Systemic complications due to endodontic manipulations

The trigeminocardiac reflex (TCR) is a well-recognized phenomenon that consists of bradycardia, arterial hypotension, apnea, and gastric hypermotility. It occurs particularly during ocular surgery and during other manipulations in and around the orbit. The parasympathetic supply to the face is carried in the trigeminal nerve. Alternative afferent pathways must exist via the maxillary and/or mandibular divisions, in addition to the commonly reported pathway via the ophthalmic division of the trigeminal nerve in the classic oculocardiac reflex. The efferent arc involves the vagus, regardless of which branch of the trigeminal nerve transmits the afferent impulses. Central stimulation of the trigeminal nerve can also cause these reflex bradycardic responses. Most cases reported have followed neurosurgery (4–6), but some have followed oral or perioral procedures (7). None has been reported following endodontic manipulation. In different experimental studies, authors have analyzed the autonomic responses elicited by the electrical, mechanical, or chemical stimulation of the trigeminal nerve system. The TCR has been reported in three healthy young adults undergoing operations that did not include any manipulation of orbital structures (8). After the patients had been anesthetized and were hemodynamically stable, profound bradycardia or ventricular asystole occurred suddenly in response to manipulations of the bony structures of the maxilla or mandible, or dissection of, or traction on, the attached soft tissue structures. The authors suggested therefore that all patients undergoing maxillofacial procedures should be monitored carefully for reflex bradycardia and ventricular asystole (8). Catecholamines, including dopamine, epinephrine, and norepinephrine, are present in the dental pulp in higher levels during inflammation than in uninflamed pulp tissue (9) and it is conceivable, therefore, that catecholamine release during endodontic manipulation could also trigger dysrrhythmias.