Effectiveness of application of microscope to treatment-resistant apical periodontitis

Objective: The purpose of this study was to evaluate the effectiveness of microscope to the treatment and the diagnosis of treatment-resistant apical periodontitis.

Methods: Of the 125 apical periodontitis teeth, twelve teeth were diagnosed as treatment-resistant apical periodontitis and were treated at the Department of General Dentistry and Clinical Education, Tsurumi University School of Dental Medicine Hospital. Based upon the microscopic observation, these 12 teeth were classified into the following 4 classes. Class1: Root canal wall: single case with suspected cracks and perforations (n=1) Class 2: Arising from periapical tissue: cases of exudates at the apex or granulation from apical foramen (n=6). Class3: complex cases involving both Class1 and 2(n= 4). Class 4: the others (n=1).

Results: Eight teeth (Class 1 n=1, Class 2 n=4, Class 3 n=2, Class 4 n=1) were successfully treated with conservative treatment that included filling crack or perforation area with adhesive resin and vaporization of granulation tissues around the apical foramen by laser irradiation. One tooth (Class 2) with muscle pain of masseter was also successfully treated with anti inflammatory agent following endodontic treatment. Three teeth were extracted with no sign of improvement (Class 2 n=1 Class3 n=2).

Conclusions: It was assumed that the treatment-resistant apical periodontitis originates from bacterial infection in the granulation tissues around the apical foramen. A high power laser irradiation to crack or perforation areas of root canal wall was effective, because the irradiated areas were vaporized and dried, thus enabling us to prepare the filling. Consequently, the application of microscope to treatment-resistant apical periodontitis was considerably effective for diagnosis and therapy.