationship * mandibular anterior teeth are so far forward they overlap maxillary anterior teeth