Periapical and bitewing radiographs lack the sensitivity to reliably diagnose horizontal root fractures, and, therefore, asymptomatic teeth with root fractures may remain undetected for years. This article reports a case in which a patient presented with a mucogingival defect on tooth No. 24 with no apparent history of dental trauma. During a free gingival graft procedure, a horizontal root fracture was observed in the apical third of the aforementioned tooth. After the clinician communicated this finding to the patient, the patient recollected two instances of trauma that had occurred to this area more than 30 years earlier. The presence of the horizontal root fracture did not affect the postoperative healing from the mucogingival procedure, and the tooth remained stable at the 1-year follow-up.