ABSTRACT
The failures in endodontic treatments are often related to anatomical variations. Some anatomical changes in anterior teeth occur in patients with cleft lip and palate. This paper aims to report the endodontic retreatment of a maxillary central incisor with two roots and two canals on a patient who presents cleft lip and palate. A male patient, 11-year-old, reported pain when chewing related to the left maxillary central incisor tooth (tooth 21) which featured a sinus tract after primary endodontic treatment. In periapical radiograph, it was observed an alteration on the anatomy of the root on the tooth 21, which featured a radiolucent area on the dental apex and had been properly endodontically treated. In cone-beam computed tomography (CBCT) images the presence of an accessory root in the palatal region was observed, that had not been prepared, or filled. Thus, the non-treated accessory canal was instrumented with the crown-down technique and filled with gutta-percha and endodontic sealer. After 1 year of follow-up, the patient presented the tooth with a normal masticatory function and no painful symptoms. Therefore, it can be concluded that the additional root canals may be present and the CBCT is an important tool to evaluate the internal root morphology. In cleft lip and palate patients, the root canals morphology should be carefully analyzed due to high prevalence of dental anomalies which may influence the success in endodontic treatment.
ABSTRACT
INTRODUCTION: The aim of the present ex vivo research was to compare the remaining filling material and the volumes of dentine removed after retreatment of curved canals with two rotary systems naming ProTaper Universal Retreatment and Mani NRT-GPR using micro-computed tomography (micro-CT). METHODS AND MATERIAL: Forty mandibular molars containing two completely separated canals, with curvature angle of 25-35° and a curvature radius <10 mm were prepared to the Mtwo instrument 35/0.04 and filled with warm gutta-percha and AH-Plus sealer. The teeth were randomly divided into 2 groups (n=20), according to the retreatment system evaluated: ProTaper Universal Retreatment (PR group) or Mani NRT-GPR (MR group). Retreatment was considered complete when the working length was reached and when smooth dentinal walls were observed, with no evidence of filling material adhered to instruments or in the irrigating solution. Preoperative and postoperative micro-CT images were obtained with an isotropic voxel size of 11.88 µm to observe the volume of residual filling material in the canals and dentine removed after retreatment. Statistical analysis was performed by Student's t-test (P<0.05). RESULTS: The mean percentage of remaining filling material was 12.96% for PR group and 24.26% for MR group (P=0.0056). The percentage of dentin removal was greater in the PR group (5.02%) than MR group (1.36%) (P=0.0028). Both systems failed to completely remove the filling material from the canals. CONCLUSION: ProTaper Universal Retreatment system was more effective than Mani NRT-GPR system regarding removal of root filling material and also removed significantly more dentine after retreatment of curved mesial root canals of mandibular molars.
