Tooth decay (clinically known as dental caries) in a 5 year old child must be treated with filling and restoration to avoid symptoms such as tooth pain or swollen gums. Dental caries in 5 year olds is mainly caused by poor oral hygiene, resulting in the proliferation of bacteria in the mouth to produce acid, which in turn corrode the teeth and make them appear caries symptoms. Dental caries can cause pain from hot and cold stimulation of the teeth or biting pain, in addition, dental caries can lead to food blockage and the symptoms of swollen and painful gums. Therefore, it is recommended that a 5-year-old child with dental caries should seek timely caries filling treatment (i.e., dental filling); the use of dental filling materials (e.g., resin materials), preformed crowns to repair the decayed portion of the caries, so as to effectively prevent caries-induced pain or periodontal swelling and pain, and other symptoms.