RESUMO

BACKGROUND/AIM: Maxillary canines have a high incidence of impaction which may be associated with unexpected damage during maxillofacial trauma. The aim of this study was to evaluate how an impacted canine could influence the stress distribution in the dentoalveolar complex during a simulated impact before and after surgical removal plus the protective effect offered by a mouthguard. MATERIALS AND METHODS: Cross-sectional finite element models of the central incisor and support structures of a patient with an impacted canine in a transverse position were made using ImageJ and Marc/Mentat software. The following impact conditions were simulated: (a) incisor with impacted canine; (b) incisor with surgical socket after impacted canine extraction; and (c) incisor after bone healing. The impacts were also simulated with a 3 mm custom-fitted ethylene vinyl acetate mouthguard. A non-linear dynamic impact finite element analysis was performed in which a rigid object hit the model at 1 m/s. Maximum and minimum principal stresses as well as von Mises stresses were analyzed. RESULTS: Higher values of compressive and tensile stresses occurred on the cortical bone in the models after impacted canine extraction. The highest stress concentrations in the enamel and dentin structures were observed after bone healing. The mouthguard reduced the stress in the alveolar bone and dental structures. CONCLUSIONS: Use of mouthguards during impact reduced the compressive and tensile stresses in the alveolar bone, mainly in the fragile regions of the impacted canine or surgical socket.

Assuntos

RESUMO

The influence of environmental factors in a semiarid climate on characteristics of fresh and frozen/thawed sperm collected from collared peccaries (Pecari tajacu) was assessed. Semen from 11 male collared peccaries was collected by electroejaculation during the peaks of the dry and rainy periods while rainfall indices, air temperatures, relative humidity levels, and wind speeds were measured. The number, motility, morphology, osmotic response, and membrane integrity of sperm in the collected ejaculates were assessed. Samples were then frozen in liquid nitrogen, thawed, and reassessed. The rainfall index of the rainy period (73.2 mm) was significantly higher than that of the dry period (13.6 mm) and the relative humidity was significantly higher during the rainy period (74.6%) than it was during the dry period (66.8%). Air temperature and wind speed did not differ between the two periods. Characteristics of sperm in the fresh samples were not affected by environmental parameters. In contrast, computerized analysis revealed that sperm in samples frozen during the rainy period exhibited better post-thaw membrane integrity (28.6 ± 6%), motility (29.5 ± 7.7%), and rapid sperm population (13.7 ± 6.2%) than did sperm in samples frozen during the dry period (23.4 ± 3% membrane integrity, 14.6 ± 4.1% motility, and 4.1 ± 1.2% rapid sperm; p < 0.05). Other characteristics of the frozen/thawed sperm did not differ depending on the period in which they were collected. We demonstrated that environmental parameters did not affect the quality of fresh sperm, but could influence the freezability of sperm collected from collared peccaries raised under a semiarid climate.

RESUMO

A synthetic procedure is described for the obtaining of superparamagnetic Co nanoparticles (NPs) via hot-injection method in the presence of sodium borohydride. The Co NPs obtained have an average diameter of 5.3 nm and saturation magnetization of 115 emu g-1. A modified Langevin equation is fitted to the magnetization curves using a log-normal distribution for the particle diameter and an effective field to account for dipolar interactions. The calculated magnetic diameter of the Co NPs is 0.6 nm smaller than TEM-derived values, implying a magnetic dead layer of 0.3 nm. The magnetic core is coated with Au to prevent oxidation, resulting in water-stable magneto-plasmonic Co/Au core/shell NPs with saturation of 71.6 emu g-1. The coating adds a localized surface plasmon resonance property with absorbance in the so-called 'therapeutic window' (690-900 nm), suitable for biomedical applications. It is suggested that these multifunctional NPs are distinguished as a potential platform for applied and fundamental research.

RESUMO

The aim of this study was to determine oxygen saturation levels in the dental pulp of maxillary premolars in different age groups. A total of 120 human maxillary premolars with normal dental pulps were selected covering the following age groups: 20-24, 25-29, 30-34, 35-39 and 40-44 years (n=24 each group). Oxygen saturation was assessed using pulse oximetry. Analysis of variance was used to assess differences in oxygen saturation levels and Tukey's test was used to identify the age groups that differed from each other. Significance was set at 0.05. Mean oxygen saturation of 120 premolars was 86.20% considering all age groups. Significantly reduced levels were found in the oldest group compared to the other groups: 40 to 44 years - 80.00% vs. 89.71, 87.67, 88.71, and 84.80% for age groups 20-24, 25-29, 30-34, 35-39 years, respectively. The mean oxygen saturation levels were similar between 20 and 39 years of age (86.20%) in the whole sample, but reduced significantly in the 40-44-year age group, suggesting that older patients present lower oxygen saturation results even in the absence of pulp tissue injury.

Assuntos

RESUMO

Abstract The aim of this study was to determine oxygen saturation levels in the dental pulp of maxillary premolars in different age groups. A total of 120 human maxillary premolars with normal dental pulps were selected covering the following age groups: 20-24, 25-29, 30-34, 35-39 and 40-44 years (n=24 each group). Oxygen saturation was assessed using pulse oximetry. Analysis of variance was used to assess differences in oxygen saturation levels and Tukey's test was used to identify the age groups that differed from each other. Significance was set at 0.05. Mean oxygen saturation of 120 premolars was 86.20% considering all age groups. Significantly reduced levels were found in the oldest group compared to the other groups: 40 to 44 years - 80.00% vs. 89.71, 87.67, 88.71, and 84.80% for age groups 20-24, 25-29, 30-34, 35-39 years, respectively. The mean oxygen saturation levels were similar between 20 and 39 years of age (86.20%) in the whole sample, but reduced significantly in the 40-44-year age group, suggesting that older patients present lower oxygen saturation results even in the absence of pulp tissue injury.

Resumo Este estudo determinou os níveis de saturação de oxigênio (SaO2) em polpas dentárias de pré-molares superiores em diferentes faixas etárias. Foram selecionados 120 pré-molares superiores humanos com polpas dentárias normais, abrangendo os seguintes grupos etários: 20-24, 25-29, 30-34, 35-39 e 40-44 anos (n=24 para cada grupo). A saturação de oxigênio foi avaliada utilizando oximetria de pulso. A análise de variância foi utilizada para avaliar diferenças nos níveis de saturação de oxigênio, e o teste de Tukey foi utilizado para identificar os grupos etários que diferiam uns dos outros. A significância foi estabelecida em 0,05. A saturação média de oxigênio foi de 86,20% considerando todos os grupos etários. Níveis significativamente reduzidos foram encontrados no grupo de indivíduos de maior idade em comparação aos outros grupos: 40 a 44 anos - 80,00% vs. 89,71, 87,67, 88,71 e 84,80% para os grupos etários 20-24, 25-29, 30-34, 35-39 anos. Os níveis médios de saturação de oxigênio foram semelhantes entre os 20 e os 39 anos de idade (86,20%), mas reduziram-se significativamente na faixa etária de 40-44 anos, sugerindo que os pacientes mais idosos apresentam menor saturação de oxigênio mesmo na ausência de lesão do tecido pulpar.

Assuntos

RESUMO

Incremental technique for resin composite restorations requires multiple physical contacts between spatulas, tooth cavities and the restorative material recipient. Thus, the decontamination of the tip's of spatula by chemical agents between each resin composite increment placement is important to reduce chances of potential cross-contamination. Objectives: To evaluate the efficacy of different solutions for decontamination of tips of spatula used in restorative procedures and to establish a decontamination standard protocol. Material and Methods: Spatulas were sterilized in autoclave at 127°C for 20 minutes and then contaminated with: 1) a suspension of half 1.0 MacFarland scale turbidity of different microorganisms, 2) the pool of equal amounts of these microorganisms; except for the control group. Decontamination techniques consisted of rubbing the tip of the spatulas (1 to 5 consecutive times) using a 2ml 70% ethanol or 2% glutaraldehyde embedded gauze. After decontamination, spatulas were immersed in thioglycolate broth and incubated for 48 hours at 37°C. Broth with visible microbial detection was submitted to bacterial identification by Gram stain. Results: Low uniformity of rubbings number was observed to eliminate different microorganisms due to different tested disinfectant agents. Four or five rubbings were needed to decontamination of the tested microorganisms using 70% ethanol. Three rubbings using 2% glutaraldehyde were able to eliminate tested microorganisms. Conclusion: The results demonstrated that 70% ethanol by friction, counting four or five rubbings, was effective to decontaminate spatula's tip.

A técnica incremental para restaurações de resina composta requer vários contatos físicos entre as espátulas, o preparo cavitário e a embalagem do material restaurador. Assim, a descontaminação da ponta da espátula por meio de agentes químicos entre cada inserção de um novo incremento de resina composta é importante para reduzir as chances de uma potencial de contaminação cruzada. Objetivos: Avaliar a eficácia de diferentes soluções para descontaminação das pontas das espátulas utilizadas em procedimentos restauradores e estabelecer um protocolo padrão de descontaminação. Material e Métodos: espátulas foram esterilizadas em autoclave a 127 °C durante 20 minutos e, em seguida, contaminadas com: 1) uma suspensão de diferentes microorganismos com turbidez equivalente ao padrão 1,0 da escala de McFarland, 2) pool de quantidades iguais destes microrganismos; exceto para o grupo de controle. As técnicas de descontaminação consistiram em esfregar a ponta das espátulas (1 a 5 vezes consecutivas) utilizando 2 ml de álcool 70% ou 2% de glutaraldeído embebidos em gazes. Após a descontaminação, as espátulas foram imersas em caldo de tioglicolato e incubadas durante 48 horas a 37 °C. O caldo com visível detecção microbiana foi submetido à identificação bacteriana pela coloração de Gram. Resultados: Baixa uniformidade do esfregaço foi observada para a eliminação de diferentes microrganismos, devido aos diferentes agentes desinfetantes testados. Quatro ou cinco esfregaços foram necessários para a descontaminação dos microrganismos testados usando álcool 70%. Três esfregaços na espátula usando glutaraldeído a 2% foram capazes de eliminar os microrganismos testados. Conclusão: Os resultados demonstraram que o álcool 70% por fricção, contando quatro ou cinco esfregaços na espátula com gazes embebida nas soluções desinfetantes, foi eficaz para descontaminar a ponta da espátula.

RESUMO

A estética dental ganhou ênfase na odontologia, o que culminou no desenvolvimento dos materiais restauradores estéticos. As coroas totais de cerâmica destacam-se no meio odontológico por apresentarem excelentes propriedades ópticas, por sua longevidade e por serem o material que mais se assemelha à aparência natural dos dentes. Objetivo: O objetivo deste artigo é apresentar um caso clínico de reabilitação em que os preparos foram totalmente guiados pelo ensaio restaurador (?Guidedprep?) e a reabilitação feita com uso do sistema IPS E.max. Caso Clínico: Coroas totais unitárias foram confeccionadas, abrangendo a região superior, do dente 15 ao 26 com o sistema IPS e.max Press/ IPS e.max Ceram. Um planejamento minucioso foi fundamental para o sucesso do tratamento. Recursos que viabilizam a comunicação com o paciente e com o técnico em prótese, a exemplo do ensaio restaurador (mock-up), uso de fotografias e modelos, respectivamente, foram muito importantes. Para arealização do preparo cavitário, o ensaio restaurador foi tomado como guia e os desgastes foram feitos sobre o mesmo, garantindo uma espessura uniforme condizente com as inclinações do dente. Conclusão: Conclui-se que o uso de guias que orientam o desgaste durante o preparo, combinadas ao sistema cerâmico IPS E.max mostraram-se como importantes alternativas na solução estética e funcional de dentes que apresentam comprometimento de cor, estrutura e/ou forma, garantindo sucesso no restabelecimento estético dos dentes.

Objective: The objective of this study is to present an oral rehabilitation case report in which the preparations were totally guided by "Guided prep" and rehabilitation was made with IPS e.max system. Case: All porcelain crowns were made to cover teeth 15-26 with IPS e.max Press / IPS e.max Ceram. Careful planning was critical to the treatment success. The use of mock-up, photographs and models were very important because they allow communication with the patient and the prosthetic technician. To make the preparations, the mock-up was used as a guide. The use of guides secured a uniform thickness in accordance with the tooth surface inclination. Conclusion: ?Guided prep? combined with the ceramic system IPS e.max showed up one in the esthetic and functional solution for the rehabilitation of teeth with defective in: color, structure and / or shape.

RESUMO

A pigmentação gengival é causada por uma deposição excessiva de melanina, principalmente na camada basal do epitélio, prejudicando muitas vezes a estética do sorriso. O objetivo é apresentar um caso clínico de pigmentação melânica gengival tratado pela técnica de gengivoplastia por abrasão epitelial. Paciente de 26 anos, melanoderma, procurou atendimento odontológico com queixa de manchas escurecidas na gengiva. Ao exame clínico pode ser observado pigmentação gengival que abrangia toda a faixa de gengiva ceratinizada na região vestibular do arco superior e inferior. O tratamento indicado foi a técnica de gengivoplastia por abrasão epitelial com instrumentos rotatórios. No acompanhamento pós-operatório de 15 diasfoi possível observar a completa cicatrização e harmonia da coloraçãodo tecido gengival. Após dois anos, pequenas áreas de repigmentação foram identificadas, porém, não interferindo no resultado estético do tratamento. A técnica proposta mostrou-se efetiva na remoção do pigmento melânico, resultando em uma estética satisfatória.

Gingival pigmentation is caused by excessive deposition of melanin, mainly in the epithelial basal layer, often damaging the smile aesthetics. The objective of this study is to present a case of gingival melanin pigmentation treated by gingivoplasty by epithelial abrasion technique. A patient of 26 years old, female, searched for dental care complaint darkened patches on the gums. On clinical examination, gingival pigmentation covering the full range of keratinized gingiva on the buccal region of the upper and lower arch can be seen. The treatment was the gingivoplasty by epithelial abrasion technique with rotary instruments. Postoperative follow-up of 15 days was possible to observe the complete healing and harmony of color of the gingival tissue. After two years, small areas of repigmentation were identified, but not interfering with the aesthetic outcome of treatment. The proposed technique was effective in removing the melanin pigment, resulting in a satisfactory aesthetic.

RESUMO

Objectives: The aim of this study was to evaluate the influence of the color of the resin luting cement in the final shade of minimally invasive porcelain veneers after accelerated artificial aging (AAA). Material and methods: 20 bovine teeth were collected, prepared and divided into two groups. The roots were removed and the buccal surfaces were polished to obtain a flat surface. Porcelain discs (IPS Empress Esthetic) were produced to a standardized shade (ET1) and thickness (0.6mm). The teeth and the veneers surfaces were prepared according to manufacturer recommendations. For group I (n=10), the White-Opaque (WO) base-paste was used and for group II (n=10) the Yellow (Y) base-paste. Each specimen was photocured for 60 s. The specimens were next subjected to AAA. They were submitted to color readings with a spectrophotometer in three moments: after the preparation (only the substrate), after the cementation and polymerization of the veneers and after the AAA. Were obtained values of L*, a* and b* and the total color change was calculated (?E*). Values obtained were subjected to statistical analysis in SPSS 17.0 for Windows with a significance of 0.05. Results: When comparing the cements, the Y cement showed higher ?E*, lower L* and higher b* after AAA than the WO. Conclusion: Both cements could mask the substrate color. With AAA, only the Y shade showed a ?E* clinically unacceptable, becoming more yellow (higher b*) and losing lightness (lower L*).

Objetivos: O objetivo do presente estudo foi avaliar a influência da cor do cimento resinoso na tonalidade final de facetas de porcelana minimamente invasivas, após envelhecimento artificial acelerado (EAA). Material e Métodos: 20 dentes bovinos foram coletados, preparados e divididos em dois grupos. As raízes foram removidas e a face vestibular foi polida para obter uma superfície plana. Discos de porcelana (IPS Empress Esthetic) foram confeccionados na cor ET1 e espessura de 0,6 mm. Os dentes e as superfícies dos discos foram preparados de acordo com as recomendações do fabricante. Para o grupo I (n=10) foi usado o cimento resinoso White-Opaque (WO) pasta-base, e para o grupo II (n-10) utilizou-se o Yellow (Y) pasta-base. Cada espécime foi fotopolimerizado por 60 s. Os espécimes foram então submetidos ao EAA. Eles foram submetidos a leituras de cor com auxílio de um espectro fotômetro em três momentos: após o preparo (apenas o substrato), após a cimentação e polimerização das facetas e após o EAA. Foram obtios valores de L*, a* e b* e o total da variação de cor foi calculado (?E*). Os valores obtidos foram submetidos à análise estatística no SPSS 17.0 para Windows, com nível de significância de 0,05. Resultados: O cimento Y apresentou maior ?E*, menor L* e maior b* após o EAA em comparação com o WO. Conclusão: Ambos os cimentos têm capacidade de mascarar a cor do substrato. Com o EAA, apenas o Y apresentou um valor de ?E* inaceitável clinicamente, se tornando mais amarelo (maior b*) e perdendo luminosidade (menor L*).

RESUMO

Objetivo: Este trabalho avaliou a resistência flexural em barras deresina acrílica reforçada com fibras de resina termoplástica submetidas a diferentes tratamentos. Material e Método: Cinco grupos experimentais foram criados (N=10), tendo como fator em estudo o tipo do tratamento superficial das fibras (controle sem fibra (Ctrl), fibra pura (FP), silanização (Fsil), pré-impregnação com adesivo (Fimp), silanização + pré-impregnação (Fsil/imp). Barras (25x2x2mm) foram submetidas a teste de resistência à flexão de 3 pontos, obtendo-se os valores de resistência flexural (RF) e módulo flexural (MF). Os dados de RF (MPa) e MF (GPa) foram submetidos ao teste ANOVA. Resultados: A análise estatística demonstrou semelhança entre grupos (p=0,298 para RF; p=0,549 para MF). Para RF, observou-se: Ctrl (15614,68±7119,25)A, FP (14903,31±5743,65)A, Fsil (11142,47±5629,92) A, Fimp (16365,10±9284,60)A, Fsil/imp (11882,56±3544,39)A. Para MF, observou-se: Ctrl (3996,30±2025,46)A, FP (3275,14±1841,26)A, Fsil (3491,54±2812,14)A, Fimp (4544,46±3357,18)A, Fsil/imp (2842,16±1193,13)A. Conclusão: Pode-se concluir que o tipo de tratamento superficial das fibras de resina termoplástica não proporciona melhorias em RF e MF em barras de resina acrílica.

Objective: This study evaluated the flexural strenght and flexuralmodulus of reinforced acrylic resin bars with thermoplastic fiber ssubjected to different treatments. Material and methods: Five experimental groups were created (N = 10), with the factor under study the type of treatment surface of fibers (control without fiber (Ctrl), pure fiber (PF), silanization (Fsil), pre-impregnated with adhesive (Fimp) , silanization + pre-impregnation (Fsil/imp)). Bars (25x2x2mm) were tested for flexural strength with 3-point bending test, obtaining the values of flexural strength (FS) and flexural modulus (FM). The RF data (MPa) and MF (GPa) were submitted to ANOVA test. Results: The statistical analysis showed similarity between groups (p = 0.298 for FS, p = 0.549 for FM). For FS, it was observed: Ctrl (15614.68 ± 7119.25) A, PF (14903.31 ± 5743.65) A,Fsil (11142.47 ± 5629.92) A, Fimp (9284 ± 16365.10 60) A, Fsil/imp(11882.56 ± 3544.39) A. For FM, observed: Ctrl (3996.30 ± 2025.46) A,FP (3275.14 ± 1841.26) A, Fsil (3491.54 ± 2812.14) A, Fimp (4544.46 ±3357 18) A, Fsil/imp (2842.16 ± 1193.13) A. Conclusion: It can be concluded that the type of surface treatment of fibers of thermoplasticresin does not provide improvements in RF and MF acrylic resin bars.