Abordagens utilizadas na avaliação do risco de cárie / Approaches used in the assessment of caries risk

Objetivo: O objetivo do presente estudo foi conduzir uma revisão de literatura para discutir a atividade de cárie, bem como os fatores, indicadores e preditores de risco a ela relacionados, os quais foram pontualmente abordados. Revisão de literatura: Nesta revisão discutem-se os principais instrumentos considerados na determinação do risco, os quais incluem a verificação da experiência e da atividade de cárie, a condução de testes salivares, a análise de hábitos dietéticos e das condições de higiene bucal e a consideração de aspec-tos socioeconômicos. Considerações finais: Com base nas evidências disponíveis conclui-se que: 1) quando analisados isoladamente, os fatores, indicadores e preditores de risco podem fornecem subsídios limitados à determinação do risco de cárie; 2) a experiência passada e a atividade de lesões incipientes são os melhores preditores do risco de cárie; 3) dentre os aspectos salivares, o fluxo caracteriza-se como o principal componente na predição do risco; 4) quando o biofilme é desorganizado e o indivíduo tem acesso a fontes de fluoreto, o consumo de sacarose parece ter um papel secundário no risco da doença; 5) aspectos socioeconômicos podem ter influência no risco de cárie.

Avaliação in vitro das alterações verificadas em canais radiculares artificiais curvos preparados por dois sistemas rotatórios / In vitro evaluation of shape changes in curved artificial root canals prepared with two rotary systems

O objetivo desta pesquisa experimental in vitro foi analisar comparativamente as deformações no canal radicular apóso uso do sistema rotatório de NiTi ProTaper Universal, ProDesign e técnicas híbridas utilizando os dois sistemas. Foram utilizados e instrumentados, setenta e cinco blocos com canais radiculares artificiais, divididos em cinco grupos(n=15). Para o grupo 1, os preparos foram realizados pelo sistema ProTaper Universal, utilizando a lima F3 no preparo apical. Para o grupo 2, utilizou-se o sistema ProDesign com preparo apical usando a lima 30/0,2. Para o grupo 3,os preparos foram realizados pelo sistema ProTaper Universal,utilizando a lima F2 no preparo apical. Para o grupo 4, os sistemas ProDesign e ProTaper foram utilizado sem conjunto com preparo realizado com a lima F2. Para o grupo 5, os sistemas ProDesign e ProTaper foram utilizados em conjunto com preparo apical realizado com as limas F1 e F2. As brocas de Gates-Glidden #5, #4, #3, #2 e#1 realizaram o preparo da porção reta de todos os canais,caracterizando o preparo cervicoapical. Foram analisados a diferença e o quociente da quantidade de resina removida nos seis milímetros de curvatura, aferidos tanto na parte interna quanto na parte externa. Zip e elbow foram quantificados pela forma final, após instrumentação em cada grupo testado. Para análise dos dados utilizou-se os testes paramétricos (ANOVA p<0,05), não paramétrico Kruskal--Wallis (p<0,05) e qui-quadrado (p<0,05). Para diferença e quociente, verificou-se melhores formas para os grupos 2 e3. Através da análise quantitativa e qualitativa, observou-se melhores preparos com o sistema ProDesign e ProTaperUniversal com preparo apical utilizando lima F2.

The aim of this in vitro experimental analysis was to comparethe changes in canal shape after the use of ProTaper UniversalNiTi rotary system, ProDesign system, and a hybridtechnique using both systems. A total of seventy-five simulatedroot canals were prepared and divided into five groups(n = 15). For Group 1, the ProTaper Universal System withapical preparation file F3 was used. For Group 2, ProDesignSystem with apical preparation using file 30/0.2 was used.For Group 3, ProTaper Universal System with apical preparationwith file F2 was applied. For Group 4, ProDesign Systemand ProTaper Universal System with apical preparationwith file F2 were applied. For Group 5, ProDesign Systemand ProTaper Universal System with apical preparation F1and F2 were used. All instrumentation was performed withthe help of Gates-Glidden drills #5, #4, #3, #2 and #1 accordingto crow-down preparation. The difference and thequotient the amount of removed resin were analyzed withinsix millimeters of the canal curvature, measured for both innerand outer walls. The amount of zip and elbow apical formationand mean final shape for each type tested were analyzed.Data were analyzed using parametric tests (ANOVA p<0.05),non-parametric test Kruskal-Wallis (p<0.05) and Chi-squaretest (p<0.05). When difference, quotient and final mean shapewere analyzed, the best preparations were observed in groups2 and 3. Through qualitative and quantitative analysis, thebest preparations were obtained with ProDesign System andProTaper Universal System with apical preparation file F2.

Dual resin cement knoop hardness after different activation modes through dental ceramics

This study investigated the influence of ceramic compositions on Knoop Hardness Number (KHN) immediately and 24 h after polymerization and the effect of activation modes on the KHN of a resin cement. Ten Panavia F 2.0 resin cement discs were activated either directly using curing light, or chemically without light, or through 1.2-thick ceramic discs. The following ceramics were evaluated: Duceram, Cergogold, IPS Empress, IPS Empress 2, Procera, Cercon, In Ceram Alumina and In Ceram Zirconia. The KHN was obtained immediately and after 24-h testing time. Two-way ANOVA and Tukey's test were performed for statistical analysis (p<0.05). Direct activation showed higher KHN than activation through ceramics and chemical activation for both immediate and 24-h post activation. The KHN for 24-h post activation time was higher than that of the immediate post activation time except for the direct activation mode. The glass and di-silicate based ceramics showed higher KHN than alumina- and zirconia-based ceramics, immediately and after 24-h. The reinforced and opaque ceramics had the lowest KHN. The ceramic composition resulted in light attenuation, lower polymerization and lower KHN, and the 24-h testing time promoted an improvement of KHN except for direct activation mode.

Este estudo investigou a influência de composições de cerâmica no número de dureza Knoop (KHN), imediatamente e 24 h após a polimerização; e o efeito de modos de ativação na KHN de um cimento resinoso. Dez discos de cimento resinoso Panavia F 2.0 foram ativados diretamente usando uma fonte de luz, ou quimicamente sem luz, ou através de discos de cerâmica com espessura de 1,2 mm. As cerâmicas avaliadas foram Duceram, Cergogold, IPS Empress, IPS Empress 2, Procera, Cercon, In Ceram Alumina e In Ceram Zirconia. O KHN foi obtido nos tempos imediatamente e após 24 h. Os testes ANOVA two-way e Tukey foram realizados para a análise estatística (p<0,05). A ativação direta apresentou maiores KHN que a ativação através das cerâmicas e ativação química, para ambos os tempos testados imediatamente e após 24 h. O KHN para o tempo de ativação testado após 24 h foi superior que o tempo imediatamente, exceto para o modo de ativação direto. As cerâmicas à base de vidro e di-silicato apresentaram KHN superiores que as cerâmicas à base de alumina e zircônia, imediatamente e após 24 h. As cerâmicas mais reforçadas e opacas resultaram um dos menores KHN. A composição da cerâmica resulta em atenuação de luz, menor polimerização e menor KHN; e o tempo de 24 h testado promove uma melhora no KHN, exceto para o modo de ativação direto.

Effect of surface treatment and storage on the bond strength of different ceramic systems

Aim: The aim of this study was to evaluate the micro shear bond strength of different ceramic systems – IPS Empress 2, Cergogold, In-Ceram Alumina and Cercon - and a dual luting agent. Methods: Twelve specimens of each ceramic were fabricated and divided according different surface treatments: Group 1: No additional treatment was applied to the ceramic surface; Group 2: Ceramics were etched with 9.5% hydrofluoric acid; Group 3: specimens treated with airborne particle abrasion for each ceramic system in accordance with manufacturer’s instructions (n=20). The tests were performed after 24 h or after water storage for 6 months. Data were then assessed statistically using the 3-way ANOVA and the Tukey’s test (P<0.05). Results: For Cergogold and IPS Empress 2 systems, the treatments performed with airborne particle abrasion and hydrofluoric acid showed no significant differences from each other, and both were superior to the groups without treatment. For Cercon and In-Ceram ceramics, no differences were found among the groups (P<0.05). When the surface was treated with hydrofluoric acid, the highest bond strength was found to IPS Empress 2 in the 6-month storage period (P<0.05). Conclusion: Lower bond strength values were only observed with IPS Empress 2 ceramic for the control group in the 6-month storage (P<0.05).

O condicionamento ácido prévio ainda é indispensável para a odontologia adesiva? / Is previous total etching still indispensable for the adhesive dentistry?

O objetivo deste trabalho foi avaliar as características dos sistemas adesivos disponíveis atualmente considerando a aplicação ou não do condicionamento prévio com ácido fosfórico. O conhecimento das estruturas e o tratamento adequado do substrato dental são fundamentais para utilização dos adesivos convencionais. Os sistemas adesivos autocondicionantes possuem técnica simplificada dispensando o condicionamento ácido prévio. O profissional deverá ter conhecimento dos mecanismos de adesão ao substrato dental, experiência clínica e domínio da técnica de aplicação do adesivo escolhido. O condicionamento ácido prévio não deve ser considerado indispensável na Odontologia adesiva atual.

Effect of the flask contention method on the displacement of maxillary denture teeth

Keeping the flask closed may reduce the stress released by the resin dough after the pressing step, preserving the tooth relationship pattern. The aim of this study was to analyze the influence of the flask contention method on tooth displacement in acrylic resin complete dentures. Twenty identical maxillary complete dentures were made using the heat-cured acrylic resins Classico and QC-20, polymerized by long and fast polymerization cycles respectively, and randomly assigned to 4 test groups according to the conventional packing method and RS tension system. Transversal and anteroposterior distances between specific teeth were measured with a linear optical microscope before and after denture processing. Analysis of variance (ANOVA) and Tukey test were used to compare the groups (p<.05). Results showed that tooth movement was significantly greater for the distance RI-LI in comparison with the others, and the tooth movement was not significantly influenced by the packing method. Within the limitations of this study, the RS tension system presented a similar performance in reducing the tooth movement, when compared with the conventional packing method. The anterior region of the denture may present changes in the tooth position after processing, which need to be clinically adjusted.

Esthetic analysis of the smile

This study analyzed the esthetics components of the smile, evaluating the relationship between the curve formed by the incisal line of the anterior superior teeth and the curve of the inferior lip, the touch of this incisal line on the inferior lip, the teeth displayed during smile, the relationship between the facial midline with the arch midline, the location of the arch midline and gender differences. Eighty-eight undergraduate students of the dentistry course of the TiradentesUniversity were selected. Two photographs were taken (smiling face and smile) using digital camera. The statistical analysis was performed after image tracing evaluation. Results show that the coincidence of the facial midline with the arch midline occurred only on half of the students. Most of the students presented parallelism between the incisal plan and the interpupillary line. Smiles with or without touch of the incisal line on the lower lip, smiles revealing up to the seconds premolars or firsts molars, and parallel or straight smiles were also most commonly observed. The majority of the men presented centeredmidline arch while women presented deviation to the right. No difference was found between the distribution of the arch midline.