词条 | Dental sealant |
释义 |
Dental sealants (also termed pit and fissure sealants,[1] or simply fissure sealants)[2] are a dental treatment intended to prevent tooth decay. Teeth have recesses on their biting surfaces; the back teeth have fissures (grooves) and some front teeth have cingulum pits. It is these pits and fissures which are most vulnerable to tooth decay because food and bacteria stick in them and because they are hard-to-clean areas. Dental sealants are materials placed in these pits and fissures to fill them in, creating a smooth surface which is easy to clean. Dental sealants are mainly used in children who are at higher risk of tooth decay, and are usually placed as soon as the adult molar teeth come through. BackgroundDental caries is an upset of the balance between loss and gain of minerals from a tooth surface.[3] The loss of minerals from the teeth occurs from the bacteria within the mouth, fermenting foods and producing acids, whereas the tooth gains minerals from our saliva and fluoride that is present within the mouth.[3] When this balance is skewed due to frequent intake of fermentable carbohydrates, poor oral hygiene, and lack of fluoride consumption, there is a continuous loss and little gain of minerals over a long period of time, which can ultimately cause what is known as tooth decay.[3]Dental sealants are a preventive treatment that is part of the minimal intervention dentistry approach to dental care.[4] These sealants are a plastic material placed in the pits and fissures (the recesses on the chewing surfaces) of primary (baby) or permanent (adult) molar and premolar teeth at the back of the mouth. These molar teeth are considered the most susceptible teeth to dental caries due to the anatomy of the chewing surfaces of these teeth, which inhibits protection from saliva and fluoride and instead favours plaque accumulation.[5] This approach facilitates prevention and early intervention, in order to prevent or stop the dental caries process before it reaches the ends stage of the disease, which is also known as the "hole" or cavitation of a tooth.[4] Once the tooth is cavitated, it requires a dental restoration in order to repair the damage, which emphasizes the importance of prevention in preserving teeth for a lifetime of chewing. Preventing tooth decay from the pits and fissures of the teeth is achieved by dental sealants providing a physical barricade to protect natural tooth surfaces and grooves, inhibiting build-up of bacteria and food trapped within such fissures and grooves. Dental sealants also provide a smooth surface that is easily accessible for both our natural protective factor, saliva and the toothbrush bristles when cleaning our teeth.[6] Multiple oral health care professionals including dentists, dental therapists, dental hygienists, oral health therapists and dental assistants (in some states in the USA) are able to apply dental sealants to teeth.[6] Preventive treatment options for dental caries besides dental sealants, involve promoting and education on toothbrushing technique with fluoride toothpaste, use of fluoride supplements and application of topical fluorides onto tooth surfaces. HistoryThere have been many attempts made within past decades to prevent the development of caries, in particular occlusal caries as it was once generally accepted that pits and fissures of teeth would become infected with bacteria within 10 years of erupting into the mouth.[7][8] G.V. Black, the creator of modern dentistry, informed that more than 40% of caries incidences in permanent teeth occurred in pits and fissures due to being able to retain food and plaque.[9] One of the first attempts to prevent occlusal caries occurred as early as 1905 by Willoughby D. Miller.[7] Miller, a pioneer of dentistry, was applying silver nitrate to surfaces of teeth, chemically treating the biofilm with its antibacterial functions against both Streptococcus mutans and Actinomyces naeslundii, which are both carious pathogens.[7][8][9][10] Silver nitrate, which was also being practiced by H. Klein and J.W. Knutson in the 1940s, was being used in attempt to prevent and arrest occlusal caries.[9][11] In 1921, T.P. Hyatt, a pioneer researcher, was the first person to recommend prophylactic odontotomy (preventive operation).[7][9][12] This procedure involved creating Class 1 cavity preps of teeth that were considered at risk of developing occlusal caries, which included all pits and fissures.[7][9][12] The widening of the pits and fissures were then filled with amalgam.[7][9][12] C.F Bödecker, a dentist and researcher, also made attempts to prevent occlusal caries. Initially, in 1926 Bödecker would use a large round bur to smooth out the fissures. 1929, Bödecker attempted to prevent occlusal caries by cleaning the pit and fissures with an explorer and then sealing the pits and fissures with dental cement, such as oxyphosphate cement.[7] Bödecker then later became an advocator for prophylactic odontotomy procedures (preventive operations).[7][12] It was in 1955, that M.G. Buonocore gave insight to the benefits of etching enamel with phosphoric acid.[7][8][9] His studies demonstrated that resin could be bonded to enamel through acid etching, increasing adhesion whilst also creating an improved marginal integrity of resin restorative material.[7][9] It was this bonding system that lead to the future successful creation of fissure sealants.[8][12] In 1966, E.I. Cueto created the first sealant material, which was methyl cyanoacrylate.[7][1] However, this material was susceptible to bacterial breakdown over time, therefore was not an acceptable sealing material.[7] Bunonocore made further advances in 1970 by developing bisphenol-a glycidyl dimethacrylate, which is a viscous resin commonly known as BIS-GMA.[1] This material was used as the basis for many resin-based sealant/composite material developments in dentistry, as it is resistant to bacterial breakdown and forms a steady bond with etched enamel.[7][1] In 1974, glass ionomer cement fissure seals (GIC) were introduced by J.W. McLean and A.D. Wilson.[1] Modern sealant materialsModern dental sealants generally are either resin based or glass ionomer based.[1] Resin based sealantsIt is customary to refer to the development of resin based sealants in generations:[1][13]
As part of the wider debate over the safety of bisphenol A (BPA), concerns have been raised over the use of resin based sealants.[1] BPA is a xenoestrogen, i.e. it mimics the relative bioactivity of estrogen, a female sex hormone. Pure BPA is rarely present in dental sealants, however they may contain BPA derivatives.[1] There is very little research about the potential estrogen-like effects of BPA derivatives.[1] A transient presence of BPA in saliva has been reported immediately following placement of some resin based sealants.[1] The longest duration of salivary BPA was 3 hours after placement, so there is little risk of chronic low-dose BPA exposure. The currently available evidence suggests that there is no risk of estrogen-like side effects with resin based sealants.[1] Several national dental organizations have published position statements regarding the safety of resin based dental materials, e.g. the American Dental Association,[14] the Australian Dental Association,[15] the British Dental Association,[16] and the Canadian Dental Association.[17] Glass ionomer sealantsGIC materials bond both to enamel and dentine after being cleaned with polyacrylic acid conditioner.[7] Some other advantages GICs have is that they contain fluoride and are less moisture sensitive, with suggestions being made that despite having poor retention, they may prevent occlusal caries even after the sealant has fallen out due to their ability to release fluoride.[7][1][18]Resin based sealants versus glass ionomer sealantsIt was shown that GIC materials were more effective in prevention of development of caries despite the higher non-successful rate compared to resin based sealants.[19] This may be accounted for due to the fluoride-releasing property of GIC which increases salivary fluoride level that may aid in preventing dental caries. Resin-based sealants are normally the preferred choice of material for denture sealants. GIC material may be used as a provisional protective material when there are concerns regarding adequate moisture control.[20] EffectivenessDental sealants are accepted as an effective preventive method for cavities and as long as the sealant remains adhered to the tooth, cavities can be prevented. It is for this reason that sealant success is now measured by the length of time a sealant remains on the tooth, rather than the decay experienced in sealed and unsealed teeth. The ability of a pit and fissure sealant to prevent dental caries is highly dependent on its ability to retain on the tooth surface. It has been demonstrated that the use of adhesive systems before applying dental sealants improves retention.[21] Traditional retention of a sealant on tooth surface is through acid etching. The most common reason for sealant failure is salivary contamination during sealing placement. Other factors include clinician inexperience, lack of client co-operation, and less effective sealant material used.[22] Sealants may be in conjunction with fluoride varnish as a preventive method which is shown to be significantly more successful than fluoride varnish alone.[23] Various factors can help contribute to the retention of fissure sealants. These include:
LongevityAlthough dental sealants do wear naturally and may become damaged over time, they usually last for around five to ten years, despite the heavy pressures endured by teeth during chewing each day. Longevity of dental sealants is also dependent on the type of material used.[25] It is not uncommon for dental sealants to be retained well into adulthood. It is believed that bacteria and food particles may eventually become entrapped under dental sealants, and can thus cause decay in the very teeth intended to be protected.{{mcn|date=July 2015}} Dental sealants are inspected during routine dental visits to ensure that they are retained in the fissures of the teeth. Damaged sealants can simply be repaired by adding new sealant material. One of the major causes of the loss of sealants in the first year is salivary contamination.[24] On the basis of limited evidence both GIC and resin materials are equally acceptable in caries prevention, however retention rates between GIC and Resin have been shown to differ.[18] Resin has been shown to be the superior product for retention. A 2-year clinical trial comparing GIC and Resin for dental sealants demonstrated that the GIC had a total loss rate of 31.78%, in contrast to the resin which had a total loss rate of 5.96% The study did acknowledge that GIC had its therapeutic advantages other than retention, this included the benefit of fluoride release and its use on partially erupted teeth.[26] Though GIC has poorer retention rates, the fact that they release active fluoride in the surrounding enamel is very important. They can exert a cariostatic effect and increased release of fluoride, and for these reasons GIC is more of a fluoride vehicle rather than a traditional fissure sealant.[27] All three materials are as effective as each other if the correct techniques are used to complete the procedure.[18] Indications and contraindicationsIndications for the use of dental sealants are individual patients or teeth that are at high risk of dental caries. This includes patients with:
Contraindications for the use of dental sealants are individual patients or teeth that are at a low risk of dental caries: This includes patients with:
Clinical procedure{{sister project|project=Wikiversity |text=Wikiversity has learning materials related to: Placement of fissure sealants |position= }} The exact technique depends on the material used and a good application technique will increase retention, which means sealants can last longer on the teeth.[29] Generally, each quadrant is treated separately by using four-handed technique with an assistant and to follow the manufacturer's recommendations.[29] The patient should wear safety glasses for protection from chemicals and curing light. Once the patient is prepared, the surface of the tooth must be cleaned to allow maximum contact of the etch and the dental sealant with the enamel surface. A rubber dam may be used to prevent saliva from contaminating the intended site to be sealed, although often these are not used, especially for younger children. Moisture control is more of an issue with resin based sealants than with glass ionomer sealants. The surface is cleaned and dried. Resin sealants require a phosphoric acid solution ("etch") to create microscopic porosity into which the sealant material can flow thereby increasing retention, increasing surface area and improving the strength of the bond between the sealant and the tooth surface.[30] Etching time varies from 15 to 60 seconds, depending on the product. After that, the tooth must be rinsed and dried thoroughly for 15 to 20 seconds. Chalky appearance on the dried tooth means the tooth has been properly etched. If the tooth does not have this chalky appearance, the etching process must be repeated. The sealant is then applied to the tooth by carefully placing the sealant material into the prepared pits and fissures by using a disposable instrument provided by the manufacturer. Overfilling on the tooth should be prevented to minimize occlusal adjustment. The material is left for 10 seconds after the placement prior to curing to allow optimum penetration of the sealant material into the pores created by the etching procedure. Finally, the sealant is hardened by a curing light, which usually takes 20 to 30 seconds. Glass ionomer does not require light curing, however it will set faster with the usage of a curing light.[31] Resin-based sealants require an absolutely dry surface until polymerization is complete, so it is essential to avoid salivary contamination of the sealant site. A rubber dam or cotton roll isolation technique can be used to isolate the sealant site from saliva which is the common reason for sealant failure. Glass ionomer sealants have the advantage of not needing a dry field to be effective. In fact, the application procedure for glass ionomers can involve pressing a saliva-moistened finger onto the occlusal surface to push the sealant material into the pits and fissures. Compared to a typical dental filling, where an injection of local anesthetic and the use of a dental drill may be involved, the application of dental sealants is significantly less invasive and generally considered quick and easy. The procedure is entirely painless, although a minor level of discomfort may be experienced by the patient. PrevalenceAccording to 2011-2012 figures, 30 to 40% of US children aged six to eleven years have at least one dental sealant.[32][33] In Greece only around 8% of all adolescents have one or more sealed molars.[34] In some other European countries, such as Denmark (about two thirds), Germany (about two thirds) and Portugal (more than half), rates are significantly higher.[35][36][37] Around 25% of Japanese children have at least one sealed molar.[37] In Saudi Arabia approximately 9% of all children's molars have been sealed.[38] Notes1. ^1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 {{cite journal | vauthors = Ahovuo-Saloranta A, Forss H, Walsh T, Nordblad A, Mäkelä M, Worthington HV | title = Pit and fissure sealants for preventing dental decay in permanent teeth | journal = The Cochrane Database of Systematic Reviews | volume = 7 | issue = 7 | pages = CD001830 | date = July 2017 | pmid = 28759120 | doi = 10.1002/14651858.CD001830.pub5 | url = https://www.research.manchester.ac.uk/portal/en/publications/pit-and-fissure-sealants-for-preventing-dental-decay-in-permanent-teeth-review(3ba02b89-33c6-4eaa-a990-225c10ba906f).html }} 2. ^{{cite book | vauthors = Scheller-Sheridan C |title=Basic Guide to Dental Materials |url=https://books.google.com/books?id=YSnQajssUSIC&pg=PA74 |date=8 May 2013 |publisher=John Wiley & Sons |isbn=978-1-118-70831-6 |pages=74–78}} 3. ^1 2 {{cite journal | vauthors = Featherstone JD | title = Dental caries: a dynamic disease process | journal = Australian Dental Journal | volume = 53 | issue = 3 | pages = 286–91 | date = September 2008 | pmid = 18782377 | doi = 10.1111/j.1834-7819.2008.00064.x }} 4. ^1 White J.M., & Eakle W.S. Rationale and Treatment Approach in Minimally Invasive Dentistry. Journal of the American Dental Association, 2000. 5. ^{{cite journal | vauthors = Welbury R, Raadal M, Lygidakis NA | title = EAPD guidelines for the use of pit and fissure sealants | journal = European Journal of Paediatric Dentistry | volume = 5 | issue = 3 | pages = 179–84 | date = September 2004 | pmid = 15471528 | url = http://www.eapd.gr/dat/D052751D/file.pdf }} 6. ^1 Fissure sealants. http://www.dentalhealth.ie/download/pdf/fissure_sealant_booklet.pdf. Dental Health. Retrieved 2014-04-11. 7. ^1 2 3 4 5 6 7 8 9 10 11 12 13 14 {{cite journal | vauthors = Avinash J, Marya CM, Dhingra S, Gupta P, Kataria S, Meenu Bhatia HP | year = 2010 | title = Pit and Fissure Sealants: An Unused Caries Prevention Tool | url = http://www.johcd.org/pdf/JOHCD%20Pit%20and%20Fissure%20Sealants%20An%20Unused%20Caries%20Prevention%20T.pdf | journal = Journal of Oral Health and Community Dentistry | volume = 4 | issue = 1| pages = 1–6 }} 8. ^1 2 3 {{cite journal | vauthors = Feigal RJ, Donly KJ | title = The use of pit and fissure sealants | journal = Pediatric Dentistry | volume = 28 | issue = 2 | pages = 143–50; discussion 192–8 | year = 2006 | pmid = 16708789 | url = http://0-web.b.ebscohost.com.alpha2.latrobe.edu.au/ehost/pdfviewer/pdfviewer?sid=5120e3d5-1bc5-4df3-8d6a-3b44f9d41f1d%40sessionmgr198&vid=2&hid=122 }} 9. ^1 2 3 4 5 6 7 https://scholarworks.iupui.edu/bitstream/handle/1805/2078/view.pdf 10. ^{{cite journal | vauthors = Donovan TE, Anderson M, Becker W, Cagna DR, Carr GB, Albouy JP, Metz J, Eichmiller F, McKee JR | title = Annual Review of selected dental literature: report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry | journal = The Journal of Prosthetic Dentistry | volume = 110 | issue = 3 | pages = 161–210 | date = September 2013 | pmid = 24029608 | doi = 10.1016/S0022-3913(13)60358-3 }} 11. ^{{cite journal | vauthors = Knight GM, McIntyre JM, Craig GG, Zilm PS, Gully NJ | title = An in vitro model to measure the effect of a silver fluoride and potassium iodide treatment on the permeability of demineralized dentine to Streptococcus mutans | journal = Australian Dental Journal | volume = 50 | issue = 4 | pages = 242–5 | date = December 2005 | pmid = 17016889 | doi = 10.1111/j.1834-7819.2005.tb00367.x | hdl = 2440/16807 }} 12. ^1 2 3 4 {{cite journal | vauthors = Zero DT | title = How the introduction of the acid-etch technique revolutionized dental practice | journal = Journal of the American Dental Association | volume = 144 | issue = 9 | pages = 990–4 | date = September 2013 | pmid = 23989836 | doi = 10.14219/jada.archive.2013.0224 }} 13. ^1 2 3 4 {{cite book| vauthors = Hiremath SS |title=Textbook of Preventive and Community Dentistry|url=https://books.google.com/books?id=Tz9cWJ3yUycC&pg=PA428|date=15 August 2011|publisher=Elsevier India|isbn=978-81-312-2530-1|pages=428–432}} 14. ^Policy statement of the American Dental Association on Bisphenol A (BPA): "[B]ased on current evidence, the ADA does not believe there is a basis for health concerns relative to BPA exposure from any dental material." 15. ^Policy statement of the Australian Dental Association on BPA (2014) 16. ^Position statement of the British Dental Association on Bisphenol (2005): "More research is needed into the extent of any dental exposure (to bisphenol A) and into the general effects of Bisphenol A exposure, but as the majority of sealants and filling materials only contain Bis-GMA, there will be no resultant oestrogenic effect from using these materials."[https://www.bda.org/dentists/policy-campaigns/public-health-science/public-health/position-statements/bisphenol] 17. ^Canadian Dental Association page on frequently asked questions regarding BPA [https://www.cda-adc.ca/en/oral_health/faqs/bpa_faqs.asp] 18. ^1 2 {{cite journal | vauthors = Seth S | title = Glass ionomer cement and resin-based fissure sealants are equally effective in caries prevention | journal = Journal of the American Dental Association | volume = 142 | issue = 5 | pages = 551–2 | date = May 2011 | pmid = 21531937 | doi = 10.14219/jada.archive.2011.0225 }} 19. ^{{cite journal | vauthors = Haznedaroğlu E, Güner Ş, Duman C, Menteş A | title = A 48-month randomized controlled trial of caries prevention effect of a one-time application of glass ionomer sealant versus resin sealant | journal = Dental Materials Journal | volume = 35 | issue = 3 | pages = 532–8 | date = June 2016 | pmid = 27086573 | doi = 10.4012/dmj.2016-084 }} 20. ^{{cite journal | vauthors = Crall JJ, Donly KJ | title = Dental sealants guidelines development: 2002-2014 | journal = Pediatric Dentistry | volume = 37 | issue = 2 | pages = 111–5 | pmid = 25905651 }} 21. ^{{Cite web|url=http://www.nationalelfservice.net/dentistry/caries/fissure-sealants-are-self-etch-sealants-more-effective/|title=Fissure sealants – are self-etch sealants more effective?|last=Richards|first=Derek | name-list-format = vanc |date=2015-12-01|website=|access-date=}} 22. ^{{cite journal | vauthors = Locker D, Jokovic A, Kay EJ | title = Prevention. Part 8: The use of pit and fissure sealants in preventing caries in the permanent dentition of children | journal = British Dental Journal | volume = 195 | issue = 7 | pages = 375–8 | date = October 2003 | pmid = 14551623 | doi = 10.1038/sj.bdj.4810556 }} 23. ^{{cite journal | vauthors = Ahovuo-Saloranta A, Forss H, Hiiri A, Nordblad A, Mäkelä M | title = Pit and fissure sealants versus fluoride varnishes for preventing dental decay in the permanent teeth of children and adolescents | journal = The Cochrane Database of Systematic Reviews | issue = 1 | pages = CD003067 | date = January 2016 | pmid = 26780162 | doi = 10.1002/14651858.CD003067.pub4 }} 24. ^1 {{cite journal | vauthors = Azarpazhooh A, Main PA | title = Pit and fissure sealants in the prevention of dental caries in children and adolescents: a systematic review | journal = Journal | volume = 74 | issue = 2 | pages = 171–7 | date = March 2008 | pmid = 18353204 }} 25. ^{{cite journal | vauthors = Deery C | title = Pit and fissure sealant retention | journal = Evidence-Based Dentistry | volume = 13 | issue = 1 | pages = 9–10 | date = March 2012 | pmid = 22436807 | doi = 10.1038/sj.ebd.6400837 }} 26. ^{{cite journal | vauthors = Forss H, Saarni UM, Seppä L | title = Comparison of glass-ionomer and resin-based fissure sealants: a 2-year clinical trial | journal = Community Dentistry and Oral Epidemiology | volume = 22 | issue = 1 | pages = 21–4 | date = February 1994 | pmid = 8143437 | doi = 10.1111/j.1600-0528.1994.tb01563.x }} 27. ^{{cite journal | vauthors = Beun S, Bailly C, Devaux J, Leloup G | title = Physical, mechanical and rheological characterization of resin-based pit and fissure sealants compared to flowable resin composites | journal = Dental Materials | volume = 28 | issue = 4 | pages = 349–59 | date = April 2012 | pmid = 22119547 | doi = 10.1016/j.dental.2011.11.001 }} 28. ^1 {{cite journal | vauthors = Beauchamp J, Caufield PW, Crall JJ, Donly K, Feigal R, Gooch B, Ismail A, Kohn W, Siegal M, Simonsen R | title = Evidence-based clinical recommendations for the use of pit-and-fissure sealants: a report of the American Dental Association Council on Scientific Affairs | journal = Journal of the American Dental Association | volume = 139 | issue = 3 | pages = 257–68 | date = March 2008 | pmid = 18310730 | doi = 10.14219/jada.archive.2008.0155 }} 29. ^1 {{cite journal | vauthors = Griffin SO, Jones K, Gray SK, Malvitz DM, Gooch BF | title = Exploring four-handed delivery and retention of resin-based sealants | journal = Journal of the American Dental Association | volume = 139 | issue = 3 | pages = 281–9; quiz 358 | date = March 2008 | pmid = 18310732 | doi = 10.14219/jada.archive.2008.0157 | url = https://www.researchgate.net/publication/5541076 }} 30. ^{{cite journal | vauthors = Frankenberger R, Tay FR | title = Self-etch vs etch-and-rinse adhesives: effect of thermo-mechanical fatigue loading on marginal quality of bonded resin composite restorations | journal = Dental Materials | volume = 21 | issue = 5 | pages = 397–412 | date = May 2005 | pmid = 15826696 | doi = 10.1016/j.dental.2004.07.005 }} 31. ^{{Cite journal|last=|title=Pit and Fissure Sealants: An Overview|url=http://www.rdhmag.com/content/dam/rdh/print-articles/Volume%2033/Issue10/1311cei_Mun%CC%83oz_RDH_7.pdf|journal=|volume=}} 32. ^{{Cite web|url=https://www.statista.com/statistics/449629/dental-sealants-in-childrens-permanent-teeth-in-the-us-by-ethnicity/|title=Dental sealants childrens' permanent teeth U.S. by ethnicity 2011-2012 {{!}} Survey|website=Statista|language=en|access-date=2019-01-03}} 33. ^{{Cite web|url=https://www.statista.com/statistics/449613/dental-sealants-in-childrens-permanent-teeth-in-the-us-by-age-group/|title=Dental sealants prevalence childrens' permanent teeth U.S. 2011-2012 {{!}} Survey|website=Statista|language=en|access-date=2019-01-03}} 34. ^{{cite journal | vauthors = Oulis CJ, Berdouses ED, Mamai-Homata E, Polychronopoulou A | title = Prevalence of sealants in relation to dental caries on the permanent molars of 12 and 15-year-old Greek adolescents. A national pathfinder survey | journal = BMC Public Health | volume = 11 | pages = 100 | date = February 2011 | pmid = 21320343 | pmc = 3048527 | doi = 10.1186/1471-2458-11-100 }} 35. ^{{cite journal | vauthors = Ekstrand KR, Martignon S, Christiansen ME | title = Frequency and distribution patterns of sealants among 15-year-olds in Denmark in 2003 | journal = Community Dental Health | volume = 24 | issue = 1 | pages = 26–30 | date = March 2007 | pmid = 17405467 }} 36. ^{{cite journal | vauthors = Veiga NJ, Pereira CM, Ferreira PC, Correia IJ | title = Prevalence of dental caries and fissure sealants in a Portuguese sample of adolescents | journal = PLOS One | volume = 10 | issue = 3 | pages = e0121299 | date = 2015-03-24 | pmid = 25803849 | pmc = 4372347 | doi = 10.1371/journal.pone.0121299 }} 37. ^1 {{Cite journal|date=2008-10-01|title=Dental healthcare reforms in Germany and Japan: A comparison of statutory health insurance policy|url=https://www.sciencedirect.com/science/article/pii/S1882761608000525|journal=Japanese Dental Science Review|language=en|volume=44|issue=2|pages=109–117|doi=10.1016/j.jdsr.2008.06.004|issn=1882-7616|last1=Nomura|first1=Mayumi}} 38. ^{{Cite web|url=http://www.emro.who.int/emhj-volume-18-2012/issue-12/05.html|title=WHO EMRO {{!}} Prevalence and socioeconomic determinants of dental sealant use among schoolchildren in Saudi Arabia {{!}} Volume 18, issue 12 {{!}} EMHJ volume 18, 2012|website=www.emro.who.int|access-date=2019-01-03}} References{{reflist|30em}} 1 : Dentistry procedures |
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