primary teeth anatomy

Question 1

When does the primary dentition start? When does calcification begin?When does calcification of primary teeth continue until?

Answer 1

Development of Primary Teeth
Primary dentition initiated b/w 6th and 8th week in utero.
Calcification begins 14th to 19th week in utero.
Calcification of primary teeth continues after birth (3-4 mos –incisors, 11 mos- 2nd primary molars).

Question 2

what is the primary dentition also known as?

Answer 2

deciduous dentition

Question 3

when is the primary dentition complete?

Answer 3

30 months

Question 4

how many teeth are there and what teeth are present? (in the deciduous)

Answer 4

TOTAL OF 20 DECIDUOUS TEETH, ONLY PRIMARY TEETH PRESENT. (Eruption of the first primary tooth to the eruption of the first permanent tooth)

Question 5

What are the 5 functions of the primary dentition?

Answer 5

1. Mastication - Crucial time for adequate nutrition as growth and development is occurring during this period of life.
2. Development of speech (short-term)
3. ESTHETICS - Development of self-esteem is important
4. Assure ADEQUATE SPACING of the dental arches for the permanent teeth.
5. Act as a stimulus for alveolar bone development (height). (Growth and development).

Question 6

What is the primary tooth numbering system?

Answer 6

F.D.I is a two digit system

first digit refers to “quadrant” 5,6,7,8

Question 7

What does Each quadrant of deciduous dentition contain?

Answer 7

1. Two incisors (central and lateral)
2. One canine
3. Two molars (1st and 2nd molars)

Question 8

what are some features of primary teeth comparing them to permanent teeth?

Answer 8

Crowns are smaller, shorter and more bulbous.

Question 9

What is a special consideration of the floor of class II boxes?

Answer 9

If the gingival floor of the proximal box is placed too far apically an area of pronounced cervical constriction will be encountered. This cervical constriction will cause a progressive reduction in the width of the gingival floor a the extnesion continues apically. To re-establish the width of the gingival floor, at this more apical position, the axial wall must be deepened excessively. This greatly increases the chances of creating a mechanical pulp exposure.

Also do not bevel at the CSM in class two boxes because the enamel in the gingival third are oriented coronally unlike the permanent teeth.

Question 10

Why does it matter that there is a small occlusal table?

Answer 10

The isthmus width of conservative restorations may be very narrow, making them prone to fracture. Conversely with even minimal bucco-lingual extension of preparations beyond ideal width, the buccal and lingual cusps may be undermined making them prone to fracture. So a compromise must be established.

Question 11

What about the dentine and the pulp?

Answer 11

In prumary teeth there is less bulk or thickness of dentine and the pulp chambers are proportionally larger than in permanent teeth. This combination increases the probability of unwanted mechanical pulp exposures if the preparation is extended beyond the recommended ideal specifications.

Question 12

what are the consequences of premature primary tooth loss?

Answer 12

1. loss of space
2. malocclusion
3. Impacted permanent teeth
4. Need for extensive orthodontic treatment.

Question 13

What are the maxillary central incisors like?

Answer 13

Mesiodistal width greater than crown height. No mammelons –straight incisal edge
No developmental lines.
Well developed lingual marginal ridges.
Root length to crown length ratio greater than in permanent teeth.
Cone-shaped Root, triangular cross section. Crown = 6 mm, Root = 10 mm.

Question 14

what are maxillary lateral incisors like?

Answer 14

• Smaller than central incisor.
  Crown height greater than mesiodistal
  width.

Question 15

what are the maxillary canines like?

Answer 15

More constricted cervically than incisors.

Question 16

What are the mandibular central incisors like?

Answer 16

• Flat labial surface, no developmental grooves
• even taper mesial and distal
• root twice as long as crown
• lingual fossa (concavity) of flat lingual surface above cingulum
• triangular shape in cross section
• crown is symmetrical in labial, lingual or incisal views
• resembles the primary mandibular lateral more than the permanent successors

Question 17

What are the mandibular lateral incisors like?

Question 18

What are the mandibular canines like?

Question 19

Do maxillary and mandibular first molars resemble any other primary or permanent molar crown?

Answer 19

NOOOOOOO

Question 20

What are the maxillary 1st primary molars like?

Answer 20

Number of cusps:

Question 21

What are the buccal and occlusal aspects like of the maxillary 1st primary molar?

Answer 21

buccal aspect:

Question 22

What is mandibular 1st primary molar like occlusally, buccal, and mesiodistal?

Answer 22

74, 84 or Mandibular D.

Occlusally:

Question 23

What are the maxillary and mandibular second molars like?

Question 24

what are the crowns like in primary teeth?

Answer 24

Prominent mesio-buccal cervical bulge in primary molars.

Question 25

what are pulps like in primary teeth?

Answer 25

Relatively larger in relation to crown size as compared to permanent teeth.
Pulps horns are closer to the occlusal surface (mesiobuccal pulp horn is the largest).
Pulp chamber is shallow and follows external anatomy

Question 26

What are the roots like in primary teeth?

Answer 26

Anterior

Question 27

How many roots are in a mandibular molar? Maxillary molar?

Answer 27

mand- 2

maxi - 3

Question 28

What are implications because of the dentin and enamel not being as thick?

Question 29

Which usually has larger pulp chambers, maxillary molars or mandibular molars?

Answer 29

mandibular molars usually have larger pulp chambers than maxillary molars in primary teeth.

Question 30

What are the number of cusps for maxillary and mandibular molars?

Answer 30

Maxillary
1st Molar 2nd Molar
Number of Cusps
4 (ML, MB, DL, DB) 4 (ML, MB, DL, DB) (Cusp of Carabelli)

Mandibular
1st Molar 2nd Molar
Number of Cusps
4 (ML, MB, DL, DB)
5 (MB, ML, DB, DL, D)

Question 31

What are the primary canine contacts like?

Answer 31

Mesial and distal contacts of primary canines are at the same level incisocervically. (In permanent canines, contacts are at different levels.)

Question 32

What are the primary dentition contacts like?

Answer 32

Contacts in the primary dentition DO NOT remain stable after eruption. Changes can result due to:
1. Growth changes in the dental arches. 2. Exfoliation of other primary teeth.

Question 33

What is occlusion like in the primary dentition?

Answer 33

Occlusion
Midlines coincident. Upright incisors. 1-2mm OJ
20-30% OB
Terminal Plane Relation
- flush terminal plane (50% - Bishara) (hitting pretty much one tooth on one tooth
- distal step (the mandibular is shifted back about a half tooth from flush terminal plane relation)
- mesial step (the mandibular is shifted forward about half a tooth from flush terminal plane relation)
(60% - Baume)

Question 34

What are the primate spaces?

Answer 34

Primate Spaces:A naturally occurring spacing between the teeth of the primary dentition. In the maxillary arch, it is located between the lateral incisors and canines, whereas in the mandibular arch the space is between the canines and first molars. It also occurs between the canine and first premolar teeth in adult primates.
Primate Spaces:

Question 35

what is the mesiodistal aspect of the mandibular 1st primary molar like?

Answer 35

Mesiodistal aspect: