Chemical Plaque Control

Chemical Plaque Control

Plaque control is one of the key elements of the practice of dentistry. It permits each patient to assume responsibility for his or her own oral health. The most dependable mode of plaque control is mechanical cleaning with a toothbrush and other hygiene aids. Absolute periodontal health can be achieved by maintaining a very high standard of plaque control.

• Such standards are attainable only in highly motivated patients who are able to demonstrate the manual dexterity and skills necessary to remove plaque from all areas of the mouth and all patients do not show these levels of motivation or skill.
• It is apparent therefore that a need exists for adjuncts to mechanical methods.

Read And Learn More: Periodontology Important Question And Answers

• Chemicals have been advocated for plaque reduction as early as 2700 BC when it was suggested that the mouth should be rinsed with honey, alum, vinegar, wine, and ever the urine of a child.
• Chemical inhibitors of plaque and calculus incorporated in mouthwashes and dentifrices have a place as adjunctive agents and should be prescribed according to the individual’s needs.
• The concept of chemical plaque control may thus be justified as a means of overcoming the inadequacies of mechanical plaque control.

Question 1. Classify chemical plaque control agents. Discuss their role in periodontal therapy.
Answer:

Chemical Plaque Control Agents Classification

• Antiplaque compounds are broadly categorized into 1st and 2nd generation agents depending on their antimicrobial effect and property of substantivity (Kornman 1986).
• The property of substantivity refers to the ability of an agent to be retained in the oral cavity and to be released over an extended period of time with retention of potency for it to exert its biological effect.

1. First-generation agents: For example, antibiotics, phenols, quaternary ammonium compounds, and sanguinarine. These are capable of reducing plaque scores by 20–50 percent but are poorly retained in the mouth.
2. Second-generation agents: Bisbiguanides, triclosan associated with a copolymer of polyvinyl methyl ether and maleic copolymer, amine fluoride, and stannous fluoride mouth rinse. They have antibacterial activity and significant substantivity. The retention of these agents is 25 to 30% after each 1-minute mouth rinse. Their slow release properties provide overall reductions in plaque scores between 70–90%.
3. Third-generation agents: These substances have mild antibacterial effects but interfere with bacterial adhesion. For example, Amine alcohols (octanol and delmopinol).
4. Fourth generation agents: A fourth generation has been proposed. The mouth flares will be individually characterized. In the laboratory, a cocktail of non-adherent bacteria would be prepared and this mixture is given to a particular individual at more or less frequent intervals, until such times as he or she acquires a personal flora mainly comprising handicapped bacteria. A low number of resident micro-organisms will not be harmful, especially if the individual continues his or her habit of brushing.

Question 2. Write a Note on Quaternary Ammonium Compounds, fluorides, Metal salts, Phenols, and Essential oils.
Answer:

Quaternary Ammonium Compounds:

• Cetylpyridinium chloride is the most widely studied quaternary ammonium compound. It is used in 0.05% concentration and absorbs readily to oral surfaces.
• Its anti-plaque activity is due to is reaction with the bacterial cell membrane phosphates thus increasing the permeability of the bacterial cell.
• However, the retention in the oral cavity is only for 3 hours.

Fluorides: A mouth rinse containing amine fluoride and stannous fluoride is available with some efficacy against plaque and gingivitis.

Metal Salts: Most polyvalent metal salts are effective plaque inhibitors at high concentrations. However, taste and toxicity problems occur at these contractions. Stannous fluoride and stannous pyrophosphate at 1% are available commercially. The major drawback is stain.

Phenols and Essential Oils

• Although not as effective as chlorhexidine these have demonstrable antiplaque activity combining essential oils with cetylpyridinium chloride has shown promising results.
• Triclosan is a non-ionic antimicrobial. At a high concentration of 0.2% in mouth rinses it has a good plaque inhibitory activity and oral retention of up to 5 hours.
• This activity may be enhanced by the addition of zinc citrate which increases its antimicrobial activity, and co-polymer polyvinyl methyl ether which increases the retention.
• When the same is issued in a paste form it has shown more benefit in controlling gingivitis than plaque. The action of the compounds is antibacterial and anti-inflammatory.
• The drug in its non-ionized form penetrates the lipid component of the cell wall of the gram-negative organisms, thus resulting in increased permeability. It also inhibits neutrophil chemotaxis, generation of neutrophil superoxide anion, and production of prostaglandin synthetase.

Question 3. Discuss chlorhexidine.
Answer:

Chlorhexidine:

• Chlorhexidine was developed in the 1940s by imperial chemical industries, in England, and marketed in 1954 as an antiseptic for skin wounds.
• Later it was used more widely in obstetrics, gynecology, urology, and skill preparation surgically. Plaque inhibition by chlorhexidine was first investigated in 1962 (Schroeder).
• It is available in 3 forms: digluconate, acetate, and hydrochloride salts. Most oral formulations use digluconate salts 2%.
• The action is mainly antibacterial. At low concentrations, the antiseptic binds to the bacterial cell membranes and increases the permeability with leakage of intracellular components like potassium.
• At higher concentrations, it causes the precipitation of bacterial cytoplasm and cell death.
• However, it’s most important characteristic which makes chlorhexidine the mouthwash of choice is its ability to bind to the surface of the tooth and other oral tissues for up to 12 hours slowly releasing the antiseptic from the surface.
• Chlorhexidine does have some minor side effects which prohibit its prolonged use. It causes a brownish discoloration of teeth and prosthesis, a bitter taste in the mouth, and sometimes mucosal erosions.
• The bitter taste may be due to:

1. Degradation of chlorhexidine molecule to release parachloraniline.
2. Catalysis of Maillard reactions.
3. Protein denaturation with mental sulfide formulation.
4. Precipitation of anionic dietary chromogenes.

The Clinical Uses of Chlorhexidine in Dentistry

1. As an adjunct to mechanical plaque cleaning.
2. Postsurgically when mechanical plaque control is difficult.
3. In all patient who are unable to efficiently maintain mechanical plaque control, for example: Mentally and physically handicapped patients, and medically compromised patients who are confined to the bed.
4. A preoperative rinse before dental procedures lead to aerosol formation to reduce bacterial contamination.
5. In patients with high caries risk.
6. In patients with fixed orthodontic appliances.
7. Patients with chronic halitosis.
8. In patients with recurrent oral lesions.

• Chlorhexidine is available in the form of mouth rinses 0.12% to 0.2%, as gels, as sprays 0.1–0.2% concentration, as toothpastes, varnishes, and chewing gums—5 mg. Several other products in the market have shown antiplaque activity but long-term gingival health has not been substantiated.
• None of the other products have proved to be as effective as chlorhexidine.

Chlorhexidine To Conclude Therefore

• Chlorhexidine due to its property of substantivity and antibacterial properties is the most effective agent to date.
• Stannous fluoride and triclosan are available with proven antiplaque activity.

Question 4. Discuss the various vehicles used for the delivery of chemical plaque control agents?
Answer:

There are several vehicles used to dispense antiplaque agents. The most commonly used ones are rinses, sprays, irrigators, dentifrices, varnishes, and chewing gums.

Rinses: These usually include active ingredients, flavoring agents, coloring agents, and preservatives such as sodium benzoate. It is very easy to use and patient compliance is excellent with rinses.

Sprays: Th advantage is that it focuses delivery on the required site.

Irrigators:

• The supragingival irrigation devices use a pulsating spray of water or antiseptics under pressure to remove debris but have limited effect on plaque deposits.
• Antiseptics like chlorhexidine (0.06%), water, essential oils, metronidazole, and sanguinarine have been used. Devices like the Water Pik are in use.
• Antiseptic agents in mouthwashes penetrate only to 1–3 mm of the periodontal pocket. This, subgingival irrigation can help deliver the solution into a pocket of less 6 mm to 90% of its depth, and in pockets greater than 6 mm the depth of penetration is around 64%.

Dentifrices

• These are the most important vehicles for effective plaque control as patient compliance is excellent.
• These are made up of abrasives (silica, alumina), detergents (sodium lauryl sulfate), thickeners (silica, gum), sweeteners (saccharin), humectants (glycerin, sorbitol), flavoring agents (peppermint), active agents (Fluorides, triclosan).

Varnishes: Varnishes containing chlorhexidine are used.

Chewing Gums: Chewing gums containing a combination of chlorhexidine 5 mg, xylitol 30%, and sorbitol 20% have been used of late. Further research is however required to substantiate these.

Conclusion

• The use of antimicrobial mouth rinses as chemotherapeutic adjuncts has become well-established in dental practice.
• A limitation of mouthwashes is that they can reach subgingival plaque only to a depth of a few millimeters within the gingival crevice and thus are of no use in deep periodontal pockets.
• Certain guidelines for the use of antiplaque agents may be one in mind. These agents due to
  their side effects though minimal should be judiciously prescribed. They are important adjuncts in patients with halitosis.
• These agents must be used in their optimum dosages and concentrations to be effective. It must be emphasized that these cannot substitute mechanical plaque control.