The microscopic diagnosis and treatment of a mandibular second premolar with four canals.

AIM: The purpose of this article is to report the case of a mandibular second premolar with four distinct canals.
SUMMARY: It is generally recognized that incomplete instrumentation and cleaning of root canals will lead to failure in root-treated teeth. Before root canal treatment is performed, the clinician should be aware of the configuration of the pulp space of the tooth that is to be treated. Frequently, root canals are left untreated because the clinician fails to identify their presence, particularly in teeth that have anatomical variations or additional root canals. Traditionally, additional canals have been detected by clinical examination of the floor of the pulp chamber, and sometimes found radiographically. More recently microscopic examination of the pulp chamber using endodontic microscopy has assisted the identification of extra canals. A case report is presented that deals with the successful treatment of a mandibular second premolar with four canals. KEY LEARNING POINTS: Even in teeth with a low frequency of abnormal root canal anatomy, the possibility of additional root canals has to be considered in the clinical and radiographic examination of the patient. The ability to recognize and locate unsuspected canals is enhanced by microscopic investigation of the pulp chamber.