tooth anatomy basics

Question 1

Which cranial nerve innervates the 1st pharyngeal arch?

Answer 1

Trigeminal (MoM)

Question 2

Which cranial nerve innervates the 2nd pharyngeal arch?

Answer 2

Facial (muscles of facial expression)

Question 3

Which cranial nerve innervates the 3rd pharyngeal arch?

Answer 3

Glossopharyngeal

Question 4

Which cranial nerve innervates the 4th pharyngeal arch?

Answer 4

Vagus

Question 5

During the cap stage, a small group of ectomesenchymal cells stop producing extracellular substances and aggregate beneath inner enamel.
What is this structure known as and which cells / tissue does this give rise to?

Answer 5

Dental Papilla -
cells are odontoblasts which produce the dentine and pulp.

Question 6

What is the structure formed where the outer and inner enamel epithelium meet and what does it give rise to?

(essential in root formation)

Answer 6

Cervical Loop -
gives rise to hertwig’s sheath.

Question 7

At what age is the root structure of primary teeth developed?

Answer 7

3 years

Question 8

Hard tissue formation of deciduous teeth occurs at how long in utero?

Answer 8

16 weeks

Question 9

Full root formation occurs how long after eruption?

Answer 9

12 months

Question 10

Which stage of root formation is impacted in hyper/hypodontia?

Answer 10

dental lamina formation

Question 11

Missing permanent tooth germs in hypodontia results in lack of exfoliation and root resorption of deciduous teeth.
What occlusion issue may this cause and which teeth are commonly affected?

Answer 11

Infraocclusion -
commonly impacts Es

Question 12

Which dentition is hyper/hypodontia most common in?

Answer 12

permanent

Question 13

Which genetic condition is commonly associated with hypodontia and microdontia?
Other features include thin hair, dry skin and absence of sweating.

Answer 13

ectodermal dysplasia

Question 14

What is the name for a supernumerary tooth that erupts in the anterior maxilla midline?

Answer 14

mesiodens

Question 15

What autosomal dominant condition is associated with hyperdontia?
Common signs include supernumerary teeth.

Answer 15

Cleidocranial Dysplasia

Question 16

Which GI condition involving growth of polyps in intestines may present with hyperdontia?

Answer 16

Gardener’s Syndrome

Question 17

What stage of tooth development is impacted when size of tooth is abnormal?

Answer 17

morphodifferentiation

Question 18

Which stage of tooth development is affected when accessory cusps are present?

Answer 18

morphodifferentiation

Question 19

Where do cusps of carabelli occur?

Answer 19

mesiopalatal of permanent maxillary 1st molars

Question 20

What is an accessory cusp of premolars known as?

Answer 20

dens invaginatus

Question 21

What is a talon cusp?

Answer 21

accessory cusp appearing on incisors

Question 22

What is taurodontism and how does this occur?
(think T Rex)

Answer 22

Where roots are shorter and the crown is longer - caused by late / failed invagination of hertwig’s root sheath.

Question 23

Pt presents with peg laterals with notches on the incisal edge and multiple rounded rudimentary cusps on permane t1 at molars.
What congenital condition do you suspect they have?

Answer 23

congenital syphilis (these are hutchinsons incisors and moons/mulberry molars)

Question 24

What intolerance can cause chronological enamel hypoplasia and what other developmental issue can it cause?

Answer 24

Coeliac Disease -
can cause delayed eruption.

Question 25

Which viral infection of the skin and lymph nodes is linked to chronological hypoplasia?

Answer 25

rubella

Question 26

Define amelogenesis imperfecta.

Answer 26

enamel deficiency caused by a lack of ameloblasts (teeth are brown due to exposed dentine)

Question 27

What can dentinogenesis imperfecta cause in relation to the pulp?

Answer 27

Pulp Canal Obliteration

Question 28

Describe the positioning of the 6s to define **Class I Occlusion**)

Answer 28

mesiobuccal cusp of U6 sits in the buccal groove of the lower

Question 29

Describe the positioning of the 6s to define **Class II Occlusion**)

Answer 29

Mesiobuccal cusp of the Upper 6 occludes **anteriorly** to the buccal groove of the lower 6.

Question 30

Describe the positioning of the 6s to define **Class III Occlusion**)

Answer 30

Mesiobuccal cusp of U6 occludes posteriorly to the buccal groove.

Question 31

Pts with cleft lip and palate typically develop which type of malocclusion?

Answer 31

Class III

Question 32

Which radiographic technique is used for locating ectopic canines?

Answer 32

**parallax technique** - OPG and PA

Question 33

Which metabolic bone disease is linked to hypercementosis?

Answer 33

Paget’s Disease - disrupts normal bone remodelling causing enlarged and deformed bones.

Question 34

Which dental anomaly can show a PA radiolucency **without presence of caries**?

Answer 34

dens invaginatus

Question 35

Best way to restore hypoplastic primary molars?

Answer 35

PMC

Question 36

Which type of dentinogenesis imperfecta is present with osteogenesis imperfecta?

Answer 36

Type 1

Question 37

What is a Turner’s tooth?

Answer 37

Enamel hypoplasia **affecting only 1 tooth** in the mouth

Question 38

What is the structure called where the OEE and IEE meet and what does this give rise to?

Answer 38

cervical loop - gives rise to hertwig’s root sheath.

Question 39

At what age is the root structure of primary teeth developed?

Answer 39

3 years old

Question 40

Full formation of roots in deciduous teeth occur how long after eruption?

Answer 40

12 months

Question 41

Which stage of tooth development is impacted in hyper/hypodontia?

Answer 41

dental lamina formation

Question 42

Missing permanent tooth germs in cases of hypodontia results in lack of exfoliation and toor resorption of deciduous teeth. **What occlusion issue may this cause?**

Answer 42

Infraocclusion

Question 43

WHat cells attach other cells to basal lamina?

Answer 43

hemidesmosomes