The tooth, the whole tooth

Question 1

What are 5 functions of teeth?

Answer 1

• Protects oral cavity
• Chewing (mastication)
• Aids in digestion
• Speech/communication
• Appearance

Question 2

What is the crown made up of and what are the two parts of the crown?

Answer 2

Composed of enamel, the two parts of the crown are the anatomical crown and the clinical crown

Question 3

What is the root made up of?

Answer 3

Cementum, found on the outside of the tooth

Question 4

Where does the crown meet the root?

Answer 4

At the cementoenamel junction (CEJ) located at the cervix of the tooth

Question 5

What is in the inner portion of the tooth?

Answer 5

The dentin, in both the crown and the root and is yellow in appearance

Question 6

What is the anatomical crown of the tooth?

Answer 6

The portion of the tooth that is covered in enamel, never changes. Starts at the CEJ and goes to the top of the enamel (top of the tooth)

Question 7

What is the clinical crown of the tooth?

Answer 7

The portion of the tooth that is visible in the clinic, may look different on different patients

Question 8

Where is the root embedded?

Answer 8

In the alveolar process (jaw bone) covered in cementum

Question 9

What are maxillary teeth?

Answer 9

Teeth in the upper jaw

Question 10

What are mandibular teeth?

Answer 10

Teeth in the lower jaw

Question 11

How many roots can teeth have?

Answer 11

1-3. All anterior teeth have 1 unless there is an anomaly and posterior teeth can have 1-3

Question 12

What is furcation?

Answer 12

The space between a multirooted tooth

Question 13

What is bifurcation?

Answer 13

When a tooth has 2 roots

Question 14

What is trifurcation?

Answer 14

When a tooth has 3 roots

Question 15

What is the apex of a root?

Answer 15

The tapered end of each root

Question 16

What is the apical of a root?

Answer 16

Anything that is situated right at the apex (bottom of the root)

Question 17

What is the periapical of a root?

Answer 17

Anything surrounding the apex of the root

Question 18

What is the apical foramen?

Answer 18

It is the opening at the apex of the root. This allows blood vessels and nerves from the alveolar process to come in and out of the pulp (root). Will have as many apical foramen as it has roots. Only case where there wouldn’t be one is if there was damage, would cause the tooth to die

Question 19

What are the tissues of the tooth?

Answer 19

Enamel, dentin, cementum and pulp (soft tissue)

Question 20

What is enamel?

Answer 20

Enamel is the hardest material in the whole body, even harder than bone. It is translucent in colour and is made up of hydroxyapatite crystals. It is not vital as it has no blood or nerves, no power to repair or grow, and any imperfections during development are permanent

Question 21

What is the chemical composition of enamel?

Answer 21

• 96% hydroxyapatite (inorganic and non vital). Rod-like structures, formed by ameloblasts (enamel forming cells)
• Other 4% composed of water and fibrous organic matter, not calcified
• Has the ability to resist water

Question 22

Difference between enamel in primary dentition and permanent dentition

Answer 22

Primary dentition - only clinical crown has enamel, teeth are also whiter due to less dentin
Permanent dentition - clinical crown can have enamel and cementum/dentin due to recession, abrasion and attrition

Question 23

What is dentin?

Answer 23

Main portion of the tooth and extends almost the entire length of the tooth. It is a living tissue (sensory), and contains odontoblasts (dentin forming cells) and intercellular substances. Dentin production continues throughout the life of the tooth. It is a hard dense calcified tissue, harder than bone but softer, less calcified than enamel

Question 24

What is the chemical composition of dentin?

Answer 24

70% inorganic, 30% organic and water

Question 25

What are some physical characteristics of dentin?

Answer 25

It is slightly elastic so can flex. It has less mineralized salts and is more radiolucent than enamel, therefore it is darker on a radiographic image. It is yellowish-brown in colour and is perforated by millions of holes

Question 26

What is cementum?

Answer 26

Covers the root of the tooth, overlies the dentin and meets the enamel at the cementoenamel junction. It is thin at the cervical line but increases at the apex. It is a bone-like structure and its primary function is to anchor the tooth to the bony socket with attachment fibres within the periodontium. It is produced by cementoblasts

Question 27

What is the chemical composition of cementum?

Answer 27

45-50% inorganic, 50-55% organic, making it less durable than dentin or enamel

Question 28

What is the union of cementum and dentin called?

Answer 28

The dentinocemental junction

Question 29

What are the two types of cementum and where on the tooth are they located?

Answer 29

- Cellular cementum - confined to the apical third of the root and can reproduce by itself - Acellular cementum - covers entire anatomical root, does not contain cementoblasts and therefore cannot reproduce by itself

Question 30

Where does cementum get its nutrition from?

Answer 30

The alveolar bone

Question 31

What is dentin pulp, where is it and what does it contain?

Answer 31

The nourishing, sensory and dentin reparative system of the tooth. Located inside the tooth, occupies the pulp chamber in the crown and pulpal canals in the root. Contains blood vessels, lymph, nerves, fibroblasts, collagen fibres and other connective tissue cells

Question 32

What develops pulp?

Answer 32

Fibroblast cells

Question 33

Characteristics of pulp

Answer 33

Walls are lined with odontoblasts to lay down primary, secondary and reparative dentin. Made up of blood vessels and nerves that enter the pulp chamber through the apical foramen. The blood supplies derives from branches of the dental arteries from the periodontal ligament. It is dentin reparative, nourishing and sensory

Question 34

What is coronal pulp?

Answer 34

Lies within the crown portion of the tooth and includes the pulp horns (extensions of the pulps that project toward the cusp tips and incised edges

Question 35

What are some names for the portion of the pulp more apically located?

Answer 35

The radicular, root pulp or pulp canals

Question 36

What is an accessory canal?

Answer 36

Extra canals that sometimes naturally form, used in case there is an issue with the apical foramen. Causes no issues unless there is a root canal needed

Question 37

What are the 3 junctions of the tooth?

Answer 37

CEJ - cementoenamel junction - where the cementum and enamel meet DEJ - dentinoenamel junction - where the dentin and enamel meet DCJ - dentinocemental junction - where the dentin and cementum meet