During a root canal therapy the microbiota is the major concern. Bacteria present in dentinal tubules, apical foramens and apical delta is related to failure of this procedure. Some studies reveal that during endodontic treatment in one session bacteria still remain in dental structures. The aim of the present study was to evaluate the endodontic treatment in one or two sessions, using calcium hydroxide plus camphorated paramonochlorophenol (CMCP) with temporary endodontic medicaments. Four dogs were used, and two animals were submitted the treatment in one session only and the others in two sessions. Premolar teeth were used in this study: second and third upper premolar teeth and second, third and fourth lower premolar teeth were divided into two groups. Opening of the pulp chamber was performed with burns, and the pulp was exposed for 60 days. After this period the group treated in only session was obtured with gutta-percha and zinc oxide and eugenol, and the group treated in two sessions received the CMCP that remained in the canal per 30 days and was afterwards obtured with the material of the other group. Clinical and radiographical control was performed twice a week, and after 60 days a small block containing the teeth, surrounding periapical tissues and the periodontium was removed for histological and microbiological study. Histological analysis revealed intense inflammatory response in both groups. Microbiological analysis showed a more severe microbial reduction in the group treated in one session. However, bacteria were still observed in the two groups, indicating that none of the treatments presented total efficiency.
Apical delta; endodontics; gutta-percha; calcium hydroxide; dog; camphorate paramonochlorophenol