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The motion of the four Galilean moons of Jupiter is studied in this work. The moons had their positions with respect to the centre of the planet measured during one week of observation by means of telescopic charge coupled device images. It is shown that their movement can be well described as a simple harmonic motion. The revolution period and the orbital radius of each moon could be extracted from the various images and they were analysed in terms of Kepler's third law and Newton's law of universal gravitation. The mass of Jupiter could be evaluated within a 2% discrepancy using this simple method. (Contains 1 table and 6 figures.)

Aim To assess the effect of 90°-oscillatory instrumentation with hand files on several morphological parameters (volume, surface area and uninstrumented surface) in C-shaped root canals after instrumentation using a single-file reciprocation system (Reciproc; VDW, Munich, Germany) and a Self-Adjusting File System ( SAF; ReDent Nova, Ra'anana, Israel). Methodology Twenty mandibular second molars with C-shaped canals and C1 canal configurations were divided into two groups ( n = 10) and instrumented with Reciproc and SAF instruments. A size 30 NiTi hand K-file attached to a 90°-oscillatory motion handpiece was used as final instrumentation in both groups. The specimens were scanned using micro-computed tomography after all procedures. Volume, surface area increase and uninstrumented root canal surface were analysed using CTAn software (Bruker-micro CT, Kontich, Belgium). Also, the uninstrumented root canal surface was calculated for each canal third. All values were compared between groups using the Mann-Whitney test and within groups using the Wilcoxon's signed-rank test. Results Instrumentation with Reciproc significantly increased canal volume compared with instrumentation with SAF. Additionally, the canal volumes were significantly increased after 90°-oscillatory instrumentation (between and within group comparison; ( P < 0.05)). Regarding the increase in surface area after all instrumentation protocols, statistical analysis only revealed significant differences in the within groups comparison ( P < 0.05). Reciproc and SAF instrumentation yielded an uninstrumented root canal surface of 28% and 34%, respectively, which was not significantly different ( P > 0.05). Final oscillatory instrumentation significantly reduced the uninstrumented root canal surface from 28% to 9% (Reciproc) and from 34% to 15% ( SAF; P < 0.05). The apical and middle thirds exhibited larger uninstrumented root canal surfaces after the first instrumentation that was significantly reduced after oscillatory instrumentation ( P < 0.05). Conclusions The Reciproc and SAF system were associated with similar morphological parameters after instrumentation of mandibular second molars with C-shaped canals except for a higher canal volume increase in the Reciproc group compared to the SAF. Furthermore, the final use of 90°-oscillatory instrumentation using NiTi hand files significantly decreased the uninstrumented canal walls that remained after Reciproc and SAF instrumentation. [ABSTRACT FROM AUTHOR]

The possibility of three canals in maxillary second premolars is quite small; however, it must be taken into account in clinical and radiographic evaluations during endodontic treatment. Many times their presence is noticed only after canal treatment, due to continuing postoperative discomfort. This article describes a clinical case of three-canal maxillary second premolars that are endodontically treated.

The authors describe a clinical case of a palato-gingival groove on a maxillary central incisor with associated localized periodontal disease and pulp necrosis. The general clinician's initial diagnosis was incorrect; this led to incomplete treatment and subsequent loss of the tooth. Recognition of the palato-gingival groove is critical, especially because of its diagnostic complexity and the problems that may arise if it is not properly interpreted and treated.

The purpose of this paper was to assess the clinical ability of two bleaching techniques. Patients with at least one darkened teeth caused by mechanical injuries or imperfection in the endodontic therapy were included in this study. The first step was to take an initial photography. After that the teeth were subjected to the bleaching procedures. The techniques employed were proposed by NUTTING & POE or LACERDA et alii. The assessments were made by three trained examiners using the initial and final pictures. The scores were attributed according to the color of the teeth. The data were submitted to the statistical analysis, when was possible to verify that both techniques were equally effective.

Our purpose was to compare incidence of post-surgical pain associated to the endodontic therapy where the instrumentation on the root canal was performed by the method of Marshall & Pappin and the method of Marshall & Pappin complemented by the ultrasonic. Seventy patients with only one tooth needing endodontic treatment were treated by one of the methods and, posteriorly, evaluated. The endodontic treatment was performed at one time and from the seventy teeth, thirty have been instrumented by the manual method complemented by the ultrasonic and forty by the manual instrumentation. The patients were clinically controlled after the endodontic treatment was finished during periods of 24, 48 and 72 hours to evaluate their post-surgical condition. The results suggest that were no statistically significant differences (p less than 0.05) in the incidence of pain between the employed methods or according to the pulpar semiologic condition in any of the observed periods. However, we have realized that there was a tendency for a smaller percentage of a postoperative pain in those cases of necropulpectamy treated by the endosonic ultrasonic synergistic system. In those cases of biopulpectomy this has been not observed.