cause tooth decay and fluoride helps strengthen the tooth. sdf is applied directly to the area of decay without first having to drill the tooth. sdf is an inexpensive option that is simple to apply; however, although it stops the decay from progressing, it does not fill the cavity, and the tooth may still need to be restored with a filling or crown. after treatment with sdf, arrested decay will become black, but a dental provider can cover the treated area with a white filling material if needed. this may be less of a problem in baby teeth, which will be lost as the child ages, than for permanent teeth. even so, because applying sdf is quick, it may be especially helpful for young children and other patients who have trouble sitting still during dental treatments, avoiding the need for sedation or general anesthesia. however, the use of sdf remains controversial and more good quality research is needed to be conclusive on its effectiveness, its need and its adverse effects on early caries and children's health especially for those in developed countries. this is particularly important in light of the fda warnings about using general anesthetics and sedation in young children. the american dental association recognizes sdf as an effective approach to conservatively manage dental decay. depending on the level of cavitation of the teeth, different types of restorations may be employed. stainless steel (preformed) crowns are pre-fabricated crown forms which can be adapted to individual primary molars and cemented in place to provide a definitive restoration or can be fitted using the hall technique. they have been indicated for the restoration of primary and permanent teeth with caries where a normal filling may not last. another approach of treating dental caries in young children is atraumatic restorative treatment (art). the art is a procedure based on removing carious tooth tissues using hand instruments alone and restoring the cavity with an adhesive restorative material. this is useful to prevent trauma and requires less chair time for the young patients. this is used in cases where the teeth are being maintained in the mouth to maintain space for the future teeth to come through. low quality evidence indicates that art may have a higher risk of filling failure when compared to usual care. despite the potential for filling failure, art is still recommended for children when access to electricity, drills, dentists, or other dental resources are limited.