Radiographic Anatomy of Deciduous and Permanent Teeth & Eruption

Question 1

Define radiopaque

Answer 1

Structures that absorb x-rays and appear white on radiographs (more dense)

Question 2

Define radiolucent

Answer 2

Structures that are penetrated by x-rays and appear black on radiographs (i.e. gingiva and maxillary sinus)

Question 3

Define crown in terms of restoration

Answer 3

A restoration over the entire tooth

Question 4

Describe what a crown looks like on a radiograph

Answer 4

Opacity covering the majority of the tooth (metal underneath) with a porcelain covering, which has a similar opacity to teeth

Question 5

What does this space (encircled in white) represent what might it entail?

Answer 5

Periapical translucency (abscess) –> suggests tooth death and possibly the need for a root canal

Question 6

What does this area circled in white respresent?

Answer 6

White filling

Question 7

Label all the parts of this tooth indicated by the arrows

Answer 7

Question 8

Define periodontal ligament

Answer 8

The attachment of the tooth root to the cortical bone. Appears as a thin black line on the outer sides of the root

Question 9

Define lamina dura

Answer 9

Cortical bone of the tooth socket. Appears as a thin white line,

Question 10

Label the parts of the developing tooth indicated by the arrows

Answer 10

Question 11

What is the follicle and what will it become?

Answer 11

Cortical bone that will become the lamina dura

Question 12

What is the purpose of the bitewings (interproximal radiographs at the top)

Answer 12

To assess caries

Question 13

Where are caries most likely to occur?

Answer 13

Bewteen teeth and in the occlusal grooves (appear as black areas on the teeth)

Question 14

Why is space between teeth good in a child’s mouth?

Answer 14

Less chance of crowding once permanent teeth are in place

Question 15

Compare the incisors of deciduous teeth with those of permanent teeth

Answer 15

Crown is rounder

• Proportionately large desio-distally than gingiva-incisally
• Rounder proximal surface
• Rounder proximo-incisal angles

Root curvature is greater

Question 16

Compare the radiology of anterior deciduous teeth versus permanent

Answer 16

• Smaller teeth, rounder
• Less radiopaque
• Enamel is thinner

Question 17

7 differences between the dental anatomy of deciduous and permanent teeth

Answer 17

• Smaller tooth, unique occlusal surfaces
• Constriction at the CEJ (waist)
• Shorter root trunk
• Thinner enamel
• Dentin thickness reduced
• Root divergence
• Roots more spindly

Question 18

What is the fate of deciduous teeth without a successor?

Answer 18

Bone of the root eventually resorbs automatically in time and the tooth will fall out anyway

Question 19

3 of the most commonly missing permanent teeth congenitally

Answer 19

• Wisdom teeth (third molars)
• 2nd mandibular premolar
• Maxillary lateral incisor

Question 20

4 shortcuts to determining the age of he patient based on their teeth

Answer 20

• Age 6 = eruption of the 6’s
• Age 11 = eruption of the maxillary canines
• Age 12 = eruption of the 7’s
• Add 3 years for the completion of the apex (post eruption)

Question 21

Determine the age of this patient

Answer 21

Age 6

Question 22

Determine the age of this patient

Answer 22

Age 3

Question 23

Determine the age of this patient

Answer 23

Age 9

Question 24

Determine the age of this patient

Answer 24

Age 10

Question 25

Determine the age of this patient

Answer 25

Age 7

Question 26

Determine the age of this patient

Answer 26

Age 13

Question 27

Determine the age of this patient

Answer 27

Age 12

Question 28

Determine the age of this patient

Answer 28

Age 12