Abstract the focus ofthis study was to testthe hypothesisthatthere would be no difference betweenthe biocompatibility of silicon dioxide nanofilms used as antimicrobial agents. Sixty male Wistar rats were divided into 4 groups (n=15): Group C (Control,Polyethylene), Group AR (Acrylic Resin), Group NP (Acrylic Resin coated with NP-Liquid), Group BG (Acrylic Resin coated with Bacterlon).the animals were sacrificed with 7,15 and 30 days and tissues analyzed as regardsthe events of inflammatory infiltrate, edema, necrosis, granulation tissue, mutinucleated giant cells, fibroblasts and collagen. Kruskal-Wallis and Dunn tests was used (P<0.05). Intense inflammatory infiltrate was shown mainly in Groups BG and AR, with significant difference from Control Group inthe time interval of 7days (P=0.004). Necrosis demonstrated significant difference between Group BG and Control Group (P<0.05) inthe time intervals of 7 days. For collagen fibers,there was significant difference betweenthe Control Group and Groups AR and BG inthe time interval of 7 days (P=0.006), and between BG and Control Groups inthe time intervals of 15 days (P=0.010).the hypothesis was rejected. Bacterlon demonstratedthe lowest level, and NP-Liquid Glassthe highest level of tissue compatibility, and best cell repair.the coating with NP-Liquid Glass was demonstrated to be highly promising for clinical use.

Resumo Introdução Poucos estudos investigaram as propriedades mecânicas dos fios ortodônticos em bráquetes cerâmicos associados às ligaduras. Objetivo O objetivo deste estudo foi comparar a carga-deflexão de fios ortodônticos com seção redonda de 0,016” de aço inoxidável (AI), níquel-titânio (NiTi) e composto de polímero reforçado com fibra de vidro (CPRFV). Material e método Sessenta espécimes obtidos a partir de 10 arcos pré-contornos seccionados (TP Orthodontics), foram divididos em 3 grupos de 20 de acordo com cada tipo de material (1 fio estético e 2 não estético) e comprimento de 50 mm. A metodologia consistiu de um teste de flexão de 3 pontos usando bráquetes estéticos cerâmicos (INVU, TP Orthodontics, Edgewise, 0,022 “x 0,025”) como pontos de suporte. Os ensaios de tração foram realizados em uma máquina de ensaios mecânicos, a uma velocidade de 10 mm / min, deflexão de 1 mm, 2 mm e 3 mm. Utilizou-se o teste não-paramétrico de comparações múltiplas de Friedman (P <0,05). Resultado O fio de níquel-titânio apresentou menor carga / deflexão em relação ao aço inoxidável. Os fios CPRFV tiveram valores de resistência mais baixos entre todos os grupos avaliados (P <0,05). O fio de aço mostrou deformação permanente após deflexão de 3 mm, fio NiTi demonstrou efeito de memória e o tipo estético teve fraturas com perda de força. Conclusão Pode-se concluir que os fios de aço têm valores de resistência elevados, exigindo a incorporação de alças e dobras para reduzir a carga / deflexão. Os fios NiTi e CPRFV produziram baixos níveis de força, porém o fio estético mostrou-se fraturado e quebrado.

Abstract Introduction Few studies investigated the mechanical properties of orthodontic wires on ceramic brackets associated the ligatures. Objective This study aimed to compare the load-deflection of orthodontic wires with round section of 0.016” made of stainless steel (SS), nickel-titanium (NiTi) and glass fiber-reinforced polymer composite (GFRPC). Material and method Sixty specimens obtained from 10 sectioned pre-contoured arches (TP Orthodontics), were divided into 3 groups of 20 according to each type of material (1 esthetic-type wire and 2 not esthetic) and length of 50 mm. The methodology consisted of a 3-point bending test using esthetic ceramic brackets (INVU, TP Orthodontics, Edgewise, 0.022”x 0.025”) as points of support. The tensile tests were performed on a mechanical test machine, at a speed of 10 mm/min, deflection of 1 mm, 2 mm and 3 mm. Friedman’s Non Parametric Multiple comparisons test was used (P<0.05). Result The nickel-titanium wire presented smaller load/ deflection compared with stainless steel. GFRPC wires had lower strength values among all groups evaluated (P<.05). The steel wire showed permanent deformation after 3 mm deflection, NiTi wire demonstrated memory effect and the esthetic type had fractures with loss of strength. Conclusion It can be concluded that steel wires have high strength values, requiring the incorporation of loops and folds to reduce the load / deflection. NiTi and GFRPC wires produced low levels of force, however the esthetic wire was shown to fracture and break.

ABSTRACT The focus of this study was to test the hypothesis that there would be no difference between the biocompatibility of resin-modified glass ionomer cements. Sixty male Wistar rats were selected and divided into four groups: Control Group; Crosslink Group; RMO Group and Transbond Group. The materials were inserted into rat subcutaneous tissue. After time intervals of 7, 15 and 30 days morphological analyses were performed. The histological parameters assessed were: inflammatory infiltrate intensity; reaction of multinucleated giant cells; edema; necrosis; granulation reaction; young fibroblasts and collagenization. The results obtained were statistically analyzed by the Kruskal-Wallis and Dunn test (P<0.05). After 7 days, Groups RMO and Transbond showed intense inflammatory infiltrate (P=0.004), only Group RMO presented greater expression of multinucleated giant cell reaction (P=0.003) compared with the control group. After the time intervals of 15 and 30 days, there was evidence of light/moderate inflammatory infiltrate, lower level of multinucleated giant cell reaction and thicker areas of young fibroblasts in all the groups. The hypothesis was rejected. The Crosslink cement provided good tissue response, since it demonstrated a lower level of inflammatory infiltrate and higher degree of collagenization, while RMO demonstrated the lowest level of biocompatibility.

Abstract The layer formed by fluoride compounds on tooth surface is important to protect the underlying enamel from erosion. However, there is no investigation into the properties of protective layer formed by NaF and TiF4 varnishes on eroded enamel. This study aimed to evaluate the thickness, topography, nanohardness, and elastic modulus of the protective layer formed by NaF and TiF4 varnishes on enamel after erosion using nanoindentation and atomic force microscopy (AFM). Human enamel specimens were sorted into control, NaF, and TiF4 varnish groups (n = 10). The initial nanohardness and elastic modulus values were obtained and varnishes were applied to the enamel and submitted to erosive challenge (10 cycles: 5 s cola drink/5 s artificial saliva). Thereafter, nanohardness and elastic modulus were measured. Both topography and thickness were evaluated by AFM. The data were subjected to ANOVA, Tukey’s test and Student’s t test (α = 0.05). After erosion, TiF4 showed a thicker protective layer compared to the NaF group and nanohardness and elastic modulus values were significantly lower than those of the control group. It was not possible to measure nanohardness and elastic modulus in the NaF group due to the thin protective layer formed. AFM showed globular deposits, which completely covered the eroded surface in the TiF4 group. After erosive challenge, the protective layer formed by TiF4 varnish showed significant properties and it was thicker than the layer formed by NaF varnish.

The aim of this study is to evaluate cytotoxicity between polyurethane and non-latex orthodontic elastomeric ligatures. Seven elastomeric ligatures of black-coloured from different manufactures (3 non-latex, 3 polyurethane and 1 latex) were divided into 7 groups of 10 elastics each: Group UK (nonlatex, 3M Unitek), Group TP (nonlatex, TP Orthodontics), Group AO (nonlatex, American Orthodontics), Group O (Polyurethane, OrthoSource), Group M (Polyurethane, Morelli), Group TD (Polyurethane, Tecnident) and Group TC (latex - Control, TP Orthodontics). The cytotoxicity essay was performed using cell cultures (L-929 line cells, mouse fibroblast) that were submitted to the cell viability test with neutral red ("dye-uptake") at 1, 2, 3, 7 and 28 days. Analysis of variance (ANOVA) with 1-way analysis followed by the Tukey post hoc test were employed (p<.05). The results showed no statistically significant differences between Groups UK, TP and AO in all experimental times (p>.05). There was a statistically differences (p<.05) between the viability cell of Groups UK, TP and AO with the Groups O, M, TD and TC at 1, 2, 3 and 7 days. There was no statistically differences (p>.05) between the groups O, M and TD at in all experimental times. It can be concluded that the nonlatex elastomeric ligatures of Unitek, TP Orthodontics, and American Orthodontics showed higher cell viability compared to others ligatures.

The objective of this article was to investigate the perception of esthetic changes in the facial profile of bilateral Class II patients treated with the Modified Thurow Appliance for extraoral treatment. Silhouettes were traced of profiles of patients who initially presented a bilateral Class II molar relationship and who, post-treatment, presented molars in a Class I relationship. Three groups were formed: the first composed of patients with maxillary protrusion (SNA >84°), the second with maxillary retrusion (SNA <80°), and the third with a well-positioned maxilla (SNA 80-84°). A panel of 200 lay evaluators judged the profile esthetics by a randomized drawing of the silhouettes. The multiple analysis results showed that the profile esthetic scores for the three positions of the maxilla were greatly influenced by significant interactions with the characteristics (like sex and age) of the evaluators: retrusive maxilla (Score *Age Group, p< 0.001), normal maxilla (Score *Sex, p= 0.024; Score *Age Group,p= 0.050) and protrusive maxilla (Score *Age Group,p< 0.001). It was observed that the profile of Class II patients with protrusion, normal relationship and retrusion of the maxilla, improved in their esthetic post-treatment result; however, the evaluators showed greater satisfaction with the groups of protrusion and normal position of the maxilla. The Modified Thurow Appliance provided significant improvements in the esthetics of the profile of patients who presented protrusion and normal position of the maxilla. However, its use was not the best treatment option for patients with maxillary retrusion.