RESUMO

Abstract Introduction The acoustic analysis of speech (measurements of the fundamental frequency and formant frequencies) of different vowels produced by speakers with the Angle class II, division 1, malocclusion can provide information about the relationship between articulatory and phonatory mechanisms in this type of maxillomandibular disproportion. Objectives To investigate acoustic measurements related to the fundamental frequency (F0) and formant frequencies (F1 and F2) of the oral vowels of Brazilian Portuguese (BP) produced by male speakers with Angle class II, division 1, malocclusion (study group) and compare with men with Angle class I malocclusion (control group). Methods In total, 60 men (20 with class II, 40 with class I) aged between 18 and 40 years were included in the study. Measurements of F0, F1 and F2 of the seven oral vowels of BP were estimated from the audio samples containing repetitions of carrier sentences. The statistical analysis was performed using the Student t-test and the effect size was calculated. Results Significant differences (p-values) were detected for F0 values in five vowels ([e], [i], [o], [o] and [u]), and for F1 in vowels [a] and [ɔ], with high levels for class II, division 1. Conclusion Statistical differences were found in the F0 measurements with higher values in five of the seven vowels analysed in subjects with Angle class II, division 1. The formant frequencies showed differences only in F1 in two vowels with higher values in the study group. The data suggest that data on voice and speech production must be included in the protocol's assessment of patients with malocclusion.

RESUMO

Introduction The acoustic analysis of speech (measurements of the fundamental frequency and formant frequencies) of different vowels produced by speakers with the Angle class II, division 1, malocclusion can provide information about the relationship between articulatory and phonatory mechanisms in this type of maxillomandibular disproportion. Objectives To investigate acoustic measurements related to the fundamental frequency (F0) and formant frequencies (F1 and F2) of the oral vowels of Brazilian Portuguese (BP) produced by male speakers with Angle class II, division 1, malocclusion (study group) and compare with men with Angle class I malocclusion (control group). Methods In total, 60 men (20 with class II, 40 with class I) aged between 18 and 40 years were included in the study. Measurements of F0, F1 and F2 of the seven oral vowels of BP were estimated from the audio samples containing repetitions of carrier sentences. The statistical analysis was performed using the Student t -test and the effect size was calculated. Results Significant differences ( p -values) were detected for F0 values in five vowels ([e], [i], [ᴐ], [o] and [u]), and for F1 in vowels [a] and [ᴐ], with high levels for class II, division 1. Conclusion Statistical differences were found in the F0 measurements with higher values in five of the seven vowels analysed in subjects with Angle class II, division 1. The formant frequencies showed differences only in F1 in two vowels with higher values in the study group. The data suggest that data on voice and speech production must be included in the protocol's assessment of patients with malocclusion.

RESUMO

BACKGROUND/AIM: The surface roughness of dental materials can make cleaning difficult, thus facilitating retention of food debris and accumulation of microorganisms. The aim of this study was to assess whether thickness, color, and the polishing process influence the surface roughness of ethylene-vinyl-acetate (EVA) sheets and the amount of microorganisms that adhere to them. MATERIALS AND METHODS: A total of 180 samples of EVA (5 × 5 mm) were divided into 9 groups according to thickness (G1 = 2 mm; G2 = 3 mm; and G3 = 4 mm), color (G4 = black and G5 = white), and type of polishing (G6 = Scheu™; G7 = Scheu™ associated with hot-air burner; G8 = Erkodent™ and G9 = Erkodent™ associated with hot-air burner). Mean value of 3 roughness parameters was assessed: Ra, Rq, and Rz (one-way ANOVA test and Tukey's test, P < .05). Seven samples of each group (n = 63) were inoculated with saliva for 2 hours to promote microbial adhesion and count the number of colony-forming units (CFUs) (one-way ANOVA test, P < .05). Scanning electron microscopy (SEM) of microbial adhesion and the effects of the polishing process on the surface was assessed. RESULTS: Only the polishing parameter presented less roughness (G2, G7 and G9; P < .05) as also observed on SEM. SEM characterized microbial adhesion but the CFU count was not statistically significant, independent of the assessed parameters. CONCLUSION: The polishing systems, Scheu™ and Erkodent™ in association with a hot-air burner, were effective in decreasing the surface roughness without influencing the amount of adhered microorganisms.

Assuntos

RESUMO

INTRODUCTION: The degradation of elastic ligatures in the oral environment results in the need of periodic replacement to maintain the optimal force during the orthodontic treatment. The purpose of this study was to perform a clinical prospective randomized study of the degradation of orthodontic elastomeric ligatures in the oral environment by scanning electron microscopy (SEM) and tensile strength test. METHODS: Two hundred elastic ligatures were randomly selected and placed around the brackets of 5 volunteers and removed in groups of 10, at different times (1, 2, 3, and 4 weeks). The control group was performed by another fifty ligatures which were not submitted to the oral degradation. The analyses were done by scanning electron microscopy (SEM) and strength mechanical test. RESULTS: The tensile strength test results showed reduction in the ultimate strength values after four weeks ageing in the oral environment and no statistical difference in the yield strength values (p < 0.05). The orthodontic elastomeric ligatures surface was significantly degraded in the oral cavity after four weeks. The elastomeric degradation began in the first week when the increase in the roughness could be detected just in some areas. Afterwards, the surface became gradually rougher and, after 4 weeks, it was totally rough with some crack areas. CONCLUSIONS: The elastic ligatures aged in the oral environment showed higher superficial degradation and lower loss of mechanical properties after the maximum experimental period.

Assuntos

RESUMO

INTRODUCTION: The degradation of elastic ligatures in the oral environment results in the need of periodic replacement to maintain the optimal force during the orthodontic treatment. The purpose of this study was to perform a clinical prospective randomized study of the degradation of orthodontic elastomeric ligatures in the oral environment by scanning electron microscopy (SEM) and tensile strength test. METHOD: Two hundred elastic ligatures were randomly selected and placed around the brackets of 5 volunteers and removed in groups of 10, at different times (1, 2, 3, and 4 weeks). The control group was performed by another fifty ligatures which were not submitted to the oral degradation. The analyses were done by scanning electron microscopy (SEM) and strength mechanical test. RESULTS: The tensile strength test results showed reduction in the ultimate strength values after four weeks ageing in the oral environment and no statistical difference in the yield strength values (p < 0.05). The orthodontic elastomeric ligatures surface was significantly degraded in the oral cavity after four weeks. The elastomeric degradation began in the first week when the increase in the roughness could be detected just in some areas. Afterwards, the surface became gradually rougher and, after 4 weeks, it was totally rough with some crack areas. CONCLUSIONS: The elastic ligatures aged in the oral environment showed higher superficial degradation and lower loss of mechanical properties after the maximum experimental period.

INTRODUÇÃO: a degradação das ligaduras elásticas no ambiente bucal resulta na necessidade de substituição periódica para manter-se a força ótima durante o tratamento ortodôntico. OBJETIVO: a proposta desse trabalho foi realizar um estudo clínico prospectivo randomizado da degradação de ligaduras elásticas ortodônticas envelhecidas no ambiente bucal por microscopia eletrônica de varredura e por ensaio de tração. MÉTODOS: duzentas ligaduras foram randomicamente selecionadas e inseridas ao redor dos braquetes de 5 pacientes voluntários e, então, removidas, em grupos de 10, após diferentes tempos (1, 2, 3 e 4 semanas). O grupo controle foi formado por outras 50 ligaduras que não foram submetidas à degradação intrabucal. RESULTADOS: o ensaio mecânico demonstrou diminuição no limite de resistência à fratura após 4 semanas de degradação e não demonstrou diferença estatisticamente significativa no limite de elasticidade. A análise por microscopia eletrônica de varredura revelou que a superfície dos elastômeros tornou-se significativamente degradada após 4 semanas. A degradação teve início na primeira semana, quando o acréscimo de rugosidade superficial pôde ser detectado em algumas áreas. Posteriormente, a superfície tornou-se gradativamente mais rugosa, sendo que após 4 semanas toda a região apresentou-se rugosa e com algumas fraturas superficiais. CONCLUSÕES: as ligaduras elásticas envelhecidas no ambiente bucal apresentaram maior degradação superficial e menor perda das propriedades mecânicas após o período experimental máximo.

Assuntos

RESUMO

UNLABELLED: The harmony of the facial profile is widely influenced by the height and form of the nasal dorsum. A few millimeters can make the lateral view aesthetically more or less pleasing and adequate in a subject's face. Professionals working with facial aesthetics should focus not only on the surgical techniques for proposed outcomes, but also with the subtleties and subjectivity that characterize aesthetic concepts and judgment. MATERIAL AND METHODS: A prospective survey to evaluate the preferences of a group of healthcare professionals working with facial aesthetics, a group of fine artists, and lay people about the best nasal radix height; the survey involved comparing 3 different nasal radix heights using computer-altered photographs of women with measurements close to the Caucasian standard. RESULTS AND CONCLUSION: The lowest position of the nasal radix--close to the height of the pupil--was preferred (53%), followed by the middle position (superior crease of the eye). The highest position, resembling classic Greek statues, was considered the worst. The authors evaluated the effect of age, gender, and educational level on the choice of the best and worst female profiles.

Assuntos

RESUMO

The harmony of the facial profile is widely influenced by the height and form of the nasal dorsum. A few millimeters can make the lateral view aesthetically more or less pleasing and adequate in a subject's face. Professionals working with facial aesthetics should focus not only on the surgical techniques for proposed outcomes, but also with the subtleties and subjectivity that characterize aesthetic concepts and judgment. MATERIAL AND METHODS: A prospective survey to evaluate the preferences of a group of healthcare professionals working with facial aesthetics, a group of fine artists, and lay people about the best nasal radix height; the survey involved comparing 3 different nasal radix heights using computer-altered photographs of women with measurements close to the Caucasian standard. RESULTS AND CONCLUSION: The lowest position of the nasal radix - close to the height of the pupil - was preferred (53 percent), followed by the middle position (superior crease of the eye). The highest position, resembling classic Greek statues, was considered the worst. The authors aos evaluated the effect of age, gender, and educational level on the choice of the best and worst female profiles.

A harmonia facial da visão de perfil é muito influenciada pela altura e forma do dorso nasal. Poucos milímetros podem determinar as diferenças que tornam o perfil esteticamente agradável e adequado a uma determinada face. Além da discussão a respeito de técnicas cirúrgicas para obter determinados objetivos, os profissionais também precisam se aprofundar nas sutilezas e subjetividades que envolvem o julgamento estético. Com forma de estudo tipo inquérito, o objetivo foi pesquisar a preferência de um grupo de profissionais de saúde que lidam com estética facial, um grupo de artistas e outro de leigos sobre três possíveis variações da altura da raiz do nariz. MATERIAIS E MÉTODOS: Fotografias de mulheres, com medidas muito próximas do modelo caucasiano, foram modificadas com computação gráfica e opiniões sobre estas variações colhidas entre profissionais, artistas e leigos. RESULTADOS E CONCLUSÃO: A população de entrevistados considerou o perfil alto, tipo grego, como indesejável. Tal convicção foi muito evidente em todos os grupos. A preferência foi pelo perfil com raiz nasal próxima da altura da pupila em 53 por cento, seguido do perfil na altura da prega tarsal. Avaliou-se também a influência da idade, sexo e escolaridade dos entrevistados sobre as escolhas dos melhores e piores perfis femininos.

Assuntos

RESUMO

INTRODUÇÃO: as principais utilizações do laser argônio na Ortodontia são a redução do tempo de polimerização durante a colagem ortodôntica e o aumento da resistência à cárie do esmalte dentário. OBJETIVO: o objetivo deste trabalho foi avaliar as alterações químicas e morfológicas do esmalte dentário humano tratado com laser argônio nos parâmetros da colagem ortodôntica. MÉTODOS: quinze primeiros pré-molares hígidos, extraídos por indicação ortodôntica, foram selecionados e seccionados no sentido do longo eixo em dois segmentos iguais. Uma metade de cada elemento dentário foi tratada e a outra permaneceu sem tratamento. Um total de 30 amostras foi analisado, criando o grupo laser (n = 15) e o grupo controle (n = 15). O tratamento foi feito com laser argônio com 250mW de potência por 5 segundos, com densidade de energia de 8J/cm². RESULTADOS: a análise de difração de raios X demonstrou duas fases em ambos os grupos, as fases apatita e monetita. A redução da fase monetita foi significativa após o tratamento com laser, sugerindo maior cristalinidade. A análise de Espectroscopia de Energia Dispersiva (EDS) indicou aumento na razão cálcio-fósforo no grupo laser, compatível com a diminuição da fase monetita. A morfologia superficial do esmalte dentário apresentou-se mais lisa após o tratamento com laser argônio. CONCLUSÕES: o aumento de cristalinidade e a lisura superficial do esmalte no grupo laser são fatores sugestivos de aumento de resistência à cárie no esmalte dentário.

INTRODUCTION: The main utilities of the argon laser in orthodontics are the high speed curing process in orthodontic bonding and the caries resistance promotion of the tooth enamel. OBJECTIVE: The objective of this study was to evaluate the chemical and morphological changes in the tooth enamel treated with the argon laser in the orthodontic bonding parameters. METHODS: Fifteen sound human first premolars, removed for orthodontic reason, were selected and sectioned across the long axis in two equal segments. One section of each tooth was treated and the other remained untreated. A total of thirty samples was analyzed, creating the laser group (n =15) and the control group (n =15). The treatment was done with 250 mW argon laser beam for 5 seconds, with energy density of 8 J/cm². RESULTS: The X-ray analysis demonstrated two different phases in both groups, the apatite and the monetite phases. The reduction of the monetite phase was significant following laser treatment, suggesting higher crystallinity. The EDS analysis showed an increase in the calcium-phosphorus ratio in the laser group, linked with the decrease of the monetite phase. CONCLUSIONS: The surface morphology was smoother after the laser exposure. The results of high crystallinity and superficial enamel smoothness in the laser group are suggestive of the caries resistance increase of the tooth enamel.

Assuntos

RESUMO

OBJETIVO: todo biomaterial metálico implantado possui alguma interação com os tecidos em contato, havendo liberação de íons por dissolução, desgaste ou corrosão. O objetivo deste trabalho foi analisar a liberação de íons metálicos por alguns tipos de biomateriais metálicos, descrevendo a interação íon/tecido e os possíveis efeitos adversos. CONCLUSÃO: os tratamentos de jateamento e ataque ácido propiciam aumento na dissolução e liberação de íons metálicos, mas o recobrimento destas superfícies com hidroxiapatita e o polimento eletroquímico reduzem esta tendência de liberação iônica. Na presença de sintomas de reação adversa ao biomaterial deve-se pesquisar sua composição, realizar testes de alergia e optar por materiais não-metálicos ou que não contenham o elemento agressor. As pesquisas sobre liberação de íons devem ser frequentes, devido ao crescente lançamento de novos biomateriais.

AIM: Every metallic biomaterial has some interaction with surrounding tissues, and ion release occurs by dissolution, wearing or corrosion of the alloy. The aim of this paper was to revise the metal ion release from some metallic biomaterials, describing the ion/tissue interaction and the possible side effects. CONCLUSIONS: Treatments such as sand blasting and etching increases the amount of metallic ion release, but the surface coated with hydroxyapatite and the polishing decreases the ion release. When clinical signs of side effects to the biomaterial are present one should search its composition, do allergic tests and choose non-metallic biomaterials or biomaterials without the aggressor element. The researches about ion release should be frequent due to the use of new biomaterials.

Assuntos

RESUMO

Por terem dimensões reduzidas os mini-parafusos para ancoragem ortodôntica possuem poucas limitações quanto ao local de implantação, eles podem ser instalados em praticamente qualquer lugar da mandíbula ou maxila. Por outro lado, as dimensões reduzidas aumentam a possibilitam de deformação durante o emprego e a fratura na inserção ou remoção. Neste trabalho foram testados mini-parafusos comerciais (Conexão Sistemas de Prótese) com diâmetros de 1,5 e 2,0 mm e comprimento de 6,0 mm. Em ensaios in vivo e in vitro mediu-se os torques para instalar e remover mini-parafusos da cortical de coelhos e de bovino, os resultados foram comparados com o limite de resistência à fratura sob torção. Os resultados mostraram que os mini-parafusos possuem limite de resistência à torção superior ao torque de instalação em cortical de elevada densidade

The size of tradicional dental implants restricts the locations in which they may be placed for orthodontic anchorage. One variety of temporary anchorage devices that has recently been developed – miniscrew - is substantially smaller than customary dental implants used. The advantage of this system include fewer limitations of the implant site. But the small size is a disvantage, because the miniscrews can fracture during the insertion. The main of the present work is to insert miniscrew into cortical bone (rabbit and bovine) and compare the insertion torque with the fracture torsion resistance of the miniscrew. The results showed that the insertion torque is higher than the remove torque and the insertion torque into hard bone is lesser than fracture torsion resistance

Assuntos