Dental products: Role of fluoride in dental caries MCQs With Answer

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Dental Products: Role of Fluoride in Dental Caries MCQs With Answer—designed for B. Pharm students—covers the science, pharmacology, and clinical applications of fluoride. This SEO-friendly guide explains fluoride’s mechanisms in enamel remineralization, inhibition of demineralization, and antimicrobial action (enolase inhibition, HF diffusion). Explore formulations and concentrations in toothpaste (NaF, SnF2, MFP), varnish, gels, APF, and mouthrinses; community water fluoridation (0.7 ppm); indications, dosing, toxicity management, and fluorosis prevention. Learn compatibility with abrasives, effects on plaque biofilm, salivary pH, and evidence-based guidelines for high‑risk patients. Ideal for exam preparation with MCQs and answers emphasizing dosing, kinetics, clinical protocols, and safety. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the primary anticaries mechanism of fluoride in dental products?

  • Promotes remineralization of enamel and inhibits demineralization
  • Acts as an analgesic to reduce tooth pain
  • Thickens saliva to coat teeth
  • Removes dental plaque mechanically

Correct Answer: Promotes remineralization of enamel and inhibits demineralization

Q2. Fluoride incorporation into enamel lowers the critical pH for enamel dissolution to approximately which value?

  • 4.5
  • 6.8
  • 7.0
  • 5.8

Correct Answer: 4.5

Q3. The optimally fluoridated community water level recommended in many countries (e.g., U.S.) is:

  • 0.7 ppm fluoride
  • 0.1 ppm fluoride
  • 2.0 ppm fluoride
  • 5.0 ppm fluoride

Correct Answer: 0.7 ppm fluoride

Q4. Typical fluoride concentration in most over-the-counter toothpastes is:

  • 1000–1500 ppm fluoride
  • 100–200 ppm fluoride
  • 5000–10,000 ppm fluoride
  • 10–20 ppm fluoride

Correct Answer: 1000–1500 ppm fluoride

Q5. A 5% sodium fluoride varnish contains approximately how much fluoride ion?

  • 22,600 ppm fluoride
  • 1,450 ppm fluoride
  • 12,300 ppm fluoride
  • 225 ppm fluoride

Correct Answer: 22,600 ppm fluoride

Q6. The fluoride concentration in acidulated phosphate fluoride (APF) gel is commonly:

  • 1.23% F (≈12,300 ppm)
  • 0.05% NaF (≈225 ppm)
  • 0.2% NaF (≈900 ppm)
  • 5% NaF (≈50,000 ppm)

Correct Answer: 1.23% F (≈12,300 ppm)

Q7. Which adverse effect is most associated with stannous fluoride products?

  • Extrinsic tooth staining
  • Tooth bleaching
  • Enamel erosion
  • Pulp necrosis

Correct Answer: Extrinsic tooth staining

Q8. Fluoride reduces bacterial acid production primarily by inhibiting which enzyme?

  • Enolase
  • DNA gyrase
  • Lipase
  • Urease

Correct Answer: Enolase

Q9. At low plaque pH, which form of fluoride diffuses across bacterial membranes?

  • Hydrogen fluoride (HF)
  • Sodium fluoride (NaF)
  • Calcium fluoride (CaF2)
  • Stannous fluoride (SnF2)

Correct Answer: Hydrogen fluoride (HF)

Q10. For children under 3 years, the recommended amount of fluoride toothpaste is:

  • A smear/rice-sized amount of ~1000 ppm paste
  • A pea-sized amount of ~1000 ppm paste
  • One full brush length of ~1450 ppm paste
  • No fluoride toothpaste at any time

Correct Answer: A smear/rice-sized amount of ~1000 ppm paste

Q11. The probable toxic dose (PTD) of fluoride is approximately:

  • 5 mg fluoride/kg body weight
  • 0.5 mg fluoride/kg body weight
  • 50 mg fluoride/kg body weight
  • 0.05 mg fluoride/kg body weight

Correct Answer: 5 mg fluoride/kg body weight

Q12. First-aid management after acute fluoride ingestion includes:

  • Administering milk or calcium to bind fluoride
  • Inducing vomiting
  • Giving acidic beverages to neutralize
  • Immediate vigorous exercise

Correct Answer: Administering milk or calcium to bind fluoride

Q13. The risk period for developing dental fluorosis in permanent teeth is primarily:

  • From birth to about 8 years of age
  • From 12 to 20 years of age
  • Only during adulthood
  • Only during the third trimester of pregnancy

Correct Answer: From birth to about 8 years of age

Q14. For high caries-risk children, professional fluoride varnish is typically applied:

  • Every 3 months
  • Once every 2 years
  • Only once in a lifetime
  • Daily

Correct Answer: Every 3 months

Q15. Which fluoride compound is most compatible with calcium carbonate abrasives in toothpaste?

  • Sodium monofluorophosphate (MFP)
  • Sodium fluoride (NaF)
  • Stannous fluoride (SnF2)
  • Acidulated phosphate fluoride (APF)

Correct Answer: Sodium monofluorophosphate (MFP)

Q16. Which professional fluoride should be avoided on porcelain or composite restorations due to etching?

  • Acidulated phosphate fluoride gel/foam
  • Neutral sodium fluoride gel
  • Fluoride varnish
  • Silver diamine fluoride

Correct Answer: Acidulated phosphate fluoride gel/foam

Q17. Contemporary estimates suggest community water fluoridation reduces caries in children by approximately:

  • About 25%
  • About 5%
  • About 80%
  • About 2%

Correct Answer: About 25%

Q18. The predominant caries-preventive effect of fluoride is:

  • Topical action after tooth eruption
  • Systemic incorporation only during tooth development
  • Systemic action after tooth eruption
  • Mechanical abrasion of plaque

Correct Answer: Topical action after tooth eruption

Q19. The pH of APF gel is typically around:

  • 3.5
  • 7.0
  • 9.0
  • 5.5

Correct Answer: 3.5

Q20. The most common analytical method to measure fluoride in water is:

  • Ion-selective electrode (ISE)
  • Western blot
  • Thin-layer chromatography
  • Atomic force microscopy

Correct Answer: Ion-selective electrode (ISE)

Q21. Fluoride uptake into enamel is increased by which condition?

  • Lower pH at the enamel surface
  • Higher pH at the enamel surface
  • Absence of plaque
  • Complete dehydration of enamel

Correct Answer: Lower pH at the enamel surface

Q22. A common school-based fluoride rinse protocol uses:

  • 0.2% NaF weekly
  • 0.05% NaF daily
  • 1.23% APF daily
  • 5% NaF weekly

Correct Answer: 0.2% NaF weekly

Q23. An over-the-counter daily fluoride mouthrinse typically contains:

  • 0.05% NaF (≈225 ppm F)
  • 0.2% NaF (≈900 ppm F)
  • 1.23% F (≈12,300 ppm F)
  • 5% NaF (≈22,600 ppm F)

Correct Answer: 0.05% NaF (≈225 ppm F)

Q24. Fluoride-mediated remineralization primarily targets which lesion zone?

  • Subsurface enamel lesion body
  • Dentin tubules only
  • Pulpal tissue
  • Cementum exclusively

Correct Answer: Subsurface enamel lesion body

Q25. The primary bacterial species associated with caries initiation is:

  • Streptococcus mutans
  • Porphyromonas gingivalis
  • Treponema denticola
  • Actinomyces israelii

Correct Answer: Streptococcus mutans

Q26. A common prescription high-fluoride toothpaste for high-risk adults contains:

  • 5000 ppm fluoride (1.1% NaF)
  • 225 ppm fluoride (0.05% NaF)
  • 100 ppm fluoride
  • 0 ppm fluoride

Correct Answer: 5000 ppm fluoride (1.1% NaF)

Q27. Fluoride supplements are indicated for children when drinking water fluoride is:

  • Below 0.3 ppm
  • Between 0.3 and 0.6 ppm
  • Above 1.0 ppm
  • Exactly 0.7 ppm

Correct Answer: Below 0.3 ppm

Q28. Which dietary factor reduces gastrointestinal absorption of ingested fluoride?

  • Milk or calcium-rich foods
  • Vitamin C
  • Table sugar (sucrose)
  • Vegetable fiber

Correct Answer: Milk or calcium-rich foods

Q29. The principal route of fluoride elimination from the body is via:

  • Renal excretion
  • Exhalation
  • Skin perspiration
  • Biliary excretion

Correct Answer: Renal excretion

Q30. Fluoride accumulates most in which tissues?

  • Bone and teeth
  • Liver and spleen
  • Skin and hair
  • Lungs and heart

Correct Answer: Bone and teeth

Q31. Approximately which salivary fluoride level is sufficient to inhibit demineralization?

  • ~0.04 ppm
  • ~4 ppm
  • ~0.0004 ppm
  • ~40 ppm

Correct Answer: ~0.04 ppm

Q32. Recommended tray application time for professional fluoride gel in-office is:

  • 4 minutes
  • 30 seconds
  • 10 minutes
  • 1 minute

Correct Answer: 4 minutes

Q33. Optimal post-brushing advice to maximize fluoride benefit is to:

  • Spit, do not rinse with water
  • Rinse vigorously with water
  • Brush then immediately eat
  • Follow with acidic mouthrinse

Correct Answer: Spit, do not rinse with water

Q34. Which technology synergizes with fluoride to enhance remineralization?

  • CPP-ACP with fluoride (CPP-ACFP)
  • Chlorhexidine alone
  • Hydrogen peroxide
  • Triclosan

Correct Answer: CPP-ACP with fluoride (CPP-ACFP)

Q35. Compared with NaF, a key additional benefit of stannous fluoride is:

  • Anti-gingivitis and antibacterial effects from stannous ion
  • Higher fluoride concentration
  • No risk of staining
  • Greater compatibility with all abrasives

Correct Answer: Anti-gingivitis and antibacterial effects from stannous ion

Q36. For patients with ceramic restorations, the preferred professional fluoride is:

  • Neutral 2% sodium fluoride gel
  • 1.23% APF gel
  • Acidic stannous fluoride gel
  • Hydrogen peroxide gel

Correct Answer: Neutral 2% sodium fluoride gel

Q37. A main clinical advantage of fluoride varnish over gels in young children is:

  • Lower ingestion risk and longer contact time
  • Higher systemic absorption
  • Immediate tooth whitening
  • Less fluoride content than toothpaste

Correct Answer: Lower ingestion risk and longer contact time

Q38. Most effective home-care measure for an older adult with xerostomia and root caries risk is:

  • Twice-daily brushing with 5000 ppm fluoride toothpaste
  • Daily non-fluoride mouthrinse
  • Brushing once weekly with 1450 ppm paste
  • Chewing sugar gum only

Correct Answer: Twice-daily brushing with 5000 ppm fluoride toothpaste

Q39. For a 4-year-old child living in an area with 0.2 ppm fluoride in water, the recommended daily fluoride supplement is:

  • 0.5 mg fluoride
  • 1.0 mg fluoride
  • 0.25 mg fluoride
  • No supplement

Correct Answer: 0.5 mg fluoride

Q40. Which index is commonly used to grade dental fluorosis severity?

  • Dean’s Index
  • DMFT Index
  • CPITN Index
  • OHI-S Index

Correct Answer: Dean’s Index

Q41. Compared with hydroxyapatite, fluorapatite is:

  • Less soluble in acid
  • More soluble in acid
  • Equally soluble in acid
  • Unrelated to enamel composition

Correct Answer: Less soluble in acid

Q42. The primary clinical use of 38% silver diamine fluoride (SDF) is to:

  • Arrest active dentinal caries
  • Etch enamel before bonding
  • Whiten extrinsic stains
  • Polish enamel surfaces

Correct Answer: Arrest active dentinal caries

Q43. The most common aesthetic adverse effect of SDF application is:

  • Black staining of arrested lesions
  • Intrinsic enamel bleaching
  • Gingival depigmentation
  • Blue discoloration of mucosa

Correct Answer: Black staining of arrested lesions

Q44. In vitro evaluation of anticaries efficacy via alternating demineralization and remineralization is called:

  • pH-cycling model
  • Patch-clamp assay
  • ELISA
  • Northern blot

Correct Answer: pH-cycling model

Q45. Fluoride absorption is increased in which gastrointestinal condition?

  • Low gastric pH (acidic stomach)
  • High gastric pH (achlorhydria)
  • Absence of saliva
  • Presence of dietary fat

Correct Answer: Low gastric pH (acidic stomach)

Q46. Maternal fluoride supplementation during pregnancy to prevent caries in offspring is:

  • Not recommended; no proven benefit
  • Strongly recommended for all
  • Only recommended in the third trimester
  • Mandatory in fluoridated areas

Correct Answer: Not recommended; no proven benefit

Q47. Which restorative material is known for fluoride release and recharge capability?

  • Glass ionomer cement
  • Amalgam
  • Gold alloy
  • Resin composite (non-fluoride)

Correct Answer: Glass ionomer cement

Q48. For children under 6 years, the preferred professional fluoride modality is:

  • Fluoride varnish
  • APF gel in trays
  • High-alcohol mouthrinse
  • No topical fluoride

Correct Answer: Fluoride varnish

Q49. Early signs of acute fluoride toxicity often include:

  • Nausea, vomiting, abdominal pain, hypersalivation
  • Bradycardia and cyanosis
  • Jaundice and pruritus
  • Diplopia and nystagmus

Correct Answer: Nausea, vomiting, abdominal pain, hypersalivation

Q50. Which statement best describes fluoride’s role in remineralization chemistry?

  • Acts as a catalyst for calcium and phosphate precipitation into larger, less soluble crystals
  • Removes calcium from enamel to create pores
  • Oxidizes enamel proteins to increase porosity
  • Only blocks dentinal tubules without affecting enamel

Correct Answer: Acts as a catalyst for calcium and phosphate precipitation into larger, less soluble crystals

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