Critical Frequency of Self-Heating in a Superelastic Ni-Ti Belleville Spring: Experimental Characterization and Numerical Simulation.

The mechanical loading frequency affects the functional properties of shape memory alloys (SMA). Thus, it is crucial to study its effect for the successful use of these materials in dynamic applications. Based on the superelastic cyclic behavior, this work presents an experimental methodology for the determination of the critical frequency of the self-heating of a NiTi Belleville conical spring. For this, cyclic compressive tests were carried out using a universal testing machine with loading frequencies ranging from 0.5 Hz to 10 Hz. The temperature variation during the cyclic tests was monitored using a micro thermocouple glued to the NiTi Belleville spring. Numerical simulations of the spring under quasi-static loadings were performed to assist the analysis. From the experimental methodology applied to the Belleville spring, a self-heating frequency of 1.7 Hz was identified. The self-heating is caused by the latent heat accumulation generated by successive cycles of stress-induced phase transformation in the material. At 2.0 Hz, an increase of 1.2 °C in the average temperature of the SMA device was verified between 1st and 128th superelastic cycles. At 10 Hz, the average temperature increase reached 7.9 °C and caused a 10% increase in the stiffness and 25% decrease in the viscous damping factor. Finally, predicted results of the force as a function of the loading frequency were obtained.

Quantitative assessment of DNA damage in the industrial ethanol production strain Saccharomyces cerevisiae PE-2.

Lignocellulosic hydrolysates remain one of the most abundantly used substrates for the sustainable production of second generation fuels and chemicals with Saccharomyces cerevisiae. Nevertheless, fermentation inhibitors such as acetic acid, furfural and hydroxymethylfurfural are formed during the process and can lead to slow or stuck fermentations and/or act as genotoxic agents leading to production strain genetic instability. We have developed a novel dominant deletion (DEL) cassette assay for quantification of DNA damage in both wild-type and industrial yeast strains. Using this assay, the ethanol production strain S. cerevisiae PE-2 was shown to be more resistant to hydrogen peroxide and furfural than the laboratory DEL strain RS112. Indeed, the PE-2 strain also showed a lower tendency for recombination, consistent with a more efficient DNA protection. The dominant DEL assay presented herein should prove to be a useful tool in the selection of robust yeast strains and process conditions for second generation feedstock fermentations.

A novel D-xylose isomerase from the gut of the wood feeding beetle Odontotaenius disjunctus efficiently expressed in Saccharomyces cerevisiae.

Carbohydrate rich substrates such as lignocellulosic hydrolysates remain one of the primary sources of potentially renewable fuel and bulk chemicals. The pentose sugar D-xylose is often present in significant amounts along with hexoses. Saccharomyces cerevisiae can acquire the ability to metabolize D-xylose through expression of heterologous D-xylose isomerase (XI). This enzyme is notoriously difficult to express in S. cerevisiae and only fourteen XIs have been reported to be active so far. We cloned a new D-xylose isomerase derived from microorganisms in the gut of the wood-feeding beetle Odontotaenius disjunctus. Although somewhat homologous to the XI from Piromyces sp. E2, the new gene was identified as bacterial in origin and the host as a Parabacteroides sp. Expression of the new XI in S. cerevisiae resulted in faster aerobic growth than the XI from Piromyces on D-xylose media. The D-xylose isomerization rate conferred by the new XI was also 72% higher, while absolute xylitol production was identical in both strains. Interestingly, increasing concentrations of xylitol (up to 8 g L-1) appeared not to inhibit D-xylose consumption. The newly described XI displayed 2.6 times higher specific activity, 37% lower KM for D-xylose, and exhibited higher activity over a broader temperature range, retaining 51% of maximal activity at 30 °C compared with only 29% activity for the Piromyces XI.

Oral manifestations of celiac disease. A case report and review of the literature.

Celiac disease is a chronic intestinal disease caused by intolerance to gluten associated with poor digestion and absorption of the majority of nutrients and vitamins, which may affect both developing dentition and oral mucosa. The aim of this study is to make a brief review of the literature about celiac disease and to report on a clinical case, showing the impact it may have on the general and oral health. A 39-year-old woman reported the presence of diarrhea, nauseas, flatulence, colic, difficulty with falling asleep, lack of appetite and loose of 18 Kg in the last two years. She also noted the appearance of symptomatic lesions in the mouth. These lesions had a mean duration of a month and occurred in any region of the oral mucosa, particularly on the tongue. Multiples ulcerations were found in the sublingual caruncula region, at the vestibular fornix and at the lingual apex. Topical treatment was instituted for the oral lesions with immediately relief of the symptoms. The diagnosis of celiac disease was established by means of medical clinical exam, biopsy of the small intestine, and by the presence of specific antibodies in the blood. The patient has been instructed to follow a gluten-free diet. Multiprofessional action with the involvement of a gastroenterologist and other health professionals, such as dentists, is important for diagnosing the disease and guiding the patient with celiac disease to achieve a good quality of life.

Chick Embryo Model for Homing and Host Interactions of Tissue Engineering-Purposed Human Dental Stem Cells.

Human dental stem cells (hDSC) have a potential for regenerative therapies and could differentiate in vitro into many tissues, such as dentin, nerve, and vascular endothelium. Gallus gallus domesticus developing fertilized egg or chick embryo is an experimental model absent of xenografts rejection, largely employed in replacement of mammal species in scientific research and preclinical studies to evaluate angiogenesis and vasculogenesis, tissue differentiation, and embryonic development. This multiscale research deals with the homing and cell signaling effects of a standardized hDSC toward the receptor tissues of G. gallus domesticus in ovo. The hDSC were obtained from the explantation from third molars, characterized by cell cytometry, and employed without any further purification procedure. Four experimental groups were studied, according to the kind of cell tracing strategy, named: Control, mCherry-labeled hDSC, QTracker-labeled hDSC, and QTracker-exposed controls. The eggs were kept in an incubator temperature of 37.6°C and humidity 86%, and the embryos were euthanized after 10 days of incubation. In vivo fluorescence and histological analysis were conducted. The fluorescence of the embryos inoculated with mCherry hDSC or the QTracker hDSC was associated with the bones and the beak tooth, and labeled cell islands could be localized in part of the samples. The inoculation of the QTracker probe resulted in proliferating bone tissue labeling. The hDSC inoculated groups presented cartilage plate hypertrophy and atypical morphology, meanwhile Control eggs were negative. The results demonstrated that hDSC can migrate to the cartilaginous tissues of the chick embryos, survive in this environment, implant, and interfere with the growth of developing bone.

Effect of air abrasion on tensile bond strength of a single-bottle adhesive/indirect composite system to enamel.

This study evaluated the efficiency of air abrasion alone and associated with phosphoric acid etching on tensile bond strength of a single-bottle adhesive/indirect composite restorative system (Bond 1/Alert) to human enamel. Forty enamel surfaces from extracted human third molars were assigned to 4 groups (n= 10). Mach 4.1 (Kreativ Inc.) air abrasion equipment was used for 20 s. A special system of rod pairs aligned in a specific apparatus was used for tensile strength tests, according to ISO/TR 11405 standard (1994) with some modifications. Bond strength means were: G1 (air abrasion + rinsing + condensable composite resin Alert) = 3.46 +/- 0.83 MPa; G2 (air abrasion + rinsing + Bond 1 adhesive system + Alert) = 4.00 +/- 1.60 MPa; G3 (air abrasion + rinsing + 37% phosphoric acid + rinsing + Bond 1 + Alert) = 20.80 +/- 3.95 MPa; and G4 (37% phosphoric acid + rinsing + Bond 1 + Alert) = 17.00 +/- 2.74 MPa. The statistical analysis by Kruskal-Wallis test revealed that G1 and G2 presented statistically significant difference (p< 0.05) from G3 and G4 (p<0.01) and G1 and G3 did not differ significantly (p> 0.05) from G2 and G4, respectively.

Case of recurrent paracoccidioidomycosis in female. 10 years after initial treatment.

This report describes a case of recurrence of chronic paracoccidioidomycosis 10 years following the initial diagnosis. A 56-year-old female was admitted to the Dental Clinic of the Pontifical Catholic University of Paraná complaining of oral soreness. Mulberry-like ulcerations were observed on the gingiva, right labial comissura, and vermillion of the lip. The patient reported persistent chronic cough, weight loss, appetite loss and fever. The anamnesis revealed that the patient had developed and been treated for paracoccidioidomycosis 10 years earlier. A biopsy was performed and microscopic examination revealed microabscesses, collections of macrophages organized into granulomas, multinucleated giant cells and Paracoccidioides brasiliensis. The patient was treated with Itraconazole and, the oral lesions disappeared within 3 months. Persistent follow-up examination in patients with a history of paracoccidioidomycosis is essential in the management of this disease.

Temperature analysis during bonding of brackets using LED or halogen light base units.

The purpose of our investigation is to compare the intrapulpal temperature changes following blue LED system and halogen lamp irradiation at the enamel surface of permanent teeth. The fixation of brackets using composite resin is more comfortable and faster when using a photo-curable composite. Several light sources can be used: halogens, arc plasma, lasers, and recently blue LED systems. An important aspect to be observed during such a procedures is the temperature change. In this study, we have used nine human extracted permanent teeth: three central incisors, three lateral incisors, and three canines. Teeth were exposed to two light sources: blue LED system (preliminary commercial model LEC 470-II) and halogen lamp (conventional photo-cure equipment). The surface of teeth was exposed for 20, 40, and 60 sec at the buccal and lingual enamel surface with an angle of 45 degrees. Temperature values measured by a thermistor placed at pulpar chamber were read in time intervals of 1 sec. We obtained plots showing the temperature evolution as a function of time for each experiment. There is a correlation between heating quantity and exposition time of light source: with increasing exposition time, heating increases into the pulpal chamber. The halogen lamp showed higher heating than the LED system, which showed a shorter time of cooling than halogen lamp. The blue LED system seems like the indicated light source for photo-cure of composite resin during the bonding of brackets. The fixation of brackets using composite resin is more comfortable and faster when using a photo-curable composite. Blue LED equipment did not heat during its use. This could permit a shorter clinical time of operation and better performance.

In-vivo bone response to titanium screw implants anodized in sodium sulfate.

PURPOSE: To evaluate the early bone response to a nanotextured dental implant treated with sodium sulfate (Na2SO4), using a rabbit model. METHODS: Twelve animals were randomly divided into group 1 (Control) - machined implants and group 2 (Test) - nanotextured implants. Extra-oral incision was performed to provide access to intended surgical site where the dental implant was inserted immediately after the extraction of the mandibular first premolar. Implant surface characterization was performed by scanning electron microscopy attached to energy dispersive spectroscopy and interferometry. Three weeks after surgery, the animals were induced to death and undecalcified sections of the samples were prepared for histological and histomorphometrical analysis. RESULTS: Surface characterization of the implant demonstrated enhanced surface area of anodized group compared to Control group with 19.2% ± 6.2 versus 1.6 ± 0.7, respectively. Histological evaluation demonstrated new bone formation starting from the buccal and lingual cortical walls on both groups. After three weeks, significant higher bone contact of 27% (p<0.05) was observed to nanotextured compared to machined implants (Control group). CONCLUSION: The anodization with sodium sulfate nanostructures to the implant surface that resulted in faster osseointegration.

Braquetes cerâmicos fabricados por impressão 3D: ensaio mecânico de resistência à torção pela aplicação de torques / Ceramic brackets manufactured by 3D printing: mechanical test of torsion resistance by application of torques

A proposição deste estudo foi comparar a nova geração de braquetes personalizados cerâmicos impressos 3D Lightforce Clear , com os braquetes cerâmicos injetados Clarity e GC Chic em um ensaio mecânico de resistência à torção pela aplicação de torque. Amostras de braquetes cerâmicos impressos de alumina policristalina de incisivos centrais superiores (n=10), o Lightforce Clear (Lightforce Orthodontics), e os braquetes cerâmicos injetados de alumina policristalina, Clarity (3M Unitek) e GC Chic (GC Orthodontics) os quais foram submetidos ao teste de resistência à fratura torcional utilizando um segmento de fio de aço inoxidável 0,019 x 0,025 polegadas em uma máquina de ensaio universal (EMIC, DL-1000) à uma velocidade de 1mm/min e célula de carga de 1000 kg. Os resultados foram submetidos à análise estatística ANOVA fator 1. Os valores médios e desvio padrão obtidos no ensaio de resistência à torção de carga máxima de fratura (N) nos três grupos de bráquetes foram: 14,53 ± 2,85 para Lightforce Clear; 12,03 ± 2,44 para Clarity e 6,65 ± 0,35 para o CG Chic. Foi observado que houve diferença estatística significante entre os grupos testados (p<0,05). Os braquetes Lightforce Clear cerâmicos impressos 3D customizados mostraram-se mais resistentes que os injetados apontando como uma alternativa factível e promissora em busca de uma ortodontia digital de precisão contudo existe a necessidade de incorporar novas pesquisas para o avanço desta tecnologia (AU).

The purpose of this study was to compare the new generation of customized ceramic brackets 3D printed Lightforce Clear, with the injected ceramic brackets Clarity and GC Chic in a mechanical test of torsion resistance by the application of torque. Samples of ceramic printed polycrystalline alumina brackets of upper central incisors (n=10), Lightforce Clear (Lightforce Orthodontics), and the injected ceramic brackets made from polycrystalline alumina, Clarity (3M Unitek) and GC Chic (GC Orthodontics) which were subjected to torsional fracture strength testing using a 0.019 x 0.025-inch stainless steel wire segment in a universal testing machine (EMIC, DL-1000) at a speed of 1 mm/min and a load cell of 1000 kg. The results were submitted to ANOVA factor 1 statistical analysis. The mean values and standard deviation obtained in the maximum fracture load (N) torsional strength test in the three groups of brackets were: 14.53 ± 2.85 for Lightforce Clear; 12.03 ± 2.44 for Clarity and 6.65 ± 0.35 for CG Chic. It was observed that there was a statistically significant difference between the groups tested (p<0.05). The customized 3D printed Lightforce Clear ceramic brackets proved to be more resistant than the injected ones, pointing as a feasible and promising alternative in the search for precision digital orthodontics, however there is a need to incorporate new research to advance this technology (AU).

Nonwoven polypropylene prosthesis in large abdominal wall defects in rats.

PURPOSE: To evaluate, in large abdominal wall defects surgically shaped in rats, if a synthetic polypropylene nonwoven prosthesis could be used as a therapeutic option to conventional polypropylene mesh. METHODS: Twenty four (24) Wistar rats were enrolled into three groups. Group 1 (Simulation group) with an abdominal wall defect of 3 X 3 left untreated and Groups 2 and 3, respectively treated with a conventional polypropylene mesh and a polypropylene nonwoven (NWV) prosthesis to cover the breach. At the 45th postoperatively day, adhesion (area and strength) and vascularization of Groups 2 and 3 were evaluated. The histological preparations with Hematoxylin-Eosin, Tricromium of Masson, Pricrosirius red and polarization with birefringence, and also the structural analysis of the prostheses carried on by Thermogravimetry and Differential Scanning Calorimetry were also assessed. RESULTS: There were no significant differences between the Groups 2 and 3. CONCLUSION: In rats, the polypropylene nonwoven prosthesis showed to be safe and has to be considered as an alternative to conventional mesh manufactured by weaving in the treatment of great defects of the abdominal wall.

Molars extraction for bone graft study in rabbits.

PURPOSE: The aim of this study was to describe an experimental surgical technique to be used in the evaluation of bone grafts in rabbits. METHODS: The operative technique was performed in jaws, with external approach from the labial commissure to the last molar tooth. An incision about 1cm extended forward to the alveolar ridge, followed by a exposing the cervical region of the alveolar bone and dental elements was done. Thus, after extraction of first molar with forceps, the tooth socket left was filled with hydroxyapatite. The bone gain was analyzed by histopathological studies. RESULTS: The histological analyses indicated formed bone surrounding the biomaterial. CONCLUSION: The experimental model using the tooth socket of the rabbit molar is a feasible procedure for studies of bone grafts.

In-vivo bone response to titanium screw implants anodized in sodium sulfate

PURPOSE: To evaluate the early bone response to a nanotextured dental implant treated with sodium sulfate (Na2SO4), using a rabbit model. METHODS: Twelve animals were randomly divided into group 1 (Control) - machined implants and group 2 (Test) - nanotextured implants. Extra-oral incision was performed to provide access to intended surgical site where the dental implant was inserted immediately after the extraction of the mandibular first premolar. Implant surface characterization was performed by scanning electron microscopy attached to energy dispersive spectroscopy and interferometry. Three weeks after surgery, the animals were induced to death and undecalcified sections of the samples were prepared for histological and histomorphometrical analysis. RESULTS: Surface characterization of the implant demonstrated enhanced surface area of anodized group compared to Control group with 19.2% ± 6.2 versus 1.6 ± 0.7, respectively. Histological evaluation demonstrated new bone formation starting from the buccal and lingual cortical walls on both groups. After three weeks, significant higher bone contact of 27% (p<0.05) was observed to nanotextured compared to machined implants (Control group). CONCLUSION: The anodization with sodium sulfate nanostructures to the implant surface that resulted in faster osseointegration. .

Nonwoven polypropylene prosthesis in large abdominal wall defects in rats / Tela de polipropileno sem tecelagem na correção de grandes defeitos da parede abdominal em ratos

PURPOSE: To evaluate, in large abdominal wall defects surgically shaped in rats, if a synthetic polypropylene nonwoven prosthesis could be used as a therapeutic option to conventional polypropylene mesh. METHODS: Twenty four (24) Wistar rats were enrolled into three groups. Group 1 (Simulation group) with an abdominal wall defect of 3 X 3 left untreated and Groups 2 and 3, respectively treated with a conventional polypropylene mesh and a polypropylene nonwoven (NWV) prosthesis to cover the breach. At the 45th postoperatively day, adhesion (area and strength) and vascularization of Groups 2 and 3 were evaluated. The histological preparations with Hematoxylin-Eosin, Tricromium of Masson, Pricrosirius red and polarization with birefringence, and also the structural analysis of the prostheses carried on by Thermogravimetry and Differential Scanning Calorimetry were also assessed. RESULTS: There were no significant differences between the Groups 2 and 3. CONCLUSION: In rats, the polypropylene nonwoven prosthesis showed to be safe and has to be considered as an alternative to conventional mesh manufactured by weaving in the treatment of great defects of the abdominal wall.

OBJETIVO: Avaliar, em grandes defeitos da parede abdominal produzidos cirurgicamente em ratos, se uma prótese sintética de polipropileno sem tecelagem poderia ser utilizada como alternativa terapêutica às telas convencionais de polipropileno. MÉTODOS: Vinte e quatro ratos foram distribuídos em três grupos numericamente iguais. Grupo 1 (Simulação), no qual um defeito de 3 x 3 cm foi constituído na parede abdominal sem tratamento. Uma tela convencional de polipropileno e uma tela de polipropileno sem tecelagem foram colocadas para cobrir o defeito, nos grupos 2 e 3 , respectivamente. No 45º dia de pós-operatório foram avaliadas a área e a força das aderências, além da vascularização. Também foram analisados os preparados histológicos com Hematoxilina-eosina, Tricrômio de Masson e Picrosirius com polarização e birrefringência, além de efetuada análise estrutural da prótese mediante Termogavimetria e Colorimetria Exploratória Diferencial. RESULTADOS: Não houve diferença significante entre os grupos 2 e 3. CONCLUSÃO: Em ratos, a tela de polipropileno sem tecelagem mostrou ser segura e deve ser considerada como uma alternativa à tela convencional manufaturada por tecelagem, no tratamento dos grandes defeitos da parede abdominal.

Molars extraction for bone graft study in rabbits / Extração de molares para estudos de enxertos ósseos em coelhos

PURPOSE: The aim of this study was to describe an experimental surgical technique to be used in the evaluation of bone grafts in rabbits. METHODS: The operative technique was performed in jaws, with external approach from the labial commissure to the last molar tooth. An incision about 1cm extended forward to the alveolar ridge, followed by a exposing the cervical region of the alveolar bone and dental elements was done. Thus, after extraction of first molar with forceps, the tooth socket left was filled with hydroxyapatite. The bone gain was analyzed by histopathological studies. RESULTS: The histological analyses indicated formed bone surrounding the biomaterial. CONCLUSION: The experimental model using the tooth socket of the rabbit molar is a feasible procedure for studies of bone grafts.

OBJETIVO: Descrever uma técnica cirúrgica em coelhos para avaliação de enxertos ósseos. MÉTODOS: A técnica operatória consiste numa incisão na topografia da comissura labial até o ultimo molar. Uma incisão de 1cm no rebordo para expor o osso alveolar e a região cervical dos molares. Realizou-se a exodontia com fórceps e o alvéolo é preenchido com hidroxiapatita. Após o tempo de cicatrização é realizada a avaliação histológica. RESULTADOS: A análise histológica mostrou o novo osso formado rodeando biomaterial. CONCLUSÃO: O modelo cirúrgico para avaliação de enxertos ósseos utilizando molares de coelhos se mostrou factível.

Tensile bond strength of dentin-resinous system interfaces conditioned with Er:YAG laser irradiation.

OBJECTIVE: The aim of this in vitro study was to assess tensile bond strength of dentin-resinous system interfaces conditioned with Er:YAG laser irradiation. BACKGROUND DATA: There are different results reported in the literature which relate to laser Er:YAG effects on dentin surface as a pretreatment during adhesives procedures. MATERIALS AND METHODS: Forty-two surfaces of human dentin from third upper molar were used after being extracted and kept in the refrigerator in 0.5% chloramines aqueous solution and then divided into three experimental groups and three control groups. The chosen restorative systems were Alert (Jeneric/Penton), Prodigy (Kerr Co.), and Z-100 (3M Co.), with correspondent dental adhesives Bond 1, Optibond Solo, and Single Bond, respectively. To conduct tensile tests, a special system of pairs of rods aligned in a specific apparatus was used, in accordance with ISO/TR 11405 standard (1994). RESULTS: By means of statistical analysis, the Kruskal Wallis test, it was noticed that group IE (laser + acid + Alert), 18.89 MPa, differed considerably from group IC (acid + Alert), 8.03 MPa (p < 0.10), but did not differ from the other groups. Group IIC (acid + Prodigy), 19.88 MPa, differed from group IIE (laser + acid + Prodigy), 12.57 MPa (p < 0.05), but did not differ from groups IIIE (laser + acid + Z-100), 14.11 MPa, and IIIC (acid + Z-100), 19.58 MPa. Group IIIE did not differ statistically from group IIIC. CONCLUSION: It was concluded that previous Er:YAG laser treatment on the dentinal structure only improved the tensile bond resistance of the Alert restorative system.

Effect of air abrasion on tensile bond strength of a single-bottle adhesive/indirect composite system to enamel

This study evaluated the efficiency of air abrasion alone and associated with phosphoric acid etching on tensile bond strength of a single-bottle adhesive/indirect composite restorative system (Bond 1/Alert) to human enamel. Forty enamel surfaces from extracted human third molars were assigned to 4 groups (n= 10). Mach 4.1 (Kreativ Inc.) air abrasion equipment was used for 20 s. A special system of rod pairs aligned in a specific apparatus was used for tensile strength tests, according to ISO/TR 11405 standard (1994) with some modifications. Bond strength means were: G1 (air abrasion + rinsing + condensable composite resin Alert) = 3.46 ± 0.83 MPa; G2 (air abrasion + rinsing + Bond 1 adhesive system + Alert) = 4.00 ± 1.60 MPa; G3 (air abrasion + rinsing + 37 percent phosphoric acid + rinsing + Bond 1 + Alert) = 20.80 ± 3.95 MPa; and G4 (37 percent phosphoric acid + rinsing + Bond 1 + Alert) = 17.00 ± 2.74 MPa. The statistical analysis by Kruskal-Wallis test revealed that G1 and G2 presented statistically significant difference (p< 0.05) from G3 and G4 (p<0.01) and G1 and G3 did not differ significantly (p> 0.05) from G2 and G4, respectively.

O objetivo deste estudo foi avaliar a eficiência da abrasão a ar associada ou não ao condicionamento com ácido fosfórico na resistência à tração de um sistema restaurador composto por adesivo frasco único/resina composta indireta (Bond 1/Alert) ao esmalte humano. Quarenta superfícies de esmalte de terceiros molares humanos extraídos foram alocadas em 4 grupos (n=10). Foi utilizado o sistema de ar abrasivo Mach 4.1 (Kreativ Inc.) durante 20 s. Um sistema especial de pares de hastes alinhadas em um equipamento específico foi usado para realização dos testes de tração, de acordo com a Norma ISO/TR 11405 (1994) com algumas modificações. Os valores médios obtidos foram: G1 (ar abrasivo + lavagem + resina condensável Alert) = 3,46 ± 0,83 MPa; G2 (ar abrasivo + lavagem + adesivo Bond 1 + Alert) = 4,00 ± 1,60 MPa; G3 (ar abrasivo + lavagem + ácido fosfórico 37 por cento + lavagem + Bond 1 + Alert) = 20,80 ± 3,95 MPa; e G4 (ácido fosfórico 37 por cento + lavagem + Bond 1 + Alert) = 17,00 ± 2,74 MPa. Pela análise estatística (teste Kruskal Wallis), G1 e G2 apresentaram diferença estatisticamente significante em relação a G3 e G4 (p<0,01) e G1 e G3 não diferiram dos grupos G2 e G4, respectivamente (p>0,05).

Dental enamel: qualitative evaluation of the surface after application of aluminum oxide (microetching) using the scanning electron microscope / Esmalte dental: avaliaçäo qualitativa da superfície tratada com jato de óxido de alumínio (\"microetching\") por meio de microscopia eletrônica de varredura

A odontologia de nossos tempos conta com inúmeros recursos para o tratamento de pacientes. Com o desenvolvimento dos materiais adesivos e a introduçäo de novas técnicas restauradoras, a estrutura dental pode receber diferentes tipos de tratamentos superficiais. O uso do fluxo de óxido de alumínio em alta velocidade para a remoçäo de estrutura dental foi descrito por Black em 1945, no entanto, a literatura pertinente ao uso do jato de óxido de alumínio ainda permanece escassa no que se refere às alteraçöes produzidas na estrutura dental. Atualmente, com o desenvolvimento de novos equipamentos de ar abrasivo, o procedimento de microabrasäo vem sendo incorporado a várias técnicas restauradoras adesivas no preparo de superfícies dentais e superfícies internas de restauraçöes indiretas, as quais receberäo a aplicaçäo de materiais adesivos. O objetivo simples deste estudo foi avaliar as alteraçöes produzidas pelo uso do ar abrasivo sobre o esmalte dental por meio de microscopia eletrônica de varredura, observando-se as alteraçöes micromorfológicas superficiais. A importância deste estudo baseia-se no fato de que tratamentos superficiais alternativos químicos e mecânicos venham a ser introduzidos para o condicionamento de superficies, inclusive do esmalte dental

Prevalência das lesões pigmentadas bucais e peribucais em laudos histopatológicos do laboratorio de patologia experimental da PUCPR no paríodo de 1999-2008

As lesões pigmentadas são relativamente incomuns na boca. Elas representam um grupo de entidades clínicas que variam desde alterações fisiológicas atá a manifestação de doenças sistêmicas ou locais. A literatura não apresenta dados concretos sobre a real prevalência das pigmentações bucais. Este estudo analisou a prevalência de lesões pigmentadas afetando a mucosa bucal e a região peribucal a partir dos laudos histopatológicos no período de 1999 a 2008. Os laudos de exames histopatológicos do Laboratório de Patologia Experimental da PUCPR foram consultados. Aproximadamente 1990 laudos foram avaliados com relação a coloração, localização anatômica, sexo e idade dos pacientes. Os dados obtidos foram tabulados e submetidos à análise estatística descritiva. As seguintes lesões pigmentadas foram diagnosticadas: nevos (0,9 por cento), argirose focal (0,5 por cento), mácula melanótica bucal (0,25 por cento), pigmentação melânica fisiológica (0,15 por cento, pigmentação pós -inflamação (0,05 por cento) e lentigo (0,05 por cento). A ocorrência de lesões pigmentadas foi mais frequente durante a terceira e quinta décadas de vida em mulheres (71,8 por cento). De acordo com esses resultados, pode-se concluir que prevalência de lesões pigmentadas na boca é baixa, entretanto, o cirurgião-dentista precisa estar atento para a realização do diagnóstico e o tratamento correto de tais entidades

Polimento imediato e mediato do amálgama: avaliaçäo clínica e laboratorial / Mediate and imediate amalgama polishing: clinical and laboratory evaluation

O amálgama dental tem sido o material restaurador mais utilizado na Odontologia desde o século dezenove, devido a suas propriedades de manipulaçäo, performance clínica favorável, baixo custo e biocompatibilidade com os tecidos bucais. No entanto, o tratamento final, segundo alguns autores, continua sendo negligenciado, embora, todos concordem que as restauraçöes de amálgama devem receber acabamento e polimento final. Os autores, neste trabalho, analisaram a viabilidade de dar o acabamento e polimento imediato em restauraçöes confeccionadas com diferentes marcas comerciais de ligas para amálgama, bem como analisaram a performance de cada retauraçäo quanto ao polimento imediato e mediato