[Analysis of difficulties in diagnosis and treatment of cracked tooth and research progress].

The occurrence of cracked tooth is closely related to the abnormal occlusal force. The cracks existing on hard tissue of tooth cannot be self-limiting. As long as the external force exists, the cracks would continue to expand, involving the pulp, periapical, and periodontal tissues, ultimately leading to splitting and tooth loss. Due to the lack of objective indicators to identify cracks, the clinical diagnosis is difficult; due to the uncontrollability of crack propagation and individual differences, the treatment prognosis is uncertain, thus, clinicians are usually confused in choosing the treatment approaches, making it difficult to diagnose and treat this disease. On the other hand, there are many terms in Chinese and English for cracked teeth, which are difficult to correspond with each other. Moreover, the research approaches and methodologies are limited, which slows down the progress of studies in pathogenesis and leads to few breakthroughs in the field of clinical research. By tracing the changes in the terminology of cracked teeth, sorting out the research progress in the literature, and analyzing the difficulties in clinical diagnosis and treatment, the paper proposes the principles and strategies for diagnosing and treating cracked teeth, to assist clinicians in figuring out the structures and clarifying the misunderstandings of this disease.