Chemical agents in control of dental plaque in dentistry: An overview of current knowledge and future challenges

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1 Available online at Advances in Applied Science Research, 2012, 3 (1): Chemical agents in control of dental plaque in dentistry: An overview of current knowledge and future challenges Maya Mhaske* 1, Baig Nazish Samad 2, Rashmi Jawade 3 and Ashok Bhansali 1 ISSN: CODEN (USA): AASRFC 1 Department of Periodotology & Implantology, CSMSS Dental College & Hospital, Aurangabad 2 Department of Prosthodontia, CSMSS Dental College & Hospital, Aurangabad 3 Department of Periodontics, MIDSR Dental College, Latur ABSTRACT As dental plaque is generally accepted to be the predominant etiologic factor in gingivitis and periodontal disease and a prerequisite for the development of caries, these observations opened a new field of research on prevention of dental disease. A variety of antiboitics and antiseptics have been a employed as adjuncts to conventional therapies to suppress pathogens,chemical plaque control could prevent or reverse gingivitis if it, 1) eliminated all plaque; 2) reduced plaque below an individuals threshold for disease 3) altered the bacterial composition of plaque in such a way that health would not convert to disease. This article considers the main chemical agents which have been used as bacterial agents in mouthwash and other vehicles to inhibit growth of the plaque. Key words: Plaque, gingivits, periodonitis, antiseptics, mouthwash. INTRODUCTION The complexity of the disease process suggests that it is prudent to encourage both personal and professional monitoring of the health status of the oral cavity. Plaque can be removed by two methods - chemical and mechanical. In the chemical control of plaque, certain antibacterial agents are effective but their long term use has not yet been evaluated. One of Mohammed s biographes wrote "Even the approach of death did not keep the prophet from demanding the siwak because it is the most elegant think that one can use and most fitting to be found beautiful, for it makes the teeth white, claribies the understanding, makes the breath gragrant, extinguishes the gall, dries up the phlegm, strengthens the gums around the teeth, male the glance clear, sharpens the power of vision. Opens the bowels and whats the appetite (Proskauer 1946) (1). There has been a vigorous search for many years for chemical agents that could supplement or even supplant patient dependent mechanical plaque control and thus reduce or prevent oral disease. Five categaries of agents for approaches have been considered. 1. Broad spectrum antiseptics. 2. Antiboitics aimed at specific bacterias. 3. Single or combinations of enzymes that could modify plaque structure or activity. 4. Non enzymatic dispersing or modifying agents. 5. Agents that could affect bacterial attachment. Antimicrobial plaque inhibitory agent in mouthwashes or toothpastes used to inhibit bacterial plaque formation and thus to prevent or resolve chronic gingivitis. 268

2 The degree of effectiveness of commercial mouthwashes is very variable and depends on the composition of both the active and various additional agents within the mouthwash. Their characteristics are best assessed under the following headings: Range of antibacterial activity against the various plaque bacteria. Substantively to the oral surface. Possible anti - inflammatory effect. Acceptable taste. Ability to promote fresh mouth sensation (1, 2, 3,). Uses of anti-plaque mouthwash (3, 4, 5):- A) To replace mechanical tooth brushing when this is not possible in the following situation. After oral or periodontal surgery and during the healing period After intermaxillary fixation used to treat jaw fractures or following cosmetic surgery. With acute oral mucosal or gingival infections when pain and soreness prevents mechanical oral hygiene. For mentally or physically handicapped patients who are unable to brush their teeth themselves. B) As an adjunct - to normal mechanical oral hygiene in situations where this may be compromised by discomfort or inadequacies. Following sub gingival scaling and root planning when the gingival may be sore for days. Following scaling when there is cervical hypersensitivity due to exposed root surface. Its use needs to be combined with measures to treat the hypersensitivity. Following scaling in situations when the patients oral hygiene remains inadequate. Number of antimicrobial agents have been studied in respect to the control of plaque and they can be divided into - Biobiguanides, Quarternary ammonium compounds, phenolic agents, oxygenating agents, natural products, miscellaneous agents. Bisbiguanides : Several bisbiguanides possess anti-plaque activity including chlorhexidine, alexidine and octenidine. Chlorhexidine gluconate (CHX), a cationic bisbiguanide is the best known and most widely used member of this class. The antiplaque properties of chlorhexidine are unsurpassed by other agents and it has much greater and more prolonged effects than other antiseptics of similar or greater antibacterial activity (6). The digluconate of chlorhexidine (1:6-Di 4 chlorophenyl-diguanidohexane) is a synthectic antimicrobial drug which is effective in-vitro against both gram-positive and gram-negative bacteria including aerobes and anaerobes, yeast and fungi. Its mechanism of action is due mainly to rupture of the bacterial cell wall and precipitation of the cytoplasm contents (6,7). It has been shown that 0.2% chlorhexidine mouthrinse will prevent the development of experimental gingivitis (Addy 1986), it has been suggestd that chlorhexidine is more effective in preventing plaque accumulation on a clean tooth surface than in reducing pre-existing plaque deposits (B.M Eley 1999)(8). The unique property of chlorhexidine is substantivity it is ability of drugs to adsorb onto and bind to soft and hard tissue is known as substantivity.substativity is influenced by the concentration of the medication,its ph and Temperature, and the length of time of contact of the solution with the oral structures. Because of this property chlorhexidine maintain effective concentrations for prolonged period of time and this prolongation of its action made it especially suitable for the inhibition of plaque formation (Bonesvoll etal 1974)(8,9,10). Commercially available chlorhexidine (CHX) mouthwash contain 0.2% CHX and recommended a 10 ml volume per rinse.the CHX mouthwash available in USA, peridex, contain 0.12% CHX and recommends a 15ml volume per rinse. The effective of mouthwash depends upon total dose of CHX delivered. 10 ml of 0.2% solution delivers 20mg and 1ml of 0.12% solution delivers 18mg (Binney et al 1995) (11). CHX is more difficult to incorporate into toothpaste and gels because of the binding of CHX to components in the toothpaste (Addy etal 1989). CHX has also been incorporated into a sugar free chewing gum (Tertin A/S,Vejle,Denmark) and in this form the CHX molecule remains unbound(12). 269

3 The major side effects of chlorhexidine are a brown staining of teeth and tongue, formation of supragingival calculus, taste alteration and oral desquamation in children. Additionally allergic reaction has been reported in some patients especially Asians (8, 13). As it affects the mucous membrane and tongue and may be related to the precipition of chromogenic dietary factors on the teeth and mucous membrane. It is probable that one cationic group attaches chlorhexidine to the tooth or mucosal surface, while the other cationic group produces the bactericidal cell wall. However, thus cationic group can also attach dietary factors such as gallic acid derivatives (polyphenols) found in some foods and beverages including tea and coffee and tannins from wines (14). It is important for these reasons to advice patients using chlorhexidine mouthwash to avoid the intake of tea, coffee and red wine for the duration of its use. When chlorhexidine is used following brushing, one should follow atleast 30 minutes between tooth brushing and rinsing with this chemical because of an interaction and possible inactivation between various positively charged dentifrices detergents and the cationic CHX. Also antagonistic interactions can also occur with the anionic fluoride ions in mouthrinses, toothpastes and stanneous fluoride products. The 30 minute interval is intended to minimize the diminution in activity of CHX (7, 12, 13). Other rare side effects of CHX mouthwash are mucosal erosion and parotid swelling (8). Essential oils/ phenolic mouthwashes (Listerine) : Listerine is the product found in this category and is neutral in electrical charge. It is a combination of phenol related essential oils, thymol and methylsalicylate. It has been shown to have moderate plaque inhibitory effects and some antigingivitis effects. Its lack of profound plaque inhibitory effect is probably because, unlike chlorhexidine, it has poor oral retention. The only adverse effect has been an initial burning sensation and bitter taste. The mechanism of action of phenols is cell wall disruption and inhibition of bacterial enzymes. The phenolic compound may be capable of extracting the lipopolysachride derived endotoxin from gram- negative bacteria(15,16). Goodson (1985) has pointed out that most phenolic compounds have anti-inflammatory and prostaglandine synthetase inhibitor activity which can occur ast concentration lower than that for antibacterial activity. Phenolic compounds are also known to act as scavengers of oxygen-free-radicals (Kuehl etal. 1977) and should have an effect on leucocyte activity. It is also demonstrated that a ssmarked suppression of superoxide anion generation in neutrophil chemotaxis for a seris of phenolic agents (1, 17). Quaternary ammonium compounds: Quaternary ammonium compound such as cetylpridinium chloride (CPC) at concentration of 0.05%.The mechanism of action is related to their abiliy to rupture the cell wall and alter cytoplasmic contents (9, 18).This group of chemical agent is cationic and bind to oral tissue but not as chlorhexidine, when used orally they strongly bind to plaque and tooth surfaces but is released more rapidly than chlorhexidine. Due to this reason they are not as effective as chlorhexidine. It has some side effect as chlorhexidine. These includes some staining and enhanced calculus formation, essentially when used at higher concentration it causes burning sensation and desquamation. A slow release system containing CPC has been tried to increase the retention time for CPC in the mouth. However, there was no difference between any of the CPC formulation which showed that the slow release system had no effect on the efficacy of CPC (18, 19). Povidone londine (PVP-I): Povidone iodine is an effective antiseptic agent however; it has been approved for external use only. PVP-I is an iodophor, a compound that consists of iodine plus solublilzing agent (polyvinyl- pyrrolidine [povidone] ).PVP-I is microbicidal for Gram +ve and Gram ve bacteria, fungi, mycobacterium, virus and protozoa s. Povidane iodine appears to have no significant plaque inhibitory activity when used as 1%, mouthwash. Also it could cause problem of iodine sensitivity in sensitized individuals(4,20s). 270

4 Salifluor : Salifluor is a salicytonide (5n-octanoyl-3-trifeuoromethylsalicylanide). Which has both antibacterial and antiinflammatory property? However, the mechanism of action is not yet properly understood. Therefore, the clinical use of salifluor should be studied in the long term duration (8, 21). Triclosan : (trichlora - 2-hydroxyl diphenyl ether) Triclosan is available in dentrifrices and mouthrinses. Triclosan is both a bisphenol and a nonionic germicide with low toxicity. It has broad spectrum of antibacterial activity and lack the staining effects of cationic agents. Since it does not bind well to oral sites due to its lack of a strong positive charge ions, therefore, it is used in combination with zinc citrate to take advantage of its potential antiplaque and anticalculus property. Incorporation of triclosan in a co-polymer of methoxy ethylene and maleic acid to increase its retension time and combination with pyrophosphates to enhance its calculus - reducing properties. Triclosan also act as an anti-inflammatory agent in morthrinses. It has been shown to inhibit both cyclo-oxygenase and lipoxygenase and thus decrease synthesis of prostaglandin and leukotiene which are key mediators in inflammation (22,23). Natural products: a) Sanguinarins chloride is currently used in both mouth rinse and toothpaste as an antiplaque and antigingivitis agents. It is an alkaloid extract from blood root plant sanguinaria candensis. It is an effective plaque inhibitory agent but is less effective than chlohexidine, unlike chlorhexidine, is not able to prevent the development of gingivitis. Its mechanism of action has not been clarified. b) Propoile or naturally occurring bee product used by bees to seal opening on their hives at mainly consist of wax and plant extracts and contains flavones, flavanones and flavonls. It has been shown that is had very low level of clinical effectiveness and significant plaque inhibitory action. Miscellaneous agents: These agents include salt of zinc and cppper, a bispyridine coctenidine and surface surface delpopinol have been evaluated as plaque reducing agent. Enzymes (Amylases, psroteases and dextranase ) have been evaluated but studies are inadequate to establish efficacy of this agents. Alcohol is an ingredient of most mouth rinses with plaque altering abilities. Alcohol is include to flavour and thus most of the taste of the active agents alcohol may irritative existing mucosal lesions and can exacerbate xerostomia (24). CONCLUSION While many of the agents discussed above have significant plaque inhibitory activity and many of more effective agents share the side effects of producing tooth staining, which limit their long term use. Only one group of agents the disguinadies of which chlorhexidine are the most effective, produce appreciable antiplaque activity and substantivity (oral retentiveness) with antibacterial activity and thus retain active in the mouth for long period after their use. Practitoners must their clinical judgment as to which product or group of products and which delivery system is best for their patients. Clinical judgment should be based on the scientific validity of the products selected and their relationship to patients specific needs. [1] I.D Mandel, J Clin periodontal, 1988, 15, REFERENCES 271

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