AAPD IN-SERVICE EXAM
QUESTIONS AND ANSWERS 2026 -
2027
Caries Risk Assessment & Prevention
Q1. In infants, what is the best indicator for future caries?
Answer: Plaque on maxillary anteriors
Rationale: The presence of plaque on maxillary anterior teeth in infants is the strongest predictor of
future caries development because it indicates insufficient oral hygiene and provides a reservoir for
cariogenic bacteria.
Q2. A pea-sized amount of fluoridated toothpaste is appropriate for what age range?
Answer: Age 2–5
Rationale: The AAPD recommends a smear/rice-sized amount for children under 2 years and a pea-sized
amount for ages 2–5 to balance caries prevention with fluorosis risk.
Q3. In a child under age 3, what factors automatically assign that child an S-ECC (Severe Early
Childhood Caries) status?
Answer: White spot lesions or any carious lesion on a smooth surface
Rationale: Per AAPD definition, any carious lesion on a smooth surface in a child under 3 years qualifies
as S-ECC, regardless of caries experience elsewhere.
Q4. Name 7 factors that assign a high caries risk to a 0–5 year old.
Answer:
1. Mother/caregiver with active caries
2. Parent/caregiver low socioeconomic status
3. Greater than three between-meal sugar-containing snacks or beverages per day
4. Child put to bed with a bottle containing natural or added sugar
5. Child has greater than 1 DMFS (decayed, missing, filled surfaces)
, 6. Child has active white spot lesions or enamel defects
7. Child has elevated mutans streptococci levels
Rationale: These factors are validated in AAPD Caries Risk Assessment Tool as predictors for high caries
risk in young children.
Q5. Name the 4 caries protective factors.
Answer:
1. Child receives optimally-fluoridated drinking water or fluoride supplements
2. Child has teeth brushed daily with fluoridated toothpaste
3. Child receives topical fluoride from health professional
4. Child has dental home/regular dental care
Rationale: These factors reduce caries risk and are documented in the AAPD Caries Risk Assessment
form as protective.
Q6. Fluoride Rinse (0.05% NaF) contains what percentage of fluoride ion and ppm?
Answer: 0.022% F ion, 220 ppm
Rationale: 0.05% NaF = 0.022% fluoride ion (multiply NaF% by 0.44). 0.022% × 10,000 = 220 ppm.
Q7. Prevident 1.1% NaF = _____ ppm and _____ % F–?
Answer: 5000 ppm, 0.5% F–
Rationale: 1.1% NaF × 0.44 = 0.5% fluoride ion; 0.5% × 10,000 = 5000 ppm. This high-concentration
prescription toothpaste is for high-caries-risk patients.
Q8. 5% NaF varnish contains how many ppm?
Answer: 22,500 ppm
Rationale: 5% NaF × 0.44 = 2.2% F– × 10,000 = 22,000–22,500 ppm. Professional application adheres to
enamel.
Q9. 1.23% APF (Acidulated Phosphate Fluoride) gel/foam contains how many ppm F–?
Answer: 12,300 ppm
, Rationale: 1.23% F– × 10,000 = 12,300 ppm. APF is not recommended for porcelain restorations or
patients with xerostomia.
Q10. Fluoride toxicity thresholds:
Probably toxic dose: 5 mg F–/kg
Certainly toxic dose: 15 mg F–/kg
Treatment at 8 mg/kg: Induce vomiting, administer milk/calcium, refer to ER
Rationale: Standard of care for acute fluoride ingestion. Emesis is indicated if ingested dose exceeds 5
mg/kg or is unknown and patient is symptomatic.
Tooth Development & Embryology
Q11. Neural crest cells develop from which embryonic layer?
Answer: Ectoderm
Rationale: Neural crest cells arise from the lateral border of the neural plate during neurulation.
Q12. What structures do neural crest cells form?
Answer: Bone, cartilage, dentin, dermis (but NOT enamel)
Rationale: Enamel is epithelial-derived (ameloblasts from oral ectoderm). Neural crest cells give rise to
mesenchyme of the head and neck.
Q13. At what embryonic age does the dental lamina begin to form?
Answer: 6 weeks
Rationale: The dental lamina appears at approximately 6 weeks in utero as a thickening of the oral
epithelium.
Q14. From what structure does the dental lamina form?
Answer: Basal layer of oral epithelium
Rationale: The dental lamina is an epithelial thickening originating from the basal cell layer lining the
primitive oral cavity.
QUESTIONS AND ANSWERS 2026 -
2027
Caries Risk Assessment & Prevention
Q1. In infants, what is the best indicator for future caries?
Answer: Plaque on maxillary anteriors
Rationale: The presence of plaque on maxillary anterior teeth in infants is the strongest predictor of
future caries development because it indicates insufficient oral hygiene and provides a reservoir for
cariogenic bacteria.
Q2. A pea-sized amount of fluoridated toothpaste is appropriate for what age range?
Answer: Age 2–5
Rationale: The AAPD recommends a smear/rice-sized amount for children under 2 years and a pea-sized
amount for ages 2–5 to balance caries prevention with fluorosis risk.
Q3. In a child under age 3, what factors automatically assign that child an S-ECC (Severe Early
Childhood Caries) status?
Answer: White spot lesions or any carious lesion on a smooth surface
Rationale: Per AAPD definition, any carious lesion on a smooth surface in a child under 3 years qualifies
as S-ECC, regardless of caries experience elsewhere.
Q4. Name 7 factors that assign a high caries risk to a 0–5 year old.
Answer:
1. Mother/caregiver with active caries
2. Parent/caregiver low socioeconomic status
3. Greater than three between-meal sugar-containing snacks or beverages per day
4. Child put to bed with a bottle containing natural or added sugar
5. Child has greater than 1 DMFS (decayed, missing, filled surfaces)
, 6. Child has active white spot lesions or enamel defects
7. Child has elevated mutans streptococci levels
Rationale: These factors are validated in AAPD Caries Risk Assessment Tool as predictors for high caries
risk in young children.
Q5. Name the 4 caries protective factors.
Answer:
1. Child receives optimally-fluoridated drinking water or fluoride supplements
2. Child has teeth brushed daily with fluoridated toothpaste
3. Child receives topical fluoride from health professional
4. Child has dental home/regular dental care
Rationale: These factors reduce caries risk and are documented in the AAPD Caries Risk Assessment
form as protective.
Q6. Fluoride Rinse (0.05% NaF) contains what percentage of fluoride ion and ppm?
Answer: 0.022% F ion, 220 ppm
Rationale: 0.05% NaF = 0.022% fluoride ion (multiply NaF% by 0.44). 0.022% × 10,000 = 220 ppm.
Q7. Prevident 1.1% NaF = _____ ppm and _____ % F–?
Answer: 5000 ppm, 0.5% F–
Rationale: 1.1% NaF × 0.44 = 0.5% fluoride ion; 0.5% × 10,000 = 5000 ppm. This high-concentration
prescription toothpaste is for high-caries-risk patients.
Q8. 5% NaF varnish contains how many ppm?
Answer: 22,500 ppm
Rationale: 5% NaF × 0.44 = 2.2% F– × 10,000 = 22,000–22,500 ppm. Professional application adheres to
enamel.
Q9. 1.23% APF (Acidulated Phosphate Fluoride) gel/foam contains how many ppm F–?
Answer: 12,300 ppm
, Rationale: 1.23% F– × 10,000 = 12,300 ppm. APF is not recommended for porcelain restorations or
patients with xerostomia.
Q10. Fluoride toxicity thresholds:
Probably toxic dose: 5 mg F–/kg
Certainly toxic dose: 15 mg F–/kg
Treatment at 8 mg/kg: Induce vomiting, administer milk/calcium, refer to ER
Rationale: Standard of care for acute fluoride ingestion. Emesis is indicated if ingested dose exceeds 5
mg/kg or is unknown and patient is symptomatic.
Tooth Development & Embryology
Q11. Neural crest cells develop from which embryonic layer?
Answer: Ectoderm
Rationale: Neural crest cells arise from the lateral border of the neural plate during neurulation.
Q12. What structures do neural crest cells form?
Answer: Bone, cartilage, dentin, dermis (but NOT enamel)
Rationale: Enamel is epithelial-derived (ameloblasts from oral ectoderm). Neural crest cells give rise to
mesenchyme of the head and neck.
Q13. At what embryonic age does the dental lamina begin to form?
Answer: 6 weeks
Rationale: The dental lamina appears at approximately 6 weeks in utero as a thickening of the oral
epithelium.
Q14. From what structure does the dental lamina form?
Answer: Basal layer of oral epithelium
Rationale: The dental lamina is an epithelial thickening originating from the basal cell layer lining the
primitive oral cavity.
