Marcelo dos Santos

In vitro study of effect of solvent on root canal retreatment

The aim of this study was to assess the effectiveness of five different solvents: xylol, eucalyptol, halothane, chloroform and orange oil on softening gutta-percha in simulated root canals. One drop of solvent was placed into a reservoir made in a simulated canal whose channel was previously instrumented and filled with gutta-percha and N-Rickert sealer. After 5 min, softening was evaluated for each solvent by the penetration of a spreader while applying force with a 442 Instron apparatus to reach a depth of 5 mm. The results were analyzed statistically by the Kruskal-Wallis test. Xylol and orange oil were better in softening gutta-percha than the other solvents. There was no significant difference between xylol and orange oil, but these were statistically different from eucalyptol, halothane and chloroform (p < 0.01).

HIF1-Alpha Expression Predicts Survival of Patients with Squamous Cell Carcinoma of the Oral Cavity

Background Oral squamous cell carcinoma is an important cause of death and morbidity wordwide and effective prognostic markers are still to be discovered. HIF1α protein is associated with hypoxia response and neovascularization, essential conditions for solid tumors survival. The relationship between HIF1α expression, tumor progression and treatment response in head and neck cancer is still poorly understood. Patients and Methods In this study, we investigated HIF1α expression by immunohistochemistry in tissue microarrays and its relationship with clinical findings, histopathological results and survival of 66 patients with squamous cell carcinoma of the lower mouth. Results Our results demonstrated that high HIF1α expression is associated with local disease-free survival, independently from the choice of treatment. Furthermore, high expression of HIF1α in patients treated with postoperative radiotherapy was associated with survival, therefore being a novel prognostic marker in squamous cell carcinoma of the mouth. Additionally, our results showed that MVD was associated with HIF1α expression and local disease relapse. Conclusion These findings suggest that HIF1α expression can be used as a prognostic marker and predictor of postoperative radiotherapy response, helping the oncologist choose the best treatment for each patient.

Managing Medical Images and Clinical Information: InCor's Experience

Patients usually get medical assistance in several clinics and hospitals during their lifetime, archiving vital information in a dispersed way. Clearly, a proper patient care should take into account that information in order to check for incompatibilities, avoid unnecessary exams, and get relevant clinical history. The Heart Institute (InCor) of Satildeo Paulo, Brazil, has been committed to the goal of integrating all exams and clinical information within the institution and other hospitals. Since InCor is one of the six institutes of the University of Satildeo Paulo Medical School and each institute has its own information system, exchanging information among the institutes is also a very important aspect that has been considered. In the last few years, a system for transmission, archiving, retrieval, processing, and visualization of medical images integrated with a hospital information system has been successfully created and constitutes the InCors electronic patient record (EPR). This work describes the experience in the effort to develop a functional and comprehensive EPR, which includes laboratory exams, images (static, dynamic, and three dimensional), clinical reports, documents, and even real-time vital signals. A security policy based on a contextual role-based access control model was implemented to regulate users access to EPR. Currently, more than 10 TB of digital imaging and communications in medicine (DICOM) images have been stored using the proposed architecture and the EPR stores daily more than 11 GB of integrated data. The proposed storage subsystem allows 6 months of visibility for rapid retrieval and more than two years for automatic retrieval using a jukebox. This paper addresses also a prototype for the integration of distributed and heterogeneous EPR

A micro-computed tomography evaluation of long-oval canal preparation using reciprocating or rotary systems.

AIM To evaluate, using micro-computed tomography, the preparation of long-oval root canals using a single reciprocating system versus a multiple-file rotary system. METHODOLOGY Distal canals of thirty mandibular molars were selected and randomly assigned to one of two instrument groups (n = 15): Reciproc 40 (VDW, Munich, Germany) or BioRaCe system (FKG Dentaire, La Chaux-de-Fonds, Switzerland). The teeth were scanned before and after preparation of the canal by a SkyScan 1172 micro-computed tomography scanner at 11-μm resolution. Morphometric variations were measured by volume increases and by the remaining untreated canal surface area in the entire canal and as well as in each third of the canal. Data were compared using the Mann-Whitney test. RESULTS The Reciproc system left significantly more areas untouched (P < 0.001) in the cervical and middle thirds (18.14% and 21.82%) as compared to BioRaCe (8.14% and 11.35%). The Reciproc system had the greatest increase in volume of both the entire canal and the apical third (P < 0.5). CONCLUSIONS Neither technique was able to completely prepare the outline of long-oval canals. The Reciproc system removed more tooth structure. The BioRaCe left fewer untouched dentine walls in the more coronal thirds of the canal, whilst Reciproc left fewer in the apical third.

Microscopic computerized tomographic evaluation of root canal transportation prepared with twisted or ground nickel-titanium rotary instruments

OBJECTIVE The aim of this study was to evaluate, ex vivo, canal transportation and the centering ability of nickel-titanium rotary instruments manufactured by twisting and by traditional grinding, with the use of microscopic computerized tomography (μCT). STUDY DESIGN Fifteen mandibular molars were embedded in a rubber-based impression material and submitted to μCT before and after instrumentation. Images were reconstructed, and cross-sections corresponding to distances 1, 2, 3, 4, 5, 6, and 7 mm from the anatomic apex were selected for analysis. Statistical analysis was performed with Mann-Whitney test. RESULTS Canal transportation and centering ability results were similar for both instruments. Statistically significant differences (P < .05) were observed only at the 3 and 4 mm cross-sections, with lower levels of apical transportation and a better centering ratio associated with twisted instruments than with ground instruments. CONCLUSIONS Our findings showed that twisted and ground instruments behaved similarly, allowing the preparation of curved canals with little transportation, which occurred in both mesial and distal directions.

Topography of four different endodontic rotary systems, before and after being used for the 12th time

Root canal preparation may damage NiTi instruments resulting in wear and deformation. The aim of this study was to make a comparative evaluation of the surface topography of the cervical third of four different rotary systems, before and after being used twelve times, in 1.440 resin blocks with simulated root canals with standardized 45° curvatures, and analyzed by atomic force microscopy – AFM. The blocks were divided into four groups and prepared according to the manufacturers recommendations: Group 1 ‐ K3®; Group 2 ‐ Protaper Universal®; Group 3 ‐ Twisted Files® and Group 4 ‐ Biorace®. After each preparation, the instruments were washed and autoclaved. A total of 240 instruments were selected, being 30 new instruments and 30 after having been used for the 12th time, from each group. These instruments were analyzed by AFM and for quantitative evaluation, the mean RMS (Root mean square) values of the cervical third of the specimens from the four groups were used. The result showed that all the rotary files used for the 12th time suffered wear with change in the topography of the cervical region of the active portion of the file (ANOVA p < 0.01). Classifying the specimens in increasing order, from the least to the greatest wear suffered, Group 3 (2.8993 nm) presented the least wear, followed by Group 4 (12.2520 nm), Group 1 (36.0043 nm) and lastly, Group 2 (59.8750 nm) with the largest amount of cervical surface wear. Microsc. Res. Tech., 2012.

Assessing apical transportation in curved canals: comparison between cross-sections and micro-computed tomography

The aim of this study was to compare two methods of assessing apical transportation in curved canals after rotary instrumentation, namely, cross-sections and micro-computed tomography (µCT). Thirty mandibular molars were divided into two groups and prepared according to the requirements of each method. In G1 (cross-sections), teeth were embedded in resin blocks and sectioned at 2.0, 3.5, and 5.0 mm from the anatomic apex. Pre- and postoperative sections were photographed and analyzed. In G2 (µCT), teeth were embedded in a rubber-base impression material and scanned before and after instrumentation. Mesiobuccal canals were instrumented with the Twisted File (TF) system (SybronEndo, Orange, USA), and mesiolingual canals, with the EndoSequence (ES) system (Brasseler, Savannah, USA). Images were reconstructed, and sections corresponding to distances 2.0, 3.5, and 5.0 mm from the anatomic apex were selected for comparison. Data were analyzed using Mann-Whitneys test at a 5% significance level. The TF and ES instruments produced little deviation from the root canal center, with no statistical difference between them (P > 0.05). The canal transportation results were significantly lower (0.056 mm) in G2 than in G1 (0.089 mm) (p = 0.0012). The µCT method was superior to the cross-section method, especially in view of its ability to preserve specimens and provide results that are more closely related to clinical situations.

Comunicação de más notícias: dilemas éticos frente à situação de morte encefálica

Communicating the diagnosis of encephalic death is a difficult task and must precede the request for organ and tissue donation for transplant. This situation may arouse ethical dilemmas permeated by religious, spiritual, cultural, economic and / or social factors. This paper aims to explain the reader about the historical and epidemiological aspects of encephalic death and to present some ethical dilemmas faced by families of potential donors after the announcement of that bad news.

Integrating Medical Images and Clinical Information

The Heart Institute (InCor) of Sao Paulo has been committed to the goal of integrating all clinical information within the institution. In the last few years, InCor has successfully created a system for transmission, archiving, retrieval, processing and visualization of Medical Images and also a Hospital Information System that stores the administrative and clinical information. These integrated subsystems form InCors Electronic Patient Record (EPR). This work describes the experience in the effort to develop a functional and comprehensive EPR, which includes access control, lab exams, images (static, dynamic and 3D), clinical reports, documents and even real-time vital signals. Currently, more than 13TB of DICOM images have been stored using the proposed architecture. The EPR stores more than 5 GB/day of integrated data and presents more than 1400 hits per day. The proposed storage subsystem allows six months of visibility for rapid retrieval and more than two years for automatic retrieval using a jukebox.

Presence of Voids after Continuous Wave of Condensation and Single-Cone Obturation in Mandibular Molars: A Micro-Computed Tomography Analysis

Introduction The objective of this study was to assess the presence of voids in mesial root canals of mandibular molar teeth obturated by using the single‐cone (SC) and continuous wave of condensation (CWC) obturation techniques, and results were analyzed by using micro–computed tomography. Methods Twenty‐four mandibular molars with fully developed roots and mesial root curvature ranging from 25° to 35° were instrumented by using Reciproc R25 files, and then they were obturated by using the SC and CWC techniques. Specimens were scanned before and after obturation for micro–computed tomography analysis (voxel size, 17.42 &mgr;m). After volumetric analysis and tridimensional reconstruction of the root canals, data were analyzed by using analysis of variance and the Tukey test. Results No significant differences were observed between the 2 techniques in terms of total percentage volume of voids: CWC = 3.91% ± 0.72%; SC = 6.52% ± 1.16% (P > .05). Only in the cervical third, CWC showed a significantly lower percentage of voids when compared with SC, namely 2.86% ± 0.94% vs 8.00% ± 1.86%, respectively (P < .05). Conclusions The percentage volume of voids was similar in the 2 groups and was influenced by the obturation technique only in the cervical third. HighlightsWe assessed the presence of voids in mesial root canals of mandibular molars after obturation.We compared the single‐cone and the continuous wave of condensation obturation techniques.Total percentage volume of voids was similar in the 2 groups.In the cervical third, CWC performed better.