Locally Acting Drugs in Dental Pharmacology

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Questions and Answers

Which of the following is a primary use of chlorhexidine?

Whitening of teeth

Treatment of acute necrotizing ulcerative gingivitis (correct)

Strengthening enamel

Prevention of dental caries

What is a common side effect of chlorhexidine?

Increased oral sensitivity

Enamel degradation

Brownish discoloration of teeth (correct)

Excessive salivation

What type of substances are demulcents?

Absorbent materials

Inert substances soothing inflamed mucosa (correct)

Astringent compounds

Antiseptic solutions

Which of the following is an example of an astringent?

Zinc sulfate Signup and view all the answers

What is the primary mechanism of action of chlorhexidine?

Disrupts bacterial cell membrane Signup and view all the answers

Which property does glycerine possess?

Mild antiseptic property Signup and view all the answers

What is the role of sucralfate in oral treatment?

Provides topical coverage for ulcers Signup and view all the answers

Which component is typically included with local anesthetics for gingival retraction?

Vasoconstrictors Signup and view all the answers

What is a characteristic of adsorbents and protectives in dental treatments?

Provides physical protection to mucosa Signup and view all the answers

What is a common misconception regarding chlorhexidine's effect on taste?

It does not affect taste at all Signup and view all the answers

What is the main purpose of locally acting drugs in dentistry?

To produce localized therapeutic effects Signup and view all the answers

Which of the following is NOT classified as a locally acting drug relevant to dentistry?

Analgesics Signup and view all the answers

What does the term 'substantivity' refer to in the context of dental pharmacology?

The persistence of a substance on oral surfaces Signup and view all the answers

Which factor does NOT modify the activity of antiseptics?

Time since last meal Signup and view all the answers

Which mechanism is NOT associated with the action of antiseptics?

Inhibition of cellular respiration Signup and view all the answers

Which antiseptic is classified as a hydrogen peroxide derivative?

Hydrogen peroxide Signup and view all the answers

The degree of reversible nonspecific binding in substantivity primarily involves which of the following?

Oral reservoirs Signup and view all the answers

Which of the following antiseptics is classified as an alcohol?

Isopropanol Signup and view all the answers

Which factor enhances the clearance of a drug from the oral cavity?

Increased salivary flow Signup and view all the answers

What type of agent is Chlorhexidine categorized as within the antiseptic classification?

Biguanide Signup and view all the answers

What is the principal constituent of clove oil, known for its mild analgesic properties?

Eugenol Signup and view all the answers

Which of the following describes a disadvantage of clove oil?

Yellowish coloration of dentine Signup and view all the answers

What is the primary function of mummifying agents in dental procedures?

Harden and dry pulp tissues Signup and view all the answers

Which mummifying agent acts by slow liberation of iodine and has antiseptic properties?

Iodoform Signup and view all the answers

What is the primary disadvantage associated with paraformaldehyde when used in dental procedures?

Possible inflammation of pulp Signup and view all the answers

Which bleaching agent is classified as an oxidizing agent used to remove pigmentation of teeth?

Hydrogen peroxide Signup and view all the answers

What type of agent is sodium thiosulphate considered when used for removing superficial stains?

Reducing agent Signup and view all the answers

How does chlorinated lime function as a bleaching agent?

By releasing chlorine Signup and view all the answers

Which of the following is a method used to bleach dentine from carbon or mercury?

Applying ultraviolet rays Signup and view all the answers

Which mummifying agent is known for precipitating proteins and avoiding bacterial action?

Tannic acid Signup and view all the answers

What is the primary use of vasoconstrictors like Epinephrine in dentistry?

To constrain blood vessels and minimize bleeding. Signup and view all the answers

Which condition is a contraindication for using vasoconstrictors?

Uncontrolled hyperthyroidism. Signup and view all the answers

What is the primary action of thrombin as a hemostatic agent in dentistry?

To promote blood coagulation. Signup and view all the answers

What property is essential for an effective antiplaque agent?

Substantial antimicrobial spectrum and substantivity. Signup and view all the answers

Why are fluorides recommended for caries prevention?

They inhibit the development of carious lesions. Signup and view all the answers

What is the recommended fluoride concentration in drinking water to reduce dental caries by 50%?

1 part to 1 million parts. Signup and view all the answers

What is the function of obtundants in dental procedures?

To alleviate sensitivity of dentine. Signup and view all the answers

Which agent is considered an example of an antiplaque agent?

Chlorhexidine. Signup and view all the answers

What is a potential side effect of excessive fluoride ingestion?

Chronic fluoride poisoning. Signup and view all the answers

What does 'substantivity' refer to in the context of antiplaque agents?

The ability to persist on dental surfaces. Signup and view all the answers

Study Notes

Locally Acting Drugs (Dental Pharmacology)

Locally acting drugs are applied topically to skin or mucous membranes to produce localized therapeutic effects.

Types of Locally Acting Drugs in Dentistry

Antiseptics: Agents used on body surfaces to prevent or cure infections by killing or inhibiting the growth of pathogenic bacteria. Antiseptics often have a wide spectrum of activity.
- Classification: Phenol derivatives (phenol), oxidizing agents (hydrogen peroxide), halogens (iodine), biguanides (chlorhexidine), soaps (sodium and potassium), alcohols (ethanol, isopropanol), aldehydes (formaldehyde), acids (boric acid, acetic acid), metallic salts (silver nitrate), and dyes (gentian violet).
- Mechanism of action: Oxidation of bacterial protoplasm, denaturation of bacterial proteins (including enzymes), and increased permeability of bacterial membranes.
- Modifying factors: Temperature, pH, contact period with microorganism, nature of organisms, size of innoculum, presence of blood, pus, or other organic matter.
- Indications: Reducing oral infections in immunocompromised patients (cancer, AIDS), healing after oral/periodontal surgery, treating infections (acute necrotizing ulcerative gingivitis, aphthous ulcers), treating denture-associated stomatitis, and routine mouthwash to prevent plaque and gingivitis.
Demulcents: Inert substances that soothe inflamed or denuded mucous membranes. Generally high molecular weight substances applied as thick colloidal or viscous solutions in water.
- Examples: Glycyrrhiza (licorice), used for throat soothing and flavoring/sweetening; glycerin, also possessing mild antiseptic properties; methylcellulose.
Adsorbants and Protectives: Powdered, inert, insoluble solids that bind noxious substances, providing physical protection to skin or mucous membranes.
- Example: Sucralfate (an aluminum salt of sulfated sucrose), used as a topical gel for aphthous ulcers; aids in healing by covering the denuded surface.
Astringents: Substances that precipitate proteins.
- Examples: Tannic acid, heavy metal salts (zinc chloride, zinc sulfate, aluminum chloride, ferrous sulfate).
- Indications: Symptomatic relief of pain, promoting healing of oral lesions, reducing dentin sensitivity, and reducing gum bleeding.
Vasoconstrictors: Agents used in dentistry, either as components of local anesthetics or for application with gingival retraction cords, to constrict blood vessels.
- Examples: Epinephrine (1:200,000/1:100,000/1:50,000), Norepinephrine (1:30,000).
- Important considerations: Avoid use in patients with uncontrolled hypertension, uncontrolled hyperthyroidism, angina, or recent myocardial infarction.
Hemostatic Agents: Agents used in dentistry to control hemorrhage.
- Examples: Thrombin (accelerates blood coagulation - apply topically, never inject), Gelatin sponge (Gel Foam).
Antiplaque Agents: Drugs for plaque control, requiring the drug to remain at the site for sustained antimicrobial effect.
- Important properties: Antimicrobial spectrum covering relevant microbes, and 'substantivity' (persistence on teeth/gum surfaces due to initial binding and subsequent slow release).
- Examples: Chlorhexidine, benzalkonium chloride, phenols, hydrogen peroxide, zinc citrate, stannous fluoride.
Obtundants: Topical drugs to alleviate dentin sensitivity, permitting painless excavation.
- Examples: Clove oil, camphor, thymol, menthol, and alcohol.
- Mechanism of Action: Can act by nerve fiber paralysis (clove oil) or precipitating nerve fiber proteins (silver nitrate, alcohol).
- Example: Clove oil: Has mild analgesic and antiseptic properties. Contains eugenol. Must be kept in well-closed containers, protected from light. Prolonged effect with no irritation. However, it can cause yellowish discoloration of dentin and slow penetration.
Mummifying Agents: Astringents and antiseptics that dry and harden pulp and root canal tissues to minimize infection in certain dental procedures.
- Examples: Tannic acid (yellowish-white to light-brown astringent; used with glycerine to harden tissues and precipitate proteins), lodoform (acts through slow iodine release; has antiseptic and local anesthetic properties). Both are used in paste form with other agents.
- Another Example: Paraform (paraformaldehyde). Combination of zinc oxide, zinc sulfate, glycerin and creosote. Acts by slowly releasing formaldehyde; its disadvantage is the potential for formaldehyde to penetrate and harm the pulp.
Bleaching Agents: Used to remove tooth pigmentation.
- Classification: Oxidizing agents (sodium peroxide, hydrogen peroxide), reducing agents (sodium thiosulphate), chlorinated lime, ultraviolet rays.

Additional Notes

Fluorides: Effective against caries but not plaque. Sodium fluoride in drinking water can significantly reduce dental caries. Topical applications also exist. Caution needed to avoid nausea, vomiting, abdominal pain, and possible chronic fluoride poisoning from chronic exposure.
Substantivity: The period during which a drug is in contact with a substrate in the oral cavity. Persistence of the substance on the surface of teeth/gums due to initial binding and subsequent slow release. Substantivity depends on reversible nonspecific binding to oral reservoirs (enamel, dentin, oral mucosa, salivary proteins, plaque) and the rate of clearance by salivary flow.

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Description

Explore the role of locally acting drugs in dental pharmacology through this quiz. Learn about their classifications, mechanisms of action, and the importance of antiseptics in preventing infections. This quiz will enhance your understanding of how these drugs are utilized in dental practice.