Micro-CT Evaluation of Gutta-Percha Removal by Two Retreatment Systems

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). Material and Methods: 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.Keywords: Dental Instruments; Endodontics; Gutta-Percha; Endodontic Retreatment

Analysis of Demineralized Chemical Substances for Disinfecting Gutta-percha Cones

Introduction: The aim of the present research was to evaluate the effectiveness of 5% malic acid, 17% EDTA and 10% citric acid solutions used to disinfect gutta-percha cones contaminated by Enterococcus faecalis (ATCC 29212). Methods and Materials: Two hundred and ten previously sterilized gutta-percha cones were contaminated with E. faecalis at concentration of 1.5×108 CFU/mL. The cones were immersed in 5% malic acid, 17% EDTA, 10% citric acid, 1% NaOCl and 2.5% NaOCl for 1, 5 and 10 min. Then each cone was kept in Eppendorf tubes containing BHI sterile solution at 37°C for 48 h. The presence of turbidity in BHI solution was analyzed. The results were statistically analyzed by Kruskal-Wallis test and 5% Dunn comparisons. P-value was considered statistically significant when P<0.05. Results: Regardless of exposure time, 1% NaOCl and 2.5% NaOCl were the most effective agents for rapid disinfection of gutta-percha cones (P<0.001). All specimens immersed in experimental demineralized solutions presented bacterial growth (P>0.05). Conclusion: Demineralized solutions tested were not effective for elimination of Enterococcus faecalis on the surface of gutta-percha cones.Keywords: Chemical Substances; Disinfection; Gutta-Percha; Irrigating Solutio

Micro Push-out Bond Strength and Bioactivity Analysis of a Bioceramic Root Canal Sealer

Introduction: Bioactive endodontic sealers have been developed to improve the quality of root canal obturation. EndoSequence Bioceramic (BC) Sealer is amongst calcium silicate-based materials recently developed for permanent root canal filling. The objective of this study was to evaluate the bioactivity of BC Sealer and its micro push-out bond strength to dentin compared to AH-Plus (AH) sealer. Methods and Materials: To perform the micro push-out test, 24 root canals of mandibular premolars were instrumented and divided into two groups (n=12). Each root was cut into 4 slices and lumens of the canals were filled with the sealers and submitted to micro push-out test. Failure mode was assessed using scanning electron microscopy (SEM). Bioactivity of BC sealer was investigated with scanning electron microscopy/energy-dispersive X-ray (SEM/EDS) and X-ray diffraction (XRD). Bioactivity assessments were reported descriptively. Bond strength data were analyzed by parametric t-test (α=5%). Results: In micro push-out test AH had higher bond strength mean values (16.29 MPa) than BC sealer (9.48 MPa) (P<0.05). Both groups had low amount of adhesive failure. SEM showed the presence of a mineral precipitate after 30 days and EDS analysis showed that those precipitates have high proportion of Ca. XRD showed peaks of crystalline phases of calcium carbonate compatible with the bioactivity. Conclusion: BC sealer showed indications of bioactivity and lower bond strength to dentine compared to AH.Keywords: Bioactivity; Bioceramic; Dentine; Micro Push-Out Bond Strength; Root Canal Seale

Spontaneous Bisphosphonate-related Osteonecrosis Associated with a Tooth that Had a Necrotic Pulp: A Case Report

This study reports the endodontic treatment performed in a patient who presented with spontaneous bone exposure in the mandible while using intravenous bisphosphonate medication (ZometaÒ, Novartis Pharmaceuticals Co., Basel, Switzerland). A 63-year-old female patient was referred to a private dental clinic at Fortaleza, Brazil. The patient reported that one year before, she had undergone chemotherapy for the treatment of lung cancer and associated bone metastasis. Among the medications administered was the zolendronic acid, with dosage of 4 mg every 21 days. In the oral exam, the presence of extensive bone exposure was observed in the lingual region near tooth 37. The patient reported severe pain on palpation in the region; in the pulpal sensitivity test with cold stimulus, there was an absence of pain, characteristic of pulp necrosis. Radiographically, no periapical lesion was observed. Thus, endodontic treatment was performed, and instrumentation with Reciproc R25 files in the mesial root canals and R40 in the distal canal was done, alongside with abundant 2.5% sodium hypochlorite irrigation. Interappointment medication with calcium hydroxide was maintained for 15 days. In the second session, there was the spontaneous detachment of the exposed cortical bone fragment. The root canals were filled with gutta-percha and Endosequence BC Sealer cement. After two years, complete tissue repair was observed, and the patient presented with normal periapical tissues and the tooth in masticatory function.   It may be concluded that a possible relationship between pulp and periapical infections and osteonecrosis exists in patients who use bisphosphonates

Ocorrência de molares supranumerários em pacientes da clínica de radiologia da Universidade Federal do Ceará

Hyperdontia is a dental anomaly, very common and widely studied, caused by excessive teeth in the oral cavity. This disturb represents an abnormal formation of one or more teeth in both dental arch. The diagnosis is normally based on conventional radiography exams, mainly panoramic radiographies, and in some cases, a computed tomography. In the present study, 1.325 panoramic radiographies were evaluated, all from patients seen by the Radiology Clinic of Federal University of Ceará, residents in Fortaleza, over the period from October 2007 to December 2008. The aim was to evaluate the occurrence of supernumerary molars. Twenty five patients presented supernumerary molars, 13 men and 12 women. However, it was not observed differences statistically significant (p= 0,5264). The occurrence in the maxilla was more common compared to the mandible. A considerable occurrence of supernumerary molars in the examined population was reported, reinforcing the importance of a premature diagnosis in this dental anomaly, in order to perform the treatment if necessary.Os dentes supranumerários constituem uma das anomalias mais conhecidas e estudadas da dentição humana. Essa alteração, também conhecida como hiperdontia, representa a formação de um ou mais dentes em número maior que o normal, podendo ocorrer em ambos os arcos dentários. O diagnóstico normalmente é realizado a partir de exames radiográficos convencionais, principalmente com a radiografia panorâmica, e em alguns casos com o uso da tomografia computadorizada. No presente trabalho foram avaliadas 1.325 radiografias panorâmicas de pacientes atendidos no serviço de Radiologia do curso de Odontologia da Universidade Federal do Ceará, residentes em Fortaleza, no período de outubro de 2007 a dezembro de 2008, com o objetivo de avaliar a prevalência de molares supranumerários. Assim, foram encontrados 25 pacientes que apresentaram molares supranumerários, sendo 13 homens e 12 mulheres, entretanto não sendo observada diferença estatisticamente significante (p=0,5264). Houve uma ocorrência mais comum na maxila do que na mandíbula. Conclui-se que os molares supranumerários apresentaram uma considerável prevalência na população examinada, reforçando a importância do diagnóstico precoce de tal anomalia dentária, a fim de se realizar o tratamento, se necessário

La hiperdontia en región de molares Hyperdontia in molar region

La hiperdontia constituye una de las anomalías más estudiadas de la dentición humana. Esa alteración representa la aparición de uno o más dientes en cantidades mayores de lo normal, que puede ocurrir en la mandíbula o maxila y de manera unilateral o bilateral. La etiología de los dientes supernumerarios puede ser explicada principalmente por hiperactividad de la lámina dentaria en la fase inicial. Es importante la detección precoz de dientes supernumerarios porque se ha visto una serie de complicaciones como los diastemas, que pueden causar en la cavidad bucal: retardo de la erupción o dientes impactados, posicionamiento inadecuado de dientes permanentes, desajuste oclusal y el desarrollo de quistes y tumores odontógenos. Así el diagnóstico es normalmente realizado a partir de un examen radiográfico convencional, principalmente la radiografía panorámica. Este trabajo tuvo como objetivo relatar 4 casos clínicos de pacientes con presencia de molares supernumerarios, que fueron atendidos en el Servicio de Radiología de la Escuela de Odontología de la Universidad Federal de Ceará.Hyperdontia is one of the more studied anomalies of human dentition. This alteration represents the appearance of one or more teeth in a number greater of normal, occurring in mandible or in maxilla and could be unilateral or bilateral. The etiology of supernumerary teeth may be explained mainly due to the hyperactivity of dental plate in its initial phase; its early detection is important because of there have been a series of complications that may to cause diastemata, eruption retard or impacted teeth, inappropriate positioning of permanent teeth, occlusal misalignment and the development of odontogenic cysts or tumors. Thus, the diagnosis is normally made from a conventional radiographic examination, mainly the panoramic X-ray. The objective of present paper is the present four clinical cases of patients presenting with supernumerary molars, seen in the Radiology Service during the course of stomatology of the Federal University of Ceará

La hiperdontia en región de molares

La hiperdontia constituye una de las anomalías más estudiadas de la dentición humana. Esa alteración representa la aparición de uno o más dientes en cantidades mayores de lo normal, que puede ocurrir en la mandíbula o maxila y de manera unilateral o bilateral. La etiología de los dientes supernumerarios puede ser explicada principalmente por hiperactividad de la lámina dentaria en la fase inicial. Es importante la detección precoz de dientes supernumerarios porque se ha visto una serie de complicaciones como los diastemas, que pueden causar en la cavidad bucal: retardo de la erupción o dientes impactados, posicionamiento inadecuado de dientes permanentes, desajuste oclusal y el desarrollo de quistes y tumores odontógenos. Así el diagnóstico es normalmente realizado a partir de un examen radiográfico convencional, principalmente la radiografía panorámica. Este trabajo tuvo como objetivo relatar 4 casos clínicos de pacientes con presencia de molares supernumerarios, que fueron atendidos en el Servicio de Radiología de la Escuela de Odontología de la Universidad Federal de Ceará

Análise comparativa da infiltração apical entre diferentes materiais retro-obturadores

The aim of this study was to compare the apical sealing ability between the white MTA, gray MTA, Super EBA and Sealapex/Zinc Oxide association when used as root-end filling materials. Forty four maxillary central incisors extracted were distributed in four groups with 10 specimens each and two control groups with two specimens each. The teeth had their crowns sectioned and their canals instrumented by step-back technique to #60 file, using constant irrigation of 2.5% sodium hypochlorite. Roots were filled with guttapercha and EndoFill sealer by Tagger's hybrid technique. The apical 3 mm of each root was resected, and 3-mm deep root-end cavity preparations were made. The root-end cavities were filled with white MTA, gray MTA, Super EBA and Sealapex/ZO. The roots were immersed in Rhodamine B and kept in an oven for 72 hours at 37ºC. A longitudinal section was performed to verify using Image Tool the dye penetration. Statistical analysis showed that the group sealed with Super EBA showed lower apical leakage than the other groups, showing significant difference (pForam distribuídos 44 incisivos centrais superiores extraídos em quatro grupos experimentais (I, II, III e IV) com 10 espécimes cada e dois grupos controles com 2 espécimes cada. Os dentes tiveram as coroas seccionadas e suas raízes foram instrumentadas pela técnica escalonada até o instrumento #60, com irrigação constante de hipoclorito de sódio 2,5%. As raízes foram obturadas com cones de guta-percha e cimento endodôntico EndoFill, pela técnica híbrida de Tagger. As raízes foram apicetomizadas com angulação de 90º, e, após impermeabilização, foram realizados os retro-preparos ultra-sônicos com 3 mm de profundidade, seguindo o longo-eixo radicular. As cavidades retrógradas foram retro-obturadas com MTA branco, MTA cinza, Super EBA e Sealapex + AH Plus, nos grupos I, II, III e IV, respectivamente. No grupo V, não foi realizado nenhuma retro-obturação e os espécimes do grupo VI foram completamente impermeabilizados. As raízes foram imersas no corante Rodamina B e mantidas numa estufa por 48 horas, à temperatura de 37ºC. Após este período, as raízes foram lavadas em água corrente por 24 horas, realizando-se, então, o desgaste longitudinal da porção apical radicular no sentido vestíbulo-palatino, a fim de serem analisadas as infiltrações com o auxílio do programa Image Tool. Após análise estatística pelo teste Kruskal-Wallis, e comparações pelo método de Dunn, verificou-se que o grupo selado com o Super EBA exibiu menores infiltrações apicais do que os demais grupos experimentais, apresentando diferença significante (

Effect of different torques in cyclic fatigue resistance of K3 rotary instruments

assess the effect of different torque values on cyclic fatigue resistance of K3 rotary nickeltitanium (NiTi) files. Methods: Eighty K3 files, size 25 mm, taper 0.04 were divided in 4 groups according to different torques (0.5, 1, 2 and 6 Ncm) and were submitted to a cyclic fatigue test. This test was performed with a device that allowed the file to rotate inside a stainless steel artificial curved canal, simulating the pecking motion. Files rotated until fracture occurred and time to failure was recorded in seconds with a stopwatch. Data were analyzed by ANOVA and Tukey tests (p<0.05). Results: All groups were compared and only the group of 6 N.cm showed statistically significant difference (p=0.0002). Conclusions: For #25.04 K3 files, the evaluated torques up to 2 N.cm had no influence on cyclic fatigue resistance. Using 6 N.cm torque value resulted in lower resistance to cyclic fatigue

Análise comparativa da infiltração apical entre diferentes materiais retro-obturadores

Foram distribuídos 44 incisivos centrais superiores extraídos em quatro grupos experimentais (I, II, III e IV) com 10 espécimes cada e dois grupos controles com 2 espécimes cada. Os dentes tiveram as coroas seccionadas e suas raízes foram instrumentadas pela técnica escalonada até o instrumento #60, com irrigação constante de hipoclorito de sódio 2,5%. As raízes foram obturadas com cones de guta-percha e cimento endodôntico EndoFill, pela técnica híbrida de Tagger. As raízes foram apicetomizadas com angulação de 90º, e, após impermeabilização, foram realizados os retro-preparos ultra-sônicos com 3 mm de profundidade, seguindo o longo-eixo radicular. As cavidades retrógradas foram retro-obturadas com MTA branco, MTA cinza, Super EBA e Sealapex + AH Plus, nos grupos I, II, III e IV, respectivamente. No grupo V, não foi realizado nenhuma retro-obturação e os espécimes do grupo VI foram completamente impermeabilizados. As raízes foram imersas no corante Rodamina B e mantidas numa estufa por 48 horas, à temperatura de 37ºC. Após este período, as raízes foram lavadas em água corrente por 24 horas, realizando-se, então, o desgaste longitudinal da porção apical radicular no sentido vestíbulo-palatino, a fim de serem analisadas as infiltrações com o auxílio do programa Image Tool. Após análise estatística pelo teste Kruskal-Wallis, e comparações pelo método de Dunn, verificou-se que o grupo selado com o Super EBA exibiu menores infiltrações apicais do que os demais grupos experimentais, apresentando diferença significante (