early carious lesions can be treated with dental sealants in order to prevent invasive dental restorations. dental sealants as treatment would be appropriate for occlusal caries which extend no more than a third of the way through dentine in the primary dentition and enamel lesions in the permanent dentition dental sealants can also be indicated for dental defects such as dens in dente, amelogenesis imperfecta and deep fissures on lateral incisors there are no specific contraindications to placing dental sealants. for resin fissure sealants to be successful excellent moisture control is needed during placement of the fissure sealant. in cases where moisture control cannot be achieved then glass ionomer fissure sealants should be placed until a time where moisture control is adequate enough to place resin fissure sealants. clinical procedure wikiversity has learning materials related to: placement of fissure sealants dental dam 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. generally, each quadrant is treated separately by using four-handed technique with an assistant and to follow the manufacturer's recommendations. 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. 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. 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. the etching gel may temporarily leave a sour taste in the mouth. pits and fissure sealants are used as effective controls in preventing caries. sealants create a barrier which removes the biofilm from the occlusal surface. there are 4 sealant materials that can be used for the purpose of sealing pits and fissures. the materials are: resin-based sealant often made up of bis-gma polymerised by light these sealants can be colourless, tinted or white glass-ionomer (gi) has fluoride releasing properties polyacid-modified resin sealants combination of resin based materials found in resin sealants and fluoride-releasing adhesive properties of gi resin-modified glass ionomer sealants longer working time that gi historically methods such as; zinc phosphate cement, mechanical fissure eradication, prophylactic odontotomy, or chemical treatment with silver nitrate, were used to seal pits and fissures. these techniques are no longer used in modern-day practice. placement techniques for sealants rely on the type of material being used. however a common factor for all is that moisture control must be achieved. the maintenance of moisture control increases the treatment time and could be counter productive. resin based sealants application technique ensure the tooth is free from any debris using a toothbrush or cotton wool roll. isolate the tooth from any moisture - this can be done using whatever the clinician finds appropriate; cotton wool rolls, dry guard, saliva ejector. using cotton wool rolls, dry guards or a salvia ejector will give optimum isolation of the site. 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 dry the tooth and etch the surface of the tooth that will be carrying the sealant - 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. etching time varies from 15 to 60 seconds, depending on the product. wash the etch with water and once again dry the tooth aiming to avoid any moisture contamination. a chalky appearance of 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. apply the resin to the surface ensuring sufficient material has been applied to cover all areas the sealant should now be light cured, this hardens the sealant check the integrity of the sealant with a probe. may need to check occlusion with articulating paper and reduce sealant height. if the sealant cannot be picked off, application is successful. these sealants should be checked at recall appointments and re-applied as required. gi sealant technique for partially erupted teeth which are difficult to isolate some will use gic (doesn't need etching) as an interim option. gic may have an advantage of fluoride release. ensure the tooth is free from any debris using a toothbrush or cotton wool roll. isolate the tooth from any moisture dry the tooth etch is not required for this technique have the gi sealant mixed gi can be applied into fissures in several ways: using an excavator or using a finger following the application of sealant in the clinicians chosen way, a small amount if petroleum jelly should be applied to the sealant. glass ionomer does not require light curing, however it will set faster with the usage of a curing light. ensure the sealant is not high in occlusion and removes any visible excess. these sealants should be checked at recall appointments and re-applied as required prevalence in the us, 42% of children aged 6–11 and 48% of adolescents aged 12–19 had fissure sealants on permanent teeth during 2011–2016. in greece, in a study from 2011, 8.3% of 12 year olds and only 8% of 15 year olds had at least one dental sealant on a molar tooth. when sealants were applied, dmfs scores were reduced by 11% in the 12 year olds and 24% in the 15 year olds. in other european countries, such as portugal, a study has shown that over half (58.8%) of adolescents had a fissure sealant applied on at least one tooth. in denmark, 66% of 15-year-old children had at least one sealed molar. in the uk in 2003, 13% of 8 year olds, 25% of 12 year olds and 30% of 15 year olds had at least one fissure sealant. in ireland, the rates were 47%, 70% and 69% comparatively. around 25% of japanese children have at least one sealed molar. a study surveying fissure sealants and dental caries in primary school girls in saudi arabia in 2017 found that only 1.3% of the children had at least 1 fissure sealant applied, but in another study, the overall figure was 9%. notes policy statement of the american dental association on bisphenol a (bpa): "ased on current evidence, the ada does not believe there is a basis for health concerns relative to bpa exposure from any dental material." policy statement of the australian dental association on bpa (2014) archived 23 may 2014 at the wayback machine 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." archived 2016-03-04 at the wayback machine canadian dental association page on frequently asked questions regarding bpa