Endodontic Management of Extra Oral Sinus in Mandibular Canine with CBCT and 6 Month Follow - Up

A sinus tract of endodontic origin is caused by pulp necrosis secondary to caries or trauma followed by invasion of microorganisms causing periapical inflammation of the affected tooth. The suppuration from the periapical inflammatory process then follows the path of least resistance creating trajectories which spread through the bone marrow, periosteum, loose connective tissue among the fascial planes, and finally drain onto the epithelial tissue through either a mucosal or, occasionally, a cutaneous sinus tract 1, 2. The sinus tract of odontogenic origin is often misdiagnosed by physicians as that of dermatologic origin. The most common cause of a cutaneous sinus tract is a chronic periradicular abscess. These abscesses arise from bacterial invasion, chemical irritation or trauma. The most common initiating factor of the periradicular abscess is carious exposure and subsequent bacterial invasion of the tooth pulp3. This process of destruction begins within a necrotic pulp and eventually spreads in the surrounding periosteum. The first change seen clinically is apical periodontitis. In later stages, the inflammation spreads apically leading to bone destruction and subperiosteal abscess formation. The periosteum is pierced, and depending on factors such as gravity, virulence of microorganisms or most importantly, anatomical arrangement of adjacent muscles and fasciae, either a cutaneous sinus or an intraoral sinus will form 4.