INTRODUCTION: Some patients refer to pre-banding orthodontic separation as a painful orthodontic procedure. Low-level laser therapy (LLLT) has been reported to have local analgesic effect. OBJECTIVE: The aim of this single-blind study was to investigate the perception of pain caused by orthodontic elastomeric separators with and without a single LLLT application (6J). METHODS: The sample comprised 79 individuals aged between 13 and 34 years old at orthodontic treatment onset. Elastomeric separators were placed in first maxillary molars at mesial and distal surfaces and kept in place for three days. The volunteers scored pain intensity on a visual analogue scale (VAS) after 6 and 12 hours, and after the first, second and third days. One third of patients received laser applications, whereas another third received placebo applications and the remaining ones were controls. Applications were performed in a split-mouth design. Thus, three groups (laser, placebo and control) were assessed. RESULTS: No differences were found among groups considering pain perception in all periods observed. CONCLUSION: The use of a single-dose of LLLT did not cause significant reduction in orthodontic pain perception. Overall pain perception due to orthodontic separator placement varied widely and was usually mild.

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RESUMOIn groups 1 and 2, the salinity level of the water was, mainly, due to the geology and the climate of the region. While for group 3 and 4, besides these factors, the water salinity was influenced by human activities. According to the results, the first and the second components (independent factors) explaining, 57.28 and 26.77%, respectively, the total variance of seven variables. The most important parameters related to the variability of the water salinity level were Cl -, CE, Na + and Mg 2+, which were related to salt solubility.

The present study assessed condylar displacement between initial maximal habitual intercuspation (MHI) and centric relation (CR), recorded after using a deprogramming occlusal splint for an average period of 7.8 +/- 2.1 months prior to any orthodontic treatment. The sample consisted of 22 subjects, 11 male and 11 female, with an average age of 14.2 +/- 1.4 years, with Class II malocclusion and with no apparent signs or symptoms of temporomandibular dysfunction (TMD). Condylar displacement was measured using a Panadent axis position indicator in decimal fractions of a millimeter. The original mean vertical displacements and the corresponding standard deviations were 4.24 +/- 2.53 mm and 3.86 +/- 2.72 mm, respectively, for the right and left sides. Because a significant negative correlation was observed between original condylar displacements and age factors, the displacement values were statistically adjusted to 2.74 +/- 2.00 mm and 2.44 +/- 1.93 mm. On the horizontal plane, the mean displacements measured were -0.72 +/- 1.53 mm on the right side and -0.51 +/- 1.98 mm on the left. The mean displacement on the transversal plane was 0.03 +/- 0.87 mm. A comparison between these values and those observed in non-deprogrammed groups, as well as those published in the related literature, indicates that use of occlusal splints results in greater mean condylar displacement values, especially vertically, between CR and MHI positions, which contributed to a more accurate orthodontic diagnosis.

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Background The use of skeletal anchorage devices for maxillary protraction in patients with class III malocclusion due to deficiency in the middle third of the face has been shown to be a promising approach to treatment of these patients. The aim of this study was to evaluate the treatment of class III patients with maxillary retrusion, using orthodontic mini-implants (MI) associated with intermaxillary elastics in comparison with the rapid maxillary expansion and facemask protocol (RME/FM). Methods In this prospective non-randomized clinical trial, the sample of 24 participants between 7 and 12 years of age (median age of 10.0 years and interquartile range = 3.0 years), at the stage prior to the pre-pubertal growth spurt, was divided in two groups. In group facemask (FM) ( n = 12), the individuals received orthopedic treatment with RME/FM. In group MI ( n = 12), two mini-implants were inserted in the region close to the maxillary first molar roots, and the other two in the region of the mandibular canines. Initial and final lateral teleradiographs were taken for cephalometric evaluation of all the cases. Statistical analysis included the Mann-Whitney, Wilcoxon, and Fisher’s exact tests. The level of significance was 5% (α = 0.05). Results Improvement was verified in the facial profile and occlusion of the participants, showing advancement of the maxilla in the two groups, with significant differences ( P ≤ 0.05) between T0 and T1 in the following measurements: SNA, ANB, Wits, Co-A, Co-Gn, NAP, A-Npog, overjet, and molar relationship. There was no statistically significant intergroup difference ( P > 0.05) in the cephalometric measurements evaluated, but the time of treatment was significant, and was faster for group MI. Conclusions The protocol with mini-implants may be an option for the correction of Class III due to maxillary deficiency.

Resumo: Neste trabalho as propriedades mecânicas de um compósito, formado a partir de uma matriz de poliuretano derivado do óleo de mamona e reforçada por um tecido tramado de juta, foram avaliadas. O efeito da adição de pequenos teores de bentonita cálcica e sódica sobre as propriedades mecânicas da matriz de poliuretano e de compósitos poliuretano/juta também foi investigado. Os resultados indicam que a incorporação de fibra de juta à matriz poliuretana promoveu melhora significativa nas propriedades sob tração dos compósitos. A adição de pequenos teores de argila à matriz alterou o desempenho mecânico dos compósitos, porém os resultados não foram os esperados. O compósito híbrido poliuretano/argila/fibra de juta, contudo, apresentou propriedades mecânicas superiores às dos compósitos reforçados unicamente com tecido de juta, o que indica uma atuação sinérgica dos reforços híbridos argila/juta. Palavras-chave:Compósito, poliuretano, fibra de juta, carga nanoparticulada. Influence of a Nanoparticulate Filler Addition on the Mechanical Properties of Polyurethane/Jute Fiber CompositesAbstract: In this work the mechanical properties of polyurethane/jute fiber composites were evaluated as a function of fiber content and mineral filler addition. A polyurethane (PU) derived from castor oil was used as the matrix and hessian cloth as reinforcement. The effect of the incorporation of small amounts of local clay (bentonite), in its calcium and sodium forms, on the mechanical properties of polyurethane/jute composites was also investigated. The results indicate that the tensile properties of the composites substantially increased with jute fiber addition and that although the mechanical properties of the matrix were affected by the addition of nanoparticulate clay, the improvement was not as expected. This was attributed to poor mixing and dispersion of the filler, which was confirmed by SEM. A synergistic effect was observed for the hybrid clay/jute fiber composites, with considerable improvement in the mechanical performance of the hybrid composites.

Individuals with Class III dentofacial deformities exhibit morphological changes and myofunctional adaptations, and an accurate diagnosis is essential for treatment planning. The purpose of this study was to evaluate the electrical activity of the masseter, temporal, and suprahyoid muscles in subjects with Class III dentofacial deformities, assessing electromyographic characteristics using functional tests. The research group consisted of 20 subjects with Class III dentofacial deformities and indications for surgical-orthodontic treatment. The control group consisted of 10 individuals presenting a good maxilla and mandible relationship. Electrical activities of the masseter and temporal were recorded during isometric contraction and maximal isometric contraction. The suprahyoid and masseter were assessed during maximal mouth opening and swallowing of saliva. Isometric contraction and maximal isometric contraction analysis showed less potential in the research group, with a significant difference regarding the masseter muscle in isometric contraction. In maximal isometric contraction, an increase in electrical activity in both groups was observed; it remained lower for the research group, but with no significant difference. With regard to symmetry, significant differences among the groups were observed only for the left masseter in the research group, as well as during isometric contraction. There was no significant difference found regarding maximal mouth opening. During swallowing of saliva, there was a high percentage of abnormal electromyographic tracings for both groups. This finding was not expected for the control group. The study found some changes in muscular activity in Class III dentofacial deformities, characterized by lower potential in the masseter muscle during isometric contractions. No other peculiarities were found that could contrast either group.