Longitudinal tooth fractures: findings that contribute to complex endodontic diagnoses

The purpose of this review is to describe and discuss the diagnostic and treatment challenges related to tooth fractures primarily in the vertical plane, that is, the long axis of the crown and/or root. This includes when and how to identify and determine the extent of the fracture, when a coronal restoration should be placed, when root canal treatment is needed, and when a tooth or root should be extracted based on the location and extent of the fracture. The term ‘longitudinal fractures’ is used because they usually represent vertical extensions of fractures over distance and time. These fractures often present problems with diagnosis and treatment, but should be considered as findings only. They are not to be considered as pulpal or periapical diagnoses, but as pathways for bacteria that may induce pulpal and/or periapical inflammation or disease. Longitudinal fractures are divided into five definitive classifications, generally from least to most severe: (1) craze lines; (2) fractured cusp; (3) cracked tooth; (4) split tooth; and (5) vertical root fracture. These differ but have frequently been confused or combined in clinical articles, creating misunderstanding and resulting in incorrect diagnosis and inappropriate treatment. These classifications have been devised to provide global definitions that researchers and clinicians can use to eliminate this confusion. This review is subdivided into these five classifications as to incidence, pathogenesis, clinical features, etiologies, diagnosis, treatment, prognosis, and prevention.