Landmarks

Question 1

What are the growth centres on developing teeth called and how many does each tooth have?

Answer 1

Lobes, each tooth develops from 4 or more.

Question 2

What are the lines on teeth formed by and what are they called?

Answer 2

The lobes grow and fuse together, but the lines will remain on the teeth even after eruption. The lines separate the primary parts of the crown and roots and are called developmental grooves

Question 3

Which teeth develop from 4 lobes?

Answer 3

Incisors, canines and premolars and second molars

Question 4

Which teeth develop from 5 lobes?

Answer 4

First molars (maxilla have 2 facial lobes and 3 lingual, mandible have 3 facial and 2 lingual)

Question 5

How many lobes does it take to develop third molars?

Answer 5

Abnormal tooth, sometimes will have 4 lobes, sometimes only 1, no set amount

Question 6

What are tubercles?

Answer 6

Small elevations of enamel on a portion of the crown (I have these on the lingual surface of my maxillary first molars)

Question 7

What is a fossa?

Answer 7

A depression on a tooth surface, canines have 2 fossae, premolars and molars have triangular fossae on the occlusal surfaces medial or distal to the marginal ridges

Question 8

What is a ridge?

Answer 8

Raised area or border that runs along a line, named by their location on the tooth. Marginal refers to the outside borders of the tooth. All cusps have 4 ridges, buccal/labial, mesial, distal, and lingual ridge

Question 9

What are cusps?

Answer 9

Elevation or mound on top of the occlusal or incisal surface, each cusp represents a lobe

Question 10

What is the cingulum?

Answer 10

The fourth lobe on anterior teeth, raised area on the lingual side of anterior teeth closest to the gingiva

Question 11

What is the pit? What are fissures?

Answer 11

The pit is a pin point hole where the lobes don’t fuse together perfectly, leaves exposed past enamel and allows for bacteria to enter and cause cavities. Fissures are natural grooves on all biting surfaces of teeth due to imperfect fusion of the lobes

Question 12

What is the difference between concavity and convexity?

Answer 12

Concavities are the carved out sections (ex. a fossa) and convexities are bulged out sections (ex. a ridge)

Question 13

What is a transverse ridge?

Answer 13

Two ridges that are across from one another, only found on posterior teeth

Question 14

What is an oblique ridge?

Answer 14

A ridge running obliquely across tooth (not straight up and down), only found on maxillary molars

Question 15

What is an incisal ridge?

Answer 15

Near the cingulum, rounded ridge on the anterior teeth

Question 16

If the explorer is getting stuck in a pit, why would we recommend a filling rather than a sealant?

Answer 16

It is likely there is already bacteria in the pit, so if we seal over it, it will be more likely to decay. Sealants need to be placed soon after eruption to avoid this

Question 17

What are mamelons?

Answer 17

When newly erupted, the central and lateral incisors have three mamelons, or rounded enamel on the incisal ridge or edge.These are to aid in the eruption of the tooth. They usually undergo attrition (wear) after eruption