This is one of the most common questions patients ask during their filling appointments! We call this device a curing light. 

Many dentists today use LED curing lights in their restorative work. To explain what it does, let us first review what fillings are. When you have a cavity, decayed tooth structure is removed, and restorative material is placed in the cavity to build the tooth back up. 

Tooth-coloured composites fillings are common today because they are very esthetic. Composite materials are malleable when first placed in the cavity, allowing the dentist to adapt it to fit your tooth. Once the material is in place, shining a blue light on it starts a reaction that hardens the composite filling.