Endodontic Diagnosis and Nonsurgical Management of a Maxillary Second Molar With Parastyle: Report of a Case With a 24-Month Follow-Up.

Parastyle is a rare dental morphological trait characterised by an accessory cusp or tubercle, often found unilaterally on the buccal surface of the mesiobuccal cusp, mainly in the second and third maxillary molars. Its size may range from a small enamel pit to an independent, well-developed cusp. When clinically present, parastyle may cause complications such as dental caries and sensitivity, localised periodontal disease and occlusal interference. This uncommon anatomical feature may further predispose to diagnostic and treatment challenges when pulp and periapical disease are established. In this case report, a rare second maxillary molar with a parastyle was diagnosed with pulp necrosis and apical periodontitis. Cone-beam computed tomography was pivotal in addressing the anatomical complexity of the internal root and root canal morphology, particularly regarding the pulp space and the location of the root canal orifices beneath the parastyle. With regard to the efficiency of endodontic management, emphasis was placed on the diagnostic and anatomical challenges posed by such unusual and complex features, as well as on the need for an advanced disinfection regimen. This was addressed with magnification, modern endodontic instrumentation, irrigation and activation techniques, the use of interappointment dressing and root filling with gutta-percha and a calcium silicate sealer. After 24 months, radiographic follow-up confirmed a reduction in the size of the periapical lesion, and the tooth was asymptomatic and functional.