Micromorphological and hardness analyses of human and bovine sclerotic dentin: a comparative study

The purpose of this study was to test the hypothesis that both human and bovine sclerotic dentin have similar hardness properties, in addition to similar micromorphological characteristics. Sixteen teeth (8 human and 8 bovine) exhibiting exposed dentin in the incisal edge and showing characteristics typical of sclerosis were used. Vickers surface microhardness testing was conducted. Three areas of the dentin surface of each specimen were selected. All teeth were processed for scanning electron microscopy in order to estimate the amount (in percentage) of solid dentin on the sclerotic dentin surface. The data were compared by Student's t test (α = 0.05). The micromorphological and microhardness data were compared by Pearson's linear correlation test (α = 0.05). The mean percentages of solid dentin of human and bovine sclerotic dentin were similar (human 90.71 ± 0.83 and bovine 89.08 ± 0.81, p = 0.18). The mean microhardness value (VHN) of human sclerotic dentin was significantly higher than that of bovine sclerotic dentin (human 45.26 ± 2.92 and bovine 29.93 ± 3.83, p = 0.006). No correlation was found between the microhardness values and the amount of solid dentin in the sclerotic dentin, irrespective of the species considered (human R² = 0.0240, p = 0.714; bovine R² = 0.0017, p = 0.923; and combined R² = 0.038, p = 0.46). We concluded that although both bovine and human sclerotic dentin present a similar amount of solid tissue, human sclerotic dentin presents higher microhardness than bovine sclerotic dentin.(FAPESP) São Paulo Research Foundation(CAPES) Coordination for the Improvement of Higher Education Personne

Estágio atual e perspectivas dos sistemas de união

The establishment of adhesion of restorative materials has been replaced by tooth-conserving adhesive methods. However, dentin bonding is still a challenge, due to the great variation of dentin. Nowadays, there is an amount of adhesives systems, depending on how the steps are accomplished or simplified. There is a trend to move away from multicomponents bonding systems toward simplified; which reduces not only the clinical application time but also the sensitivity of the technique. In spite of this, the micromechanical bonding mechanism offered by the current adhesives must be analyzed under different aspects, in order to decrease a nanoleakage. Therefore, the aim of this review is approach the most recent concepts in adhesive systems and perspectives for the future.O tratamento restaurador com a preservação de estrutura dental está fundamentado na utilização dos sistemas adesivos. Entretanto, a adesão à dentina tem sido um grande desafio para os pesquisadores, por ser um substrato heterogêneo. Atualmente, existe no mercado uma infinidade de marcas comerciais de sistemas adesivos com diferentes composições, métodos de aplicação e número de passos clínicos. Muitas vezes são lançados e retirados rapidamente do mercado, não havendo tempo para uma adequada avaliação clínica. Todos, de uma forma geral, têm como objetivo reduzir o número de passos operatórios e a sensibilidade da técnica adesiva e por sua vez, a microinfiltração. Diante desse questionamento, esta revisão teve como objetivo abordar o estágio atual em que se encontram os sistemas adesivos e quais as perspectivas futuras

Estudo da rugosidade e ultra-estrutura superficial do esmalte dental humano submetido a diferentes métodos profiláticos

Este trabalho teve como propósito estudar a rugosidade e ultra-estrutura superficial in vitro do esmalte dental humano submetido a três métodos profiláticos. Selecionaram-se 69 molares humanos com faces vestibulares hígidas e divididos em três grupos. No primeiro grupo, utilizou-se uma mistura de pedra-pomes (SSWhite) e água destilada com o auxílio de taça de borracha, montadas em contra-ângulo; no segundo, pasta profilática Herjos-F (Vigodent), taça de borracha e contra-ângulo e no terceiro, jato de bicarbonato com o aparelho Profi II Ceramic (Dabi Atlante). Todos os procedimentos foram realizados pelo mesmo operador durante 10 s, lavados e armazenados em água destilada. As mensurações da rugosidade superficial, em æm, foram realizadas antes e após os procedimentos com o aparelho Perthomether S8P em 54 amostras e o restante foram metalizadas e avaliadas por meio de MEV. Os resultados obtidos pelas leituras no rugosímetro foram submetidos à análise estatística através do teste t (Student) de pares equiparados e o teste de Kruskal-Wallis associado ao teste de comparação múltipla de Dunn (5%). Pôde-se observar que a rugosidade superficial do esmalte humano obtida pelo tratamento com o jato de bicarbonato mostrou-se maior de maneira estatisticamente significante quando comparada àquela obtida com a pedrapomes, enquanto que a utilização da pasta profilática não apresentou diferenças estatisticamente significantes em relação à utilização dos outros dois métodos. Na avaliação ultra-estrutural, observou-se a presença de inúmeros grânulos com diâmetros variados e depressões acentuadas nas superfícies tratadas com o jato de bicarbonato. Concluiu-se que o jato de bicarbonato aumentou a rugosidade superficial quando comparado à pedrapomes.The purpose of this in vitro study was to evaluate alterations in the surface roughness and micromorphology of human enamel submitted to three prophylaxis methods. Sixty nine caries-free molars with exposed labial surfaces were divided into three groups. The first group was treated with a rotary instrument set at a low speed, rubber cup and a mix of water and pumice slurry; the second, a rotary instrument set at a low speed, rubber cup and prophylaxis paste Herjos-F (Vigodent) and the third group, jet abrasive system with sodium bicarbonate Profi II Ceramic (Dabi Atlante). All procedures were performed by the same operator for 10 s, and samples were rinsed and stored in distilled water. Pre and post-treatment surface evaluation was completed using a surface profilometer (Perthomether S8P) in 54 samples. In addition, the other samples were coated with gold and examined in a scanning electron microscope (SEM). The results of this study were statistically analyzed with paired t-test (Student), Kruskal-Wallis test and Dunn (5%) test. The treatment with sodium bicarbonate jet significantly increased the human enamel surface roughness when compared with that of pumice paste. The use of prophylaxis paste Herjos-F, however, showed no statistically significant difference when compared with the other methods. Based on micromorphology analysis, the sodium bicarbonate jet presented an irregular surface with granular material and erosions. Based on this study, it could be concluded that there was increased enamel surface roughness when a tooth was treated with sodium bicarbonate jet when compared with pumice paste.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

In vitro comparative study of organic and inorganic components analysis of health and sclerotic human and bovine dentin: nanohardness, Ca and P concentration and morphological analysis

A dentina esclerosada é um substrato comumente encontrado em pacientes idosos. No entanto, existem poucos estudos comparativos entre dentina humana e bovina esclerosadas. O objetivo deste estudo foi comparar os componentes inorgânicos e orgânicos da dentina saudável e esclerosada humana e bovina, através de cinco parâmetros: nanodureza, módulo de elasticidade, análise quantitativa da concentração de Cálcio (Ca) e Fósforo (P), densidade tubular e morfologia do colágeno. Trinta dentes humanos e 30 bovinos foram distribuídos em 4 grupos experimentais (n=15 por grupo): dentina humana saudável (DHS), esclerosada humana (DEH), bovina saudável (DBS), e bovina esclerosada (DBE). Os dentes saudáveis foram preparados na mesma altura e inclinação dos dentes esclerosados expondo níveis similares da dentina e obtendo fragmentos com 2mm de espessura. Foram realizadas 3 medições por espécime em 3 áreas pré determinadas de dentina intertubular com a utilização do Nanoindentador (carga de 500N por 5 s). Cinco espécimes de cada grupo foram preparados para Microscopia Eletrônica de Varredura (MEV). Com o auxílio da Energia Dispersiva por Raios-X EDX foram obtidos os valores (em percentagem) das concentrações de Ca e P e calculada a relação Ca:P. A contagem dos túbulos por área foi realizada em todas as eletromicrografias. Após descalcificação e preparo, o restante dos espécimes foi analisado em Microscopia Eletrônica de Transmissão (MET). DBS obteve maiores valores de nanodureza comparada à DBE e DHS. DHE sem diferenças com DHS e DBE (p=0,0008). DBS exibiu maiores valores de módulo de elasticidade somente comparada à DHS (p=0,000). A análise estatística não demonstrou diferenças estatisticamente significantes (p=0,71) entre as concentrações de Ca e P. Quanto à densidade tubular (número de túbulos/mm²), os grupos saudáveis foram maiores que os esclerosados e os humanos maiores que os bovinos. As fibras colágenas da DBS mostraram-se mais compactadas e mais desorganizadas que as demais. Pôde se concluir que apenas as concentrações de Ca e P foram similares e que as dentinas esclerosadas humana e bovina mostraram similaridade. Esta pesquisa teve suporte da Fapesp sob o número 2008/10290-8.The sclerotic dentin has been commonly found in elderly patients. However, there are scarce reports in the literature comparing on the use of human and bovine sclerotic dentins. The objective of this study was to compare inorganic and organic components of healthy and sclerotic dentins from human and bovine. Five parameters were analyzed: nanohardness, elastic modulus, quantitative analysis of Calcium (Ca) and Phosphorous (P) concentrations, tubular density and ultrastructural morphology. Thirty human teeth plus 30 bovine teeth were distributed in 4 experimental groups (n=15 per group): human healthy dentin (HHD), human sclerotic dentin (HSD), bovine healthy dentin (BHD) and bovine sclerotic dentin (BSD). Healthy teeth were cut in the same level and inclination of the sclerotic superficial dentins. The nanohardness and elastic modulus (GPa) of three pre determined areas of each exposed dentin was measured using a nanoindenter (500N for 5s). Five samples of each group were prepared for scanning electron microscopy (SEM) examination. Energy Dispersive X-ray (EDX) was used for obtaining the Ca/P ratio. The tubular density was obtained by counting the tubules in scanning electron micrographs taken in the same magnification and work distance. Data were statistically analyzed by ANOVA complemented by the Tukeys test (p0.05). The ultrastructure of the dentins was observed in specimens processed for transmission electron microscopy (TEM). BHD exhibited significant higher nanohardness than BSD and HHD. HSD nanohardness was similar to those of HHD and BSD (p=0,0008). BHD exhibited significant higher elastic modulus than HHD (p=0,000). The Ca:P ratios were similar amongst all groups (p=0.71). The tubular densities were higher in the healthy dentins than in the sclerotic for both human and bovine. The human dentins presented higher tubular densities than bovine dentins (p=0.000). The intertubular dentin of BHD showed short collagen fibers distributed in a condensed fashion; whereas the other dentins exhibited well-organized long bundles of collagen fibers. It was concluded that sclerotic dentins of human and bovine share most morphological and structural characteristics. This research was supported by Fapesp grants number 2008/10290-8

Roughness of Human Enamel Surface Submitted to Different Prophylaxis Methods

The purpose of this in vitro study was to evaluate alterations in the surface roughness and micromorphology of human enamel submitted to three prophylaxis methods. Sixty-nine caries-free molars with exposed labial surfaces were divided into three groups. Group I was treated with a rotary instrument set at a low speed, rubber clip and a mixture of water and pumice; group II with a rotary instrument set at a low speed, rubber cup and prophylaxis paste Herjos-F (Vigodent S/A Industria e Comercio, Rio de Janeiro, Brazil); and group III with sodium bicarbonate spray Profi II Ceramic (Dabi A dante Indtistrias Medico Odontologicas Ltda, Ribeirao Preto, Brazil). All procedures were performed by the same operator for 10 s, and samples were rinsed and stored in distilled water. Pre and post-treatment surface evaluation was completed using a surface profilometer (Perthometer S8P Marh, Perthen, Germany) in 54 samples. In addition, the other samples were coated with gold and examined in a scanning electron microscope (SEM). The results of this study were statistically analyzed with the paired t-test (Student), the Kruskal-Wallis test and the Dunn (5%) test. The sodium bicarbonate spray led to significantly rougher surfaces than the pumice paste. The use of prophylaxis paste showed no statistically significant difference when compared with the other methods. Based on SEM analysis, the sodium bicarbonate spray presented an irregular surface with granular material and erosions. Based on this study, it can be concluded that there was an increased enamel stuface roughness when teeth were treated with sodium bicarbonate spray when compared with teeth treated with pumice paste

Roughness of Human Enamel Surface Submitted to Different Prophylaxis Methods

The purpose of this in vitro study was to evaluate alterations in the surface roughness and micromorphology of human enamel submitted to three prophylaxis methods. Sixty-nine caries-free molars with exposed labial surfaces were divided into three groups. Group I was treated with a rotary instrument set at a low speed, rubber clip and a mixture of water and pumice; group II with a rotary instrument set at a low speed, rubber cup and prophylaxis paste Herjos-F (Vigodent S/A Industria e Comercio, Rio de Janeiro, Brazil); and group III with sodium bicarbonate spray Profi II Ceramic (Dabi A dante Indtistrias Medico Odontologicas Ltda, Ribeirao Preto, Brazil). All procedures were performed by the same operator for 10 s, and samples were rinsed and stored in distilled water. Pre and post-treatment surface evaluation was completed using a surface profilometer (Perthometer S8P Marh, Perthen, Germany) in 54 samples. In addition, the other samples were coated with gold and examined in a scanning electron microscope (SEM). The results of this study were statistically analyzed with the paired t-test (Student), the Kruskal-Wallis test and the Dunn (5%) test. The sodium bicarbonate spray led to significantly rougher surfaces than the pumice paste. The use of prophylaxis paste showed no statistically significant difference when compared with the other methods. Based on SEM analysis, the sodium bicarbonate spray presented an irregular surface with granular material and erosions. Based on this study, it can be concluded that there was an increased enamel stuface roughness when teeth were treated with sodium bicarbonate spray when compared with teeth treated with pumice paste

Influence of the coloring agent concentration on bleaching gel and pulp chamber temperatures during dental bleaching

This study evaluated the Influence of the coloring agent concentration on the temperature of the gel layer and pulp chamber during dental bleaching with an LED/laser light source. Ten human incisors and a digital thermometer with K-type thermocouples were used. Using a high-speed spherical diamond bur, endodontic access was gained through openings on the lingual faces until pulp chamber was exposed. One end of the thermocouple was placed on the labial surface (immersed in bleaching gel) and the other end in the pulp chamber. The same 10 specimens were used in the 12 groups, according to the type and concentration of bleaching gel. Each bleaching gel was used in four different concentrations: manipulated without coloring, with normal quantity recommended by the manufacturer, with double the recommended amount of coloring, and with triple the recommended amount of coloring. The temperature rise was measured every 30 seconds for three minutes with a K-type thermocouple. The data were analyzed by ANOVA to examine the concentration and type of bleaching gel. This test was followed by Tukey's test, which was performed Independently for the gel at the labial surface and the pulp chamber (a = 5%). For both surfaces, values of p = 0.00 were obtained for all factors and for the Interaction between them. The varying concentrations of coloring agent produced statistically significant differences in terms of temperature increase for both the gel layer and the pulp chamber during activation