Zahed Mohammadi - Iranian Center for Endodontic Research, Research Institute of Dental Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Islamic Republic of Iran; Iranian National Elite Foundation, Tehran, Islamic Republic of Iran.
Luciano Giardino - Private Practice, Crotone, Italy
Flavio Palazzi - Department of Odontostomatological and Maxillofacial Sciences, Federico II University of Naples, Naples, Italy
Raffaele Paragliola - Department of Endodontics and Restorative Dentistry, University of Siena, Siena, Italy

Aim: Most endodontic sealers show antimicrobial activity before setting, but most of them also lose this ability after setting. Addition of an antibiotic may affect the properties of sealers such as sealing ability, setting time, and so on. The aim of this study was to assess whether the addition of antibiotics (amoxicillin, doxycycline, and clindamycin) improves the sealing ability of AH 26 sealer. Materials and Methods: Seventy extracted human mandibular premolars were used. After cleaning and shaping the canals, the teeth were divided into six groups: group 1: gutta-percha and AH 26 sealer, group 2: gutta-percha and AH 26 sealer+doxycycline, group 3: gutta-percha and AH 26 sealer+amoxicillin, group 4: gutta-percha and AH 26 sealer+clindamycin, group 5: gutta-percha without sealer (positive control), and group 6: gutta-percha and AH 26 sealer (the root surfacewere covered with nail varnish) (negative control). A microbial leakage model was used to assess the sealing ability. Results: Group 2 had the greatest resistance against bacterial leakage. Furthermore, combining AH 26 sealer with amoxicillin and clindamycin increased mean leakage time compared to AH 26 sealer solely. However, the differences between groups 1 and 3 as well as between groups 1 and 4 were not statistically significant. Conclusion: Incorporating antibiotics especially doxycycline into AH 26 sealer increases its resistance against bacterial leakage.      

AH26 sealer, Antibiotics, Bacterial Leakage, Enterococcus faecalis