Repeated facial swelling caused by pericoronitis in a patient with megacystis microcolon intestinal hypoperistalsis syndrome: a case report

Background: Facial swelling due to pericoronitis associated with tooth eruption commonly involves the wisdom teeth, but can rarely involve deciduous teeth or permanent premolars. We report a very rare case of repeated facial swelling caused by pericoronitis associated with the eruption of deciduous molars and a premolar. Case: The patient was a 13-year 7-month-old Japanese girl with megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS), gingival fibromatosis and numerous impacted teeth. She visited our clinic for investigation and treatment of left facial swelling. Extraoral examination revealed swelling of the left mandibular angle accompanied by a feeling of heat, and two submandibular lymph node masses were palpable. Intraoral examinations revealed that the lower left deciduous molars had started erupting and the gingiva on the buccal side of the deciduous molars was red and swollen, while gingiva still covered the first premolar. We diagnosed facial swelling due to pericoronitis of the lower left deciduous molars and first premolar. We disinfected the periodontal pockets, then injected antibacterial ointment into them. Systemic antibiotic was also administered and facial swelling disappeared. However, the patient stopped taking the antibiotic and swelling of the left face recurred. We therefore resected the gingiva covering the deciduous molars and first premolar to expose the crowns after the inflammatory response subsided. No further swelling has occurred since the tooth crowns were exposed. Conclusions: Gingival excision exposing tooth crowns after the inflammatory response subsides appears effective for improving facial swelling associated with tooth eruption in patients with MMIHS, by removing the bacterial flora causing inflammation.