When tooth decay occurs in the baby teeth, it is necessary to take treatment measures as soon as possible. Some people think that milk teeth will fall off sooner or later and there is no need to treat decayed teeth, but this is totally wrong. Because when the decayed teeth are formed, it will obviously affect the chewing function and need to repair the decayed teeth. The shallow caries, medium caries and deep caries can be treated by filling and restoration of caries. If the caries develops further and reaches to pulpitis or periapical inflammation, root canal treatment is also needed for milk teeth. For the root canal treatment of milk teeth, absorbable root canal fillings such as calcium hydroxide are used. If chronic periapical inflammation is not treated early, it may lead to abnormal eruption and development of secondary teeth, and it is important to take early treatment measures for decayed milk teeth.