The best way to deal with adjacent surface caries is related to the depth of caries, shallow caries can generally be observed or local fluoride, medium and deep caries need to be removed from the jaw surface of the decayed material after resin filling. 1. Shallow caries: Shallow caries on the neighboring surface will be self-conscious about the roughness of the side wall of the tooth when using dental floss, and there is generally no self-conscious symptom, and the X-ray shows that there is a shadow on the neighboring surface that does not reach the dentin. Due to the shallow caries, and in the neighboring position, generally temporary observation or the use of remineralization solution or fluoride local coating to slow down the progress of caries. 2. Medium and deep caries: For caries that reaches the dentin, there is often sensitivity to hot and cold stimuli, and the probe can be hooked for inspection. The best treatment is to grind from the maxillofacial surface to the adjacent surface using specialized instruments, remove the decayed tooth tissue on the adjacent surface, and then use resin to fill the cavity. If it leads to pulpitis, root canal treatment is needed first. If decay occurs inside, it needs to be examined and treated in a timely manner to avoid deepening the decay.