If secondary caries occurs after filling, it is possible to remove the original filling and refill it. Because secondary caries is a relatively common phenomenon, mainly occurs in the patient’s own oral hygiene condition maintenance is unfavorable, especially for the patient’s own dental quality is relatively bad, easy to occur caries, in the filling should be extra attention and prevention. As long as secondary caries has not injured the dental nerve, it is possible to remove the original filling and refill it, but when filling, attention should be paid to protecting the dental nerve, avoiding injury to the dental nerve or bacterial invasion of the dental nerve, and it can be taken to protect the pulp, such as calcium hydroxide cushion, or the top of a layer of 3M glass ions for the protection of the pulp, to prevent the further destruction of secondary caries, and at the same time, when filling, it is necessary to avoid micro-osmosis, to prevent the further destruction of secondary caries. At the same time, when filling, to avoid microleakage, the main can use rubber barrier for moisture barrier.