Calcipex II, calcium hydroxide paste, is used widely as intracanal dressing material during root canal treatment. When extrusion of calcium hydroxide through root canal occurred, various tissue reactions have been reported. Herein, we report a case of chronic maxillary sinusitis induced by extrusion of Calcipex II. A 20-year-old male was referred our institution during #26 root canal treatment. Radiographically, it was presented radiopaque round mass with sinus mucosal thickening. The mass was excised and analyzed histologically. Histology revealed Calcipex II granules engulfed by macrophages and chronic maxillary sinusitis around Calcipex II granules.

Ⅰ. INTRODUCTION
 Ⅱ. CASE REPORT
 Ⅲ. DISCUSSION
 Ⅳ. REFERENCE

• 이윤창(원광대학교 치과대학 대전치과병원 구강악안면외과) | Yoon-Chang Lee
• 유동뢰(원광대학교 치과대학 대전치과병원 구강악안면외과) | Dong-Lei Ryui
• 이준(원광대학교 치과대학 대전치과병원 구강악안면외과, 원광골재생연구소) | Jun Lee
• 윤정훈(구강병리과, 원광골재생연구소) | Jung-Hoon Yoon Corresponding Author