Effect of chemical degradation followed by toothbrushing on the surface roughness of restorative composites

OBJECTIVES: The aim of the present study was to assess the effect of the exposure to food-simulating liquids prior to brushing simulation on the surface roughness of five composite materials (Quixfil, Filtek Supreme, Esthet-X, Filtek Z250, Tetric Ceram). Material and METHODS: Twenty cylinders (5 mm diameter and 4 mm height) of each composite were randomly allocated to 4 groups (n=5), according to the food-simulating liquid in which they were immersed for 7 days at 37°C: artificial saliva, heptane, citric acid, and ethanol. After this period, the top surface of composite cylinders was submitted to 7,500 brushing cycles (200 g load). Measurements of the surface roughness (Ra, »m) were carried out before and after the exposure to the chemicals/brushing simulation. Changes on the morphology of composite surfaces were observed through scanning electron microscopy (SEM). RESULTS: The statistical analysis (ANOVA with cofactor / Tukey's test, α=5 percent) detected a significant interaction between solutions and composite resins. Esthet-X, Filtek Z250 and Tetric Ceram were not affected by the food-simulating liquids/toothbrushing. Citric acid and ethanol increased the surface roughness of Quixfil and Filtek Supreme, respectively. SEM images corroborate the surface roughness findings, demonstrating the negative effect from chemical solutions and mechanical abrasion. CONCLUSIONS: The surface roughness of composite resin materials are differently affected by the food-simulating solutions, depending on the immersion media.

Effect of chemical degradation followed by toothbrushing on the surface roughness of restorative composites.

OBJECTIVES: The aim of the present study was to assess the effect of the exposure to food-simulating liquids prior to brushing simulation on the surface roughness of five composite materials (Quixfil, Filtek Supreme, Esthet-X, Filtek Z250, Tetric Ceram). MATERIAL AND METHODS: Twenty cylinders (5 mm diameter and 4 mm height) of each composite were randomly allocated to 4 groups (n=5), according to the food-simulating liquid in which they were immersed for 7 days at 37°C: artificial saliva, heptane, citric acid, and ethanol. After this period, the top surface of composite cylinders was submitted to 7,500 brushing cycles (200 g load). Measurements of the surface roughness (Ra, microm) were carried out before and after the exposure to the chemicals/brushing simulation. Changes on the morphology of composite surfaces were observed through scanning electron microscopy (SEM). RESULTS: The statistical analysis (ANOVA with cofactor / Tukey's test, α=5%) detected a significant interaction between solutions and composite resins. Esthet-X, Filtek Z250 and Tetric Ceram were not affected by the food-simulating liquids/toothbrushing. Citric acid and ethanol increased the surface roughness of Quixfil and Filtek Supreme, respectively. SEM images corroborate the surface roughness findings, demonstrating the negative effect from chemical solutions and mechanical abrasion. CONCLUSIONS: The surface roughness of composite resin materials are differently affected by the food-simulating solutions, depending on the immersion media.

Effect of different light-curing devices and aging procedures on composite knoop microhardness.

The aim of this study was to evaluate the effect of light-curing devices (Halogen/HAL, Light Emitting Diodes/LED, Argon Laser/LAS and Plasma Arc/PAC) and aging procedures (Mechanical Cycling/MC, Thermal Cycling/TC, Storage/S, MC+TC and MC+TC+S) on the micro-hardness of bottom/B and top/T surfaces of 2-mm-high composite resin cylinders. The Knoop microhardness test (25 g, 20 s) on both B and T was performed before and after each aging procedure. For B and T, before aging procedures, PAC showed reduced polymerization effectiveness when compared with HAL. In the T, after TC, PAC and LAS had also showed reduced polymerization effectiveness when compared to HAL and LED. For all light-curing devices, MC+TC+S and S affected the Knoop microhardness values. In the B, no difference could be observed among the aging procedures for PAC. From all light-curing units, PAC may have rendered composites of reduced quality and the storage aging procedures were the most harmful to the polymer hardness.

Effect of different light-curing devices and aging procedures on composite knoop microhardness

The aim of this study was to evaluate the effect of light-curing devices (Halogen/HAL, Light Emitting Diodes/LED, Argon Laser/LAS and Plasma Arc/PAC) and aging procedures (Mechanical Cycling/MC, Thermal Cycling/TC, Storage/S, MC+TC and MC+TC+S) on the micro-hardness of bottom/B and top/T surfaces of 2-mm-high composite resin cylinders. The Knoop microhardness test (25 g, 20 s) on both B and T was performed before and after each aging procedure. For B and T, before aging procedures, PAC showed reduced polymerization effectiveness when compared with HAL. In the T, after TC, PAC and LAS had also showed reduced polymerization effectiveness when compared to HAL and LED. For all light-curing devices, MC+TC+S and S affected the Knoop microhardness values. In the B, no difference could be observed among the aging procedures for PAC. From all light-curing units, PAC may have rendered composites of reduced quality and the storage aging procedures were the most harmful to the polymer hardness.

Nutrição para idosos / Nutrition for the elderly

Este artigo tem por objetivo discutir a contribuição da nutrição na qualidade vida dos indivíduos idosos e de que forma ela pode influenciar para uma velhice mais saudável. Serão abordados os aspectos bioquímicos e fisiológicos do envelhecimento, os aspectos relacionados à saúde bucal e às necessidades nutricionais dos idosos, assim como serão evidenciadas as alterações fisiológicas que direta ou indiretamente afetam a sua alimentação.

The main of this article is to discuss the influence of nutrition in the orderly?s quality of life and whether it can implicate in oral health or to contribute for a healthier old age. Considerations on biochemical and physiologic aspects of the aging will be considered, associated with the senior?s nutritional needs, as well as it will be evidenced the physiologic changes that directly or indirectly affect elder food consumption.

Effectiveness of resin composite polymerization when cured at different depths and with different curing lights.

This study evaluated how photocuring devices affected the microhardness of composite resin cylinders. For this study, 120 specimens of composite were fabricated and allocated randomly into 12 groups (n = 10), according to the light source (quartz-tungsten-halogen (QTH), LED, argon laser, plasma arc) and the height of the specimen (2.0, 4.0, or 6.0 mm). Twenty-four hours after the specimens were fabricated, the Knoop microhardness test was performed on bottom and top surfaces. Statistical analysis showed significant interaction among light sources, between light sources and specimen heights, and between the surfaces. Compared to the QTH specimens, the argon laser and plasma arc specimens showed reduced polymerization on the top surface, while the plasma arc specimens showed reduced polymerization on the bottom surface. The 4.0 mm samples demonstrated higher Knoop microhardness than the 2.0 mm and 6.0 mm samples, especially when argon laser and plasma arc curing lights were used. The microhardness was always higher on the top surface than on the bottom surface. No photocuring unit was able to properly polymerize the bottom surface as completely as the top surface.

Freqüência clínica dos biótipos periodontais considerando o formato geométrico dos incisivos centrais superiores / Clinical frequency of periodontal biotypes among different geometric forms of maxillary incisors

O objetivo deste estudo clínico foi avaliar a freqüência dos biótipos periodontais, considerando os diferentes formatos geométricos dos incisivos centrais superiores, através de parâmetros anatômicos dentários e gengivais. Quarenta voluntários foram agrupados de acordo com a forma dos incisivos centrais superiores (ICS, n = 10): retangular (grupo 1), triangular (grupo 2), quadrado (grupo 3) ou oval (grupo 4). Para cada voluntário, foi determinado o biótipo periodontal através de consenso entre 3 examinadores calibrados e foram medidos: o comprimento (CC) e a largura (LC) da coroa; a razão entre a largura e o comprimento da coroa (PLC); a altura do ponto de contato entre os ICS (APC); a distância entre os zênites gengivais dos ICS (ZG1); a distância entre os zênites gengivais do incisivo central e do incisivo lateral superiores (ZG2); a altura da papila entre os ICS (AP1); e a altura da papila entre o incisivo central e o incisivo lateral superiores (AP2). Os dentes quadrados obtiveram os menores valores de comprimento coronário (9,36 ± 0,97, p = 0,0012) e a maior proporção entre a largura e o comprimento da coroa (0,93 ± 0,06, p = 0,0001), quando comparados aos dos demais grupos. Os dentes triangulares apresentaram significativamente a maior distância (8,44 ± 0,89, p = 0,0438) considerando o parâmetro ZG2. O biótipo periodontal fino/festonado foi predominante no total de voluntários desse estudo (60%), e mais freqüente em indivíduos com dentes retangulares. Voluntários com dentes quadrados apresentaram maior freqüência de periodonto plano e espesso (60%), embora o teste exato de Fisher não tenha encontrado diferenças estatisticamente significantes entre os grupos.

The aim of this clinical study was to evaluate the frequency of periodontal phenotypes among different geometric forms of maxillary central incisors. Some clinical parameters such as tooth and papillae dimension, localization of contact points and distances between gingival vertices were also evaluated. Forty patients were selected and divided into 4 groups (n=10) according to geometric form of maxillary central incisors: rectangular (group 1), triangular (group 2), squared (group 3) or ovoid (group 4). Squared teeth showed the lowest coronal length values (9.36±0.97; p=0.0012 and the highest coronal width/length ratio (0.93±0.06; p=0.0001), when compared to the other groups. Thin and scalloped gingival phenotype was predominant in this clinical study (60%), and was frequent in groups 1, 2 and 4. In contrast, squared teeth (group 3) presented predominantly thick and plan gingiva. Nevertheless, Fisher’s exact test did not found any statistical difference among groups.

Bond strength of a resin cement to dentin using the resin coating technique.

The aim of this study was to evaluate the bond strength of a resin cement to dentin using different adhesive systems (AS) in the presence or absence of a low-viscosity composite liner (Protect Liner F - PLF) applied over the bonded dentin. The adhesive systems selected were: AdheSE/Vivadent (AD); Clearfil Protect Bond/Kuraray (CP); One-Up Bond F/Tokuyama (OU); Single Bond/3M ESPE (SB); Tyrian SPE/One-Step Plus/Bisco (TY); Xeno III/Dentsply (XE) and Unifil Bond/GC (UN). After removing the labial and lingual enamel surfaces of bovine incisors, dentin fragments were prepared and randomly divided into 15 groups (n = 8). The dentin substrates were bonded with the AS and the PLF was applied or not before application of the resin cement (Panavia F, Kuraray). In the control group, the ED Primer (ED) and the resin cement without PLF were used. The AS, PLF and resin cement tested were used according to the manufacturers' instructions, and all treated dentin surfaces were temporized. After water storage for one week, three cylinders of resin cement were applied to each bonded dentin surface, using tygon tubing molds. The specimens were subjected to micro-shear testing and the data were statistically analyzed (two-way ANOVA, Tukey and Dunnett tests, p < 0.05). The observed mean shear bond strengths in MPa were: ED: 20.2 +/- 2.3; AD: 30.3 +/- 6.5; CP: 25.3 +/- 4.4; OU: 28.3 +/- 6.6; SB: 25.6 +/- 6.9; TY: 24.5 +/- 2.5; XE: 17.3 +/- 3.4; UN: 28.4 +/- 6.2; AD+PLF: 32.8 +/- 4.1; CP+PLF: 29.9 +/- 3.9; OU+PLF: 34.1 +/- 4.1; SB+PLF: 29.5 +/- 8.2; TY+PLF: 29.2 +/- 3.9; XE+PLF: 32.8 +/- 6.7; UN+PLF: 32.2 +/- 4.5. The bond strength of the resin cement to dentin using the tested AS was increased when the low-viscosity composite liner was applied.

Bond strength of a resin cement to dentin using the resin coating technique

The aim of this study was to evaluate the bond strength of a resin cement to dentin using different adhesive systems (AS) in the presence or absence of a low-viscosity composite liner (Protect Liner F - PLF) applied over the bonded dentin. The adhesive systems selected were: AdheSE/Vivadent (AD); Clearfil Protect Bond/Kuraray (CP); One-Up Bond F/Tokuyama (OU); Single Bond/3M ESPE (SB); Tyrian SPE/One-Step Plus/Bisco (TY); Xeno III/Dentsply (XE) and Unifil Bond/GC (UN). After removing the labial and lingual enamel surfaces of bovine incisors, dentin fragments were prepared and randomly divided into 15 groups (n = 8). The dentin substrates were bonded with the AS and the PLF was applied or not before application of the resin cement (Panavia F, Kuraray). In the control group, the ED Primer (ED) and the resin cement without PLF were used. The AS, PLF and resin cement tested were used according to the manufacturers' instructions, and all treated dentin surfaces were temporized. After water storage for one week, three cylinders of resin cement were applied to each bonded dentin surface, using tygon tubing molds. The specimens were subjected to micro-shear testing and the data were statistically analyzed (two-way ANOVA, Tukey and Dunnett tests, p < 0.05). The observed mean shear bond strengths in MPa were: ED: 20.2 ± 2.3; AD: 30.3 ± 6.5; CP: 25.3 ± 4.4; OU: 28.3 ± 6.6; SB: 25.6 ± 6.9; TY: 24.5 ± 2.5; XE: 17.3 ± 3.4; UN: 28.4 ± 6.2; AD+PLF: 32.8 ± 4.1; CP+PLF: 29.9 ± 3.9; OU+PLF: 34.1 ± 4.1; SB+PLF: 29.5 ± 8.2; TY+PLF: 29.2 ± 3.9; XE+PLF: 32.8 ± 6.7; UN+PLF: 32.2 ± 4.5. The bond strength of the resin cement to dentin using the tested AS was increased when the low-viscosity composite liner was applied.

Avaliação clínica de próteses parciais removíveis com 2 a 4 anos de uso / Clinical survey of removable partial dentures after 2 to 4 years usage

O objetivo deste estudo foi avaliar o desempenho clínico de próteses parciais removíveis (PPR) com 2 a 4 anos de uso, desenvolvidas por estudantes de odontologia da Universidade Federal do Espírito Santo (UFES). As próteses foram avaliadas de acordo com critérios preestabelecidos pela California Dental Association (CDA), considerando 4 quesitos de avaliação: (1) indicação da PPR como tratamento reabilitador; (2) qualidade do material utilizado para fabricação; (3) características do desenho e; (4) função da prótese. Estes quesitos foram ranqueados dentro de 4 categorias de qualidade: (i) excelente; (ii) aceitável; (iii) necessita substituição e; (iv) necessita remoção. Os dados foram registrados em uma ficha clínica, assim como a satisfação com o tratamento protético, além das condições de saúde oral dos pacientes. Compareceram para a pesquisa 30 pacientes (n=37 PPR). A avaliação dos 4 quesitos considerados indicou que 91,9% (n=34) das próteses foram consideradas satisfatórias quanto sua indicação; 97,3% (n=36) das próteses mantinham seus materiais em adequada condição; 89,2% (n=31) apresentaram um desenho satisfatório e 78,4% (n=29) foram classificadas como adequadas quanto à sua função. A avaliação da performance clínica das próteses parciais removíveis demonstrou que 67,5% (n=25) apresentavam-se em condições apropriadas de uso, dentre as quais 22% (n=8) apresentavam problemas passíveis de ajuste. Contudo, 32,5% (n=12) dos aparelhos protéticos tiveram sua substituição ou remoção indicada. Pôde-se verificar que, após o tempo de utilização avaliado, um maior número de falhas estava relacionado com problemas no desenho e função das próteses

Ainda, o índice de necessidade de ajustes (22%) e, principalmente, o índice de "insucessos" dos aparelhos (32,5%), apesar de dentro dos padrões encontrados na literatura para próteses com 2 a 4 anos de uso, podem indicar a importância de um programa de controle posterior regular para os pacientes tratados com este tipo de aparelho protético