Pulpitis is a relatively common dental disease with pain as the main symptom, even severe and unbearable pain, which often makes patients restless and difficult to eat and drink. The common saying “toothache is not a disease, but a pain that really kills you” refers to this disease process. Pulpitis is mainly caused by the infection from the tooth body. Deep caries, cuneiform defects and other hard tissue diseases can cause pulpitis if they are not effectively controlled and treated in a timely manner, making it one of the most frequent and common diseases in the oral cavity. Disease Classification Acute pulpitis Acute pulpitis can develop from pulp filling or from an acute attack of chronic pulpitis. Depending on the course of inflammation, acute pulpitis can be divided into the pulp phase and the suppurative phase. 1. Acute pulpy pulpitis is often a continuation of the development of pulpal congestion. The extent of the lesion is limited to the crown pulp for localized pulpitis. When the lesion spreads to the root pulp, it is a total pulpitis. In the short pulp phase of pulpitis, the exuded leukocytes continue to necrotize and liquefy, forming an abscess, which is called acute suppurative pulpitis. Chronic pulpitis Chronic pulpitis (chronic pulpitis) is the most common type of pulpitis in clinical practice, with atypical clinical symptoms, and in some cases there may be no spontaneous pain. If the virulence of the bacteria invading the pulp is low and the body’s resistance is high, the inflammation of the pulp tissue is most often a chronic process. If the exudate of acute inflammation is drained, but the inflammation is not completely eliminated, it can also be transformed into chronic inflammation. Conversely, if the resistance of the body is reduced, or if the local drainage is poor, chronic pulpitis can be transformed into acute pulpitis, i.e., an acute attack of chronic pulpitis. 1, chronic closed pulpitis (chronic closed pulpitis) The pulp has not yet been exposed, but can be detected in deep cavities, crown fillings or other dental hard tissue disorders near the pulp, and there is no pulp hole visible to the naked eye after removing the decaying necrotic material. If the virulence of bacteria does not increase and no new infection invades from outside, the encapsulated lesion will not develop outward temporarily, so the chronic inflammation can be maintained for a long time. There is no obvious spontaneous pain or occasional dull pain clinically, but almost all patients have a long history of painful cold or hot irritation. 2, chronic ulcerative pulpitis (chronic ulcerative pulpitis) The pulp tissue is exposed and ulcers are formed on the surface. There is usually no obvious spontaneous pain, but severe pain occurs when food is embedded in the cavity of the affected tooth. Patients are afraid of pain and use the affected tooth for a long time, so that a lot of soft tartar and tartar accumulate. Patients often have a history of spontaneous pain, and another typical symptom is severe pain when the affected tooth is provoked by cold or hot stimulation. 3.chronic hyperplastic pulpitis occurs mostly in young people, where the pulp has been exposed and the hyperplastic reaction is caused by mild but persistent stimulation. There is a red “mushroom” shaped pulp polyp in the large and deep cavity of the affected tooth, which can fill the whole cavity and reach the occlusal surface, and it is painless to probe but bleeds easily. Generally there is no spontaneous pain, sometimes the affected tooth feels pain when eating or has bleeding phenomenon when eating, therefore, it dares not chew food with the affected side for a long time. Due to long-term disuse, tartar buildup is often seen on the affected tooth and its adjacent teeth. Causes The main cause of pulp inflammation is infection. Bacteria and their toxins from any cause invade the pulp cavity and cause inflammation of the pulp. The pulp tissue enters the pulp cavity in the center of the tooth through the apical foramen and is surrounded by hard dentin and enamel, which are normally protected from bacterial attack, but when the hard tissue of the tooth is damaged for various reasons, bacteria can invade and infect the pulp. When the caries damages the enamel, reaches the deep layer of dentin and even penetrates the dentin to reach the pulp cavity, the bacteria in the mouth will infect the pulp and cause the inflammation of the pulp. Other causes include dental defects caused by abnormal tooth development, and the pulp is exposed by fractured crowns caused by accidents, which also directly damage the pulp. In addition, in severe periodontal disease, the periodontal pocket reaches deep into the apical region and bacteria can also enter the pulp cavity through the apical foramen or some tiny branches of the root causing pulp inflammation. Pathogenesis The dental pulp undergoes different pathological changes depending on the pathogenic stimuli and the resistance of the body, which can manifest clinically as a series of different symptoms and signs. The initial pathological manifestation of pulp stimulation is vasodilation and blood filling. If the pathogenic stimulus is removed in time, this purely congested state can be relieved and the pulp returns to its original condition. After a longer duration of pulp congestion, the condition is transformed into acute pulp inflammation. If the virulence of the bacteria invading the pulp is low and the body’s resistance is high, the inflammation of the pulp tissue mostly manifests itself as a chronic process. If the exudate of acute inflammation is drained, but the inflammation is not completely eliminated, it can also be transformed into chronic inflammation. That is, chronic pulpitis, the most common type clinically, has atypical clinical symptoms, and in some cases there may be no spontaneous pain. Conversely, if the resistance of the organism is reduced, or if local drainage is poor, chronic pulpitis can be transformed into acute pulpitis, i.e., an acute attack of chronic pulpitis. Because the pulp tissue is in the four-walled hard and inelastic pulp cavity, its blood circulation can only pass through the tiny apical foramen, lack of lateral circulation, once the pulp becomes inflamed, the inflammatory exudate is not easily drained, and the pressure in the pulp cavity quickly increases, producing severe pain. The most common cause of pulpitis is caries, and the incidence of caries in China is high. Most patients can not consult the doctor in time until the complication of pulp inflammation and pain is unbearable, and they often need to receive root canal treatment. The process of root canal treatment is complicated and the cost is high, which causes a big economic pressure to individuals and society. Therefore, we should pay attention to oral health care, reduce the incidence of caries, regularly check and timely treat caries and other dental diseases to avoid further development causing pulp inflammation, which brings great pain and unnecessary economic burden.