Methods for sealing the carious lesion Fissure sealing over non-cavitated carious lesion What it is and when to use it Sealant materials can control non-cavitated lesions on occlusal surfaces where there is no significant breach in the surface integrity of the tooth, even if the lesion can be seen clinically (through shadowing), or radiographically, to extend into dentine.55,56,57,58,59,60 These are also known as micro-invasive treatments. How it works and clinical effectiveness As well as being highly effective for prevention of dental caries,30 placing a well-sealed fissure sealant over a carious lesion will arrest it and stop it from progressing.57,58,59,60 While shallow or moderately deep lesions are likely to be successfully managed, there is not enough evidence to make recommendations for deeper lesions for long-term management. Although they may provide a good seal, they will not add much to the strength of the tooth. Their application is limited to teeth where there is less weakening of the tooth structure (that is, less extensive lesions) and the tooth structure can support them. In cases where the lesion is extensive, the sealant may not be able to withstand breakdown of the lesion surface if the forces are high. Although they have a lower retention rate than resin sealants, the therapeutic effect of GIC on the tooth seems to balance the bulk material loss. There is good evidence to support a high caries-preventive effect from high-viscosity glass-ionomer sealants.30 However, there is little directly comparable evidence, as yet, on their relative performances sealing dentinal carious lesions. Non-AGP use Resin fissure sealant application involves use of the air-water syringe, creating an aerosol. Clinicians could consider using GIC or HVGIC ART sealants instead, as these do not require rinsing or desiccation for placement, to prevent further progression of lesions. More long-term treatment may be required later, but there may be sufficient success from the sealant to allow it to be managed by re-sealing rather than replacing with a restoration. Resin infiltration What it is and when to use it Resin infiltration (RI) is a technique that arrests non-cavitated carious lesions.61,62 It can treat non-cavitated lesions on smooth and approximal surfaces in both dentitions effectively. Lesions have to be limited to enamel and the outer third of dentine.61,62,63,64,65 It can also camouflage the whitish appearance of hypomineralised enamel on smooth surfaces.62,64 Similar to sealants, this is also known as a micro-invasive treatment. How it works and clinical effectiveness A very low-viscosity resin infiltrate is introduced into the micro-porosities of carious lesions to fill them through capillary action and arrest their progress.65 Systematic reviews show RI to be an effective micro-invasive treatment at timespans up to 36 months.61,65 Low AGP use The diffusion of the RI results from surface and sub-surface dehydration conditions created by hydrochloric acid followed by ethanol. The air-water syringe has to be used to rinse and dry which may produce aerosols. Rubber dam, sealing material and high-volume evacuators should be used.5,66 Hall Technique What it is and when to use it The HT is a method for treating asymptomatic carious primary molar teeth where the lesion has extended into dentine (cavitated or non-cavitated). The correct size of preformed metal crown is chosen and then pushed over the tooth to seal the carious lesion.67 The HT has been used in some secondary care settings for temporary management of partially erupted permanent molars affected by molar incisor hypomineralisation. However, there are currently no clinical trials to support this use. If practitioners are considering using the HT as a temporary non-AGP measure for permanent molar teeth, there are a few points, besides the lack of supporting evidence, that they should consider. Firstly, the crowns should only be placed on teeth that are not yet in occlusion. Secondly, the HT in this cas , unlike primary teeth HT use, provides only a temporary solution until more definitive restorative treatment and this will necessitate an AGP to remove the crown. Finally, permanent tooth preformed crowns are less easy to fit than those for primary teeth and almost always need to be trimmed with scissors, crimped and polished. How it works and clinical effectiveness It provides full coronal coverage and the risk of future carious lesion development on another surface of the tooth is avoided.67 The HT is technically simple to carry out and is well accepted by children, their parents and dentists.68,69 It has a strong evidence base showing high long-term success rates in randomised control trials (>90%) compared to conventional restorations (50-80%) and comparable to conventional crowns.68,69,70 The high rate of success, its durability and cost-effectiveness have meant use of the HT has increased, with a recent survey including 709 paediatric dentists from six continents showed that 92% had heard about it and 51% were using it.71 Non-AGP use The HT is AGP-free as there is no removal of carious tissue and no tooth preparation. No local anaesthesia is required. The luting cement is GIC. As with all clinical procedures, careful case selection with accurate lesion and pulp status diagnoses (clinically and radiographically) are essential for success. Parents have to be happy with the appearance before placement, although children generally like the crown's appearance.