Structures and tissues of the teeth

Question 1

Anatomical Structures of Teeth

Answer 1

• each tooth consists of 3 anatomical structures:
  1. Crown - covered in enamel
  2. Cervix - neck of the tooth where Crown and Root meet
  3. Root - covered by a thin, hard shell called the cementum, each tooth has 1-4 roots

Question 2

Tissues of the Teeth

Answer 2

1. Enamel
2. Dentin
3. Periodontal ligament
4. Pulp chamber
5. Pulpal tissue
6. Apical Foramen
7. Pulp cavity

Question 3

Maxillary alveolar process and mandibular alveolar process

Answer 3

Tooth sockets of the upper and lower jaws

Question 4

Enamel

Answer 4

• covers the crown
• 99% inorganic matter and cannot regenerate, so if damaged, cannot repair itself
• hardest substance in the human body…like quartz

Question 5

Dentin

Answer 5

• makes up bulk of the tooth

- a living cellular substance similar to bone

Question 6

Periodontal Ligament (PDL)

Answer 6

• made up of connective fibers that help to hold the tooth in the alveolar socket (in the jawbone)
• provides protection and nourishment
• attaches to the tooth at the cementum (the thin hard covering of the root surface
• the point where the enamel meets the cementum is call the cemento-enamel junction (CEJ)

Question 7

Tissues of the tooth - Pulp

Answer 7

Pulp chamber - center of the crown, where pulpal tissue (composed of connective tissue, blood vessels and nerves) are found.

Apical foramen is the small opening at the tip or Apex of the root where the blood vessels and nerves enter the tooth

Root canal is the pulp cavity where the the blood vessels and nerves travel thru the tooth to get to the pulp chamber

Question 8

mouth quadrants - how many, where are they and how are they numbered?

Answer 8

Dentists divide mouths into 4 quadrants

1. Maxillary (upper) right quadrant. (Patient’s right side) = quadrant I
2. Maxillary left quadrant (Patient’s left side) = quadrant II
3. Mandibular (lower) left quadrant (Patients left side under the Maxillary left quad) = quadrant III
4. Mandibular (lower) right quadrant (patient’s right side under the Maxillary right quad) equals quadrant IV (or 4)

Question 9

Sextants

Answer 9

Dental arches are sometimes divided into sextants or six sections to make our lives more difficult.
First sextant - Max(illary) right posterior molars and premolars on the right, back side
Second sextant - Maxillary anterior … canines and incisors
Third sextant - Max left posterior ie molars and premolars on the left side
Forth - Mandibular left posterior … molars and premolars on the left side bottom
Fifth - Mand anterior ie canines and incisors
Sixth - Mand right posterior ie. molars and premolars on the right side

Question 10

Occlusion

Answer 10

• means come together in the chewing surfaces of opposing posterior teeth
• it is the relationship between the maxillary and mandibular arches in terms of the way they meet or touch
• perfect occlusion- teeth meet at specific contact points

Question 11

Malocclusion

Answer 11

teeth are out of alignment or occlusion (bite)

Question 12

Types of Malocclustion

Answer 12

1. Overjet - relationship of teeth where the incisal (cutting) edges or buccal (cheek) cusps of the maxillary teeth extend forward/facially to the same mandibular teeth…overbite (vertical overlapping of upper teeth over lower teeth
2. Open bite - space left between upper and lower teeth when jaws close
3. Cross-bite - where the cusps of the tooth in one arch exceed the cusps of the opposite arch either buccally ( cheeks) or lingually (tongue)
4. Class 1 Occlusion - normal relationship between the arches
5. Class 2 Occlusion - mandibular (bottom) molars are posterior (behind) their normal position
6. Class 3 Occlusion - mandibular (bottom) molars are anterior (in front of) their normal position

Question 13

TEETH - Most humans have two sets of teeth….what are they?

Answer 13

1. Primary dentition - consists of 20 teeth
2. Permanent dentition - consists of 32 teeth

Not all the primary teeth are lost/shed/EXFOLIATED and replaced at the same time resulting in Mixed Dentition

Question 14

Primary Teeth

Answer 14

In each quadrant you have:
1 Central incisor
1 Lateral incisor 
1 Canine
1 first molar
1 second molar

Question 15

Permanent Dentition

Answer 15

Each quad has: 
1 central incisor
1 lateral incisor
1 canine
2 premolars (bicuspids)
3 molars

Question 16

Anterior teeth

Answer 16

Anterior (toward the front) - are central incisors, lateral incisors and cuspids (canines)

Incisors - have thin, sharp cutting edges ( like scissors) that cut food

Cuspids (canines, eyeteeth, vampire teeth) are strong and longer, have a sharp point (cusp) and are designed for grasping and tearing food

Question 17

Anterior Teeth of the Maxillary and Mandibular arch from (patient’s) right to left

Answer 17

Canine, lateral incisor, Central incisor, Central incisor, Lateral incisor, and canine

Note: canine’s have slightly thicker enamel, a larger crown and come to a point, their roots are the longest and are the cornerstones of dentition

Question 18

Posterior teeth…teeth in the back of the mouth

Answer 18

moving from the canine… first premolar(bicuspid), second premolar(bicuspid), first molar, second molar and third molar (wisdom tooth)

these teeth have flat surfaces with rounded projections (cusps) used for grinding and crushing

Note: premolars are only found in the permanent dentition

Question 19

Molars

Answer 19

First permanent molars erupt at approx. age 6