If the small cavity is not repaired and filled in time, it is easy to expand gradually. And if the cavity on the caries is not repaired for a long time, it will easily lead to the accumulation of food residue after daily meal and mix with the bacteria and other microorganisms around the caries, which will lead to the following bad consequences: 1, bad breath: the food residue will accumulate in the cavity of the caries and produce unpleasant smell after mixing with the bacteria, which will cause the situation of orogenic bad breath. When the patient talks with others, it is easy to leave a bad impression to the other party, and will also lead to inferiority complex; 2.Inflammation: the cavity of dental caries will be enlarged continuously, which will lead to the decay and deterioration of the affected tooth tissue gradually. When the cavity further deepens, it will even affect the dental pulp and lead to inflammation, such as common pulpitis, periapical inflammation, etc. At this time, the patient will mostly have spontaneous toothache, and if the inflammation keeps spreading, it will also affect the periodontium, leading to the expanding pain range. If the cavity gradually expands to the whole tooth, it will seriously affect the patient’s chewing function, and eventually need to be extracted; 3, jaw bone pulpitis: if periapical periodontitis is still not treated in time, apical fistula or jaw bone pulpitis may appear, causing infection in the surrounding space, and serious cases may lead to bacteraemia, sepsis or systemic multi-organ infection. Therefore, it is suggested that patients who find tooth decay and already have cavities should actively carry out treatment and repair at early stage to avoid further deterioration of the situation, which will affect the aesthetics and also reduce the quality of life.