Desensitising Agents and Caries Prevention Practice Questions
20 free Desensitising Agents and Caries Prevention practice questions for the CDA. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
What is the primary purpose of desensitising agents in dentistry?
- A To whiten the teeth
- B To block transmission of stimuli through dentinal tubules
- C To remove plaque from enamel
- D To replace missing enamel
Correct answer: To block transmission of stimuli through dentinal tubules
Desensitising agents reduce sensitivity by sealing or blocking dentinal tubules. This prevents fluid movement that triggers pain.
Which ingredient in toothpaste is commonly used to reduce dentin hypersensitivity?
- A Carbamide peroxide
- B Potassium nitrate
- C Calcium sulfate
- D Hydrogen peroxide
Correct answer: Potassium nitrate
Potassium nitrate reduces nerve excitability within dentinal tubules. It is a key component in sensitivity-control toothpastes.
Which professional desensitising agent works by forming a protective mineral layer over exposed dentin?
- A Glass ionomer cement
- B Sodium hypochlorite
- C Calcium-phosphate varnish
- D Alginate
Correct answer: Calcium-phosphate varnish
Calcium-phosphate varnishes encourage remineralization and tubule occlusion. They strengthen the surface and reduce sensitivity.
What effect does fluoride have on exposed root surfaces?
- A It causes erosion
- B It strengthens dentin and reduces caries risk
- C It dehydrates tooth surfaces
- D It prevents plaque formation entirely
Correct answer: It strengthens dentin and reduces caries risk
Fluoride helps remineralize softened dentin and reduce sensitivity. It also lowers the risk of root caries.
Which desensitising treatment works by physically blocking open dentinal tubules?
- A Potassium nitrate
- B Sealants
- C Fluoride varnish
- D Oxalate-based desensitisers
Correct answer: Oxalate-based desensitisers
Oxalate compounds form crystals inside the tubules, reducing fluid movement. This lowers hypersensitivity.
Which patient habit most increases the likelihood of dentin hypersensitivity?
- A Use of fluoride toothpaste
- B Aggressive tooth brushing with abrasive toothpaste
- C Drinking water frequently
- D Avoiding sugary foods
Correct answer: Aggressive tooth brushing with abrasive toothpaste
Overbrushing can wear enamel and expose dentin. This leads to sensitivity and increases caries risk at the cervical area.
Which preventive measure best protects against early enamel demineralisation?
- A Carbamide peroxide rinses
- B Routine fluoride exposure
- C Long brushing sessions
- D Rinsing with water after meals only
Correct answer: Routine fluoride exposure
Fluoride enhances remineralisation and strengthens enamel. Regular exposure helps resist demineralisation.
Which professional product arrests active caries by disrupting bacterial activity?
- A Fluoride foam
- B Silver diamine fluoride
- C Glass ionomer liners
- D Potassium nitrate varnish
Correct answer: Silver diamine fluoride
Silver diamine fluoride kills cariogenic bacteria and hardens softened dentin. It is effective for arresting active lesions.
Which dietary behaviour contributes most to caries development?
- A Eating whole grains
- B Frequent consumption of sugary snacks
- C Drinking milk with meals
- D Eating high-protein foods
Correct answer: Frequent consumption of sugary snacks
Frequent sugar intake provides constant fuel for bacterial acid production. This accelerates enamel breakdown.
What is the main purpose of glass ionomer sealants in caries prevention?
- A To whiten teeth gradually
- B To release fluoride over time and protect at-risk surfaces
- C To replace enamel fully
- D To strengthen gingival tissues
Correct answer: To release fluoride over time and protect at-risk surfaces
Glass ionomer sealants provide fluoride release for extended periods. They are helpful for high-risk caries patients.
Which home-care product helps remineralize early white-spot lesions?
- A Chlorhexidine rinse
- B Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)
- C Saltwater rinse
- D Hydrogen peroxide rinse
Correct answer: Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)
CPP-ACP delivers bioavailable calcium and phosphate ions. These components assist in remineralizing early lesions.
Which finding indicates root caries risk during an exam?
- A Thick salivary flow
- B Gingival recession exposing dentin
- C Heavy calculus deposits
- D Crowded anterior teeth
Correct answer: Gingival recession exposing dentin
Root surfaces are more vulnerable once exposed due to recession. They demineralize more easily than enamel.
Which factor most reduces the effectiveness of fluoride treatments?
- A Rinsing immediately after application
- B Avoiding sugary foods
- C Using a soft toothbrush
- D Regular brushing
Correct answer: Rinsing immediately after application
Immediate rinsing removes fluoride before it can be absorbed. Patients are typically instructed not to rinse for several hours.
Which property makes glass ionomer cement valuable in high-caries-risk patients?
- A Its shade gradually changes color over a period of time
- B It contains antimicrobial silver particles within the matrix
- C It bonds chemically to tooth structure and releases fluoride
- D It sets fully without requiring any moisture control at all
Correct answer: It bonds chemically to tooth structure and releases fluoride
Glass ionomer materials bond to dentin and enamel while releasing fluoride. This helps protect margins and prevent recurrent decay.
What is the main purpose of chlorhexidine in caries prevention protocols?
- A To seal deep pits and fissures
- B To reduce mutans streptococci
- C To whiten discoloured teeth surfaces
- D To occlude exposed dentinal tubules
Correct answer: To reduce mutans streptococci
Chlorhexidine kills bacteria that contribute to caries. It is often used for high-risk patients with high bacterial loads.
Which behaviour can reduce dentin hypersensitivity over time?
- A Use of a soft-bristled toothbrush
- B Brushing multiple times per hour
- C Using high-abrasive toothpaste
- D Avoiding fluoride exposure
Correct answer: Use of a soft-bristled toothbrush
Soft bristles reduce abrasion of exposed dentin surfaces. This prevents sensitivity from worsening.
Which caries-preventive agent works by enhancing enamel crystal size and resistance?
- A Potassium chloride
- B Fluoride
- C Silver nitrate
- D Hydrogen peroxide
Correct answer: Fluoride
Fluoride helps form fluorapatite, which is more resistant to acid attacks. This strengthens enamel long-term.
Which professional application is recommended for patients with a history of frequent caries?
- A Fluoride varnish every 3–6 months
- B Whitening gel monthly
- C Chlorhexidine rinse daily for a year
- D Air polishing only
Correct answer: Fluoride varnish every 3–6 months
Frequent fluoride varnish applications support remineralization. They are ideal for high-caries-risk individuals.
Which condition increases a patient’s susceptibility to root caries?
- A High salivary flow
- B Xerostomia
- C Fluoride-rich diet
- D Thick keratinized gingiva
Correct answer: Xerostomia
Dry mouth reduces natural cleansing and buffering abilities. Xerostomic patients develop root decay more easily.
Which desensitising technique provides immediate relief by blocking nerve conduction?
- A Professionally applied desensitising gel
- B Fluoride varnish reapplied at each recall visit
- C Bonded composite restoration of the lesion
- D Fitting a custom night guard appliance
Correct answer: Professionally applied desensitising gel
Professional gels can quickly reduce nerve response. They are useful for patients needing rapid relief from sensitivity.