Focus on caries prevention
There is overwhelming evidence and agreement that fluoride is safe and highly effective for the prevention of tooth decay.[i] There are a range of fluoride modalities in the modern day that help to reduce the prevalence and severity of dental caries. These include individual use at home, through fluoridation of water and by professional application. Fluoride is readily available, inexpensive and works to control caries in several ways.
When concentrated in plaque and saliva, fluoride inhibits the demineralisation of enamel and enhances remineralisation. It impedes the process by which cariogenic bacteria produce acid. But also, as cariogenic bacteria break down fermented carbohydrates and produce acids, fluoride is released from dental plaque in response to a lowered pH in the oral cavity. The released fluoride as well as the fluoride present in saliva is then taken up by the demineralised tooth enamel and along with calcium and phosphate, is used to remineralise and repair its crystal structure. This improved structure is more acid resistant and contains more fluoride and less carbonate.[ii]
For decades dental professionals have applied fluoride compounds, such as gels and varnish, directly to patients’ teeth in the assumption that it is incorporated into the crystalline structure of the tooth enamel to develop more acid resistance. However, research conducted in the 1980s revealed that in fact, these compounds form a fluoride-like material on the surface of the enamel, which releases fluoride when pH levels drop, helping the remineralisation process to take place.[iii]
Fluoride varnish applications are usually targeted at children with a high risk of caries or where it is considered beneficial to complement the fluoride found in water, from dietary sources and toothpaste. The preventive effect of fluoride varnish has been the subject of numerous studies conducted over many years in children, adolescents and adults.[iv],[v],[vi] There are claims that fluoride varnish can substantially reduce the incidence of caries and even reduce the number of caries related hospitalisations. However, new research published in Caries Research in June 2019, has revealed some interesting information.
A systematic review and meta-analysis to assess the effectiveness of fluoride varnish therapy in reducing the risk of developing new cavities and tooth decay-related hospitalisations was conducted with pre-school age children. After reviewing 20 past studies about the use of fluoride varnish, which included 13,650 children aged between 2 and 5 years, it was found that fluoride varnish resulted in caries on one fewer tooth surface per child who received treatment. At tooth level, no significant difference was observed between children that received fluoride varnish and those that did not. The meta-analysis showed the risk of developing new dentine caries lesions was reduced to 12 percent for children when fluoride varnish was applied. This was described as a ‘rather modest benefit’ as a large number of children developed new dentine caries lesions regardless of fluoride varnish use. The researchers found that in a population of pre-school children with 50% caries incidence, fluoride varnish must be applied in 17 children to avoid new caries in just one child. They concluded that applied fluoride through varnish made hardly any difference for the risk of developing new caries in children. Furthermore, no study reporting on caries-related hospitalisations was found.[vii]
As part of an overall prevention strategy, dental sealants may also be used to protect the teeth from caries. First developed in the 1970s and 80s, these thin plastic-coatings are used to fill depressions, pits and fissures and form a protective shield over the tooth enamel. This provides a smoother, easier surface for patients to clean and acts as a barrier from cavity forming plaque and acids. Sealants are usually applied to the chewing surfaces of the permanent molars soon after eruption (at around the age of 6 or 7 years) and last for as long as 5 to 10 years.[viii] Their efficacy has been established and confirmed in various studies and a report released by the Centres for Disease Control and Prevention in 2016 stated that school-age children without sealants have almost three times more cavities than children with sealants.”[ix]
Research indicates that the long-term success of dental sealants is dependent on their retention to the tooth surface.[x] It appears that resin-based sealants give more guarantees of success at 12 months, but there is good evidence for the need to review the retention of all sealants at least annually.[xi]
Bisphenol A or BPA as it is commonly known as, is a chemical used for the manufacture of polycarbonate plastics, epoxy resins and methacrylate resins and is widely used in many products including dental sealants. In animal studies, a number of adverse health effects have been associated with BPA including effects on hormonal activity, asthma, diabetes, obesity, behavioural changes, cancer, infertility and genital malformations.[xii] BPA has been reported to leach from some resin based dental materials such as pit and fissure sealants and increased concentrations in saliva and urine have been demonstrated after use in dental treatments.12
The other major concern is that BPA may have an oestrogen effect. When low doses of BPA were administered to pregnant mice for example, there was a significant increase in adult prostate weight in the male offspring compared with controls.[xiii] Other animal studies have also indicated that BPA is effective in stimulating prolactin hormones from the pituitary glands and increased growth activity in cells lining the mammary glands.13 However, the contribution of BPA exposure from sealants is small and has been described as “negligible” as much larger sources of human exposure to BPA are from food and beverages packaging, such as cans coated with BPA based epoxies.12 Consequently, the benefits of dental sealants may far outweigh the risks.
Educational, evidence-based, preventive care
For obvious reasons, the effectiveness of any strategy to prevent caries can be improved by assessing the risks and educating patients. Indeed, given the latest updates, some may argue that efforts are best devoted to the evidence-based approach to caries management.
To support this approach, and to revolutionise the way in which dental caries are managed, a team of cariologists and industry experts have developed the CALCIVIS® imaging system. This unique dental device uses a bioluminescent photoprotein to detect free calcium ions as they are released from actively demineralising tooth surfaces. By capturing this information as glowing images, the CALCIVIS® imaging system provides definitive evidence of the caries disease process at the very early stages (as the tooth enamel first begins to lose minerals). This means that preventive, non-invasive measures can be implemented to prevent further progression at a much earlier stage than has been previously possible.
The CALCIVIS® imaging system enables dental professionals to differentiate between actively progressing and arrested lesions but also it allows them to assess patients in terms of risk and accurately monitor the tooth surfaces for activity over time. The system also acts as a powerful educational and communication tool as the engaging images are displayed at the chair side. This personal information helps patients to understand their oral health status more effectively and empowers them to take the necessary preventive steps to avoid further disease progression.
Of course, for patients that remain at high risk of dental decay the application of a preventive treatment, or a dental sealant, may be beneficial. Yet, innovation now enables dental professionals to identify these patients more easily and intervene during the initial stages of the disease process to improve the way this prolific disease managed.
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[i] Pollick H. The Role of Fluoride in the Prevention of Tooth Decay. Paediatric Clinics of North America. 2018; 65, 923-940. https://www.researchgate.net/publication/327732309_The_Role_of_Fluoride_in_the_Prevention_of_Tooth_Decay#pfe [Accessed 23rd July 2019]
[ii] Centre for Disease Control and Prevention. Fluoride Recommendations Work Group. Recommendations for Using Fluoride to Prevent and Control Dental Caries in the United States. Aug 2001 50(RR14):1-21. https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5014a1.htm [Accessed 23rd July 2019]
[iii] Dijkman T.G. et al. The role of ‘CaF2-like’ material in topical fluoridation of enamel in situ. Acta Odontol Scand. 1988 Dec;46(6):391-7. https://www.ncbi.nlm.nih.gov/pubmed/3213447 [Accessed 23rd July 2019]
[iv] Holm G.B. et al. The caries-preventive effect of a fluoride varnish in the fissures of the first permanent molar. Acta Odontol Scand. 1984 Aug;42(4):193-7. https://www.ncbi.nlm.nih.gov/pubmed/6594021 [Accessed 23rd July 2019]
[v] Marinho V.C.C et al. Fluoride varnishes for preventing dental caries in children and adolescents. Cochrane Database of Systematic Reviews 2013, Issue 7. Art. No.: CD002279. http://www.mhsmobiledental.com/uploads/2/6/5/3/2653728/cochrane-caries_prevention_in_children.pdf [Accessed 23rd July 2019]
[vi] Weyant R.J. et al. Topical fluoride for caries prevention. Executive summary of the updated clinical recommendations and supporting systematic review. J Am Dent Assoc. 2013 Nov; 144(11): 1279–1291. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4581720/ [Accessed 23rd July 2019]
[vii] de Sousa F.S.O et al. Fluoride Varnish and Dental Caries in Pre-schoolers: A systemic review and meta-analysis. Caries Research. June 2019. https://www.karger.com/Article/FullText/499639 [Accessed 23rd July 2019]
[viii] NHS. Live well. Children’s teeth. Healthy body. https://www.nhs.uk/live-well/healthy-body/taking-care-of-childrens-teeth/ [Accessed 23rd July 2019]
[ix] American Dental Association. (ADA) Sealants. https://www.mouthhealthy.org/en/az-topics/s/sealants [Accessed 23rd July 2019]
[x] Condo R. Sealants in dentistry: a systematic review of the literature. Oral Implantol (Rome). 2013 Mar; 6(3): 67–74. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3982302/ [Accessed 23rd July 2019]
[xi] Azarpazhooh A. Pit and fissure sealants in the prevention of dental caries in children and adolescents: A systematic review. JCDA March 2008. 74: (2) 171-183.
https://www.researchgate.net/profile/Patricia_Main/publication/5499627_Pit_and_Fissure_Sealants_in_the_Prevention_of_Dental_Caries_in_Children_and_Adolescents/links/55ec896908ae21d099c74098/Pit-and-Fissure-Sealants-in-the-Prevention-of-Dental-Caries-in-Children-and-Adolescents.pdf [Accessed 23rd July 2019]
[xii] Becher R. et al. Presence and leaching of bisphenol a (BPA) from dental materials. Acta Biomater Odontol Scand. 2018; 4(1): 56–62. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5974758/ [Accessed 23rd July 2019]
[xiii] Rathee M. et al. Bisphenol A in dental sealants and its oestrogen like effect. Indian J Endocrinol Metab. 2012 May-Jun; 16(3): 339–342. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3354837/ [Accessed 23rd July 2019]