The causes of acute pulpitis mainly include the following: 1, it may be due to deeper caries, which leads to infection into the pulp cavity, resulting in acute pulpitis; 2, biting hard objects make teeth produce hidden cracks, bacteria will also enter the gap and enter into the pulp, leading to acute pulpitis; 3, incorrect brushing methods, horizontal brushing, pull-saw brushing leads to wedge-shaped defects, which also leads to acute pulpitis; 4, periodontitis is deeper, more destruction, more bone resorption, leading to pulpitis; 5, deeper wear also leads to pulpitis.