One of the most conservative ways to retain tooth structure, preserve pulpal health, and avoid invasive treatment is to simply completely seal established carious lesions. A tight seal to isolate the biofilm and arrest the lesion can be successfully achieved using a sealant material such as resin or glass-ionomer for non-cavitated lesions, a restorative material for cavitated lesions, or, for primary teeth, preformed stainless-steel crowns. This chapter focuses on sealants and restorative materials. Sealant materials are a viable treatment option for controlling non-cavitated lesions in occlusal and proximal surfaces where there is no significant breach in the surface integrity of the tooth, even if the lesion extends into dentine. Resin infiltration can also be used to manage proximal non-cavitated lesions. Even when the exact depth of lesion that can be sealed has not been established, evidence supports sealing shallow and moderate deep lesions into dentine. For cavitated lesions, sealing lesions without carious tissue removal might be an option when removal of tooth tissue is not required to provide a hard periphery around the lesion/cavity margin (to enhance bonding or to increase cavity depth for enough restorative material to be placed to last). There is little evidence for placing a restorative material over cavitated carious lesions without tissue removal or preparation. However, where there is a significant breach in the surface integrity of the tooth but there is still enough sound tooth tissue to provide bonding for an adhesive restoration, sealing in carious tissue might still be an option.