Maxillofacial Injuries and Diseases That Cause an Open Mouth in Cats

Abstract

Oral and maxillofacial disorders in the cat can present as an inability to close the mouth and reaching an accurate diagnosis can be challenging if all of the differentials are not systematically considered. This review focuses on the six conditions that commonly result in a cat being unable to close the mouth. Differential diagnoses include: luxation of the temporomandibular joint, fracture of the temporomandibular joint, caudal mandibular fracture, impingement of the coronoid process of the mandible on the zygomatic arch, mechanical obstruction, and neuropathy. Maxillofacial anatomy, including the temporomandibular joint, muscles of mastication and their innervation will be reviewed. This paper primarily focuses on review of the relevant literature describing each disorder and the diagnostic procedures and treatment options that should be considered when evaluating a cat that is unable to close its mouth. Emphasis is placed on the importance of a complete intraoral examination and evaluation of occlusion to allow the clinician to identify the cause for this clinical sign in cats since periodontal disease causing tooth-to-tooth contact is a common and often unrecognized cause for open mouth in cats.