In cases where the body tolerates the extraction procedure, the removal of the second premolar may result in a corresponding reduction in chewing function. In normal people, the premolar and molar teeth serve the function of grinding and chewing food, and when the second premolar is removed, it will somewhat reduce the efficiency of mastication and affect the integrity of the jaw curve at the same time. However, if for patients with malocclusion, the impact of removing the second premolar is greater than the disadvantages, orthodontics for crowded teeth in order to align the teeth, often need to remove the premolar, which is conducive to the alignment of the teeth to prevent malocclusion caused by dental caries. After the second premolar extraction, there are advantages and disadvantages for different oral conditions, specifically need to go to the hospital to judge according to their own oral conditions.