The plaque inhibitor chlorhexidine digluconate was used for intra- and transcanal irrigation in the endodontic treatment triad for periapical lesions (circumscribed, diffuse, fistulating, cystic, suspected cystic lesions). 50 patients were followed up by clinical and standardized radiologic studies. In another 18 patients microbiologic criteria were also used. 16 root canals showed pretreatment infection with mixed aerobic and anaerobic organisms. Mechanical preparation of the root canals with or without extension of the foramen and triple irrigation with 0.5% chlorhexidine digluconate produced clinical relief of symptoms (49 pts.), sterility (14 of 18 pts.) and reduction of the size of periapical lesions (12 pts.). At a mean follow-up of 24 months 30 patients have so far shown complete restitution of periapical bone.
