Metalloproteinases in Restorative Dentistry: An In Silico Study toward an Ideal Animal Model.

In dentistry, various animal models are used to evaluate adhesive systems, dental caries and periodontal diseases. Metalloproteinases (MMPs) are enzymes that degrade collagen in the dentin matrix and are categorized in over 20 different classes. Collagenases and gelatinases are intrinsic constituents of the human dentin organic matrix fibrillar network and are the most abundant MMPs in this tissue. Understanding such enzymes' action on dentin is important in the development of approaches that could reduce dentin degradation and provide restorative procedures with extended longevity. This in silico study is based on dentistry's most used animal models and intends to search for the most suitable, evolutionarily close to Homo sapiens. We were able to retrieve 176,077 mammalian MMP sequences from the UniProt database. These sequences were manually curated through a three-step process. After such, the remaining 3178 sequences were aligned in a multifasta file and phylogenetically reconstructed using the maximum likelihood method. Our study inferred that the animal models most evolutionarily related to Homo sapiens were Orcytolagus cuniculus (MMP-1 and MMP-8), Canis lupus (MMP-13), Rattus norvegicus (MMP-2) and Orcytolagus cuniculus (MMP-9). Further research will be needed for the biological validation of our findings.

Fabrication and characterization of low-shrinkage dental composites containing montmorillonite nanoclay.

Dental composites are aesthetic materials widely used in Dentistry for replacing hard dental tissues lost due to caries or traumas. The aim of this study was to fabricate low-shrinkage dental composite charged with nanoclay fillers (montmorillonite Cloisite®-MMT) and evaluate their cytotoxicity and physicomechanical properties. Four dental composites were produced from the same organic matrix: Bis-GMA/TEGDMA (30 wt.%). The filler system was constituted of BaSi, SiO2, and MMT in the following concentrations (wt.%): 93.8/6.2/0, 89.1/5.9/5, 86.7/5.8/7.5, and 84.4/5.6/10 (E0: 0; E5: 5%; E7.5: 7.5%; E10: 10% of MMT nanoclays). The following properties were tested: in vitro cytotoxicity, flexural strength, elastic modulus, volumetric shrinkage, water sorption, water solubility, and hygroscopic expansion. Scanning electron microscopy was used to characterize composites' topography. Data were analyzed by one-way ANOVA and Tukey's HSD post hoc test (p < 0.05). MMT nanoclays did not affect the cytotoxicity. E5 and E7.5 groups showed a significant decrease in polymerization shrinkage while maintained the overall physicomechanical properties. The inclusion of 5 and 7.5 wt.% of MMT nanoclays allowed the fabrication of dental composites with low cytotoxicity and low polymerization shrinkage, without jeopardizing the overall behaviour of their physicomechanical properties (flexural strength, elastic modulus, water sorption, water solubility, and hygroscopic expansion). These aspects suggest that the usage of MMT nanoclays could be an effective strategy to formulate new dental composites with clinical applicability.

In vitro comparison of peracetic acid and autoclave sterilization in the corrosion of orthodontic pliers: a pilot study.

INTRODUCTION: The most currently recommended method for sterilization of orthodontic pliers is the autoclave, while peracetic acid has also been shown to be effective in the chemical sterilization process. OBJECTIVE: This study sought to compare the corrosive effects of peracetic acid and autoclave sterilization process of orthodontic pliers. METHODS: Four active tungsten carbide (WC) stainless steel tie-cutting pliers from the manufacturers Quinelato (Rio Claro, SP, Brazil) and ICE (Cajamar, SP, Brazil) were selected. The active ends of the pliers were sectioned, and six active tips were obtained and distributed into the following groups: 1) control group (no sterilization); 2) AC group (two active pliers tips submitted to 100 autoclave sterilization cycles); and 3) AP group (two active pliers tips submitted to 100 cycles of sterilization by immersion in 2% peracetic acid solution for 30 minutes). RESULTS: Chemical analysis using X-ray dispersive energy spectroscopy showed that after autoclave sterilization, only the ICE pliers presented oxidation corrosion (Δ[O] = +24.5%; Δ[Fe] = +5.8%; Δ[WC] = -1.9%). In comparison, following peracetic acid sterilization, both manufacturers ICE (Δ[O] = +1.8%; Δ[Fe] = +18.0%; Δ[WC] = -1.1%) and Quinelato (Δ[O] = +5.3%; Δ[Fe] = -10.4%; Δ[WC] = -15.2%) showed corrosion. The morphological analysis revealed that peracetic acid caused a pitting and localized corrosion in both brands, while the autoclave caused uniform surface corrosion on the ICE pliers. CONCLUSION: Autoclave application was the sterilization method that generated less corrosive damage to the orthodontic cutting pliers, when compared to the immersion in 2% peracetic acid.

In vitro comparison of peracetic acid and autoclave sterilization in the corrosion of orthodontic pliers: a pilot study

ABSTRACT Introduction: The most currently recommended method for sterilization of orthodontic pliers is the autoclave, while peracetic acid has also been shown to be effective in the chemical sterilization process. Objective: This study sought to compare the corrosive effects of peracetic acid and autoclave sterilization process of orthodontic pliers. Methods: Four active tungsten carbide (WC) stainless steel tie-cutting pliers from the manufacturers Quinelato (Rio Claro, SP, Brazil) and ICE (Cajamar, SP, Brazil) were selected. The active ends of the pliers were sectioned, and six active tips were obtained and distributed into the following groups: 1) control group (no sterilization); 2) AC group (two active pliers tips submitted to 100 autoclave sterilization cycles); and 3) AP group (two active pliers tips submitted to 100 cycles of sterilization by immersion in 2% peracetic acid solution for 30 minutes). Results: Chemical analysis using X-ray dispersive energy spectroscopy showed that after autoclave sterilization, only the ICE pliers presented oxidation corrosion (Δ[O] = +24.5%; Δ[Fe] = +5.8%; Δ[WC] = -1.9%). In comparison, following peracetic acid sterilization, both manufacturers ICE (Δ[O] = +1.8%; Δ[Fe] = +18.0%; Δ[WC] = -1.1%) and Quinelato (Δ[O] = +5.3%; Δ[Fe] = -10.4%; Δ[WC] = -15.2%) showed corrosion. The morphological analysis revealed that peracetic acid caused a pitting and localized corrosion in both brands, while the autoclave caused uniform surface corrosion on the ICE pliers. Conclusion: Autoclave application was the sterilization method that generated less corrosive damage to the orthodontic cutting pliers, when compared to the immersion in 2% peracetic acid.

RESUMO Introdução: O método mais recomendado para a esterilização dos alicates ortodônticos é a autoclave; porém, o ácido peracético mostrou-se eficaz no processo de esterilização química. Objetivo: O objetivo do presente estudo foi avaliar o efeito corrosivo do ácido peracético e da autoclave no processo de esterilização de alicates ortodônticos. Métodos: Foram selecionados quatro alicates de corte de amarrilho de aço inoxidável, com ponta ativa de carboneto de tungstênio (WC), das marcas Quinelato (Rio Claro/SP, Brasil) e ICE (Cajamar/SP, Brasil), que foram distribuídos em três grupos: 1) Controle (C), o qual não foi submetido à esterilização; 2) Grupo AC, constituído por duas pontas ativas de alicates submetidas a 100 ciclos de esterilização em autoclave; e 3) Grupo AP, formado por duas pontas ativas de alicates submetidas a 100 ciclos de esterilização por imersão em solução de ácido peracético a 2% durante 30 minutos. Resultados: Por meio da análise química (EDS, energia dispersiva de raios X), constatou-se que, após esterilização em autoclave, somente o alicate ICE apresentou corrosão por oxidação (Δ[O] = +24,5%; Δ[Fe] = +5,8% e Δ[WC] = -1,9%), enquanto na esterilização em ácido peracético, ambas as marcas, ICE (Δ[O] = +1,8%; Δ[Fe] = +18,0% e Δ[WC] = -1,1%) e Quinelato (Δ[O] = +5,3%; Δ[Fe] = -10,4% e Δ[WC] = -15,2%), apresentaram corrosão. A análise morfológica demonstrou que o ácido peracético causou uma corrosão localizada em pite em ambas as marcas, enquanto a autoclave ocasionou uma corrosão superficial uniforme no alicate ICE. Conclusão: A autoclave foi o método de esterilização que gerou menor dano corrosivo aos alicates ortodônticos, em comparação à imersão em ácido peracético a 2%.

Influence of activation mode, fatigue, and ceramic interposition on resin cements' diametral tensile strength.

This study evaluated the influence of activation modes, on Diametral Tensile Strength (DTS) of dual cured resin cements subjected to a Mechanical Fatigue test (MF). Four dual-cured resin cements (RelyX UNICEM [U], RelyX ARC [A], ENFORCE [E] and Nexus 2 [N]) were activated by three different curing modes as follows: Self-Curing (SC), Dual Cure activation with photoactivation executed directly (DC) and Dual Cure activation with Photoactivation Through Porcelain (DCTP). After 24 hours, half of the sample was subjected to 30.000 fatigue cycles at 1 Hz frequency and 12 N load. Then, all specimens were subjected to DTS test in Instron Universal Testing Machine and data were analyzed by three-way ANOVA and Tukey's Test (5%). The results of DTS test means (MPa) and standard deviation, for each cement factor activated by SC, DC and DCTP was respectively: U (28.12 ± 5.29; 37.44 ± 6.49 and 40.10 ± 4.39), A (49.68 ± 8.42; 55.12 ± 5.16 and 63.43 ± 6.92), E (49.12 ± 3.89; 56.42 ± 8.88 and 56.96 ± 6.45) and N (61.89 ± 11.21; 59.26 ± 9.47 and 62.56 ± 10.93). Turkey's test indicated that DC is related to the highest DTS values; Nexus 2 DTS remained the same independently of activation mode and that the Porcelain disk interposition enhanced DTS only for RelyX ARC the ANOVA statistical test indicated that MF didn't alter the DTS values for all experimental groups. MF results clinical implication is that all cements tested exhibited, in an immediate loading, good cross linked bonds quality.

How do the optical properties of the bulk fill posterior composites change after 2 years of simulated toothbrushing? / Como as propriedades ópticas de compósitos bulk fill se comportam após 2 anos de escovação simulada?

Objective: The objective of this study was to evaluate the alteration of the optical properties of bulk fill resin-based composites after two years of simulated toothbrushing. Material and Methods: Three high-viscosity bulk fill resin composites and one conventional sculptable resin composite (control) were analyzed. Five specimens of each resin composite were prepared, and roughness, color, translucency and gloss were evaluated initially and after one and two years of simulated toothbrushing. The specimens were submitted to electric simulated toothbrushing (14600 strokes / 100 g) using a commercially available soft bristle toothbrush and toothpaste slurry in a proportion of 1:2 by weight. The brushing scheme was of 40 cycles per day (2 cycles per second / 280 cycles in a week). The optical properties and the roughness data were analyzed by a multifactor analysis of variance (MANOVA) and a Tukey post hoc test. Results: The baseline and final values of Ra and Sa were submitted to linear regression analyses, all of which were performed at a significance level of 5%. Gloss and roughness presented statistical differences between the resin-time interactions in all composite resins. The gloss (72.5%) and roughness (89.4%) worsened significantly after brushing, but the authors didn't find statistically significant differences when evaluating translucency and color. Conclusion: Based in the results, it could be concluded that the simulated brushing degraded the gloss and roughness of the used high-viscosity bulk fill composites. (AU)

Objetivo: O objetivo deste estudo foi avaliar a alteração das propriedades ópticas de resinas compostas do tipo bulk fill após dois anos de escovação simulada. Material e Métodos: Foram analisadas três resinas compostas do tipo bulk fill de alta viscosidade e uma resina composta convencional (controle). Cinco corpos-deprova de cada resina composta foram preparados e a rugosidade, cor, translucidez e brilho foram avaliados inicialmente e após um e dois anos de escovação simulada. Os espécimes foram submetidos a escovação dental simulada (14.600 golpes / 100 g) utilizando-se escova de dentes de cerdas macias comercialmente disponíveis e uma pasta composta de dentifrício e água na proporção de 1:2 em peso. O esquema de escovação foi de 40 ciclos por dia (2 ciclos por segundo / 280 ciclos por semana). As propriedades ópticas e os dados de rugosidade foram analisados por uma análise de variância multifatorial (MANOVA) e um teste post hoc de Tukey. Resultados: Os valores iniciais e finais de Ra e Sa foram submetidos a análises de regressão linear, todas realizadas ao nível de significância de 5%. O brilho e a rugosidade apresentaram diferenças estatísticas entre as interações resina-tempo em todas as resinas compostas. O brilho (72,5%) e a rugosidade (89,4%) pioraram significativamente após a escovação, mas os autores não encontraram diferenças estatisticamente significativas ao avaliar a translucidez e a cor. Conclusão: Com base nos resultados, pôde-se concluir que a escovação simulada degradou o brilho e a rugosidade das resinas compostas do tipo bulk fill avaliadas. (AU)

Influence of activation mode, fatigue, and ceramic interposition on resin cements' diametral tensile strength

Abstract This study evaluated the influence of activation modes, on Diametral Tensile Strength (DTS) of dual cured resin cements subjected to a Mechanical Fatigue test (MF). Four dual-cured resin cements (RelyX UNICEM [U], RelyX ARC [A], ENFORCE [E] and Nexus 2 [N]) were activated by three different curing modes as follows: Self-Curing (SC), Dual Cure activation with photoactivation executed directly (DC) and Dual Cure activation with Photoactivation Through Porcelain (DCTP). After 24 hours, half of the sample was subjected to 30.000 fatigue cycles at 1 Hz frequency and 12 N load. Then, all specimens were subjected to DTS test in Instron Universal Testing Machine and data were analyzed by three-way ANOVA and Tukey's Test (5%). The results of DTS test means (MPa) and standard deviation, for each cement factor activated by SC, DC and DCTP was respectively: U (28.12 ± 5.29; 37.44 ± 6.49 and 40.10 ± 4.39), A (49.68 ± 8.42; 55.12 ± 5.16 and 63.43 ± 6.92), E (49.12 ± 3.89; 56.42 ± 8.88 and 56.96 ± 6.45) and N (61.89 ± 11.21; 59.26 ± 9.47 and 62.56 ± 10.93). Turkey's test indicated that DC is related to the highest DTS values; Nexus 2 DTS remained the same independently of activation mode and that the Porcelain disk interposition enhanced DTS only for RelyX ARC the ANOVA statistical test indicated that MF didn't alter the DTS values for all experimental groups. MF results clinical implication is that all cements tested exhibited, in an immediate loading, good cross linked bonds quality.

Low-level laser treatment applied at auriculotherapy points to reduce postoperative pain in third molar surgery: A randomized, controlled, single-blinded study.

OBJECTIVE: Evaluate the effectiveness of LLL (Low level laser therapy) in auriculotherapy points for pain reduction following lower third molar extractions. STUDY DESIGN: Randomized, controlled, single-blinded study. METHODS: Eighty-four bilateral, symmetrical third molar surgeries were performed in 42 healthy patients using a split-mouth design. In the immediate postoperative period, each side was randomly treated in a single-blind method with an LLL at the auriculotherapy points or simulation of its use (contralateral side) over a 21-day interval. This protocol was repeated 24 and 48 hours after surgery. All patients used the same analgesic (paracetamol) but only in case of pain. The primary variable was postoperative pain according to the visual analogue scale, and the secondary variables were mouth opening, edema, local temperature, dysphagia, and the presence of infection (systemic temperature, lymphadenopathy). These variables were evaluated at baseline and at 24 hours, 48 hours and seven days after surgery. Adverse effects were recorded and reported. RESULTS: There was no difference between the groups in relation to any of the evaluated parameters (p>0.05). CONCLUSION: For this experimental model, application of a low-intensity laser at auriculotherapy points did not prevent postoperative pain following lower third molar surgery. TRIAL REGISTRATION: This trial is registered at ClinicalTrials.gov; the registration number is NCT02657174 and the Unique Protocol ID number is 1.100.869. (https://register.clinicaltrials.gov/prs/app/template/EditRecord.vm?epmode=View&listmode=Edit&uid=U0002BEY&ts=11&sid=S0006026&cx=6g4wff).

Evaluation of low-level laser at auriculotherapy points to reduce postoperative pain in inferior third molar surgery: study protocol for a randomized controlled trial.

BACKGROUND: A comfortable postoperative return to daily activities has increased the need to control inflammation after third molar surgery. Anti-inflammatory drugs and analgesics are not exempt from adverse effects such as allergies and chronic gastritis, and they are not without cost. The association between low-level laser and auricular acupuncture can be an alternative when conventional drugs are contraindicated. Among its advantages, we can mention the low risk of side effects, low cost and simplicity of application. The objective of this study is to evaluate the efficiency of low-level laser at auriculotherapy points in reducing postoperative pain in lower third molar surgery. METHODS/DESIGN: Ninety bilateral, symmetrical lower third molar surgeries will be performed in 45 healthy patients. Each patient will be their own control, through a split-mouth crossover study. One side of the mouth will be randomly chosen and, immediately after surgery, will be treated with low-level laser. After 21 days, the contralateral side will be operated on with low-level laser simulation used postoperatively. This regimen (laser application or not) will be repeated at 24 and 48 h after surgery. All patients will be requested to take analgesics (acetaminophen) if they have pain, i.e. in case of pain. Neither the surgeon nor the patients will know the assigned treatment. The primary variable will be postoperative pain assessed using a Visual Analog Scale, and the secondary variables will be trismus, edema, local temperature, dysphagia, presence of infection and painkiller ingestion. These variables will be assessed at baseline, 24 h, 48 h and 7 days after surgery. Blood samples for systemic inflammatory cytokine (TNF-α, IL-1, IL-6 and IL-8) analysis will be assessed at baseline and 24 h after surgery. DISCUSSION: Some authors believe that using a wavelength of 633 to 670 nm is a good option for laser therapy in the field of acupuncture. This wavelength can penetrate biological tissue to a depth of about 3 mm. However, for auriculotherapy points, the stimulus (mustard seeds, needles 1 to 2.5 mm) does not penetrate so deeply. For this reason, we chose a laser wavelength of 660 nm (red wavelength). TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02657174 , registered on 11 January 2016.

Influence of stress corrosion on the mechanical properties of laser-welded titanium.

STATEMENT OF PROBLEM: Whether laser-welded (LW) titanium can resist the stress corrosion produced by the combination of fluoride ions and stress in the oral environment is unknown. PURPOSE: The purpose of this in vitro study was to investigate the influence of stress corrosion on the mechanical properties of LW titanium. MATERIAL AND METHODS: Twenty-seven titanium bars (25×2 mm) with a circular cross-section were cut in half and laser-welded, while another 27 nonwelded (NW) bars were used as the control. Thirty bars were submitted to a flexural load of 480 N at 1 Hz and immersed in artificial saliva at pH 6 (S1) or in 1000 ppm fluoride-containing saliva at pH 6.0 (S2) or 2.0 (S3) at room temperature for up to 4000 cycles. After the stress corrosion simulation, the tensile strength and Vickers microhardness were determined (n=5). Twelve LW and NW bars were submitted to the corrosion immersion test media for 51 days (n=2) to determine polarization curves (n=2) in an artificial saliva media. The corroded surface was examined with scanning electron microscopy (SEM). RESULTS: The combination of fluoride and low pH significantly decreased the tensile strength of LW (P<.05). Stress corrosion did not affect the hardness of LW or NW (P>.05). NW bars immersed in S3 exhibited progressive surface dissolution, while LW bars spontaneously fractured at the welded area after 25 days of immersion in the same medium. SEM images demonstrated pitting corrosion without the presence of cracks in both groups immersed in S3. CONCLUSIONS: Stress corrosion caused by acidic fluoride-containing saliva and flexural load cycling decreased the tensile strength and hardness of LW titanium bars.

Antibiotic therapy in fully impacted lower third molar surgery: randomized three-arm, double-blind, controlled trial.

PURPOSE: The aim of this study was to evaluate the efficacy of three drug protocols in patients undergoing extraction of fully impacted lower third molars. METHODS: Eighty surgeries were performed on healthy patients using three randomized double-blind drug protocols: group 1 (G1), amoxicillin (1 g) 1 h before surgery + 500 mg 8/8 h for 7 days; group 2 (G2), 1-g amoxicillin 1 h before surgery plus placebo, with identical appearance to G1, 8/8 h for 7 days; and group 3 (G3), placebo 1 h before surgery and 500 mg 8/8 h for 7 days. The primary outcome criterion was mouth opening, and the secondary outcome criteria were facial edema and pain. Signals as body temperature, lymphadenopathy, and dysphagia characterize the sample. Evaluation was performed at baseline and on the 4th and 7th postoperative days by the same researcher. RESULTS: There was no difference among groups with respect to any of the parameters evaluated (p > 0.05). CONCLUSION: Under these experimental conditions, there is no advantage in the administration of antibiotics in healthy patients undergoing extraction of fully impacted lower third molars with a controlled aseptic chain.

Low-shrinkage composites: an in vitro evaluation of sealing ability after occlusal loading.

The objective of this in vitro study was to compare the microleakage of a flowable low-shrinkage-stress resin composite--in a Class II fatigue-loading design when used as a 4 mm dentin replacement--to a conventionally layered silorane-based resin composite. Eighty standardized 4 mm deep cavities, divided into 4 subgroups, were restored with the 2 tested materials. Half of the restorations were submitted to mechanical loading, and all of the restorations were prepared for microleakage evaluation. The evaluation of the marginal adaptation to dentin was performed with scanning electron microscopy. The results showed that both silorane-based composite groups had higher rates of microleakage in comparison to the low-shrinkage-stress resin composite groups.

Cimentação em cerâmicas: evolução dos procedimentos convencionais e adesivos / Cementation in ceramics: improvement of conventional and adhesive procedures

O objetivo deste estudo foi coletar dados científicos para revisão de literatura sobre cimentação de cerâmicas, ressaltando propriedades, técnicas, indicações e contraindicações. O agente cimentante ideal deve apresentar como principais características alta resistência à compressão, tração e cisalhamento, além de selamento marginal adequado, baixa solubilidade aos fluidos bucais e espessura mínima de película. Em relação à técnica, foi observado que diferenças na microestrutura e composição dos sistemas cerâmicos exigem protocolos específicos de preparo da peça cerâmica e da superfície dentária. Atualmente, os tipos de agentes cimentantes disponíveis são: fosfato de zinco, ionômero de vidro convencional e modificado por resina, cimentos resinosos e autoadesivos. A evolução desses materiais ocorre no sentido de melhorar propriedades e simplificar a técnica.

The objective of the study was to collect scientific data to perform a literature review of ceramic cementation, highlighting their properties, techniques, indications and contraindications. An ideal luting agent has to present as main characteristics high compressive strength, tensile and shear, adequate marginal sealing, low solubility to oral fluids and minimal thickness of film. Concerning the technique, it was observed that differences on microstructure and composition on ceramic systems require specific protocols on preparation for the ceramic structure and for the dental element surface. Nowadays, the available luting agents are: zinc phosphate, conventional and modified glass ionomer, resin cements and self adhesive cements. The evolution of these materials occurs to improve properties and to simplify technique.

Efeito do modo de ativação de um cimento resinoso autoadesivo na espessura da linha de cimento de copings metálicos cimentados sobre pilares protéticos / Effect of the cure mode on the marginal opening of metal copings luted to implant abutments with a self-adhesive resin cement

O objetivo deste trabalho foi analisar a influência do tipo de cimento e do modo de ativação na espessura da linha de cimento de copings metálicos cimentados sobre pilares protéticos. Foram utilizados 6 pilares e 6 cilindros do sistema Cera One cimentados com cimento autoadesivo RelyX U200 (3M ESPE, St. Paul - EUA) e também um cimento de fosfato de zinco (S.S. White Artigos Dentários Ltda. - Rio de Janeiro - RJ - Brasil). Foram cimentados 2 cilindros com fosfato de zinco, 2 cilindros com RelyX fotoativado e 2 não fotoativados sendo levados ao microscópio eletrônico de varredura para mensuração da linha de cimento. A diferença entre os grupos foi pequena e o modo de ativação do cimento autoadesivo interfere pouco na espessura da linha de cimento de copings metálicos cimentados sobre pilares protéticos.

The aim of this study was to analyse the effect of the luting agent and the cure mode on the marginal opening of metal copings luted to implant abutments. To test a self-adhesive resin cement and a zinc phosphate cement, were used 6 abutments and 6 cylinders of the Cera One system. The cylinders were luted 2 with zinc phosphate cement, 2 with resin cement light cured and 2 with resin cement not light cured. Afterwards the cylinders were taken to SEM analysis to calculate the marginal opening. The cure mode has a little effect on the marginal opening of metal copings luted to implant abutments.

A rugosidade do esmalte dental e o tratamento clareador / Dental enamel roughness and bleaching treatment

O objetivo deste estudo in vitro foi avaliar a morfologia do esmalte dental perante a ação de agentes clareadores, quantitativamente, por meio da mesuração de rugosidade superficial. As superfícies vestibulares de 20 terceiros molares foram seccionadas em duas partes, posicionadas sobre a resina acrílica incolor e armazenadas em água destilada. As amostras foram analisadas em microscópio óptico para a definição de 15 amostras homogêneas e distribuídas aleatoriamente em três grupos experimentais, cada um contendo cinco delas: Grupo 1 - imersão em água destilada, Grupo 2 - gel peróxido de hidrogênio 35 por cento e Grupo 3 - gel peróxido de hidrogênio a 35 por cento e ativação por luz LED (light emitting diodes). As medições da rugosidade foram realizadas para a comparação entre os grupos foi o teste 1 pareado. Não houve diferença estatisticamente significante nos grupos 1 e 2, sendo o valor de p maior do que 0,05. Entretanto, sob as condições experimentais deste trabalho, a técnica clareadora com ativação por luz resultou em alteração eTsatisticamente significante da rugosidade média do esmalte dental, cujo valor foi de p menor do que 0,05. O tratamento clareador com peróxido de hidrogênio a 35 por cento e com fotoativação causou aumento significativo da rugosidade do esmalte dental humano

Avaliação da tensão de contração durante a polimerização de uma resina em função da área aderida / Evaluation of shrinkage stress during polymerization of a resin related to the adhesion area

Este artigo tem como objetivo avaliar as tensões de contração de um compósito geradas pela polimerização em função da área aderida. Cilindros de vidro com 2 mm de diâmetro (G1) ou com 4 mm (G2) foram posicionados nas porções inferior e superior da máquina de testes. A distância dos cilindros de G1 era 2 mm e de G2 1 mm. Em cada grupo, a resina (Fill-Magic - Vigodent) foi inserida e fotoativada entre os cilindros e a t ensão m edida p or 1 5 m inutos ( n = 5 ). Os dados foram analisados pelo teste t-Student (p< 0,05). A maior área de adesão gerou menor tensão de contração para o material testado.

The aim of this study is to evaluate the shrinkage stress generated during polymerization of a composite resin related to the adhesion area. Cylinders of glass with 2 mm in diameter (G1) or 4 mm (G2) were positioned on the upper and lower portions of the testing machine. The distance from the cylinders was 2 mm in G1 and 1 mm in G2. In each group, the resin (Fill-Magic - Vigodent) was inserted and photopolymerized between the cylinders and the stress was measured for 15minutes (n = 5). Data were analyzed by Student t test (p < 0,05). The largest area of adhesion generated lower shrinkage stress to the tested material.

Reanatomização estética de incisivos laterais superiores possibilitando o tratamento ortodôntico: caso clínico / Esthetic reanatomization of upper lateral incisors allowing orthodontic treatment: case report

O presente trabalho teve como objetivo relatar um caso clínico de reanatomização estética de ambos os incisivos laterais superiores a fim de possibilitar o tratamento ortodôntico. A paciente,de 14 anos de idade, procurou tratamento ortodôntico na clínica da Universidade do Estado do Rio de Janeiro. Durante o exame clínico, observou-se a presença de um incisivo lateral superior permanente com tamanho atípico (12) e outro conoide mesializado (22), além de vários diastemas entre os dentes anteriores. Assim, foi realizado o encaminhamento à Clínica de Dentística para a reanatomização estética de ambos os dentes, a fim de possibilitar a colagem de braquetes ortodônticos. Restaurações diretas de resina composta foram confeccionadas através da técnica da guia de silicone. Após o procedimento, a paciente pôde realizar o tratamento ortodôntico. Contudo, será novamente encaminhada à clínica de Dentística para realização de fechamento dos diastemas depois da remoção do aparelho ortodôntico, já que a aproximação dentária necessária causaria encurtamento da arcada superior.Muitas vezes, a integração entre Dentística e Ortodontia é fundamental para a obtenção de um resultado satisfatório.

This paper aims to report a case of esthetic reanatomization of both upper lateral incisors in order to allow orthodontic treatment. A 14 year-old patient presented at the State University of Rio de Janeiro clinic for orthodontic treatment. During the clinical exam, it was possible to observe an atypically shaped upper lateral incisor (#12) and a peg-shaped mesially positioned upper lateral incisor (#22),aside from multiple diastemas between upper teeth. She was then referred to the Operative Dentistry clinic for the esthetic reanatomization of both upper lateral incisors, in order to allow the bonding of orthodontic brackets. Direct restorations using composite resin were performed using a silicone guide. After the accomplishment of the restorations, the patient was able to undergo the orthodontic treatment. However, she will return to Operative Dentistry clinic for closing diastemas after the removal of orthodontic brackets, because the dental approximation needed would cause shortening of the upper arch. In many situations,the association between Operative Dentistry and Orthodontics is mandatory for a satisfactory result.

Doença do refluxo gastroesofágico e erosão dentária / Gastroesophageal reflux disease and dental erosion

0 objetivo do presente estudo foi abordar a erosão dentária (ED) decorrente da doença do refluxo gastroesofágico (DRCE) nas diferentes faixas etárias e sua associação com outras doenças, com particular atenção para diagnóstico, prevenção e potenciais perspectivas de tratamento. A elevada prevalência da DRGE, tanto em adulto quanto em criança, observada nas últimas duas décadas, tem sido responsável por tornar esta afecção um problema de saúde pública. Esta doença pode ainda comprometer sítios extradigestórios, como pulmão e ouvido. Ou estar associada com doenças sistêmicas, tal como a diabetes, desordens alimentares, como a bulimia, ou o consumo abusivo de álcool de forma regular. A associação entre a DRCE e o processo de ED, decorrente da acidificação do meio bucal, fragiliza os tecidos mineralizados acarretando a perda destes tecidos. Cabe ressaltar que a ED não está relacionada com o envolvimento bacteriano. Ela é um processo irreversível, que altera aparência, funcionalidade e pode levar à perda do elemento dentário.

Efeito do método de fotoativação e armazenamento de um compósito na sua resistência coesiva / Efects of cohesive strength of a composite after photoactivation and storage media

A proposta deste estudo é avaliar a resistência à tração diametral após dois tipos de fotoativação e armazenamento.Foram confeccionados 24 espécimesdivididos em quatro grupos: G1- fotoativação convencional armazenado em água destilada; G2- pulso tardioarmazenado em água destilada; G3- convencional armazenado em álcool e G4- pulso tardio armazenado em álcool (n = 6). Os grupos foram armazenados a37º C por 24 horas. O foi realizado a uma velocidade de 1.0 mm/min. Os resultados (G1:130.9, G2:127.6, G3:130.8, G4:110.8 MPa) foram submetidos à análise de variância Anova (p ≥ 0,05) e apontam para uma semelhança estatística. Não foi encontrada diferençana resistência coesiva do compósito nos diferentes métodos de fotoativação e meios de armazenamento.

Flexural bond strength of repaired composite resin restorations: influence of surface treatments and aging.

The objective of this study was to evaluate the effect of storage in deionized water at room temperature, for seven days and six months, on the flexural strength of a repaired photocured microhybrid composite resin, using different surface treatments. After each surface treatment, the adhesive interface was analyzed with a surface roughness tester. The flexural strength of samples from each group was determined by three-point bending in a testing machine at a crosshead speed of 0.5 mm/min with a 50 N load cell. Data were analyzed using ANOVA (p=0.0001) and compared with the Newman-Keuls multiple comparison test. It was verified that flexural strength of the unrepaired specimens, after both seven days and six months, was similar (p>0.05) and was in accordance with ISO specifications (minimum of 50 MPa), with values ranging from 52-63 MPa. The authors concluded that the use of an unfilled resin agent is necessary prior to the repair to increase the adhesive strength. Further, the use of a silane agent prior to use of the unfilled resin agent is unnecessary, since it does not increase the adhesive strength.