Fábio Luis Miranda Pedro

Methodological model of chronic stress associated with ligature-induced periodontitis in rats: a radiographic study

This study evaluated the time efficiency of stress associated with ligature-induced periodontitis in rats. Sixty adult Wistar rats, housed in temperature-controlled rooms and receiving water and food ad libitum, were randomly separated into stress (n = 30) or control groups (n = 30). All animals were anesthetized, and nylon ligatures were placed at the gingival margin level of the maxillary right second molars. After the induction of periodontitis, rats in the stress group were subjected to physical restraint for 12 hours daily. The animals were euthanized after 7, 15 and 30 days by anesthetic overdose (10 animals per group per period). The right hemimaxillae were stored in formalin solution for 48 hours. Parallel radiographic images of the hemimaxillae were taken and processed following standard procedures. Radiographic examination was performed by a blinded and previously calibrated investigator. Bone height level was measured, and data were submitted to analysis of variance and post hoc Bonferroni tests (p < 0.05). Rats in the stress group had greater bone loss than those in the control group at 7 and 15 days post-induction (p < 0.05). After 30 days, there was no statistically significant difference between the groups (p > 0.05). Restraint stress modulates the short-term progression of periodontal disease in rats. Therefore, the 12-hour daily physical restraint stress model in rats applied for up to 15 days is suitable for the investigation of the combined effect of ligation and restraint stress on periodontal degradation.

Customized Polymethyl Methacrylate Implants for the Reconstruction of Craniofacial Osseous Defects

Craniofacial defects represent alterations in the anatomy and morphology of the cranial vault and the facial bones that potentially affect an individuals psychological and social well-being. Although a variety of techniques and restorative procedures have been described for the reconstruction of the affected area, polymethyl methacrylate (PMMA), a biocompatible and nondegradable acrylic resin-based implant, is the most widely used alloplastic material for such craniomaxillofacial reconstruction. The aim of this study was to describe a technique for aesthetic and functional preoperative customized reconstruction of craniofacial bone defects from a small series of patients offered by the Brazilian public health system. Three adult male patients attended consultation with chief complaints directly related to their individual craniofacial bone defects. With the aid of multislice computed tomography scans and subsequent fabrication of the three-dimensional craniofacial prototype, custom-made PMMA implants were fabricated preoperatively. Under general anesthesia, with access to the craniofacial defects with a coronal approach, the PMMA implants were adapted and fixated to the facial skeleton with titanium plates and screws. Postoperative evaluation demonstrated uneventful recovery and an excellent aesthetic result. Customized prefabricated PMMA implants manufactured over the rapid prototyping models proved to be effective and feasible.

Conventional Treatment of Maxillary Incisor Type III Dens Invaginatus with Periapical Lesion: A Case Report

Dens invaginatus is a developmental dental anomaly clinically characterized by a palatine furrow that can be limited to the coronal pulp or may extend to the radicular apex. The purpose of this paper was to present a clinical case of type III dens invaginatus, identified on the maxillary right central incisor in anterior periapical radiographs, in which the tooth was submitted to conventional endodontic treatment. The results obtained after five years of clinical and radiographic followup demonstrated that conventional endodontic treatment is a clinically viable alternative in cases of type III dens invaginatus.

Comparative analysis of physicochemical properties of root perforation sealer materials

Objectives This study evaluated the solubility, dimensional alteration, pH, electrical conductivity, and radiopacity of root perforation sealer materials. Materials and Methods For the pH test, the samples were immersed in distilled water for different periods of time. Then, the samples were retained in plastic recipients, and the electrical conductivity of the solution was measured. The solubility, dimensional alteration, and radiopacity properties were evaluated according to Specification No. 57 of the American National Standards Institute/American Dental Association (ANSI/ADA). Statistical analyses were carried out using analysis of variance (ANOVA) and Tukeys test at a significance level of 5%. When the sample distribution was not normal, a nonparametric ANOVA was performed with a Kruskal-Wallis test (α = 0.05). Results The results showed that white structural Portland cement (PC) had the highest solubility, while mineral trioxide aggregate (MTA)-based cements, ProRoot MTA (Dentsply-Tulsa Dental) and MTA BIO (Ângelus Ind. Prod.), had the lowest values. MTA BIO showed the lowest dimensional alteration values and white PC presented the highest values. No differences among the tested materials were observed in the the pH and electrical conductivity analyses. Only the MTA-based cements met the ANSI/ADA recommendations regarding radiopacity, overcoming the three steps of the aluminum step wedge. Conclusions On the basis of these results, we concluded that the values of solubility and dimensional alteration of the materials were in accordance with the ANSI/ADA specifications. PCs did not fulfill the ANSI/ADA requirements regarding radiopacity. No differences were observed among the materials with respect to the pH and electrical conductivity analyses.

Analysis of Metal Contents in Portland Type V and MTA-Based Cements

The aim of this study was to determine, by Atomic Absorption Spectrometry (AAS), the concentration levels of 11 metals in Type V gray and structural white PC, ProRoot MTA, and MTA Bio. Samples, containing one gram of each tested cement, were prepared and transferred to a 100 mL Teflon tube with a mixture of 7.0 mL of nitric acid and 21 mL of hydrochloric acid. After the reaction, the mixture was filtered and then volumed to 50 mL of distilled water. For each metal, specific patterns were determined from universal standards. Arsenic quantification was performed by hydride generator. The analysis was performed five times and the data were statistically analyzed at 5% level of significance. Only the cadmium presented concentration levels of values lower than the quantification limit of the device. The AAS analysis showed increased levels of calcium, nickel, and zinc in structural white PC. Type V PC presented the greatest concentration levels of arsenic, chromium, copper, iron, lead, and manganese (P < 0.05). Bismuth was found in all cements, and the lowest concentration levels were observed in Portland cements, while the highest were observed in ProRoot MTA. Both PC and MTA-based cements showed evidence of metals inclusion.

Root Canal Transportation and Centering Ability of Nickel-Titanium Rotary Instruments in Mandibular Premolars Assessed Using Cone-Beam Computed Tomography

Introduction: The aim of this study was to evaluate, using cone-beam computed tomography (CBCT), transportation and centralization of different nickel-titanium (NiTi) rotary instruments. Methods: One hundred and twenty eight mandibular premolars were selected and instrumented using the following brands of NiTi files: WaveOne, WaveOne Gold, Reciproc, ProTaper Next, ProTaper Gold, Mtwo, BioRaCe and RaCe. CBCT imaging was performed before and after root canal preparation to obtain measurements of mesial and distal dentin walls and calculations of root canal transportation and centralization. A normal distribution of data was confirmed by the Kolmogorov-Smirnov and Levene tests, and results were assessed using the Kruskal-Wallis test. Statistical significance was set at 5%. Results: ProTaper Gold produced the lowest canal transportation values, and RaCe, the highest. ProTaper Gold files also showed the highest values for centering ability, whereas BioRaCe showed the lowest. No significant differences were found across the different instruments in terms of canal transportation and centering ability (P > 0.05). Conclusion: Based on the methodology employed, all instruments used for root canal preparation of mandibular premolars performed similarly with regard to canal transportation and centering ability.

O emprego do agregado trióxido mineral (MTA) em Pulpotomia de Dente Decíduo: relato de caso

A proposta deste artigo e discutir como a internet alterou a forma de divulgacao cientifica no Brasil com todas as suas peculiaridades, enfatizando as noticias sobre energias renovaveis. E inegavel que a internet causou um impacto significativo nas formas de comunicacao cientifica e nos sistemas de informacao. Por esta razao, a velocidade, que a sociedade cresce e se modifica, exige respostas rapidas e precisas em razao do dinamismo que a Rede oferece ao encurtar as distâncias geograficas. Propoe-se apresentar a alteracao gerada no comportamento social uma vez que, nos dias atuais as pessoas se relacionam mais no ambiente virtual do que no âmbito presencial como forma de acelerar processos e resolucoes. Assim, percebe-se como a Rede pode auxiliar, significativamente, a divulgacao sobre energias renovaveis, impactando diretamente o comportamento da sociedade quanto a um tema ainda tao pouco socializado entre as pessoas comuns. Nao so sera abordado como a internet e uma ferramenta importante para a divulgacao cientifica em especial, das noticias sobre Energias Renovaveis, como tambem precisa ser observada e aproveitada. Isso ocorre a fim de que estudiosos e pesquisadores tenham interesse e compromisso de divulgar ciencia atraves da Rede Mundial para beneficiar toda a coletividade.Este artigo aborda brevemente o modo como a Analise do Comportamento – ciencia embasada pela filosofia Behaviorista Radical, obra do Psicologo norte americano B. F. Skinner (1904-1990) – tem se relacionado com o campo educacional, especialmente naquilo o que se refere a formacao de educadores. Na tentativa de evitar equivocos comuns, sao abordados conceitos referentes a Analise do Comportamento, alem de um breve historico de suas contribuicoes efetivas para a educacao norte americana e brasileira, demonstrando o grande interesse por este intercâmbio entre as decadas de 1960 e 1980. Apresentam-se ainda alguns dos pontos que potencialmente marcam o declinio deste interesse, relacionando-o com o material didatico sobre o tema apresentado aos educadores em formacao. Finalmente, algumas das contribuicoes propostas pela teoria sao apresentadas, discutindo sobre o modo como o intercâmbio entre a Analise do Comportamento e os educadores formados ou em formacao podem gerar produtos ferteis para ambas as areas.O presente artigo promove o aproveitamento de uma area degradada pelo garimpo de diamantes para uso da piscicultura na Fazenda Sao Jose em Poxoreu, municipio do estado de Mato Grosso. O estudo se preocupa com a coleta de informacoes junto ao proprietario e as organizacoes representativas do setor rural do municipio, para avaliar aspectos economicos e ambientais. A metodologia adotada foi a descrita por Yin (1994) conjuntamente com o levantamento das caracteristicas ambientais locais. Por meio dos resultados obtidos na area estudada, pode-se afirmar que o aproveitamento da area degradada pelo processo de garimpagem com a piscicultura e considerado economicamente viavel e ambientalmente correto.

Antimicrobial effectiveness of different trademarks mouthwashes with and without alcohol against different organisms: in vitro study

Purpose: The aim of this in vitro study was to evaluate the effect of mouthwashes with and without alcohol on some microorganisms. Methods: Periogard®, Cepacol®, Plax Classic® and Oral-B® were the substances used for this purpose. For this study, 40 plates of Petri with medium blood agar were used for the following microorganisms: Staphylococcus aureus, Candida albicans, Enterococcus faecalis, Pseudomonas aeruginosa. To measure the inhibition zones, a single trained examiner used a stereomicroscope and a digital caliper. After data collection, the medias were compared using the ANOVA (analysis of variance) with Bonferroni test post-hoc correction for 5% significance level. Results: Periogard®, with and without alcohol, showed the best results. Plax® without alcohol presented the poorest results. Plax® with alcohol was the best substance in relation to S. aureus. The others results remained with better effectiveness in relation to control substance. Conclusion: The alcohol-free mouthwashes did not have the same efficacy of antimicrobial rinses with alcohol in relation to microorganisms tested in this study.

Effectiveness of different endodontic irrigants against Enterococcus faecalis: an ex vivo study.

Aim: To evaluate the effectiveness of different endodontic irrigants against Enterococcus faecalis (ATCC 29212). Methods: Seventy bovine mandibular incisors were prepared, inoculated with a bacterial strain for 60 days and divided into the following groups: positive control; negative control; 2.5% NaOCl; 17% EDTA; 0.2% chitosan; 2.5% NaOCl + 0.2% chitosan; and 2.5% NaOCl + 17% EDTA. The irrigation protocol was performed using an experimental peristaltic pump device, with the irrigating solutions circulating within the apparatus at a constant flow for 10 min. Paper-point samples were then collected from the root canals and immersed in 7 mL of brain heart infusion broth, followed by incubation at 37°C for 48 h. Bacterial growth was assessed by turbidity of the culture medium. Results: E. faecalis was present in all samples after the use of different irrigants. Conclusion: The different irrigants tested were not effective in completely eliminating dentin bacterial contamination with E. faecalis .

Assessment of the Amount of Calcium Ions Released after the use of Different Chelating Agents and Agitation Protocols

Background: The main goal of endodontic treatment is to achieve cleaning and shaping prior to the filling process. Objective: This study aimed to evaluate, using atomic absorption spectrometry, the release of Calcium ions after the use of different chelating agents and protocols of agitation. Method: Ninety human canine teeth were randomly assigned to one of nine groups (n=10), as follows: 1) 0.2% Chitosan and manual agitation; 2) 0.2% Chitosan and sonic agitation; 3) 0.2% Chitosan and ultrasonic agitation; 4) 17% EDTA and manual agitation; 5) 17% EDTA and sonic agitation; 6) 17% EDTA and ultrasonic agitation; 7) distilled water and manual agitation; 8) distilled water and sonic agitation; 9) distilled water and ultrasonic agitation. Following instrumentation, all chelating substances remained inside the root canal for 3 min. Then the fluid was collected for the identification and quantification of Calcium ions. The amount of Calcium ions released in each group was compared using analysis of variance (ANOVA) and the Kolmogorov-Smirnov and Levene tests followed by Tukey’s post-hoc test. Significance was set at 5%. Results: The groups in which 0.2% Chitosan was used showed the highest concentration of Calcium ions (p<0.05). Concerning the agitation method, ultrasonic agitation showed the greatest values, followed by sonic and manual agitation (all comparisons, p<0.05). Conclusion: The present findings suggest that, among the combinations here tested, Chitosan associated with ultrasonic agitation yielded the greatest release of Calcium ions.