No pain during the day and toothache at night may be caused by pulpitis, body position or psychological factors. 1. Pulpitis: pulpitis is characterized by increased pain at night compared to the daytime, the pulp parasympathetic nerve activity is more active at night, so the daytime pain at night toothache. 2. Positional reasons: acute pulpitis caused by pain is long-term, but the patient generally maintains a standing or sitting position during the day, sleeping at night is lying down, and the inflammatory fluid and periodontal pockets in the liquid will be with the different position of the flow and accumulation, which leads to increased pressure, pain aggravation, the emergence of daytime pain at night toothache symptoms. 3. Psychological factors: the pain caused by pulpitis persists, the patient’s attention will be attracted to other things during the day, the night time, the spirit will be more focused, so it will be daytime pain at night toothache. Daytime no pain at night toothache, need to go to the dentist in a timely manner, clear cause with the doctor after the correct treatment, usually pay attention to oral hygiene, avoid eating too sweet food.