Meditação para estresse e ansiedade em universitários: um ensaio clínico randomizado / Meditation for stress and anxiety relief in undergraduate students: a randomized clinical trial

Resumo: Introdução: O estresse é um estado no qual ocorrem ameaças à homeostase do organismo, com respostas adaptativas fisiológicas e comportamentais. A ansiedade é uma sensação desagradável advinda da percepção de uma ameaça potencial futura. Quando prolongados, ambos levam a repercussões metabólicas, cardiovasculares, imunológicas e neuropsiquiátricas. Os estudantes universitários são mais susceptíveis a sintomas de estresse e ansiedade do que a população em geral. A técnica de mindfulness permite que os seus praticantes se tornem mais conscientes de suas emoções, passando a responder de forma habilidosa ao estresse e à ansiedade Objetivo: Este estudo teve como objetivo avaliar a eficácia de um programa de mindfulness na redução de sintomas de estresse e ansiedade em estudantes de Medicina e Odontologia. Método: Trata-se de um ensaio clínico, randomizado, simples-cego. Acadêmicos regularmente matriculados do primeiro ao oitavo período desses cursos de uma instituição de ensino superior responderam ao Inventário de Sintomas de Stress para Adultos de Lipp (ISSL) (n = 418) e ao Inventário de Ansiedade Traço-Estado (IDATE) (n = 369). Os participantes que apresentaram sintomas de estresse e/ou ansiedade e aceitaram participar da intervenção (n = 59) foram randomizados em grupos mindfulness (programa modificado de duas semanas) e de controle. Ao final da intervenção, o ISSL e o IDATE foram reaplicados. Resultado: As prevalências globais de estresse e ansiedade foram de 67% (n = 280) e 76,4% (n = 282), respectivamente. Ao final da segunda semana, a redução dos sintomas de estresse e ansiedade foi de 30,8% e 22,2%, respectivamente. Não houve diferença estatisticamente significativa entre os grupos mindfulness e de controle (p > 0,05). Conclusão: Percebe-se uma alta prevalência de sintomas de estresse e ansiedade na população estudada. Um programa de mindfulness em formato reduzido não foi capaz de diminuir significativamente os sintomas de estresse e ansiedade em comparação ao grupo de controle, em acadêmicos de Medicina e Odontologia dessa instituição.

Abstract: Introduction: Stress is a state in which the body homeostasis is threatened, leading to adaptive, physiological and behavioral responses. Anxiety is an unpleasant feeling that occurs whenever a future potential threat is perceived. Whenever these states are prolonged, both lead to metabolic, cardiovascular, neuropsychiatric and immunological consequences. University students are more susceptible to stress and anxiety symptoms than the general population. Mindfulness is a technique that allows its practitioners to become more aware of their emotions, dealing with stress in a more skilled way. Objective: To; evaluate the efficacy of a modified mindfulness program in reducing stress and anxiety symptoms in medicine and dentistry undergraduate students. Methods: This was a single blinded, randomized, clinical trial. Students from the aforementioned courses enrolled in the 1st to the 8th semesters of a higher education institution, answered Lipp's Inventory of Stress symptoms for Adults (ISSL) (n=418) and the State-Trace Anxiety Inventory (STAI) (n=369). Those who showed a positive score for symptoms of stress and/or anxiety and accepted to take part in the intervention (n=59), were randomized into one of the two groups - mindfulness (a 2-week modified program), or control. After the intervention, the students were asked to answer the STAI and ISSL tools once again. Results: The global prevalence of stress and anxiety symptoms were 67% (n=280) and 76.4% (n=282), respectively. At the end of the second week, symptoms of stress and anxiety decreased 30.8% and 22.2%, respectively. There were no statistically significant differences between the mindfulness and control groups (p>0.05). Conclusion: Symptoms of stress and anxiety are highly prevalent among the studied population. Among medicine and dentistry undergraduate students in this higher education institution, a shortened mindfulness program was unable to reduce symptoms of stress and anxiety in a statistically significant way when compared to a control group.

Sun exposure, skin lesions and vitamin D production: evaluation in a population of fishermen.

BACKGROUND: Exposure to UVR provides benefits related to vitamin D synthesis, but also causes harms, since UVB is considered a complete carcinogen. There is no definition of the level of sun exposure and the proportion of exposed body required for proper synthesis of vitamin D in the skin without causing it damage. OBJECTIVES: This study aims to analyze the sun exposure index, vitamin D levels and clinical changes in the skin caused by constant sun exposure in the fishermen population. METHODS: It is a cross-sectional, observational and analytical study. The sample consisted of fishermen and was calculated in 174 individuals. The questionnaire was applied, the dermatological examination was carried out and the examinations of calcidiol, parathyroid hormone, calcium and phosphorus were requested. Data were expressed as percentages. The comparative analysis was done through the Chi-square test, and the correlations were established through the Pearson's linear coefficient. Results: We observed that there was vitamin D deficiency in a small part of the cases (11.46%), and the frequency of diagnosis of skin cancer was 2.7% of the cases surveyed. STUDY LIMITATIONS: The difficulty in categorizing the sun exposure index. CONCLUSION: The fact that fishermen expose themselves to the sun chronically and have been exposed to the sun for more than 15 years, between 21 and 28 hours a week, and without photoprotection, were indicative factors for protection against vitamin D deficiency. Chronic exposure to sun and high vitamin levels D may be indicative of protection of this population against skin cancer.

Sun exposure, skin lesions and vitamin D production: evaluation in a population of fishermen

Abstract: Background: Exposure to UVR provides benefits related to vitamin D synthesis, but also causes harms, since UVB is considered a complete carcinogen. There is no definition of the level of sun exposure and the proportion of exposed body required for proper synthesis of vitamin D in the skin without causing it damage. Objectives: This study aims to analyze the sun exposure index, vitamin D levels and clinical changes in the skin caused by constant sun exposure in the fishermen population. Methods: It is a cross-sectional, observational and analytical study. The sample consisted of fishermen and was calculated in 174 individuals. The questionnaire was applied, the dermatological examination was carried out and the examinations of calcidiol, parathyroid hormone, calcium and phosphorus were requested. Data were expressed as percentages. The comparative analysis was done through the Chi-square test, and the correlations were established through the Pearson's linear coefficient. Results: We observed that there was vitamin D deficiency in a small part of the cases (11.46%), and the frequency of diagnosis of skin cancer was 2.7% of the cases surveyed. Study Limitations: The difficulty in categorizing the sun exposure index. Conclusion: The fact that fishermen expose themselves to the sun chronically and have been exposed to the sun for more than 15 years, between 21 and 28 hours a week, and without photoprotection, were indicative factors for protection against vitamin D deficiency. Chronic exposure to sun and high vitamin levels D may be indicative of protection of this population against skin cancer.

Gustatory Stimulations and Their Capacity Influence Buffering of the Saliva

Objective: To evaluate the influence of gustatory stimuli on the buffering capacity of saliva. Material and Methods: The buccal ph of 18 male volunteers aged 18-35 years was measured after a mouthwash with 20 ml of water as a control, and in individual disposable cups they collected the saliva for two minutes. Then, each of chewed bubble gum with sugar for two minutes, discarding the gum and made new collection of saliva, for two minutes in other disposable cups individualized. After collection, each volunteer was again subject to regular brushing with toothpaste and waited another ten minutes. The same procedure was repeated with all other substances. Salivary buffer capacity was determined by Ericsson technique. Data were submitted to analysis of variance and the means were compared by the Scott-Knott grouping test and Mann-Whitney test at 5% probability. Estimates of Pearson correlations were calculated in order to determine possible associations between the variables. Results: It was not found statistically significant differences between the initial pH variation and after eating food (p>0.05), or between gustatory stimulation and variation of salivary buffer capacity (p>0.05). Conclusion: There is no influence of gustatory stimulus aroma and flavor on the variation of salivary buffer capacity.

Factors associated with vocal health and quality of life in teachers/professors / Fatores associados à saúde vocal e a qualidade de vida em professores

ABSTRACT Purpose: to analyze the association of self-reported vocal symptoms with personal, occupational and clinical aspects and relate them to the quality of life of teachers/professors of the federal network of vocational and technological education. Methods: study carried out with 157 teachers from a federal public institution of vocational and technological education, who answered the World Health Organization Quality of Life questionnaire (WHOQOL-bref), Quality of Life in the Voice (V-RQOL) questionnaire and a data form (on social information, health conditions, vocal symptoms, habits, organization and working environment). Statistical analysis was performed using the Chi-square test. Results: 29% of the teachers presented vocal symptoms. The prevalent complaints were dry throat (38.2%), cough (37.6%) and hoarseness (30.6%). There was a higher prevalence of symptoms in females. For the WHOQOL-bref, the average was 71.3 points, which is considered regular. The domain with the highest score was the psychological one with 75.3. Regarding V-RQOL, the average score in the global domain was 92.5 points, and the physical score was the most compromised one. 90.5% of teachers showed low voice impact on quality of life. Conclusion: although these teachers present vocal complaints, they do not reflect in the limitation of the quality of life.

RESUMO Objetivo: analisar a associação de sintomas vocais autorreferidos com aspectos pessoais, ocupacionais, clínicos e relacionar com a qualidade de vida de professores da rede federal de ensino profissional e tecnológico. Métodos: estudo com 157 docentes de uma instituição pública federal de educação profissional e tecnológica, que responderam aos questionários World Health Organization Quality Of Life/bref (WHOQOL-bref), Qualidade de Vida em Voz (QVV) e o formulário de dados (sociais, condições de saúde, sintomas vocais, hábitos, organização e ambiente de trabalho). A análise estatística foi realizada por meio do teste Qui-quadrado. Resultados: 29% dos professores apresentaram sintomas vocais. As queixas prevalentes foram garganta seca (38,2%), tosse (37,6%) e rouquidão (30,6%). Houve maior prevalência dos sintomas no sexo feminino. Para o WHOQOL-bref, a média foi 71,3 pontos, considerada regular. O domínio com maior pontuação foi o psicológico com 75,3. Quanto ao QVV, o escore médio no domínio global foi de 92,5 pontos, sendo o físico o mais comprometido. 90,5% dos docentes apresentaram baixo impacto da voz na qualidade de vida. Conclusão: embora os docentes apresentem queixas vocais, elas não se refletem na limitação da qualidade de vida.

A importância do planejamento reverso na preservação de estrutura dental em casos de laminados cerâmicos / The importance of reverse planning for tooth preservation in ceramic laminate cases

Os avanços na tecnologia dos materiais odontológicos têm permitido o desenvolvimento de técnicas mais conservadoras e aumentaram as chances de obter resultados estéticos mais previsíveis. Considerando as particularidades de cada técnica, a cerâmica tem sido usada devido à sua biocompatibilidade, longevidade e semelhança com a aparência natural do dente. O objetivo deste trabalho foi utilizar uma técnica minimamente invasiva previsível tanto esteticamente quanto funcionalmente para a confecção de dez laminados cerâmicos. Foi possível concluir que a proposta deste trabalho cumpriu com os requisitos para que uma reabilitação seja adequada nos quesitos de estética, função e estabilidade em longo prazo.

Technology advances in dental materials has allowed the development of more conservative techniques and increased the chances of more predictable aesthetics results. Considering the particularities of each technique, ceramics have been used due to its biocompatibility, longevity and likeness with the tooth natural appearance. The aim of this study was to use a predictable minimally invasive technique both aesthetically and functionally to fabricate 10 ceramic laminate veneers. It was concluded that the proposed technique in this work met the requirements for an esthetic, functional, and stable long-term rehabilitation.

Impact of Tooth Loss on Quality of Life

Objective: To evaluate the impact of tooth loss on the quality of life of patients at the Cesmac University Center. Material and Methods: A cross-sectional study was performed, whose sample was composed of 224 volunteers from various health units of the selected health service with at least 12 years of age and one missing tooth. Quality of Life (QOL) was assessed using the Oral Health Impact Profile (OHIP -14) and tooth loss was assessed with the dental chart. A structured interview that assessed the socio-economic condition of the individual was also applied. For interpretation of the OHIP-14, values were assigned using the multiplicative method: 0-3 points = no impact; 3.01 to 6 points = low impact; 6.01 to 10 points = moderate impact; and> 10.01 points = high impact. All volunteers received guidance on oral health and, when necessary, a referral to the dental care provided by this institution was performed. Results: The mean OHIP ranged from no impact (30.9%) to high impact (27.8%). The correlation between the number of missing teeth and QOL scores was statistically significant (p <0.05), as well as the correlation between number of missing teeth and age of volunteers (p <0.0001). The dimensions of the OHIP-14 that showed the most influenced domains were pain, psychological discomfort, psychological disability. Conclusion: Increasing age has shown influence on tooth and tooth loss affected the QOL of volunteers. QOL may be influenced by other factors such as loss of anterior teeth and schooling.

Improved adhesion of Y-TZP ceramics: a novel approach for surface modification.

The aim of this study was to evaluate the effect of novel surface treatments of Y-TZP ceramics on initial shear bond strengths to resin cement. Eighty-four samples (7 x 6 x 5 mm) were randomly divided into 6 groups (n=14): Group1 (G1), no treatment; Group 2 (G2), air-borne particle abrasion with silica-coated aluminum oxide particles; Group 3 (G3), vitreous application 1 + etching with hydrofluoric acid; Group 4 (G4), vitreous application 1 + tribosilicatization; Group 5 (G5), vitreous application 2 + etching; Group 6 (G6), vitreous application 2 + tribosilicatization. Surface roughness (Ra) evaluation was performed by optical profilometry, scanning electron microscopy, and X-ray spectroscopy. The samples were silanized, and resin cement cylinders (3 x 2 mm) were built on the treated surfaces, light-cured and submitted to shear testing (1 mm/min). The failure mode was evaluated by SEM. Bond strength data were statistically analyzed using 1-way ANOVA and Tukey's test (α=0.05). Bond strength results were significantly affected by surface treatments (P = 0.0001). G5 and G3 presented increased Ra parameters and showed highest bond strength results (17.8 ± 5.5 and 13.3 ± 4.1, respectively). Failure modes were mainly mixed in all groups except for G1. The results confirmed that the approach of coating surface-conditioned Y-TZP with a vitreous material increased the initial shear bond strength to resin cement.

Influence of three types of drinks on the surface of human dental enamel: in vitro study / Influência de três tipos de bebidas sobre a superfície de esmalte dentário humano: estudo in vitro

Objective: The aim of this study was to evaluate the erosive effect of three beverages which are considered to be acidic in vitro study.Methods: We used 45 third molars. The teeth were cut to obtain 90 4x4 mm enamel blocks, obtained from the buccal and lingual surfaces of each tooth. The groups were divided by type of beverage (Coca-Cola®, Coca-Cola do Brasil, Rio de Janeiro, Brazil; Coca-Cola Zero®, Coca-Cola do Brasil, Rio de Janeiro, Brazil and Gatorade uva®, Ambev, Jaguariúna, Brazil) and number of cycles (7, 15 and 30 cycles). For each cycle, the specimens were immersed in the drink for 2.5 minutes by alternating with immersion in saliva for 1 hour. Each cycle simulates one day of intake. Statistical analysis, ANOVA and Tukey 5% for profilometry showed the statistical difference between the kind of beverages and between periods.Results: Coca-Cola® (Coca-Cola do Brasil, Rio de Janeiro, Brazil) (3.99±1.25) differed from other kinds of beverage. All the periods differed and the period of 30 days saw the greatest structural loss. For microhardness, the statistical analysis showed greater loss of surface hardness for the group Coca-Cola® (Coca-Cola do Brasil, Rio de Janeiro, Brazil) within 30 days (126.02 ± 30.98) SHL. Conclusion: IIt was concluded that the soft drink Coca Cola® (Coca-Cola do Brasil, Rio de Janeiro, Brazil) had the greatest erosive effects and the higher the number of cycles the greater the influence on the process of dental erosion.

Objetivo: Avaliar o efeito erosivo de três bebidas ácidas sobre o esmalte dentário num estudo in vitro. Métodos: Foram utilizados 45 terceiros molares humanos. Noventa blocos de esmalte de dente humano (4X4 mm) foram obtidos a partir das faces vestibular e lingual de terceiros molares. Os blocos de esmalte foram divididos de acordo com o tipo de bebida testada (Coca-Cola®, Coca-Cola do Brasil, Rio de Janeiro, Brasil; Coca-Cola Zero®, Coca-Cola do Brasil, Rio de Janeiro, Brasil e Gatorade uva®, Ambev, Jaguariúna, Brasil) e quantidade de ciclos (7, 15 e 30 ciclos). Cada ciclo simulava um dia de ingestão, o qual compreendia a imersão dos corpos de prova (n=10/tipo de bebida e quantidade de ciclos) nas bebidas (2,5 minutos), alternados por imersão em saliva (1 hora). Para quantificação do efeito erosivo, foi avaliada a perfilometria (?m±DP) e a perda de dureza superficial. Os dados foram analisados por ANOVA 2 fatores e Tukey 5%. Resultados: A perfilometria demonstrou diferença estatística entre as bebidas e entre os períodos, sendo que a Coca-Cola® (Coca-Cola do Brasil, Rio de Janeiro, Brasil) (3.99±1,25) diferiu das outras bebidas. Todos os períodos diferiram entre si sendo que para o período de 30 dias ocorreu a maior perda de estrutura. Para a microdureza a análise estatística demonstrou maior perda de dureza superficial para o grupo Coca-Cola® (Coca-Cola do Brasil, Rio de Janeiro, Brasil) no período de 30 dias (126,02 ± 30,98) perda de dureza superficial. Conclusão: Concluiu-se que a Coca-Cola® (Coca-Cola do Brasil, Rio de Janeiro, Brasil) apresentou os maiores efeitos erosivos e quanto maior número de ciclos, maior a influência no processo dentário erosivo.

Durability of adhesion between feldspathic ceramic and resin cements: effect of adhesive resin, polymerization mode of resin cement, and aging.

PURPOSE: Adhesive cementation is an important step for restorations made of feldspathic ceramic as it increases the strength of such materials. Incorrect selection of the adhesive resin and the resin cement to adhere to the ceramic surface and their durability against aging can affect the adhesion between these materials and the clinical performance. This study evaluated the effect of adhesive resins with different pHs, resin cements with different polymerization modes, and aging on the bond strength to feldspathic ceramic. MATERIALS AND METHODS: One surface of feldspathic ceramic blocks (VM7) (N = 90) (6.4 × 6.4 × 4.8 mm(3) ) was conditioned with 10% hydrofluoric acid for 20 seconds, washed/dried, and silanized. Three adhesive resins (Scotchbond Multi-Purpose Plus [SBMP], pH: 5.6; Single Bond [SB], pH: 3.4; and Prime&Bond NT [NT], pH: 1.7) were applied on the ceramic surfaces (n = 30 per adhesive). For each adhesive group, three resin cements with different polymerization modes were applied (n = 10 per cement): photo-polymerized (Variolink II base), dual polymerized (Variolink II base + catalyst), and chemically polymerized (C&B). The bonded ceramic blocks were stored in water (37°C) for 24 hours and sectioned to produce beam specimens (cross-sectional bonded area: 1 ± 0.1 mm(2) ). The beams of each block were randomly divided into two conditions: Dry, microtensile test immediately after cutting; TC, test was performed after thermocycling (12,000×, 5°C to 55°C) and water storage at 37°C for 150 days. Considering the three factors of the study (adhesive [3 levels], resin cement [3 levels], aging [2 levels]), 18 groups were studied. The microtensile bond strength data were analyzed using 3-way ANOVA and Tukey's post hoc test (α= 0.05). RESULTS: Adhesive resin type (p < 0.001) and the resin cement affected the mean bond strength (p= 0.0003) (3-way ANOVA). The NT adhesive associated with the chemically polymerized resin cement in both dry (8.8 ± 6.8 MPa) and aged conditions (6.9 ± 5.9 MPa) presented statistically lower bond strength results, while the SBMP adhesive resin, regardless of the resin cement type, presented the highest results (15.4 to 18.5 and 14.3 to 18.9 MPa) in both dry and aged conditions, respectively (Tukey's test). CONCLUSION: Application of a low-pH adhesive resin onto a hydrofluoric acid etched and silanized feldspathic ceramic surface in combination with chemically polymerized resin cement did not deliver favorable results. The use of adhesive resin with high pH could be clinically advised for the photo-, dual-, and chemically polymerized resin cements tested.

Does the ultrasonic cleaning medium affect the adhesion of resin cement to feldspathic ceramic?

PURPOSE: To evaluate the effect of different cleaning media on the adhesion of resin cement to feldspathic ceramic after etching. MATERIALS AND METHODS: The cementation surfaces of ceramic blocks (N = 20, n = 5 per group) were etched with 10% hydrofluoric acid (HF) gel for 20 s and rinsed for 60 s. They were then randomly assigned to 4 groups: G1: air-water spray+drying (control); G2: ultrasonic cleaning in distilled water for 4 min+drying; G3: ultrasonic cleaning in 99.5% acetone for 4 min+drying; G4: ultrasonic cleaning in 70% alcohol for 4 min+drying. The ceramic blocks were silanized and cemented (RelyX ARC) to the composite blocks. Subsequently, the microtensile bond strength test (µTBS) was performed. In addition, EDS analysis was made to assess the elemental composition of the conditioned and cleaned ceramic surfaces. RESULTS: A significantly higher mean µTBS was obtained when specimens had been ultrasonically cleaned in distilled water (G2: 18.8 ± 0.4 MPa) (p < 0.05) compared to other groups (G1: 16.6 ± 0.5; G3: 16.1 ± 0.9; G4: 15.8 ± 1.4) (one-way ANOVA). EDS analysis indicated the presence of F- only in G1. Dissolved precipitates after HF etching were removed by ultrasonic cleaning. CONCLUSION: Cleaning the HF-etched ceramic surface ultrasonically in distilled water is recommended, instead of rinsing it with air-water spray only.

Effect of disinfectant solutions on a denture base acrylic resin.

The aim of this study was to evaluate the hardness, roughness and mass loss of an acrylic denture base resin after in vitro exposure to four disinfectant solutions. Forty specimens (Clássico, Brazil) were prepared and randomly assigned to 4 groups n = 10) according to the disinfectant solution: G1: control, stored in distilled water at 37 degrees C; G2: 1% sodium hypochlorite; G3: 2% glutaraldehyde; G4: 4% chlorhexidine. G2 to G4 were immersed for 60 minutes in the disinfectant solution. Measurements were carried out both before and after immersion in the solution. The surface was analyzed with a surface roughness tester (Surfcorder SE 1700 KOZAKALAB), a microdurometer FM-700 (Future Tech) and a scanning electron microscope (DSM 962-ZEISS). Loss of mass was determined with a digital weighing scale. After disinfection procedures, values were analyzed statistically. The acrylic denture base resin may be vulnerable to surface changes after in vitro immersion in the disinfectant solutions studied.

Resistência de união e discrepância marginal absoluta de infraestruturas feitas em cerâmica Y-TZP: influência de novos métodos de tratamento de superfície / New approach for surface modification of a Y-TZP ceramic: resin bond strength quality, surface micro-morphological evaluations and marginal fit of Y-TZP frameworks

O objetivo deste trabalho foi avaliar o efeito de diferentes tratamentos de superfície da cerâmica Y-TZP na resistência de união, durabilidade e discrepância marginal. Para os testes de resistência adesiva, foram obtidos 144 corpos de prova (cp) da cerâmica VITA In-Ceram YZ for InLab (5,25 x 3,75 x 4,5 mm), que foram divididos em 6 grupos (G) (n=24), conforme o tratamento de superfície: G1: sem tratamento (controle); G2: jateamento com partículas de alumínio revestidas por sílica (CoJet®-Sand, 3M ESPE AG) (silicatização); G3: vitrificação 1 (Glaze Spray VITA AKZENT), condicionamento com ácido fluorídrico (HF) (1 min); G4: vitrificação 1 (Glaze Spray VITA AKZENT), silicatização; G5: vitrificação 2 (Glaze VITA AKZENT), condicionamento com HF (1 min); G6: vitrificação 2 (Glaze VITA AKZENT), silicatização. Após todos os tratamentos, as superfícies foram silanizadas por 5 min (ESPE-SIL) e a cimentação com Panavia F (Kuraray) foi realizada. Metade dos espécimes de cada tratamento foi ensaiada 24h após cimentação (SECO), a outra metade foi submetida à armazenagem (150 dias) e termociclagem (12.000x) (TC), e então realizado o ensaio de cisalhamento (1 mm/min). G7: G1+TC; G8: G2+TC; G9: G3+TC; G10: G4+TC; G11: G5+TC; G12: G6+TC. Superfícies tratadas foram analisadas por perfilometria óptica 3D para obtenção dos dados de rugosidade (Ra) e microscopia eletrônica de varredura (MEV) (1000x). Análise por energia dispersiva de raio-X (EDS) foi realizada para determinar os elementos químicos presentes na superfície de cada grupo. Para a análise de adaptação marginal foram confeccionadas 60 infraestruturas (adaptadas em um troquel metálico) nas quais foram realizados os mesmos tratamentos de superfície. Os dados obtidos foram analisados estatisticamente. Constata-se que tanto na condição Seco como na condição TC os grupos que receberam tratamento de superfície via vitrificação (vitrificação 1 e vitrificação 2) apresentaram mais alta resistência de união comparada ao grupo...

The aim of this study was to evaluate the effect of different surface treatments of Y-TZP ceramic on bond durability and marginal fit. 144 specimens of VITA In-Ceram YZ for InLab ceramic (5.25 x 3.75 x 4.5 mm) were obtained and divided into 6 groups (n=24) according to the surface treatment: G1: no treatment (control); G2: chairside tribochemical silica coating system (CoJet®-Sand, 3M ESPE AG) (Cojet); G3: vitrification 1 (Glaze Spray VITA AKZENT), conditioning with hydrofluoric acid (HF) (1 minute); G4: vitrification 1 (Glaze Spray VITA AKZENT), Cojet; G5: vitrification 2 (Glaze VITA AKZENT), conditioning with HF (1 minute); G6: vitification 2 (Glaze VITA AKZENT), Cojet. Then, the ceramic surfaces were silanized and the cement Panavia F (Kuraray) was applied. Half of the specimens from each treatment was tested 24 hours after cementation (DRY), the remaining specimens were stored in distilled water for150 days, thermocycled(12,000x) (AGING) and then the shear test was performed (1mm/minute). Conditioned surfaces were evaluated by 3D optical profilometry in order to obtain roughness data (Ra) and analysed by scan electronic microscopy (SEM) (1000x). Analysis by energy x-ray dispersive (EDS) was performed to determine the chemical elements present in each surface group. For analysis of marginal adaptation 60 crowns were produced (adapted into a metal die) and the same surface treatments were carried out on the internal surface of the crowns. The data were analysed using. The results suggest the vitrification 1 and vitrification 2 groups showed the highest bond strength compared to the control group. The highest marginal discrepancies were observed in the vitrification groups (117.36±29.61 to 105.78±12.23) comparing with the other groups (55.29±8.71 and 55.04±8.55). The proposed new surface treatment changed the Y-TZP ceramic morphology improving its adhesion to the resin cement...

Effect of bleaching agent on dental ceramics roughness

The aim of this study was to assess the effect of bleaching agents (10% and 16% carbamide peroxide) on the roughness of two dental ceramics in vitro, and to analyze the surface by scanning electronic microscopy (SEM). Two bleaching agents (10% and 16% / Whiteness, FGM Gel) and two microparticle feldspathic ceramics (Vita VM7 and Vita VM13) were used. Forty disks of Vita VM7 and Vita VM13 ceramic were manufactured, measuring 4mm in diameter and 4mm high, in accordance with the manufacturers’ recommendations, and were divided into 4 groups (n=10): (1) VM7 + Whiteness 10%; (2) VM7 + Whiteness 16%; (3) VM13 + Whiteness 10%; (4) VM13 + Whiteness 16%. The bleaching agent was applied for 8 hours a day for 15 days and during the intervals the test specimens were stored in distilled water at 37°C. The roughness (Ra) of the test specimens was evaluated before and after exposure to the bleaching agents using a laser roughness meter and the topographic description was analyzed by SEM. The statistical analysis of roughness data showed significant differences in the VM7 groups, using paired t-test, p=0.05 (VM7 + Whiteness 10%: p=0.002; VM7 + Whiteness 16%: p=0.001) and two-sample t-test (VM7 p=0,047), and no significant difference was found among VM13 groups. The qualitative SEM analysis showed different degrees of surface changes. The results suggest that the roughness of the tested ceramic surfaces increased after exposure to the bleaching agents.

O objetivo do estudo foi avaliar o efeito de agente clareador (10% e 16% de peroxido de carbamida) na rugosidade de duas ceramicas dentais in vitro e analisar a superficie atraves da microscopia eletronica de varredura (SEM). Foram utilizados dois agentes clareadores (10% e 16% / Whiteness, FGM Gel) e duas ceramicas feldspaticas microparticuladas (Vita VM7 e Vita VM13). Foram confeccionados quarenta discos de ceramica Vita VM7 e Vita VM13, com 4mm de diametro e 4mm de altura, de acordo com as recomendacoes do fabricante, sendo divididos em 4 grupos (n=10): G1- VM7 + Whiteness 10%, G2- VM7 + Whiteness 16%, G3- VM13 + Whiteness 10% e G4- VM13 + Whiteness 16%. O agente clareador foi aplicado por 8 horas durante 15 dias e durante os intervalos os corpos de prova (cp) ficavam armazenados em agua destilada a 37°C. A rugosidade (Ra) dos cp foi avaliada antes e apos a exposicao aos agentes clareadores utilizando o rugosimetro a laser Perthomether S8P, e a descricao topografica foi analisada no MEV. A analise estatistica na rugosidade mostrou diferenca significante entre os grupos da VM7, usando o teste pareado, p=0.05 (VM7 + Whiteness 10%: p=0.002; VM7 + Whiteness 16%: p=0.001) e nao foi encontrado diferenca estatistica para os grupos da VM13. A descricao qualitativa no SEM evidenciou alteracao nas superficies em diferentes graus. Os resultados sugeriram que as superficies das ceramicas testadas aumentaram a rugosidade apos a exposicao ao agente clareador.

The effect of carbamide peroxide bleaching agents on the microhardness of dental ceramics.

This study examined the effect of 10% and 16% carbamide peroxide bleaching agents on the surface microhardness of micro-particulate feldspathic ceramics (VM7 and VM13, Vita Zahnfabrik). Forty specimens (8-mm diameter, 2-mm thickness) were divided into four groups (n=10): GI-VM7 + 10% Whiteness, G2-VM7 + 16% Whiteness, G3-VM13 + 10% and G4-VM13 + 16% Whiteness. The home-use bleaching agents were applied for 8 hours on 15 days, and the specimens were stored in distilled water at 37 degrees C. The Vickers hardness number (HV) was determined for each specimen. Data were analyzed by the Wilcoxon and Mann-Whitney tests (p < 0.05). The microhardness values before exposure were: g1-433 (57); g2-486 (22); g3-509 (28); g4-518 (24), and after exposure: G1-349 (32); G2-496 (95); G3-519 (38); G4-502 (81). G2 exhibited a higher and significant difference than GI in VM7 groups, and the effect of bleaching concentration was shown to be significant by the Mann-Whitney test. And for VM13, both the Wilcoxon and Mann-Whitney tests showed no significant differences. When using 10% carbamide peroxide, the microhardness of VM7 ceramic was affected, and there were no effect on the microhardness between VM7 and VM13 ceramics when 16% carbamide peroxide was used.

The effect of carbamide peroxide bleaching agents on the microhardness of dental ceramics

This study examined the effect of 10% and 16% carbamide peroxide bleaching agents on the surface microhardness of micro-particulate feldspathic ceramics (VM7 and VM13, Vita Zahnfabrik). Forty specimens (8-mm diameter, 2-mm thickness) were divided into four groups (n=10): G1- VM7 + 10% Whiteness, G2- VM7 + 16% Whiteness, G3- VM13 + 10% and G4- VM13 + 16% Whiteness. The home-use bleaching agents were applied for 8 hours on 15 days, and the specimens were stored in distilled water at 37°C. The Vickers hardness number (HV) was determined for each specimen. Data were analyzed by the Wilcoxon and Mann- Whitney tests (p<0.05). The microhardness values before exposure were: g1- 433 (57); g2- 486 (22); g3- 509 (28); g4- 518 (24), and after exposure: G1- 349 (32); G2- 496 (95); G3- 519 (38); G4- 502 (81). G2 exhibited a higher and significant difference than G1 in VM7 groups, and the effect of bleaching concentration was shown to be significant by the Mann-Whitney test. And for VM13, both the Wilcoxon and Mann-Whitney tests showed no significant differences. When using 10% carbamide peroxide, the microhardness of VM7 ceramic was affected, and there were no effect on the microhardness between VM7 and VM13 ceramics when 16% carbamide peroxide was used.

Este estudo examinou o efeito do agente clareador peroxido de carbamida a 10% e a 16% na microdureza superficial de ceramicas feldspaticas micro-particuladas (VM7 e VM13, Vita Zahnfabrik). Quarenta corpos-de-prova (8 mm de diametro, 2 mm de espessura) foram divididos em quatro grupos (n=10): G1- VM7 + 10% Whiteness, G2- VM7 + 16% Whiteness, G3- VM13 + 10% e G4- VM13 + 16% Whiteness. Os agentes clareadores foram aplicados por 8 horas durante 15 dias e os cp foram armazenados em agua destilada a 37°C. A dureza Vickers (HV) de cada cp foi determinada. Os dados foram analisados pelos testes de Wilcoxon e Mann-Whitney (p<0.05). Os valores da dureza antes da exposicao ao agente clareador foram: g1- 433 (57); g2- 486 (22); g3- 509 (28); g4- 518 (24), e depois da exposicao: G1- 349 (32); G2- 496 (95); G3- 519 (38); G4- 502 (81). G2 exibiu diferenca significante e microdureza maior comparado ao G1 nos grupos da VM7 e o efeito da concentracao do clareador foi significante, apresentados atraves dos testes Mann-Whitney. Para VM13, ambos testes, Wilcoxon e Mann-Whitney, nao apresentaram diferenca significante. Quando o peroxido de carbamida a 10% foi avaliado, a microdureza da ceramica VM7 foi afetada, e nao houve diferenca na microdureza entre as ceramicas VM7 e VM13 quando o peroxido de carbamida a 16% foi utilizado.

Effect of bleaching agent on dental ceramics roughness.

The aim of this study was to assess the effect of bleaching agents (10% and 16% carbamide peroxide) on the roughness of two dental ceramics in vitro, and to analyze the surface by scanning electronic microscopy (SEM). Two bleaching agents (10% and 16%/Whiteness, FGM Gel) and two microparticle feldspathic ceramics (Vita VM7 and Vita VM13) were used. Forty disks of Vita VM7 and Vita VM13 ceramic were manufactured, measuring 4 mm in diameter and 4 mm high, in accordance with the manufacturers' recommendations, and were divided into 4 groups (n = 10): (1) VM7 + Whiteness 10%; (2) VM7 + Whiteness 16%; (3) VM13 + Whiteness 10%; (4) VM13 + Whiteness 16%. The bleaching agent was applied for 8 hours a day for 15 days and during the intervals the test specimens were stored in distilled water at 37 degrees C. The roughness (Ra) of the test specimens was evaluated before and after exposure to the bleaching agents using a laser roughness meter and the topographic description was analyzed by SEM. The statistical analysis of roughness data showed significant differences in the VM7 groups, using paired t-test, p = 0.05 (VM7 + Whiteness 10%: p = 0.002; VM7 + Whiteness 16%: p = 0.001) and two-sample t-test (VM7 p = 0.047), and no significant difference was found among VM13 groups. The qualitative SEM analysis showed different degrees of surface changes. The results suggest that the roughness of the tested ceramic surfaces increased after exposure to the bleaching agents.

Durability of the bond strength of self-adhesive resin cements to human dentin.

This study subjected two self-adhesive resin cements and two conventional resin cements to dry and aging conditions, to compare their microtensile bond strengths (microTBS) to dentin. Using four different luting systems (n = 10), 40 composite resin blocks (each 5 x 5 x 4 mm) were cemented to flat human crown dentin surfaces. The specimens were stored in water for 24 hours (37 degrees C), at which point each specimen was sectioned along two axes to obtain beams that were divided randomly into two groups: dry samples, which were tested immediately, and samples that were subjected to accelerated aging conditions (12,000 thermocycles followed by storage for 150 days). The microTBS results were affected significantly by the luting system used (P < 0.0001). Only the microTBS of Rely-X Unicem was reduced significantly after aging; the microTBS remained stable or increased for the other self-adhesive resin cement and the two conventional cements.

Knowledge of general dentists in the current guidelines for emergency treatment of avulsed teeth and dental trauma prevention.

A high prevalence of dental trauma exists and its effects on function and esthetics deserve the attention of general dentists. The aim of this study was to assess the level of general dental practitioners' (GDPs) knowledge about guidelines for dental avulsion and its prevention using a questionnaire. The 21-item questionnaire was distributed among 264 GDPs and the survey was realized between August-November 2006. The data obtained were statistically analyzed using descriptive analysis and Pearson's Chi-square test to determine associations between knowledge regarding emergency treatment and dentists from public or private dental schools and years of experience. The results showed that the participants exhibited appropriate knowledge concerning procedures in cases of tooth avulsion and its prevention. The number of correct answers was low in relation to recommended treatment at the site of injury. Storage medium, preparation of the alveolus and splint time for receiving the avulsed tooth received a high number of correct answers. One statistically significant association between years of experience and recommended treatment at the site of the injury in the case an avulsed tooth (chi(2) = 9.384, P = 0.009). In conclusion, this survey showed appropriate knowledge of dental avulsion management and its prevention among the surveyed dentists. The findings also showed that communication between dentists and the population is deficient, especially concerning practitioners of high risk and contact sports.

Ultrasonic versus high-speed cavity preparation: analysis of increases in pulpal temperature and time to complete preparation.

STATEMENT OF PROBLEM: The use of ultrasonic tips has become an alternative for cavity preparation. However, there are concerns about this type of device, particularly with respect to intrapulpal temperatures and cavity preparation time. PURPOSE: The purpose of this study was to analyze pulpal temperature increases generated by an ultrasonic cavity preparation with chemical vapor deposition (CVD) tips, in comparison to preparation with a high-speed handpiece with a diamond rotary cutting instrument. The time required to complete the cavity preparation with each system was also evaluated. MATERIAL AND METHODS: Thermocouples were positioned in the pulp chamber of 20 extracted human third molars. Slot-type cavities (3 x 3 x 2 mm) were prepared on the buccal and the lingual surfaces of each tooth. The test groups were: high-speed cavity preparation with diamond rotary cutting instruments (n=20) and ultrasonic cavity preparation with CVD points (n=20). During cavity preparation, the increases in pulpal temperature, and the time required for the preparation, were recorded and analyzed by Student's t test for paired samples (alpha=.05). RESULTS: The average pulpal temperature increases were 4.3 degrees C for the high-speed preparation and 3.8 degrees C for the ultrasonic preparation, which were statistically similar (P=.052). However, significant differences were found (P<.001) for the time expended (3.3 minutes for the high-speed bur and 13.77 minutes for the ultrasound device). CONCLUSIONS: The intrapulpal temperatures produced during cavity preparation by ultrasonic tips versus high-speed bur preparation were similar. However, the use of the ultrasonic device required 4 times longer for the completion of a cavity preparation.