FE-SEM Evaluation of Dental Specimens Prepared by Different Methods for In Vitro Contamination

Objective. To evaluate through FE-SEM the cleanliness and dentinal alterations promoted by different methods of dental sample preparation. Methods. Twenty-five human single-rooted teeth were used. The teeth were cleaned and autoclaved in wet medium and randomly divided into 5 groups (n = 5), according to the preparation methods employed—control group: no solutions applied; group 1: cement removal and irrigation with 5.25% NaOCl  + 17 % EDTA for 4 minutes each; group 2: 17%  EDTA + 2.5% NaOCl (4 minutes ultrasonic bath); group 3: cement removal and 17%  EDTA + 5.25%  NaOCl + phosphate buffer solution + distilled water (10 minutes ultrasonic); group 4: 17%  EDTA + 5.25% NaOCl (3 minutes ultrasonic bath). Specimens were analyzed by field emission scanning electron microscope (FE-SEM), at 1500x magnification. Data were submitted to qualitative analysis according to a scoring system and submitted to Kruskal-Wallis test. Results. In ascending order, as to bind parameters, (i) cleanliness: control, group 2, group 3, group 5, and group 4, (ii) dentinal alterations: group 1, group 5, group 2, group 3, and group 4. Conclusion. The proposed protocol was suitable for subsequent microbiological contamination, because it showed less dentinal morphological alterations with increased removal of organic waste

POSSIBILIDADES TERAPÊUTICAS NO TRATAMENTO DE DENTES JOVENS PORTADORES DE POLPA VIVA: uma revisão da literatura

A abordagem tradicional da dentina em cáries profundas, não raro resulta em exposição da polpa, o que coloca em risco sua vitalidade e exige medidas de tratamento mais invasivas. Uma vez determinada a condição de vitalidade do dente, a terapia pulpar em dentes jovens com polpa normal ou pulpite reversível pode ser realizada através de técnicas mais conservadoras, visando à manutenção da vitalidade do dente. A modalidade de tratamento a ser implementada deve variar em decorrência da idade do paciente, do fator etiológico, do diagnóstico pulpar e do estágio de formação radicular do dente. Assim, este estudo tem como objetivo apresentar as alternativas terapêuticas e os materiais utilizados no tratamento da polpa de dentes jovens, visando a manutenção da vitalidade pulpar.Descritores: Cárie; Diagnóstico; Endodontia.Abstract: The traditional approach of dentin deep caries often results in exposition of the pulp, thus putting at risk its vitality and requiring more invasive treatments. Once determined the tooth vitality, the pulp therapy in young teeth with normal pulp or reversible pulpitis can be accomplished by more conservative techniques, aiming at the maintenance of the tooth vitality. The modality of treatment to be implemented should vary due to the patient’s age, etiology, diagnosis and root formation stage. Thus, this study aims to present the therapeutic alternatives and the materials used in the pulp treatment of young teeth, in order to maintain pulp vitality.Descriptors: Caries; Diagnosis; Endodontics

LIM protein Ajuba promotes liver cell proliferation through its involvement in DNA replication and DNA damage control.

The LIM-domain protein Ajuba is associated with cell proliferation, a fundamental process of tissue regeneration and cancer. We report that in the liver, Ajuba expression is increased during regeneration and in tumor cells and tissues. Knockout of Ajuba using CRISPR/Cas9 is embryonic lethal in mice. shRNA targeting of Ajuba reduces cell proliferation, delays cell entry into S-phase, reduces cell survival and tumor growth in vivo, and increases expression of the DNA damage marker γH2AX. Ajuba binding partners include proteins involved in DNA replication and damage, such as SKP2, MCM2, MCM7 and RPA70. Taken together, our data support that Ajuba promotes liver cell proliferation associated with development, regeneration, and tumor growth and is involved in DNA replication and damage repair

Avaliação, por meio da microtomografia computadorizada, do acúmulo de debris dentinários após o preparo do canal com um instrumento único reciprocante

The aim of the present study was to evaluate and quantify the presence of hard-tissue debris inside curved canals, after root canal preparation with a single-fi le reciprocating system, with the aid of microcomputed tomography (micro-CT). Twenty-four mesial canals of mandibular molars were subjected to microtomographic scanning before and after preparation with R25 Reciproc instruments, using the SkyScan 1176 X-ray microtomograph, at a resolution of 17.42 µm. After reconstruction of the resulting images, co-registration was accomplished with DataViewer software. The CTAn and CTvol softwares were used for binarization of the objects of interest, volumetric analysis and 3D model reconstruction. Analysis of the micro-CT scans revealed debris accumulated inside the root canal, occupying an average 3.4% of the canal’s volume. It was concluded that micro-CT enabled identifying and quantifying the hard-tissue debris produced after instrumentation of mesial canals of mandibular molars with a single-fi le reciprocating system.O objetivo do presente estudo foi avaliar e quantificar a presença de debris dentinários em canais curvos, apó s o preparo químico-cirúrgico com um instrumento único reciprocante, utilizando a microtomografia computadorizada (micro-CT). Vinte e quatro canais mesiais de molares inferiores foram submetidos a exames microtomográficos antes e após o preparo com instrumentos Reciproc R25, utilizando um microtomógrafo de raios X SkyScan 1176, a uma resolução de 17,42 μm. Apó s a reconstrução das imagens resultantes, o corregistro das mesmas foi realizado com o programa DataViewer. Os programas CTAn e CTvol foram utilizados para binarização dos objetos de interesse, aná lise volumétrica e reconstrução de modelos 3D. As aná lises de micro-CT revelaram debris dentinários acumulados no interior dos canais radiculares, ocupando uma porcentagem mé dia de 3,4% em relação ao volume do canal. Concluiu-se que a micro-CT possibilitou identifi car e quantifi car debris dentinários produzidos após a instrumentação de canais mesiais de molares inferiores com um instrumento único reciprocante

Endodontic Retreatment of a Maxillary Central Incisor with Two Root Canals in a Patient with Cleft Lip and Palate

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.Keywords: Cleft Lip-palate; Cone-Beam Computed Tomography; Dental Anatomy; Endodontic Retreatment; Maxillary Central Inciso

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

Metodologias Ativas e Tecnologia na Educação Odontológica: Avaliação como Ferramenta de Aprendizagem

The effectiveness of the teaching-learning process should be highlighted in the student evaluation. The changes in communication and the application of new technologies in education require a continued study to establish new strategies for the process as a whole. The strategy presented here was based on these precepts, with the purpose of promoting undergraduate students in the evaluation of their own performance, so that they could communicate and exchange information with teachers, colleagues and / or search the books and the internet, taking into account andragogy. The motivation was to observe their reactions, performance and personal observations. The evaluation of a class from the FOUSP night Dentistry Course, with 53 students, was held and remained open for one week, allowing the student to complete it and correct it up two times before it was closed. Everyone was encouraged to seek help from colleagues, teachers, the library and the internet. Students who score less than 6.00 would make the correction with the teacher. All the students were submitted to a questionnaire to find out how they studied and what they considered about the strategy. The average mark of the class was 6.21; the maximum was 9.17 and the minimum was 2.50. It was concluded that there was an exchange of information with colleagues and teachers and also the consultation of books and internet. What was considered “cheat” became an instrument of learning. The strategy is feasible and makes the student co-responsible for their learning and performance.A eficácia do processo de ensino-aprendizagem deve ser destacada na avaliação discente. As mudanças ocorridas no âmbito da comunicação e a aplicação de novas tecnologias na educação exigem estudo continuado para que se estabeleçam novas estratégias para o processo como um todo. A estratégia aqui apresentada foi pautada nesses preceitos, com o objetivo de promover entre os alunos de graduação a avaliação de seus próprios desempenhos, para que se comunicassem e trocassem informações com professores, colegas e/ou as buscassem conteúdos nos livros e na internet, atendendo à andragogia. A motivação foi observar suas reações, desempenho e observações pessoais. A avaliação de uma turma de 53 alunos do curso de Odontologia noturno da FOUSP foi realizada a distância e permaneceu aberta durante uma semana, permitindo que cada um a preenchesse e a corrigisse até duas vezes antes de ela ser encerrada. Todos foram estimulados a buscar ajuda de colegas, professores, bem como recorrer a pesquisas na biblioteca e na internet. Os alunos que alcançassem nota inferior a 6,00 fariam a correção junto ao professor. Todos foram submetidos a um questionário para averiguar como estudaram e o que consideraram a respeito da estratégia. A nota média da turma foi 6,21; a máxima, 9,17; e a mínima, 2,50. Concluiu-se que houve troca de informações com colegas e professores e também a consulta de diferentes materiais. O que se considerava “cola” passou a constituir um instrumento de aprendizagem. A estratégia é viável e torna o estudante corresponsável por sua aprendizagem e desempenho

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