Introduction: A torn labial frenum is widely regarded as pathognomonic of abuse.
Methods: We systematically reviewed the evidence for this, and to define other intra-oral injuries found in physical abuse. Nine studies documented abusive torn labial frena in 27 children and 24 [corrected] were fatally abused: 22 were less than 5 years old. Only a direct blow to the face was substantiated as a mechanism of injury.
Results: Two studies noted accidentally torn labial frena, both from intubation. Abusive intra-oral injuries were widely distributed to the lips, gums, tongue and palate and included fractures, intrusion and extraction of the dentition, bites and contusions.
Conclusions: Current literature does not support the diagnosis of abuse based on a torn labial frenum in isolation. The intra-oral hard and soft tissue should be examined in all suspected abuse cases, and a dental opinion sought where abnormalities are found.