Background: Systemic sclerosis (SSc), or scleroderma, is an uncommon disease that affects the collagen in multiple organ systems. It can lead to the mandibular resorption of different regions. Only 19 cases of complicated mandibular resorption, involving over three regions, have been described in the literature. Methods: A case of severe resorption with the posterior border of rami, involving both the processus condylaris and the inferior border of the mandibular body, is reported and discussed with a review of the literature. Results: We report a case of severe mandibular resorption in which the range of resorption reached the inferior wall of the mandibular canal and anesthesia of the lower lip occasionally occurs.