Formulation and preparation of toothpastes MCQs With Answer is a focused study area for B. Pharm students covering formulation principles, excipients, manufacturing steps, stability, and quality control of dentifrices. This introduction emphasizes toothpaste components—abrasives, humectants, thickeners, surfactants, fluoride sources, preservatives, sweeteners and flavoring agents—plus interactions (e.g., fluoride–abrasive compatibility), rheology, microbial limits, and regulatory/safety considerations. Understanding excipient selection, R&D tests (RDA, viscosity, extrudability, microbial limits) and common manufacturing techniques (mixing, homogenization, tube filling) is essential for safe, effective dentifrice design. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which statement best describes the primary functions of a modern toothpaste?
- Only to whiten teeth and remove stains
- To clean teeth, provide anticaries benefit, control plaque/tartar, and improve oral freshness
- To act solely as a fluoride delivery system
- To replace toothbrush mechanical action
Correct Answer: To clean teeth, provide anticaries benefit, control plaque/tartar, and improve oral freshness
Q2. Which abrasive is most widely used in contemporary toothpaste formulations for dentine-safe cleaning?
- Hydrated silica
- Kaolin clay
- Graphite powder
- Magnesium oxide
Correct Answer: Hydrated silica
Q3. What is the principal role of humectants (e.g., glycerin, sorbitol) in toothpaste?
- Act as primary abrasives
- Prevent drying and crystallization, maintain paste consistency and mouthfeel
- Provide antimicrobial activity
- Supply fluoride ions for anticaries effect
Correct Answer: Prevent drying and crystallization, maintain paste consistency and mouthfeel
Q4. Which polymeric thickening agent is commonly used to control toothpaste viscosity and provide thixotropic behavior?
- Sodium carboxymethylcellulose (CMC)
- Sodium chloride
- Calcium carbonate
- Sorbitol
Correct Answer: Sodium carboxymethylcellulose (CMC)
Q5. Which surfactant is most commonly used in toothpastes for foaming and cleaning?
- Sodium lauryl sulfate (SLS)
- Polysorbate 80
- Benzalkonium chloride
- Cetyltrimethylammonium bromide
Correct Answer: Sodium lauryl sulfate (SLS)
Q6. Which fluoride sources are routinely employed in commercial dentifrices for anticaries action?
- Sodium fluoride (NaF) and sodium monofluorophosphate (MFP)
- Calcium fluoride and magnesium fluoride only
- Hydrofluoric acid
- Potassium fluoride as the sole accepted agent
Correct Answer: Sodium fluoride (NaF) and sodium monofluorophosphate (MFP)
Q7. Which fluoride compound is generally considered incompatible with calcium carbonate abrasives due to loss of available fluoride?
- Sodium monofluorophosphate (MFP)
- Sodium fluoride (NaF)
- Stannous fluoride when combined with silica
- Calcium fluoride as an additive
Correct Answer: Sodium fluoride (NaF)
Q8. What does the RDA (Relative Dentin Abrasivity) value measure in toothpaste evaluation?
- The flavor intensity of toothpaste
- The whitening potential on enamel only
- The abrasive effect on dentin compared to a reference
- The antimicrobial potency against Streptococcus mutans
Correct Answer: The abrasive effect on dentin compared to a reference
Q9. How does formulation pH influence fluoride efficacy and stability in dentifrices?
- pH has no effect on fluoride chemistry
- Extremely acidic or alkaline pH can reduce fluoride availability and stability of some fluoride compounds
- Only basic pH enhances fluoride uptake regardless of abrasive
- Neutral pH causes immediate fluoride volatilization
Correct Answer: Extremely acidic or alkaline pH can reduce fluoride availability and stability of some fluoride compounds
Q10. Which preservatives are frequently used to control microbial growth in toothpaste formulations?
- Methylparaben and propylparaben
- Mercuric chloride
- Sodium fluoride as sole preservative
- Hydrogen peroxide permanently
Correct Answer: Methylparaben and propylparaben
Q11. Which sweetener used in toothpaste also offers anticariogenic benefits?
- Sucrose
- Sodium saccharin
- Xylitol
- Fructose
Correct Answer: Xylitol
Q12. Which antimicrobial ingredient was widely used historically in toothpastes but has faced regulatory restrictions in some regions?
- Triclosan
- Chlorhexidine gluconate
- Fluoride
- Hydrogen peroxide
Correct Answer: Triclosan
Q13. Which particle properties of an abrasive most directly influence toothpaste abrasivity and enamel/dentin wear?
- Color and odor
- Particle size distribution and hardness
- Solubility in ethanol only
- Electrical conductivity
Correct Answer: Particle size distribution and hardness
Q14. Besides moisture retention, what additional formulation problem do humectants like glycerin and sorbitol help prevent?
- Increase abrasive hardness
- Crystallization of soluble ingredients and syneresis
- Enhance microbial growth intentionally
- Accelerate tube oxidation
Correct Answer: Crystallization of soluble ingredients and syneresis
Q15. What is the primary role of pyrophosphates or polyphosphates in toothpaste?
- Provide fluoride ions for remineralization
- Act as anti-calculus (tartar) agents by chelating calcium
- Function solely as sweeteners
- Serve as primary abrasives
Correct Answer: Act as anti-calculus (tartar) agents by chelating calcium
Q16. Which adverse oral effect has been associated with sodium lauryl sulfate (SLS) in susceptible patients?
- Permanent tooth loss
- Mucosal irritation and increased incidence of recurrent aphthous ulcers in some individuals
- Systemic fluoride poisoning
- Impaired taste receptor development
Correct Answer: Mucosal irritation and increased incidence of recurrent aphthous ulcers in some individuals
Q17. What is the typical correct order of mixing operations during toothpaste manufacture?
- Add abrasives last, then mix humectants and soluble ingredients, finish with flavor
- Mix flavor and preservatives first, then fill the tube
- Combine humectants and soluble ingredients, slowly add abrasives and thickeners, homogenize, then add flavor and preservative
- Dry blend all powders, then add water and immediately fill tubes
Correct Answer: Combine humectants and soluble ingredients, slowly add abrasives and thickeners, homogenize, then add flavor and preservative
Q18. Which quality control test assesses how easily toothpaste can be expelled from a tube by consumers?
- RDA test
- Extrudability or tube-squeeze test
- Microbial limit test
- pH titration
Correct Answer: Extrudability or tube-squeeze test
Q19. What is the primary function of zinc salts (e.g., zinc citrate) when included in dentifrice formulations?
- Increase enamel abrasivity
- Reduce calculus and malodor by inhibiting volatile sulfur compounds and plaque enzymes
- Act as primary humectants
- Replace fluoride for remineralization
Correct Answer: Reduce calculus and malodor by inhibiting volatile sulfur compounds and plaque enzymes
Q20. Which surfactant is known for producing high foam and strong detergency in toothpaste?
- Cocamidopropyl betaine only
- Sodium lauryl sulfate (SLS)
- Glycerin
- Calcium carbonate
Correct Answer: Sodium lauryl sulfate (SLS)
Q21. Which thickening agent contributes to desirable shear-thinning (pseudoplastic) behavior in a dentifrice?
- Liquid paraffin
- Xanthan gum or cellulose derivatives such as CMC
- Sodium chloride at high concentration
- Magnesium stearate
Correct Answer: Xanthan gum or cellulose derivatives such as CMC
Q22. Which clinical index is commonly used to evaluate long-term anticaries efficacy of a dentifrice in epidemiological studies?
- RDA index
- DMFT (Decayed, Missing, Filled Teeth) index
- pH meter reading
- Sensory taste panel score
Correct Answer: DMFT (Decayed, Missing, Filled Teeth) index
Q23. Which packaging format is most common and practical for commercial toothpaste products to maintain hygiene and control dosing?
- Open glass jar
- Tube (laminated or polyethylene)
- Cardboard box without liner
- Loose powder sachets only
Correct Answer: Tube (laminated or polyethylene)
Q24. What is the typical fluoride concentration range (as fluoride ion) recommended for adult over-the-counter toothpastes?
- 0–50 ppm
- 1000–1500 ppm
- 10,000–15,000 ppm
- Only trace amounts under 10 ppm
Correct Answer: 1000–1500 ppm
Q25. Which ingredient in toothpaste can reduce the effectiveness of a subsequently used chlorhexidine mouthwash due to interaction?
- Sodium fluoride
- Sodium lauryl sulfate (SLS)
- Glycerin
- Xylitol
Correct Answer: Sodium lauryl sulfate (SLS)
Q26. Which abrasive also provides mild alkalinity and can neutralize oral acids while helping remove stains?
- Silica
- Sodium bicarbonate (baking soda)
- Hydrated alumina
- Graphite
Correct Answer: Sodium bicarbonate (baking soda)
Q27. How do anti-calculus agents in toothpaste mechanistically reduce tartar formation?
- By supplying calcium for crystal growth
- By chelating calcium and inhibiting crystal growth and adherence of mineralized plaque
- By increasing salivary flow only
- By mechanically abrading enamel to prevent calculus
Correct Answer: By chelating calcium and inhibiting crystal growth and adherence of mineralized plaque
Q28. Which abrasive type is generally preferred when formulating with sodium fluoride (NaF) to preserve free fluoride availability?
- Calcium carbonate
- Hydrated silica (silica-based abrasives)
- Calcium phosphate without modification
- Magnesium oxide
Correct Answer: Hydrated silica (silica-based abrasives)
Q29. Which microbiological test is routinely performed to assess acceptable microbial contamination levels in toothpaste batches?
- Total aerobic microbial count (TAMC) / total viable count
- Hemolysis assay on blood agar only
- Endotoxin test exclusively
- Virus plaque assay
Correct Answer: Total aerobic microbial count (TAMC) / total viable count
Q30. Which rheological parameters are most critical to control to ensure consistent filling and consumer feel of toothpaste during extrusion manufacturing?
- Color and refractive index
- Viscosity and yield stress (flow properties)
- Specific heat capacity
- Electrical conductivity and pH only
Correct Answer: Viscosity and yield stress (flow properties)
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