Dentifrices MCQs With Answer for B. Pharm Students
Dentifrices—including toothpastes, tooth powders, and gels—are key dental products designed for plaque removal, caries prevention, and oral hygiene. For B. Pharm students, understanding toothpaste formulation is vital: abrasives (hydrated silica, calcium carbonate), humectants (glycerin, sorbitol), binders (CMC, carrageenan), surfactants (SLS, sarcosinate), flavors/sweeteners, and therapeutic actives such as fluoride (sodium fluoride, stannous fluoride, sodium monofluorophosphate), desensitizers (potassium nitrate), anti-calculus agents (pyrophosphates, zinc), and whitening agents. Topics include RDA (Relative Dentin Abrasivity), pH, compatibility (e.g., NaF with silica vs SMFP with calcium), stability, preservatives, packaging, ISO 11609, and fluoride assay. Now let’s test your knowledge with 50 MCQs on this topic.
Q1. What is the primary function of abrasives in dentifrices?
- Provide flavor and sweetness
- Remove pellicle and stains mechanically
- Act as preservative against microbes
- Reduce saliva viscosity
Correct Answer: Remove pellicle and stains mechanically
Q2. Which abrasive is most commonly used in clear gel toothpastes?
- Calcium carbonate
- Hydrated silica
- Kaolin
- Talc
Correct Answer: Hydrated silica
Q3. Which humectant is frequently added to prevent toothpaste from drying out?
- Glycerin
- Ethanol
- Ammonia
- Urea
Correct Answer: Glycerin
Q4. What is the main role of binders (e.g., CMC, carrageenan) in dentifrice formulation?
- Increase abrasivity
- Provide viscosity and prevent phase separation
- Enhance sweetness
- Release fluoride ions
Correct Answer: Provide viscosity and prevent phase separation
Q5. Which surfactant is most widely used as a foaming agent in toothpastes?
- Sodium lauryl sulfate (SLS)
- Polysorbate 80
- Poloxamer 407
- Tween 20
Correct Answer: Sodium lauryl sulfate (SLS)
Q6. Typical fluoride ion concentration in adult dentifrices is:
- 50–100 ppm
- 250–500 ppm
- 1000–1500 ppm
- 5000–10000 ppm
Correct Answer: 1000–1500 ppm
Q7. Which fluoride source is most compatible with calcium carbonate abrasives?
- Sodium fluoride
- Sodium monofluorophosphate
- Stannous fluoride
- Amine fluoride
Correct Answer: Sodium monofluorophosphate
Q8. Sodium fluoride is generally incompatible with calcium carbonate due to formation of:
- Calcium phosphate
- Calcium fluoride
- Calcium citrate
- Calcium tartrate
Correct Answer: Calcium fluoride
Q9. According to common guidance, the maximum acceptable RDA value for daily-use dentifrice is about:
- 50
- 100
- 250
- 500
Correct Answer: 250
Q10. Which desensitizing agent reduces dentinal hypersensitivity by depolarizing intradental nerves?
- Potassium nitrate
- Strontium chloride
- Hydrated silica
- Zinc citrate
Correct Answer: Potassium nitrate
Q11. Which active can reduce sensitivity by occluding dentinal tubules and also provides antimicrobial benefits?
- Sodium monofluorophosphate
- Stannous fluoride
- Calcium carbonate
- Sodium saccharin
Correct Answer: Stannous fluoride
Q12. Typical pH range of toothpastes to balance stability and enamel safety is:
- 2.0–3.0
- 4.0–5.0
- 6.5–8.0
- 9.5–11.0
Correct Answer: 6.5–8.0
Q13. Beyond sweetness, humectants like glycerin and sorbitol primarily:
- Increase abrasivity
- Reduce water activity and prevent drying
- Provide antimicrobial action
- Act as opacifiers
Correct Answer: Reduce water activity and prevent drying
Q14. Which of the following is NOT typically used as a binder/thickener in dentifrices?
- Carboxymethylcellulose
- Carrageenan
- Xanthan gum
- Sodium benzoate
Correct Answer: Sodium benzoate
Q15. Which surfactant is commonly associated with oral mucosal irritation in sensitive users?
- Sodium lauryl sulfate
- Poloxamer 188
- Glyceryl monostearate
- PEG-400
Correct Answer: Sodium lauryl sulfate
Q16. A milder alternative surfactant to SLS in low-irritancy formulations is:
- Cocamidopropyl betaine
- Sodium dodecylbenzene sulfonate
- Span 60
- Sodium stearate
Correct Answer: Cocamidopropyl betaine
Q17. Which of the following functions primarily as a preservative in dentifrices?
- Methylparaben
- Titanium dioxide
- Dicalcium phosphate dihydrate
- Potassium nitrate
Correct Answer: Methylparaben
Q18. Which non-cariogenic sweetener is commonly used in toothpastes?
- Sucrose
- Sodium saccharin
- Glucose
- Fructose
Correct Answer: Sodium saccharin
Q19. Which packaging best protects flavor and fluoride while offering good collapsibility?
- Glass jars with metal lids
- Single-layer HDPE bottles
- Laminated collapsible tubes with aluminum barrier
- Open-mouth aluminum tins
Correct Answer: Laminated collapsible tubes with aluminum barrier
Q20. The preferred analytical method to assay fluoride in dentifrices is:
- UV–Visible spectrophotometry
- Ion-selective electrode (fluoride ISE)
- NMR spectroscopy
- Karl Fischer titration
Correct Answer: Ion-selective electrode (fluoride ISE)
Q21. Which antiplaque ingredient has been largely phased out from many toothpastes?
- Chlorhexidine
- Triclosan
- Zinc citrate
- Essential oils
Correct Answer: Triclosan
Q22. Which ingredient helps prevent calculus by inhibiting crystal growth?
- Tetrapotassium pyrophosphate
- Sodium chloride
- Magnesium sulfate
- EDTA disodium
Correct Answer: Tetrapotassium pyrophosphate
Q23. How do zinc salts (e.g., zinc citrate) help control halitosis?
- By bleaching pigmented molecules
- By neutralizing stomach acid
- By binding volatile sulfur compounds
- By anesthetizing taste buds
Correct Answer: By binding volatile sulfur compounds
Q24. Which dentifrice ingredient acts as a biomimetic remineralizing agent?
- Nano-hydroxyapatite
- Calcium carbonate
- Magnesium stearate
- Peppermint oil
Correct Answer: Nano-hydroxyapatite
Q25. The standard metric used to compare abrasivity of dentifrices is:
- HLB
- RDA
- SPF
- LOD
Correct Answer: RDA
Q26. Which ISO standard specifies requirements and test methods for dentifrices?
- ISO 10993
- ISO 11609
- ISO 11607
- ISO 22196
Correct Answer: ISO 11609
Q27. Which abrasive system enables transparent gel toothpastes due to refractive index matching?
- Dicalcium phosphate dihydrate
- Calcium carbonate
- Hydrated silica
- Pumice
Correct Answer: Hydrated silica
Q28. Why is sodium monofluorophosphate often used with calcium-based abrasives?
- It tastes sweeter than NaF
- It is less reactive with calcium because fluoride is bound in the P–F bond
- It produces more foam
- It increases viscosity
Correct Answer: It is less reactive with calcium because fluoride is bound in the P–F bond
Q29. A formulation challenge with stannous fluoride dentifrices is:
- High volatility
- Color instability and extrinsic staining
- Incompatibility with silica
- Lack of antimicrobial effect
Correct Answer: Color instability and extrinsic staining
Q30. Which polymeric thickener is used in some clear gel toothpastes and requires neutralization?
- Carbomer
- Gelatin
- Povidone-iodine
- Polyethylene
Correct Answer: Carbomer
Q31. For children aged 3–6 years, the recommended amount of fluoride toothpaste is:
- A smear/rice-sized amount
- A pea-sized amount under supervision
- A full brush-length strip
- No fluoride toothpaste at all
Correct Answer: A pea-sized amount under supervision
Q32. Which ingredient provides an optical whitening effect by depositing a blue hue on teeth?
- Blue covarine
- Potassium nitrate
- Stannous fluoride
- Sodium benzoate
Correct Answer: Blue covarine
Q33. The common opacifier that gives white appearance to opaque pastes is:
- Titanium dioxide
- Magnesium oxide
- Zinc oxide
- Silicon dioxide
Correct Answer: Titanium dioxide
Q34. Which anionic surfactant is considered milder than SLS for some users?
- Sodium lauroyl sarcosinate
- Sodium dodecylbenzene sulfonate
- Sodium stearate
- Lauric acid
Correct Answer: Sodium lauroyl sarcosinate
Q35. Which fluoride source delivers free fluoride ions immediately upon brushing?
- Sodium fluoride
- Sodium monofluorophosphate
- Calcium fluoride
- Amorphous calcium phosphate
Correct Answer: Sodium fluoride
Q36. Which abrasive is incompatible with sodium fluoride in aqueous pastes due to fluoride binding?
- Hydrated silica
- Dicalcium phosphate dihydrate
- Alumina
- Perlite
Correct Answer: Dicalcium phosphate dihydrate
Q37. Sodium hexametaphosphate in dentifrices primarily:
- Acts as a sweetener
- Enhances stain and calculus control by sequestering calcium
- Increases foam height
- Acts as an opacifier
Correct Answer: Enhances stain and calculus control by sequestering calcium
Q38. The desirable rheological behavior that allows easy extrusion yet good retention on the brush is:
- Dilatancy
- Thixotropy
- Newtonian flow
- Bingham plasticity only
Correct Answer: Thixotropy
Q39. Which QC test evaluates how readily a paste is dispensed from its tube?
- Spreadability
- Extrudability
- Foam height
- LOD (Loss on drying)
Correct Answer: Extrudability
Q40. Microbial limits for dentifrices typically require absence of which specified pathogens?
- Pseudomonas aeruginosa and Staphylococcus aureus
- Escherichia coli and Candida auris
- Bacillus subtilis and Lactobacillus casei
- Streptococcus mutans and Actinomyces viscosus
Correct Answer: Pseudomonas aeruginosa and Staphylococcus aureus
Q41. A common buffering and mild abrasive ingredient in some dentifrices is:
- Sodium bicarbonate
- Calcium chloride
- Potassium iodide
- Ammonium carbonate
Correct Answer: Sodium bicarbonate
Q42. An oxidizing agent used in whitening dentifrices is:
- Hydrogen peroxide
- Ascorbic acid
- Sodium sulfite
- Thioglycolic acid
Correct Answer: Hydrogen peroxide
Q43. Which bioactive glass releases calcium and phosphate ions to aid remineralization?
- Calcium sodium phosphosilicate (NovaMin)
- Borosilicate glass
- Lead silicate glass
- Phosphate-free silica
Correct Answer: Calcium sodium phosphosilicate (NovaMin)
Q44. Recommended brushing time to maximize fluoride contact is at least:
- 15 seconds
- 30 seconds
- 1 minute
- 2 minutes
Correct Answer: 2 minutes
Q45. Why should chlorhexidine rinses be separated in time from SLS-containing toothpastes?
- SLS enhances chlorhexidine absorption
- Anionic surfactants reduce chlorhexidine’s activity by ionic interaction
- Chlorhexidine increases foam excessively
- It hardens the toothpaste
Correct Answer: Anionic surfactants reduce chlorhexidine’s activity by ionic interaction
Q46. Which fluoride provides anti-erosion benefits by forming a protective tin-rich layer?
- Sodium fluoride
- Sodium monofluorophosphate
- Stannous fluoride
- Amine fluoride
Correct Answer: Stannous fluoride
Q47. PVM/MA copolymer (Gantrez) is included in some dentifrices to:
- Sweeten the formulation
- Enhance retention of actives and boost anti-calculus performance
- Increase RDA
- Act as a bleaching agent
Correct Answer: Enhance retention of actives and boost anti-calculus performance
Q48. Which humectant is commonly used at high concentration in clear gels and helps refractive index matching?
- Sorbitol (70% solution)
- Propylene glycol monostearate
- Water for injection only
- Mineral oil
Correct Answer: Sorbitol (70% solution)
Q49. Which sweetener also exhibits anti-caries benefits by inhibiting S. mutans metabolism?
- Glucose
- Xylitol
- Maltose
- Lactose
Correct Answer: Xylitol
Q50. In fluoride ISE analysis, TISAB is added primarily to:
- Color the solution for easier reading
- Maintain constant ionic strength and complex interfering ions
- Dissolve silica abrasives
- Oxidize organic flavors
Correct Answer: Maintain constant ionic strength and complex interfering ions
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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