Dental plaque fluoridation

Fluorides. Most woddwide reductions in dental decay can be ascribed to fluoride incorporation into drinking water, dentifrices, and mouth rinses. Numerous mechanisms have been described by which fluoride exerts a beneficial effect. Fluoride either reacts with tooth enamel to reduce its susceptibihty to dissolution in bacterial acids or interferes with the production of acid by bacterial within dental plaque. The multiple modes of action with fluoride may account for its remarkable effectiveness at concentrations far below those necessary with most therapeutic materials. Fluoride release from restorative dental materials foUow the same basic pattern. Fluoride is released in an initial short burst after placement of the material, and decreases rapidly to a low level of constant release. The constant low level release has been postulated to provide tooth protection by incorporation into tooth mineral. 

Mechanical removal of plaque is the most effective measure against plaque-caused diseases, dental caries, and periodontal diseases. Even before the advent of fluoride treatments, it was assumed that a clean tooth does not decay. A toothbmsh is effective in removing dental plaque and, for those individuals who optimize its use, it usually can adequately control plaque. Despite the proven efficacy of mechanical plaque removal, the amount of patient involvement is such that only about 30% of the population in developed countries and considerably less in undeveloped countries can be expected to adequately remove plaque (1). Hence, supplementary measures such as dentifrices and dental rinses are necessary. 

The addition of therapeutic or cosmetic agents to dentifrices has paralleled advances in knowledge about factors affecting the human dentition. Agents added to dentifrices can act directly on the host tooth stmcture or on specific oral accumulations, for example, the principal action of fluoride is on the tooth enamel. The primary action of an abrasive, however, is on an accumulated stained pellicle. Oral accumulations of interest to preventive dentistry are dental pellicles, dental plaque, dental calculus (tartar), microbial populations responsible for oral malodor, and oral debris (food residues, leukocytes, etc). Plaque is most important because of its potential to do harm. 

Nixon277 compared atomic absorption spectroscopy, flame photometry, mass spectroscopy, and neutron activation analysis as methods for the determination of some 21 trace elements (<100 ppm) in hard dental tissue and dental plaque silver, aluminum, arsenic, gold, barium, chromium, copper, fluoride, iron, lithium, manganese, molybdenum, nickel, lead, rubidium, antimony, selenium, tin, strontium, vanadium, and zinc. Brunelle 278) also described procedures for the determination of about 20 elements in soil using a combination of atomic absorption spectroscopy and neutron activation analysis. 

When fluoridated toothpastes are used, one of the effects is that fluoride levels increase, and such an effect is detectable after a single use [156]. This fluoride is taken up both by the dental plaque [157,158] and by the demineralised enamel [159] as a result of increases in fluoride levels in saliva between 100 and 1000 times the initial level. Although this initial elevation in concentration lasts for only 1-2 h [160], regular use of fluoridated toothpaste can raise the general level of fluoride in the saliva. This shift in baseline fluoride level can be maintained over considerable periods of time [157,158]. 

Mouthrinses containing fluoride consist of a concentrated solution that is prepared for use at daily or weekly intervals. As is the case for toothpastes, fluoride from mouthrinses is retained by the dental plaque and increases the concentration in saliva [172]. Mouthrinses have the advantage that their viscosity is low [173], which is aided by the use of ethanol as at least part of the carrier liquid. This enables mouthrinses to penetrate into interproximal regions, and hence carry the fluoride to parts of the tooth that are difficult to access by other means, for example, with toothpastes. 

The levels of fluoride in body fluids (plasma, saliva, urine) give some indication of recent fluoride intake. Fluoride ion does not produce any metabolites, and so is itself the measured indicator. This indicator, however, does not well reflect the fluoride body burden or the accumulation of fluoride in the body, because the relation between fluoride concentrations in bone and in extracellular fluids is incompletely defined. The concentration of fluoride in plasma, urine, saliva and dental plaque is dependent on the intake via water, diet, fluoride supplements and fluoride-containing dentifrices [92-97],... 

In general, saliva (as well as plaque fluid) is supersaturated with respect to calcium-phosphate salts, and they prevent tendency to dissolve mineral crystals of teeth. Moreover, precipitation of calcium-phosphate salts that include hydroxyapatite may also occur (remineralization) in early lesions of tooth surfaces injured by acidic bacterial products (i.e., lactic acid). Salivary fluoride facilitates calcium-phosphate precipitation, and such crystals (i.e., fluorapatite) show lower acid solubility properties that lead to an increased caries preventive effect. The increase of pFI (i.e., buffer capacity and pH of saliva, as well as ureolysis in dental plaque) also facilitates crystal precipitation and remineralization (4, 13). 

Dental plaque also tends to concentrate fluoride. This could increase possible antienzymatic activity. Some caries protection from this may be expected. Additionally, studies have suggested that topical application of fluoride may also reduce smooth surface plaque, with a resulting beneficial effect on the periodontal tissues. 

Tinanoff, N. Hock, J. Camosci, D. Hellden, L. Effect of stannous fluoride mouthrinse on dental plaque formation. J. Clin. Periodontol. 1980, 7 (3), 232-241. 

The fluoride ion can exchange for hydroxyl in the crystal structure of apatite, a main component of skeletal bone and teeth. This stabilizes the regenerating tooth surface. Fluoride is available from saliva and may also be released from dental plaque at low pH. Initially, benefit was considered solely to be for the erupting teeth of children, but topical effects on adult teeth are now also thought to reduce decay. There is some initial evidence from small studies that pharmacological doses of fluoride may reduce the incidence of bone fracture in patients with osteoporosis. However, a metaanalysis of fluoride therapy from 11 controlled studies on 1429 subjects found that although this increased lumbar bone density, the incidence of vertebral fractures was not significantly decreased. ... 

Voegel JC, Frank RM The influence of salivary glycoproteins and fluoride on synthetic apatite dissolution, in Leach SA (ed) Dental Plaque and Surface Interactions in the Oral Cavity. Ixmdon, IRL Press, 1980, pp 301-311. 

Kalo K, Nakagaki H, Arai K, Pearce EIF The influence of salivary variables on fluoride retention in dental plaque exposed to a mineral-enriching solution. Caries Res 2002 36 58-63. 

Kato K, Nakagaki H, Takami Y, Tsuge S, Ando S, Robinson C A method of determining the distribution of fluoride, calcium and phosphorus in human dental plaque and the effect of a single in vivo fluoride rinse. Arch Oral Biol 1997 42 521-525. 

Oliveby A, Weetman DA, Geddes DA, Lagerlof F The effect of salivary clearance of sucrose and fluoride on human dental plaque acidogenicity. Arch Oral Biol 1990 35 907-911. 

Very little research has been carried out on the rates of diffusion of substances into or from dental plaque in vivo. Primosch et al. (1986) studied topical fluoride distribution in the oral cavity and rates of clearance following different methods of dissolution of fluoride tablets. They found that after the chewing, sucking, or passive dissolution of the tablets, fluoride was not evenly distributed in the mouth, and that retention of fluoride was reduced by increased salivary flow rate. Thus, it would seem likely that the rate of renewal of the film of saliva over plaque must influence diffusion rates into and from plaque. 

Stannous chloride (SnCy is an important component in various plating processes it is also used in nuclear medicine for the reduction of TCO4. Other tin(II) salts, such as fluoroborate, are used in the electronic industry. Tin fluoride (Snp2) is used as an effective agent against tooth decay and many clinical trials since 1955 have shown better results against both dental caries and dental plaque than those obtained with other fluoride formulations [3]. Stannous octanoate is an important catalyst in the continuous production of flexible polyurethane foam [1]. 

Giertsen, E. (2004). Effects of mouthrinses with tri-closan, zinc ions, copolymer, and sodium lauryl sulphate combined with fluoride on acid formation by dental plaque in vivo. Caries Research, 38, 430. 

Controlled and sustained drug delivery has recently begun to make an impression in the area of treatment of dental diseases. Many researchers have demonstrated that controlled delivery of antimicrobial agents, such as chlorhexidine [128-130], ofloxacin [131-133], and metronidazole [134], can effectively treat and prevent periodontitis. The incidence of dental caries and formation of plaque can also be reduced by controlled delivery of fluoride [135,136]. Delivery systems used are film-forming solutions [129,130], polymeric inserts [132], implants, and patches. Since dental disease is usually chronic, sustained release of therapeutic agents in the oral cavity would obviously be desirable. 

The most important form of protection against caries involves avoiding sweet substances (foods containing saccharose, glucose, and fructose). Small children in particular should not have very sweet drinks freely available to them. Regular removal of plaque by cleaning the teeth and hardening of the dental enamel by fluoridization are also important. Fluoride has a protective effect because fluoroapatite (see A) is particularly resistant to acids. 

Mild tooth staining has been observed after use of stannous fluoride products. The ADA Council on Dental Therapeutics endorses fluorides for their caries-inhibiting effect but not for plaque inhibition. 

The important role of plaque as a reservoir for active agents, such as fluoride from dental products and calcium and phosphate from saliva, is reviewed in Chapter 6. Recent findings on the dependence of the concentration and retention of these agents on plaque location are included. The relationship between plaque fluid chemistry and tooth mineral is the key to caries formation and control. This interdependence is also discussed in Chapter 3. Here both the thermodynamic approach of Margolis and coworkers and the kinetic approach of... 

Heath, K, Singh, V., Logan, R., McIntyre. J.(2001). Analysis of fluoride levels retained intraorally or ingested following routine clinical applications of topacal fluoride products. Australian Dental Journal, Vol.46, No. 1, pp.24-31, ISSN 00450421 LagerlSf, F., Dawes, C.(1984). The volume of saliva in the mouth before and after swallowing, Journal of Dental Research, Vol.63, No.5, p>p. 618-621, ISSN 0022-0345 Lecomte, R, Dawes, C.(1987).The influence of salivary flow rate on diffusion of pwtassium chloride from artificial plaque at different sites in the mouth. Journal of Dental Research, Vol.66, No.ll, pp.1614-1618, ISSN... 

Microbial plaque is the primary cause of both deutal caries and periodontal disease [134,135]. In principle, most plaque can be ranoved using appropriate oral hygiene devices, such as toothbrushes aud dental floss, but in practice many patients lack both the skill and the motivation to maintain a reliable plaque-free state [136]. For this reason, professional dental prophylaxis has an important part to play in helping maintain sound oral health in individuals. The primary function of such prophylaxis is ranoval of plaque, stain and calculus [137] and elimination of the factors that cause plaque to build up and be retained [138]. This may be augmented by the topical application of fluoride in an appropriate form. 

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