Avaliação qualitativa da infiltração marginal nas restaurações em compositos polimerizados com laser de argonio e luz halogena

Orientador: Luis Alexandre Maffei Sartini PaulilloTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O propósito deste estudo foi avaliar a infiltração marginal, através da penetração de corante, em restaurações classe V em compósitos, comparando-se a polimerização com lâmpada de luz halógena e laser de Argônio. Cavidades circulares foram preparadas em 114 terceiros molares, na JCE, e aleatoriamente divididas em seis grupos. Todos os grupos foram restaurados utilizando-se o mesmo sistema adesivo, Scotchbond Multi-Uso Plus, polimerizando-se por 5 segundos com o laser de Argônio e 10 segundos com lâmpada de luz halógena. Os dentes foram restaurados com diferentes resinas compostas: Charisma,Natural Flow e Solitaire. A polimerização foi de 20 segundos com laser de Argônio e 40 segundos com lâmpada de luz halógena. Logo em seguida, foram armazenados em 100% de umidade relativa a 37°C por 24 h antes do acabamento e polimento. Os espécimes foram termociclados por 2000 ciclos às temperaturas: 50º C e 55º C durante 1 minuto em cada banho e imersos em solução de azul de metileno a 2% por 4 h. Seccionaram-se os dentes no sentido vestíbulo-lingual e a infiltração nas margens em esmalte e dentina, avaliada por dois examinadores calibrados, que atribuíram escores representativos para os níveis de penetração de corante: O- não infiltrou; 1-infiltração até 1/3 da parede gengival/oclusal; 2- até 2/3 da parede gengival/oclusal; 3- até 3/3 da parede gengival/oclusal; 4-infiltração na parede axial. Foi realizado teste de Kruskal-Wallis (5%) que indicou não haver diferença estatística significativa para as diferentes resinas compostas avaliadas e tipo de polimerização empregada: lâmpada de luz halógena e laser de ArgônioAbstract: The purpose of this study was to evaluate the marginal leakage through dye penetration, in class V composite resin restorations, comparing the conventional visible light and argon laser polymerization. Circular cavities (2mm x 1,5 mm) were prepared on the CEJ on the buccal surfaces of 114 extracted human third molars. The teeth were randomly divided into 6 groups of 19 each. Adhesive system Scotchbond MP was used for all groups, and the adhesive was polymerized by an argon laser for 5s and conventional visible light for 10s, following manufacturers' recommendations. The teeth were restored with different composite resins: Charisma, Solitaire and Flowable. The argon laser polymerization lasted for 20s and the conventional visible light polymerization lasted for 40s, following manufacturers' recommendations. The teeth were stored in 100% relative humidity at 37° C for 24h, after that, they were finished and polished. The specimens were thermocycled between 5Oº C and 55ºC for 2000 cycles for 1 minute dwell time, followed by imersion in a 2% methylene blue solution for 4h. The teeth were sectioned buccolingually. The microleakage was evaluated for margins of enamel and dentin/cementum and separately scored as follows : O-no microleakage; 1 microleakage 1/3 oclusal or gengival wall; 2-microleakage 2/3 oclusal or gengival wall; 3-microleakage ali oclusal or gengival wall; 4-microleakage axial wall. Statistical analysis using Kruskal-Wallis test indicated not significant differences among ali groups (a=0,05). It can be concluded that: the argon laser does not reduce microleakage when compared to conventional visible lightDoutoradoDentísticaDoutor em Clínica Odontológic

Mechanical performance of experimental acrylic resins modified by nanoparticles after chemical and mechanical degradation

Different materials have been incorporated into the polymethylmethacrylate matrix to improve its performance. The aim of this study was to evaluate the degree of conversion (DC), the flexural strength (FS), the elasticity modulus (EM), and the effect of

Influence of the combined effect of desensitizing dentifrices and universal adhesives on dentin bond strength under erosive conditions

Objective: This study aimed to evaluate whether the use of desensitizing dentifrices containing obliterating agents can affect bond strength of eroded/abraded dentin. Methodology: A total of 100 dentin samples were obtained from human molars. The teeth were cut into 3 mm-thickness discs and allocated in five groups (n=20), according to the toothpaste used: WoF – abrasion with fluoride-free toothpaste (Cocoricó); Arg – toothpaste containing arginine (Colgate Sensitive Pro-Relief); Nov – calcium sodium phosphosilicate toothpaste (Sensodyne Repair and Protect); SnF – fluoride-containing toothpaste (AmF/SnCl2/SnF2 – Elmex Erosion); and Control (no erosive/abrasive process). The erosive/abrasive cycle consisted of immersion in citric acid (1%, pH 2.6, 5 min, 4×/day) and abrasion (2×/day, 120–20 sec abrasion, 100 sec immersion) with each toothpaste. During intervals, samples were immersed in artificial saliva. This cycle was performed for five days. Two resin cylinders (2 mm in diameter) were constructed on each sample for the shear bond strength test using a universal adhesive system. The self-etch and etch-and-rinse (Scotchbond Universal) strategies were employed, each in half of the total sample (n=10). Bond strength (MPa) was measured in a shear test and failure modes were assessed with a stereomicroscope. Statistical analysis was performed using the two-way analysis of variance (ANOVA) and Tukey tests (p<0.05). Results: A statistically significant difference was found between the adhesive strategies tested (p<0.001), with the self-etching form showing higher values than the etch-and-rinse. Moreover, no significant differences were observed between the tested toothpastes (p=0.750) and interactions (p=0.438). Conclusion: The use of toothpaste containing obliterating agents does not affect bond strength to dentin subjected to erosive/abrasive conditions when a universal adhesive is used. However, the self-etch strategy might be preferred for eroded/abraded dentin

Influence of thickness and translucency of lithium disilicate ceramic on degree of conversion of resinous materials

In this study was assessed the degree of conversion (DC) of amine-free resin cements light cured through lithium disilicate-reinforced ceramics at different thicknesses and translucency. Specimens were divided into 21 groups (n = 5) according to luting agent used: Variolink Esthetic LC (Light shade), RelyX Ultimate (A1 shade), and Filtek Z350 XT Flow (A1 shade); the ceramic translucency: low (LT) and high (HT); and the ceramic thickness: no ceramic (control), 0.5 mm, 1 mm, and 2 mm. A Teflon mold with (5 x 5 x 0.5 mm) was used to standardize the cement and over it the ceramic block from each group was placed. Set was cured using a polywave LED light (1200 mW/cm2 - Bluephase G2) for 40 s. FTIR spectra of uncured and cured materials was obtained and DC calculated from the height of the peaks 1610 and 1640 cm-1. Data were submitted to ANOVA followed by Tukey?s test (? = 0.05). There was a significant difference for luting agents (p< 0.0001) and translucency (p = 0.025), but not for thickness (p = 0.73). Dual amine-free RelyX Ultimate showed the lowest DC values and higher translucency promoted higher DC. Dual amine-free cement showed the lowest monomer conversion and higher translucency ceramics promoted a higher DC

Chemical composition and roughness of enamel and composite after bleaching, acidic beverages and toothbrushing

In this study was assessed the surface roughness and chemical composition of tooth enamel and composite resin after bleaching treatment, immersion in acidic beverages, and simulated toothbrushing. One hundred and twenty dental blocks (10 x 10 x 3 mm) were randomly assigned (n = 10) according to surface treatment [none (N), bleaching (B), toothbrushing (T), and B+T] and storage medium [saliva (S), whiskey (W), and orange juice (O)]: experimental groups - N+S, N+W, N+O, B+S, B+W, B+O, S+T, W+T, O+T, B+S+T, B+W+T, and B+O+T. Two bleaching sessions were conducted using 38% hydrogen peroxide (3 applications). Surface roughness was measured using a roughness tester and composition was determined by micro energy-dispersive X-ray fluorescence spectrometry (µ-EDXRF) before and after treatments. Calcium/phosphorus (Ca/P) ratio in enamel and silica (Si) content in composite were evaluated. Data were statistically analyzed by ANOVA and Tukey?s test (? = 0.05). Overall, increased values of surface roughness for enamel and composite were observed mainly after immersion in orange juice and bleaching/toothbrushing association. Moreover, this association and immersion in whiskey resulted in lower Ca/P ratio and after aging methods, bleached and bleached/toothbrushed groups showed decreased in Ca/P ratio compared to initial values. All groups showed Si content decrease at the end, except the group without surface treatment and immersed in saliva, and bleaching followed by immersion in orange juice and toothbrushing caused the highest Si reduction. Bleaching and toothbrushing combination strengthened the effects caused by acidic drinks on roughness and chemical composition of enamel and composite

Análise comparativa do grau de clareamento dos géis Póla Office, Opalescence Extra e Whiteness HP através de fotorreflectância

The aim of tis study was to evaluate quantitatively the color change of the teeth´ pieces, with different bleaching agents and application times, through reflectance spectrophotometer. Fifteen crowns of bovine teeth were divided in four pieces (4x4x3 mm), and, later submitted to bleaching agents (G1: Póla Office, SDI, G2: Opalescence Extra, Ultradent, G3: Whiteness HP, FGM), totalizing 30 samples. The samples of each group received a initial register, considered as control group, and for the dental bleaching, the manufactor´s instructions were followed. Other registers of reflectance spectrophotometer analysis were done, during seven and fourteen days of bleaching treatment. The statistical test Anova was applied to the experimental groups and demonstrated to exist the interaction effect; and to determine the statistics’ difference, was applied the Tukey test. On the second register, Opalescence Extra showed differences from the control group and Whitness HP bleaching agent on the different evaluating times. Póla Office and Whitness HP didn´t show any statistical difference from control group. Opalescence Extra, showed higher results on the dental bleaching, considering the others bleaching agents, Póla Office and Whitness HP.O propósito deste estudo foi avaliar quantitativamente, a mudança da cor de fragmentos dentários, com diferentes géis e tempos de aplicação, através de fotorreflectância. Foram utilizados quinze coroas de incisivos bovinos, divididas em quatro fragmentos (4x4x3 mm), posteriormente submetidos à géis clareadores (G1: Póla Office, SDI, G2: Opalescence Extra, Ultradent, G3: Whiteness HP, FGM), totalizando 30 espécimes. Os espécimes de cada grupo receberam uma leitura inicial, que foi considerada como controle, e para o clareamento dentário foram seguidas as recomendações de cada fabricante. Foram realizadas leituras de fotorreflectância após sete (1a sessão) e quatorze dias (2a sessão) de tratamento clareador. O teste estatístico ANOVA de medidas repetidas foi aplicado aos grupos de estudo e indicou existir o efeito interação e para determinar a diferença estatística, aplicou-se o teste de Tukey. Verificou-se que na segunda leitura, o agente clareador Opalescence Extra diferiu do controle e do agente clareador Whitness HP nos diferentes tempos de avaliação. Observando-se os tempos de avaliação, Póla Office e Whitness não diferiram do controle. O gel Opalescence foi superior em eficácia, aos demais géis clareadores

Bonding performance of universal adhesives with concomitant use of silanes to CAD/CAM blocks

ABSTRACT Objective: This study assessed whether the use of a silane coupling agent influence the bond strength of two universal adhesives to ceramic or resin CAD/CAM blocks. Methods: Forty-eight samples were obtained from each resin nano-ceramic hybrid block (RCBs) and lithium disilicate ceramic blocks (LD). Samples were treated with silane with MDP (Monobond - S-MDP), silane without MDP (Prosil - PS), and no silane application (Control - Ctr) followed by universal adhesive with silane (UAS) and without silane (UA) (n=8). Three polyurethane tubes (1.5 mm of internal diameter) were positioned in each sample treated surface and filled with a dual cured resin cement. Bond strength was assessed by microshear bond strength test and failure analysis was performed for all samples. Results: For the RCBs, UAS presented the highest bond strength values (p=0.004). Silane application was not significant in bond strength values (p=0.444). For LD, silane application was significant in bond strength values (p<0.001), but the adhesive was not (p=0.066). Failure analysis showed high prevalence of adhesive failures for both substrates. Conclusion: A silane-containing universal adhesive promoted the best bond strength results to the resin nano-ceramic hybrid block. For bonding to a glass-ceramic CAD/CAM material, additional silane (without MDP) application presented the best results

Effect of bleaching agents on hardness, surface roughness and color parameters of dental enamel

In this study was evaluated the effect of carbamide peroxide (CP) and hydrogen peroxide (HP) in different concentrations on hardness, roughness, and color parameters (color change - ?E, lightness - ?L, and yellow-blue axis - ?b) of bovine teeth. Fifty square dental blocks (7 x 7 x 2 mm) were submitted to initial readings of Knoop hardness, surface roughness (Ra), and color parameters. Specimens were divided into 5 groups (n = 10): control group was kept in artificial saliva during the experimental period; CP 20% was bleached for 2 h daily for 14 days, HP 9.5% was bleached for 30 min daily for 14 days, HP 38% the bleaching gel was applied for 15 min, gel was removed and it was reapplied for two more times, the bleaching session was repeated for another 2 times every 7 days, totaling three sessions, and in CP 45% three sessions of 30 min each were performed of 7 in 7 days. All groups after the bleaching procedures had the bleaching gel removed, washed, and kept in artificial saliva. At the end of bleaching treatment, the hardness, roughness, and color parameters (?E, ?L, and ?b) were re-evaluated. Data were analyzed by ANOVA, Tukey, and Dunnett tests (? = 0.05). Bleaching promoted a reduction in hardness, the CP 45% showed the lowest hardness and the CP 20% the highest, the HP 9.5% and HP 38% showed intermediate values of hardness. Bleaching agents did not affect the roughness. CP 20% and HP 38% promoted the highest values of ?E and higher reduction of yellowish tone of tooth. Lightness increase after bleaching treatment for all groups. All the bleaching agents tested showed effectiveness, but with reduced hardness

In vitro effects of hydrogen peroxide combined with different activators for the in-office bleaching technique on enamel

The aim of this study was to evaluate the alteration of human enamel bleached with high concentrations of hydrogen peroxide associated with different activators. Fifty enamel/ dentin blocks (4 x 4 mm) were obtained from human third molars and randomized divided according to the bleaching procedure (n = 10): G1 = 35% hydrogen peroxide (HP -Whiteness HP Maxx); G2 = HP + Halogen lamp (HL); G3 = HP + 7% sodium bicarbonate (SB); G4 = HP + 20% sodium hydroxide (SH); and G5 = 38% hydrogen peroxide (OXB - Opalescence Xtra Boost). The bleaching treatments were performed in three sessions with a 7-day interval between them. The enamel content, before (baseline) and after bleaching, was determined using an FT-Raman spectrometer and was based on the concentration of phosphate, carbonate, and organic matrix. Statistical analysis was performed using two-way ANOVA for repeated measures and Tukey's test. The results showed no significant differences between time of analysis (p = 0.5175) for most treatments and peak areas analyzed; and among bleaching treatments (p = 0.4184). The comparisons during and after bleaching revealed a significant difference in the HP group for the peak areas of carbonate and organic matrix, and for the organic matrix in OXB and HP+ SH groups. Tukey's analysis determined that the difference, peak areas, and the interaction among treatment, time and peak was statistically significant (p < 0.05). The association of activators with hydrogen peroxide was effective in the alteration of enamel, mainly with regards to the organic matrix737516521FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP05/60082-4 01/14384-