NBDE Part 1 - Dental Anatomy Questions
and Answers
What is Turner Tooth? - correct answers✅✅- *Focal Enamel
Hypoplasia* (underdevelopment of tissue/organ) resulting from
*inflammation* or *trauma* during development of an individual
tooth
- Typically caused by local factors including injury to the
developing permanent tooth through extraction of primary, or
infection of the primary tooth
- Permanent tooth erupts into mouth with hypocalcification spot
due to insult from abscessed predecessor
What are the Dentition Periods? - correct answers✅✅*1.
Primary Dentition* = 6 months - 6 years
*2. Mixed Dentition* = 6 years - 12 years
*3. Permanent Dentition* = After last primary exfoliates
What is the Universal Tooth Designation System for Primary
Dentitions? - correct answers✅✅
What are the Differences between *Primary* teeth vs
*Permanent* teeth? - correct answers✅✅Primary vs
Permanent
1. *Smaller* in *size*
- Anterior: Wider M-D and shorter I-G
- Posterior: Thinner M-D and shorter I-G
2. *Whiter enamel* (↑ opacity)
3. *Broad, flat contacts*
,NBDE Part 1 - Dental Anatomy Questions
and Answers
- Flatter B/L surfaces
4. Prominent cervical bulge
- The *primary central incisor* exhibits *prominent cervical ridge*
both on *facial and lingual*
5. *Smaller* crown-to-root ratio
6. *Narrower* crowns/occlusal table at CEJ
7. *Thinner*, even layers of enamel & dentin
8. *Enamel rods* in gingival 1/3 *extends occlusally* from DEJ
- *Permanent teeth* extends *gingivally*
9. *Roots narrower, longer, & more divergent*
- Gives space for succedaneous tooth
10. Short root trunks
- *Molars lack an identifiable root truck (small/absent)*
11. *Large pulp horns* and *pulp chambers*
12. Pulp horns closer to outer surface of tooth (especially to
*mesial pulp horn*)
- Shorter distance for cavity to reach pulp
Pictures of Primary Teeth - correct answers✅✅
What are the Characteristics of Primary Teeth? - correct
answers✅✅1. Primary teeth are *less mineralized = more
worn*
,NBDE Part 1 - Dental Anatomy Questions
and Answers
2. Difference in arch space from primary and permanent is *2-
4mm*
3.. *Mamelons* that remain after *age 10* indicate an *open bite*
4.. *Calcification* of primary *roots* completed at *3-4 years old*
5.. *Primary spacing* for *anterior teeth* are most frequently
caused by *growth of dental arch*
6. *Delayed resorption* of primary *incisors* cause permanent
incisors to erupt *lingually* (*shark teeth*)
Age Estimates of Eruption Teeth - correct answers✅✅- No
teeth ~ 0-6 months old
- Lower central incisors erupting ~ 6 months old - - All primary
incisors ~ 12-18 months old
- All primary teeth ~ 3 years to 6 years old
- Mobile lower central incisors ~ 6 years old
- Erupting permanent first molars ~ 6 years old
- Mixed dent. (12 primary/12 permanent) ~ 8-10 y/o
- All permanent dentition ~ 12+ years old
What are the Eruption Times for Primary Dentition? - correct
answers✅✅1. Last primary tooth to erupt is the Max. 2nd molar
2. First primary tooth to erupt are Mand. central incisors
3. Around 1 year, child is expected to have erupted primary Max
and Mand. incisors and M1s
, NBDE Part 1 - Dental Anatomy Questions
and Answers
- Parent notices new primary tooth at 12 months, most likely a
Mand. M1 (12 month molar)
4. Primary M2s expected to erupt around child's 2nd birthday
What are the Rule of 4? - correct answers✅✅- Eruption of 4
teeth every 4 months
- Start with 4 teeth at 7 months
What are the Eruption Times for Permanent Dentition? - correct
answers✅✅
What Occurs in the Mixed Dentition Period - correct
answers✅✅*Mixed Dentition* = 6 years - 12 years
*a) Age 6*
- Get Mand. Molars at age 6
- By 6 have 20 primary and 4 permanent M1s
*b) Age 7*
- Have 18 primary and 6 permanent (4 perm molars, 2 mand.
perm central incisors)
*c) Age 8*
- 12 primary + 12 permanent
- Have Permanent M1s, central & lateral incisors, primary canines
& molars
- Permanent Max. M1 have no distal contact yet
*d) Age 9*
and Answers
What is Turner Tooth? - correct answers✅✅- *Focal Enamel
Hypoplasia* (underdevelopment of tissue/organ) resulting from
*inflammation* or *trauma* during development of an individual
tooth
- Typically caused by local factors including injury to the
developing permanent tooth through extraction of primary, or
infection of the primary tooth
- Permanent tooth erupts into mouth with hypocalcification spot
due to insult from abscessed predecessor
What are the Dentition Periods? - correct answers✅✅*1.
Primary Dentition* = 6 months - 6 years
*2. Mixed Dentition* = 6 years - 12 years
*3. Permanent Dentition* = After last primary exfoliates
What is the Universal Tooth Designation System for Primary
Dentitions? - correct answers✅✅
What are the Differences between *Primary* teeth vs
*Permanent* teeth? - correct answers✅✅Primary vs
Permanent
1. *Smaller* in *size*
- Anterior: Wider M-D and shorter I-G
- Posterior: Thinner M-D and shorter I-G
2. *Whiter enamel* (↑ opacity)
3. *Broad, flat contacts*
,NBDE Part 1 - Dental Anatomy Questions
and Answers
- Flatter B/L surfaces
4. Prominent cervical bulge
- The *primary central incisor* exhibits *prominent cervical ridge*
both on *facial and lingual*
5. *Smaller* crown-to-root ratio
6. *Narrower* crowns/occlusal table at CEJ
7. *Thinner*, even layers of enamel & dentin
8. *Enamel rods* in gingival 1/3 *extends occlusally* from DEJ
- *Permanent teeth* extends *gingivally*
9. *Roots narrower, longer, & more divergent*
- Gives space for succedaneous tooth
10. Short root trunks
- *Molars lack an identifiable root truck (small/absent)*
11. *Large pulp horns* and *pulp chambers*
12. Pulp horns closer to outer surface of tooth (especially to
*mesial pulp horn*)
- Shorter distance for cavity to reach pulp
Pictures of Primary Teeth - correct answers✅✅
What are the Characteristics of Primary Teeth? - correct
answers✅✅1. Primary teeth are *less mineralized = more
worn*
,NBDE Part 1 - Dental Anatomy Questions
and Answers
2. Difference in arch space from primary and permanent is *2-
4mm*
3.. *Mamelons* that remain after *age 10* indicate an *open bite*
4.. *Calcification* of primary *roots* completed at *3-4 years old*
5.. *Primary spacing* for *anterior teeth* are most frequently
caused by *growth of dental arch*
6. *Delayed resorption* of primary *incisors* cause permanent
incisors to erupt *lingually* (*shark teeth*)
Age Estimates of Eruption Teeth - correct answers✅✅- No
teeth ~ 0-6 months old
- Lower central incisors erupting ~ 6 months old - - All primary
incisors ~ 12-18 months old
- All primary teeth ~ 3 years to 6 years old
- Mobile lower central incisors ~ 6 years old
- Erupting permanent first molars ~ 6 years old
- Mixed dent. (12 primary/12 permanent) ~ 8-10 y/o
- All permanent dentition ~ 12+ years old
What are the Eruption Times for Primary Dentition? - correct
answers✅✅1. Last primary tooth to erupt is the Max. 2nd molar
2. First primary tooth to erupt are Mand. central incisors
3. Around 1 year, child is expected to have erupted primary Max
and Mand. incisors and M1s
, NBDE Part 1 - Dental Anatomy Questions
and Answers
- Parent notices new primary tooth at 12 months, most likely a
Mand. M1 (12 month molar)
4. Primary M2s expected to erupt around child's 2nd birthday
What are the Rule of 4? - correct answers✅✅- Eruption of 4
teeth every 4 months
- Start with 4 teeth at 7 months
What are the Eruption Times for Permanent Dentition? - correct
answers✅✅
What Occurs in the Mixed Dentition Period - correct
answers✅✅*Mixed Dentition* = 6 years - 12 years
*a) Age 6*
- Get Mand. Molars at age 6
- By 6 have 20 primary and 4 permanent M1s
*b) Age 7*
- Have 18 primary and 6 permanent (4 perm molars, 2 mand.
perm central incisors)
*c) Age 8*
- 12 primary + 12 permanent
- Have Permanent M1s, central & lateral incisors, primary canines
& molars
- Permanent Max. M1 have no distal contact yet
*d) Age 9*
