Oral Biology

Question 1

What cells form enamel?

Answer 1

Ameloblasts

Question 2

What cells form dentine?

Answer 2

Odontoblasts

Question 3

How does dentine differ from enamel?

Answer 3

• dentine is permeable
• softer than enamel
• greater compressive & tensile strength compared with enamel

Question 4

What is dentine composed of?

Answer 4

• hydroxyapetite (50%)
• water (20%)
• organic matrix (30%)

Question 5

How does the structure of dentine determine caries progression?

Answer 5

Caries progresses along dentinal tubules

Question 6

What is predentine?

Answer 6

unmineralised dentine that is formed by odontoblasts during tooth formation

Question 7

What type of tissue is dental pulp? What cells are found within it?

Answer 7

connective tissue
- odontoblasts
- fibroblasts
- defence cells

Question 8

What are the functions of the dental pulp?

Answer 8

• nutritive
• dentine growth
• dentine repair
• defence

Question 9

What is the function of cementum?

Answer 9

provides attachment for periodontal fibres

Question 10

What are the different types of cementum?

Answer 10

ACELLULAR
- no cells
- adjacent to dentine
- formed first

CELLULAR
- contains cementocytes
- formed later

Question 11

Where is acellular cementum located?

Answer 11

adjacent to dentine & more coronally

Question 12

Where is cellular cementum located?

Answer 12

apical part of root and furcation regions

Question 13

What nerves are found in the periodontal ligament & state their function?

Answer 13

Mechanoreceptors = evaluates how much force is being applied to PDL

Nociceptors = their function is to look for dangerous/harmful stimuli

Question 14

What function does the PDL have?

Answer 14

• attaches tooth to bone
• transmits biting forces to alveolar bone

Question 15

What width is the PDL approx?

Answer 15

0.2mm

Question 16

What are the cell layers of epithelium?

Answer 16

• stratum corneum
• stratum granulosum
• stratum spinosum
• stratum germinativum (basal layer)

Question 17

What type of mucosa is located on dorsum of tongue?

Answer 17

(keratinsised) gustatory mucosa

Question 18

What protective functions do oral fluids have?

Answer 18

• cleansing
• mucosal protection
• buffering
• remineralisation
• antimicrobial

Question 19

What can a reduction in salivary flow promote?

Answer 19

Increased incidence of:
- caries
- stomatitis
- dysaesthesia
- impaired oral function
- diminished taste perception

Question 20

What type of secretions are from submandibular gland?

Answer 20

mucous secretions

Question 21

What type of secretions are from sublingual gland?

Answer 21

mixed serous & mucous secretions

Question 22

What type of secretions are from parotid gland?

Answer 22

serous secretions

Question 23

what type of secretions occur from minor salivary glands?

Answer 23

mostly mucous

Question 24

What do histatins inhibit?

Answer 24

candida albicans & streptococcus mutans

Question 25

Describe mechanical salivary stimulation:

Answer 25

pressure on PDL –> increases flow from ipsilateral salivary glands (same side chewing on)

Question 26

What are examples of PDL fibres?

Answer 26

Sharpey’s fibres

Question 27

What is shown on the Stephan Curve?

Answer 27

A graph of the plaque pH change over time as plaque micro-organisms generate acid by metabolising sugars (eg sucrose)