Correlation between Bond Strength to Dentin and Sealers Penetration by Push-Out Test and CLSM Analysis.

This study correlated the bond strength (BS) and dentin penetration of different sealers by push-out test and Confocal Laser Scanning Microscopy (CLSM) analysis. Forty-five root canals were prepared according to the crown-down technique and filled with gutta-percha associated to the following sealers (n=15): Endofill, AH Plus and MTA Fillapex. Five canals of each group were filled with the sealers added with 0.1% Rhodamine B dye. Next, the specimens were transversely sectioned and submitted to the push-out test (n=10) and CLSM analysis (n=5). The BS data showed the following means (MPa) and standard deviation: AH Plus (4.17±1.86); MTA Fillapex (3.13±1.96) and Endofill (2.10±1.03). Statistical analysis (two-way ANOVA, α=0.05) showed significant difference among sealers (p<0.001) and root canal thirds (p<0.001). The BS results of Endofill and MTA Fillapex were statistically similar (p>0.05), however, they were statistically different from AH Plus (p<0.001). The regional analysis of BS showed similarity between middle and apical thirds (p>0.05), and both were different from coronal portion (p<0.001). CLSM analysis verified tags formation in all groups and higher penetration of the specimens filled with AH Plus (p<0.05). The Kendall test (correlation between BS to dentin and sealer penetration into dentinal tubules) and the Pearson test (between failures pattern and sealer penetration into dentinal tubules) did not show correlation between the variables evaluated for all the tested sealers (p>0.05). AH Plus group had higher BS to dentin, and deeper tags formation than the other sealers. There was no significant correlation between BS and intratubular penetration of the tested sealers.

Influence of Infected Root Dentin on the Bond Strength of a Self-adhesive Resin Cement.

AIM: The aim of this study was to determine the bond strength (BS) of a self-adhesive resin cement to the contaminated root dentin. MATERIALS AND METHODS: The crown and apical third of twenty single-rooted teeth were removed. The root canals were flared and 1-mm-thick root sections were obtained. The sections were rinsed, dried, and sterilized. The control group (n=20) was composed of one section of each third, which remained immersed in sterile trypticase soy broth (TSB) for 2 months. The other sections comprised the experimental group (n = 40) and were immersed in a suspension of Enterococcus faecalis. The culture medium was changed at every 4 days for 2 months. The sections were rinsed with distilled water, dried, and the root canal space was filled with the self-adhesive resin cement RelyX™ U200. After 24 h, the push-out test was performed and the types of interface failure were observed on a stereo microscope. STATISTICAL ANALYSIS: Data were statistically analyzed by the nonparametric Mann-Whitney test (α=5%). RESULTS: A significant reduction was observed in the BS of resin cement to the contaminated dentin compared to the healthy dentin, for both thirds analyzed (P < 0.05). The BS was significantly greater at the cervical third compared to the middle third for specimens in the experimental group (P < 0.05). Adhesive and mixed failures were observed more frequently in specimens contaminated with E. faecalis. CONCLUSION: Bacterial contamination negatively infl uenced the BS of the self-adhesive resin cement to the root dentin, and there was a predominance of adhesive and mixed failures.

Comparison of two observational methods, scanning electron and confocal laser scanning microscopies, in the adhesive interface analysis of endodontic sealers to root dentine.

OBJECTIVES: To compare the accuracy of confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) during the analysis of the adhesive interface integrity and intratubular penetration of root canal sealers to radicular dentine. MATERIALS AND METHODS: Twenty roots of human maxillary incisors were prepared and distributed into two groups (n = 10), followed by filling with gutta-percha and Endofill (G1) or AH Plus (G2). After 7 days, roots were sectioned and analyzed under CLSM and SEM. Score systems were used to evaluate the adhesive interface integrity (0-4) and sealer intratubular penetration (0-3). Data were submitted to Wilcoxon-Mann-Whitney and Kendall correlation statistical tests (α = 5%). RESULTS: In the adhesive interface analysis, CLSM was similar (P = 0.157) to SEM for Endofill; however, the results were different for AH Plus (P = 0.029). Intratubular penetration had significant difference between observational methods for both sealers (P < 0.0001). Correlation analysis between SEM and CLSM for adhesive interface was moderate for Endofill and low for AH Plus. Intratubular penetration was low for both sealers. CONCLUSION: SEM and CLSM analysis had similar results when sealers were compared, with a more homogeneous adhesive interface, and greater intratubular penetration for AH Plus. Comparison between observational methods demonstrated low positive correlation for adhesive interface and intratubular penetration analysis. CLINICAL RELEVANCE: A proper interface formed between sealer and dentine is very important for final quality of root canal filling. Observational methods which allow an accurate analysis of this interface must be selected to assess such features.

Reparo em resina composta - efeito do condicionamento ácido e dos sistemas adesivos / Composite resin repair - effect of acid etching and adhesive systems

O objetivo deste trabalho foi avaliar o efeito do condicionamento ácido e do tipo de adesivo sobre a resistência de união de reparos em compósitos tratados com jato de óxido de alumínio. Foram confeccionados 60 discos com compósito, cor A2 (Filtek Z350 - 3M ESPE®), envelhecidos por seis meses em água. Após o polimento, as superfícies foram submetidas ao jato de óxido de alumínio (45 -jm) e distribuídas em seis grupos com dez espécimes cada um: G1: Adper Scotchbond Multi-Purpose (3M ESPE®), sem condicionamento ácido e sem "primer"; G2: Adper Scotchbond Multi-Purpose (3M ESPE®), após condicionamento com ácido fosfórico 37% e sem "primer"; G3: Adper Single Bond 2 (3M ESPE®), sem condicionamento ácido; G4: Adper Single Bond 2 (3M ESPE®), após condicionamento com ácido fosfórico 37%; G5: Adper Easy One (3M ESPE), sem condicionamento ácido e G6: Adper Easy One (3M ESPE®), após condicionamento com ácido fosfórico 37%. Os reparos foram confeccionados com o compósito Opallis (FGM®), cor A2. Após 24 horas os corpos de prova foram submetidos aos ensaios de cisalhamento (Instron - 0,5 mm/min). Os valores médios (MPa) após ANOVA2 e teste de Tukey e T de student (5%) foram: G1: 18,34 (6,73); G2: 16,49 (3,65); G3: 13,11 (3,64); G4: 19,86 (5,85); G5: 20,88 (4,82) e G6: 23,48 (4,36). O condicionamento com ácido fosfórico a 37% aumentou significativamente a resistência de união dos reparos confecciona¬dos com o sistema Adper Single Bond 2 (3M ESPE®) e não proporcionou aumento significativo na resistência de união dos reparos com os sistemas Adper Scotchbond Multi-Purpose (3M ESPE®) e Adper Easy One (3M ESPE®).

The aim of this study was to evaluate the effect of acid etching and type of adhesive on the bond strength of composite repairs treated with aluminum oxide. Sixty discs were fabricated with composite shade A2 (Filtek Z350 - 3M ESPE®), and aged for 6 months in water. After polishing, the surfaces were subjected to aluminum oxide treatment (45 pm) and divided into 6 groups with 10 specimens each: G1: Adper Sotchbond Multipurpose (ASM) (3M ESPE®) without etching and without primer, G2: Adper Sotchbond Multipurpose (ASM) (3M ESPE®) after etching with phosphoric acid 37% and without primer, G3: Adper Single Bond 2 (ASB) (3M ESPE®) without etching, G4: Adper Single Bond 2 (ASB) (3M ESPE®) after etching with phosphoric acid 37%, G5: Adper Easy One (AEO) (3M ESPE®) without etching, and G6: Adper Easy One (AEO) (3M ESPE®) after etching with phosphoric acid 37%. Repairs were made with the composite Opallis (FGM®), shade A2. After 24 hours the specimens were submitted to shear tests (Instron - 0.5 mm/min). Mean values (MPa) after ANOVA2, Tukey test and T stu¬dent (5%) were: G1: 18.34(6.73), G2: 16.49 (3.65), G3: 13.11 (3.64), G4: 19.86 (5.85), G5: 20.88 (4.82), and G6: 23.48 (4.36). The phosphoric acid at 37% significantly increased the bond strength of repair with the system ASB and did not increase the bond strength of repair with the systems ASM and AEO.

Evaluation of adhesive systems in primary dentin by nanoleakage: effects of aging

Introduction: Nanoleakage evaluation by silver uptake in permanent teeth provides good spatial resolution of submicron defects at the hybrid layer, which have not been tested in primary teeth. Objective: This study evaluated the nanoleakage at the dentin-adhesive interface in primary teeth by two methods, for three adhesive systems, immediately (IM) and six months (6M) after adhesive procedures. Material and methods: Crowns of primary molars were occlusal flat grounded and divided into three groups according to the adhesive system tested (n = 6-7). Scotchbond Multi-purpose/SMP, Single Bond/SB and Clearfil SE Bond/CSB adhesive systems were applied with a composite resin (Filtek Z-250). Crowns were sectioned so that 0.8 mm² sticks were obtained and subdivided depending on the time of evaluation: IM or 6M. They were immersed into silver nitrate solution and evaluated by SEM-EDS. Data (%) were analyzed by ANOVA (p < 0.05) and the scores by Kruskal-Wallis and U Mann-Whitney tests (p < 0.05). Results: There was no difference between groups regarding to the evaluation time (aging) percentage. In terms of scores, there was a significant difference for the adhesive variable: SMP and SB showed similar results with less leakage, while CSB demonstrated higher leakage. Conclusion: Nanoleakage was not influenced by aging, but noticeable difference was observed between total-etch and self-etching adhesives. Total-etch showed better performance.

Facetas estéticas pré-fabricadas como procedimento restaurador – um caso clínico / Prefabricated aesthetic veneers as a restorative procedure – case report

Reconstruir ou embelezar sorrisos sempre foi uma tarefa difícil, uma vez que a estética depende muito de critérios objetivos e subjetivos. Para facilitar esse trabalho surgiram facetas ou lâminas cerâmicas e de resinas compostas, excelentes alternativas de reabilitação estética, porém requerem muita habilidade do cirurgião dentista (diretas) ou de um técnico de laboratório (indiretas), consumindo muito tempo ou gerando um alto custo operacional. Para superar essas dificuldades, fabricantes colocam à disposição facetas pré-fabricadas de resina composta de cores e tamanhos pré-estabelecidos, obedecendo os mais altos padrões estéticos. Este trabalho aborda de forma despretensiosa essa nova classe de materiais estéticos, bem como ilustra passo a passo um caso clínico, enaltecendo as facilidades e a praticidade da técnica.

Reconstruction or remodeling of a natural smile is still a challenge, since aesthetics depends on objective and subjective criteria. Ceramic laminate veneers and composite veneers are excellent alternatives to aesthetic rehabilitation. However, they require high skills of the dentist or of the lab technician, which may delay the final result or increase costs. To overcome these difficulties, manufacturers have launched prefabricated composite laminate veneers, with different colors and sizes as well as appropriate aesthetic proportions. This paper has the intention to approach this new modality of treatment as well as to show a clinical case step-by-step, reinforcing raves of the technique

Resistência à fratura de dentes com restaurações MOD: efeito da matriz resinosa e do método de fotoativação / Fracture resistance of teeth with MOD restorations: effect of the resin matrix and the photoactivation method

Objetivo: Avaliar o efeito de dois compósitos, de diferentes matrizes poliméricas, e da técnica de fotoativação, sobre a resistência à fratura, por compressão, de pré-molares superiores com restaurações de classe II. Materiais e Métodos: Cavidades MOD foram preparadas em 56 pré-molares superiores, simulando tratamentos endodônticos. Os dentes foram divididos em quatro grupos (n=14): G1 - fotoativação convencional, restauração com Filtek Z350XT (3M ESPE) e adesivo Adper Single Bond 2 (3M ESPE); G2 - fotoativação pulso tardio, restauração Filtek Z350XT e adesivo Adper Single Bond2; G3 - fotoativação convencional, restauração Filtek P90 (3M ESPE) e adesivo próprio da Filtek P90 (3M ESPE); e G4 - fotoativação pulso tardio, restauração Filtek P90 e adesivo próprio da Filtek P90. No G1 e G3 (fotoativação convencional), a aplicação de compósito foi em incrementos de 2 mm, cada incremento fotoativado por 40 segundos, com aparelho LED, intensidade de 500 mW/cm2, aferida com radiômetro (Demetron). No G2 e G4 (fotoativação por pulso tardio) aplicação de compósito também foi com incrementos de 2mm, porém, cada incremento fotoativado, inicialmente durante 5s., com 300 mW/cm2. Após um período de 5 minutos foi realizada fotoativação, por 40s., intensidade de 500 mW/cm2. A fotoativação foi repetida para cada incremento. Após 24 horas, os espécimes foram polidos e submetidos ao teste de compressão, com ponta ativa de formato cilíndrico/arredondado (Instron-0,5mm/ min). Para análise estatística foi usado ANOVA 2 e Teste de Tukey (p > 0,05). Resultados: Os valores médios (newtons) foram: G1 - 1157,98 (±444,62); G2 - 1404,14 (±391,82); G3 - 1255,30 (±422,34); e G4 - 1213,76 (±419,95). A resistência à fratura, por compressão, dos pré-molares com restaurações MOD foi estatisticamente similar nos quatro grupos avaliados. Conclusão: Não foram verificadas diferenças significativas relacionadas aos dois compósitos, com diferentes matrizes poliméricas e diferentes métodos de fotoativação.(AU)

Aim: To evaluate the effect of two composite resins of different polymeric matrices and the photoactivation technique as regards fracture resistance by, compression of maxillary pre-molars with Class II restorations. Materials and Methods: MOD cavities were prepared in 56 premolars, simulating endodontic treatments. The teeth were divided into four groups (n=14): G1: conventional photoactivation, restoration with Filtek Z350XT (3M ESPE) and adhesive Adper Single Bond 2 (3M ESPE); G2: Pulse delay photoactivation, restoration with Filtek Z350XT and adhesive Adper Single Bond 2; G3: conventional photoactivation, restoration with Filtek P90 (3M ESPE) and self-adhesion of Filtek P90 (3M ESPE); and G4: pulse delay photoactivation, restoration with Filtek P90 and self-adhesion of Filtek P90. In G1 and G3 (conventional photoactivation), the composite resin was applied at 2 mm increments, each of which was light cured for 40 seconds, using a LED unit, at an intensity of 500 mw/cm2, measured with a radiometer (Demetron). In G2 and G4 (pulse delay photoactivation), the composite resin was also applied at 2 mm increments; however, each increment was initially photoactivated for 5 seconds at 300 mw/cm2. After a period of 5 minutes, a new photoactivation was performed for 40 seconds at an intensity of 500 mw/cm2. The photoactivation was repeated for each increment. After 24 hours, the specimens were polished and tested for compression, with cylindrical/round active tip (Instron - 0.5 mm/ min). The ANOVA 2 and Tukey tests were used for statistical analyses (p > 0.05). Results: Mean values (Newtons) were as follows: G1: 1157.98 (±444.62); G2: 1404.14 (±391.82); G3: 1255.30 (±422.34); and G4: 1213.76 (±419.95). The resistance to fracture by compression of the pre-molars with MOD restorations proved to be statistically similar in the four evaluated groups. Conclusion: No significant differences could be observed regarding the two composite resins with different polymeric matrices and the different photoactivation methods.(AU)

Resistência à fratura de dentes com restuarações MOD: efeito da matriz resinosa e do método de fotoativação / Fracture resistance of teeth with MOD restorations: effect of the resin matrix and the photoactivation methods

Objetivo: Avaliar o efeito de dois compósitos, de diferentes matrizes poliméricas, e da técnica defotoativação, sobre a resistência à fratura, por compressão, de pré-molares superiores com restaurações de classe II. Materiais e Métodos: Cavidades MOD foram preparadas em 56 pré-molares superiores, simulando tratamentos endodônticos. Os dentes foram divididos em quatro grupos (n=14): G1 - fotoativação convencional, restauração com Filtek Z350XT (3M ESPE) e adesivo Adper Single Bond 2 (3M ESPE); G2 - fotoativação pulso tardio, restauração Filtek Z350XT e adesivo Adper Single Bond2; G3 - fotoativação convencional, restauração Filtek P90 (3M ESPE) e adesivo próprio da Filtek P90 (3M ESPE); e G4 - fotoativação pulso tardio, restauração Filtek P90 e adesivo próprio da Filtek P90. No G1 e G3 (fotoativação convencional), a aplicação de compósito foi em incrementos de 2 mm, cada incremento fotoativado por 40 segundos, com aparelho LED, intensidadede 500 mW/cm2, aferida com radiômetro (Demetron). No G2 e G4 (fotoativação por pulso tardio) aplicação de compósito também foi com incrementos de 2mm, porém, cada incremento fotoativado, inicialmente durante 5s., com 300 mW/cm2. Após um período de 5 minutos foi realizada fotoativação, por 40s., intensidade de 500 mW/cm2. A fotoativação foi repetida para cada incremento. Após 24 horas, os espécimes foram polidose submetidos ao teste de compressão, com ponta ativa de formato cilíndrico/arredondado (Instron-0,5mm/min)...

Fracture resistance, two point bending strength and morphological characteristics of pulpless teeth restored with fiber-reinforced composite posts

Introduction: Fiber-reinforced composite posts (FRC posts) have been used for tooth reinforcement after endodontic treatment. The mechanical characteristics of FRC posts can influence the clinical prognostic. Objective:The aim of this study was to evaluate the flexural strength and fracture resistance of commercially available FRC posts. Material and methods: Fourteen human single-rooted premolars with completely formed apices were selected and received endodontic treatment. The specimens were divided into two groups related to the post system: i) Group A - cylindrical-conical fiber-reinforced post (White post DC, FGM), and ii) group B - conical fiber-reinforced post (EXACTO, Angelus). The fracture resistance was evaluated and two point bending tests were carried out. The glass fiber characteristics and the tag penetration of the luting material into the radicular dentin structure were evaluated through scanning electronic microscopy in an illustrative way. One-way ANOVA and Tukey's HSD test (α = 0.05) were applied. Results: The values obtained for fracture resistance and two point bending test were, respectively, 399.29 N and 109.5 N for group A, and 386.25 N and 119.5 N for group B. No significant differences in strength values among the groups were found. Conclusion: There were no significant statistical differences between the two post groups regarding to fracture strength and two point bending strength. It can be concluded that the posts selected for this study performed satisfactorily in terms of mechanical properties so that they can be used for tooth reinforcement after endodontic treatment.

Estado da arte das cerâmicas odontológicas / State of the art of ceramics in dentistry

A demanda por estética e por restaurações que cada vez mais mimetizem as estruturas dentais levaram ao desenvolvimento de novos sistemas cerâmicos. Além de excelência estética, tais sistemas exibem excelentes propriedades mecânicas, o que amplia a gama de procedimentos aos quais podem ser aplicados. Atualmente, diversos materiais estão disponíveis, o que exige conhecimento por parte do profissional para uma adequada seleção. Dentro desse contexto, objetivou-se neste artigo realizar uma breve revisão sobre os atuais sistemas cerâmicos disponíveis no mercado e apresentar um relato de caso clínico com o sistema IPS e.max Press (Ivoclar Vivadent AG)

The demand for the aesthetic and restorative procedures that mimetize the dental structures, had lead to the development of new ceramic systems. Besides aesthetic excellency, such systems show excellent mechanical properties, that extend the gamma of procedures which can be applied. Nowadays, as diverse materials are avaiable, the adequate selection demands knowledge of the professionals. The objective of this article is to review the ceramic systems available on the market and show a clinical case with one of them, the system IPS e.max Press (Ivoclar Vivadent AG)

Avaliação da influência do led/laser em diferentes concentrações de peróxido de hidrogênio no clareamento dentário imediato / Evaluation of the influence of led/laser on different concentrations of hydrogen peroxide for in-office dental bleaching

O objetivo desta pesquisa foi avaliar a influência de um sistema luminoso led/laser - com 6 leds de 470nm e 3 diodos lasers infravermelhos de 830nm de 0,2W de potência - sobre o peróxido de hidrogênio a 35% (Lase Peroxide 35% Sensy, DMC Equipamentos) e a 25% (Lase Peroxide 25% Sensy, DMC Equipamentos) em 10 voluntários. Os agentes clareadores foram aplicados com espessura próxima a 1mm em cada arcada de um mesmo paciente: peróxido de hidrogênio 35% na arcada superior e 25% na arcada inferior. O conjunto led/laser foi aplicado por 1 minuto, intercalado com intervalo de 1 minuto sem irradiação luminosa, por três vezes. Então, esperou-se 4 minutos para o gel ser substituído. Esse protocolo foi repetido três vezes nas hemiarcadas direitas. Nas hemiarcadas esquerdas, o gel clareador não sofreu irradiação luminosa, protegido por uma placa divisora de arcadas, permanecendo pelo mesmo tempo que nas hemiarcadas direitas (10 minutos, por 3 vezes). Após sete dias, os voluntários retornaram para avaliação da percepção do grau de clareamento e de sensibilidade. De acordo com a avaliação do pesquisador e dos pacientes, através do questionário, não houve diferença perceptível do grau de clareamento entre as hemiarcadas direita e esquerda (com e sem aplicação de sistema luminoso, respectivamente), para ambas as concentrações de gel clareador (25 e 35%). Também foi relatada similaridade no grau de sensibilidade entre as hemiarcadas.

Evaluation of shear bond strength between self-etching adhesive systems and dentin and analysis of the resin-dentin interface.

This study evaluated the shear bond strength between dentin and four self-etching adhesive systems: Clearfil SE Bond (Group 1), Optibond Solo Plus SE (Group 2), Adper Prompt SE (Group 3), and Tyrian SPE (Group 4). A single-bottle adhesive system (Optibond Solo Plus) was used as the control (Group 5). The resin-dentin interface was analyzed by using scanning electron microscopy (SEM). The facial and lingual surfaces of 40 human molars were wet-ground flat; the teeth then were assigned randomly to one of five groups. Each adhesive system was applied to the dentin and the respective resin was applied using a Teflon mold. After 24 hours, the specimens were sheared at a crosshead speed of 1 mm/minute. Five additional teeth were prepared for SEM. Mean scores (+/-SD) in MP a were highest for Group 1 (33.23 +/- 12.67), followed by Group 2 (32.41 +/- 9.90), Group 5 (30.68 +/- 4.08), Group 4 (21.37 +/- 5.87), and Group 3 (17.50 +/- 4.24). The statistical analysis by Kruskal-Wallis and Wilcoxon Rank-Sum tests revealed no significant difference (p > 0.05) between Groups 1, 2, and 5. Groups 3 and 4 were different from the others and from each other (p < 0.05). The fracture modes were mostly interfacial/adhesive and cohesive in the resin. SEM analysis of the resin-dentin interface showed a homogeneous gap-free hybrid layer for all groups.

Microtensile bond strength of 4 dentin adhesives to primary dentin.

PURPOSE: This study's purpose was to evaluate the aging effect on the bond strength of 4 adhesive systems on primary dentin 24 hours and 6 months after bonding. METHODS: The crowns of extracted, caries-free primary molars were grounded and flat surfaces were prepared and distributed into 4 groups (n=7-9). The adhesives Scotchbond Multi-purpose (SMP), Single Bond (SB), Clearfil SE Bond (CSB), and Adper Prompt L-Pop (APL) were applied with the composite resin Filtek Z-250. Specimens were stored in distilled water (37°C/24h), the crowns were sectioned, and 0.8-mm² resin-dentin sticks were obtained and divided into 2 groups: (1) 24h; and (2) 6m. Each group's specimens were tested under tensile at 0.5 mm/minute until they fractured. The fractured sticks were examined by scanning electron microscopy. The data were analyzed by 2-way repeated measures: analysis of variance; Tukey's test (P<.05); and Kruskal-Wallis test (P<.05). RESULTS: The mTBS (MPa) means values were: SMP=33.28 (2.05), SB=23.27 (4.78), APL=20.64 (10.66), and CSB=18.94 (11.94) for the 24-hour group; and SMP=30.59 (6.29), SB=22.39 (5.9), CSB=21.50 (10.67), and APL=17.19 (6.88) for the 6-month group. The most frequent fracture type found was cohesive failure of the adhesive and mixed, with no statistically significant difference found between the groups. CONCLUSIONS: Resin bond strength on primary dentin was not influenced by aging for the adhesive systems tested.

Resistência de união ao cisalhamento de cimentos resinosos autocondicionantes à dentina / Dentin shear bond strength of two self-etch resin cements

OBJETIVO: Avaliar a resistência de união à dentina de dois cimentos resinosos autocondicionantes: RelyX UnicemTM, 3M ESPETM (G1) e MaxcemTM – Kerr (G2), e de um cimento resinoso convencional: RelyX ARC – 3M ESPETM (G3), por meio de teste cisalhamento. MATERIAL E MÉTODO: Vinte e três molares humanos, hígidos e recém-extraídos, foram seccionados no limite amelocementário e no sentido mésio-distal, aproveitando-se as superfícies vestibulares e linguais das coroas. Os fragmentos foram embutidos com resina acrílica em tubos de PVC, de modo que as faces vestibulares e linguais ficassem expostas. Utilizaram-se lixas de carbeto de silício, sob refrigeração, para a obtenção de superfícies planas de dentina. Após a delimitação das áreas destinadas à cimentação, a amostra foi distribuída em três grupos de 15 espécimes cada. Uma matriz de teflon bipartida permitiu a confecção de cilindros dos cimentos coincidentes com as áreas delimitadas. Os testes de resistência de união, sob cisalhamento, foram realizados em máquina Instron 4444 (0,5 mm/min.), após 24 horas de armazenagem em água a 37oC. Os dados foram analisados por ANOVA e teste de Tukey (5%). RESULTADOS: Os valores médios para cada grupo foram (MPa): G1:7,15 (2,74); G2:4,15 (1,87); G3:9,69 (3,02); foram observadas diferenças estatisticamente significativas entre os três grupos avaliados. CONCLUSÕES: Os resultados demonstraram superioridade do cimento resinoso convencional sobre os autocondicionantes; estes também apresentaram diferenças entre si.

OBJECTIVE: To evaluate the dentin shear bond strength of two self-etch resin cements: RelyX Unicem-3M ESPETM (G1) e Maxcem-KerrTM (G2) and a conventional cement: RelyX ARC-3M ESPETM (G3). MATERIAL AND METHOD: Twenty-three freshly extracted noncarious human molars were cut at the dentin enamel junction and posteriorly mesiodistally in order to use lingual and buccal surfaces of the crowns. The fragments were embedded in PVC tubes with acrylic resin exposing the buccal and lingual surfaces, which were grinded under refrigeration on silicon carbide papers to obtain a flat and smooth dentin surface. After demarcation of cementation’s areas, the specimens were distributed into three groups (n=15). A special split Teflon mold allowed manufacturing of cement cylinders, which match the demarcated areas. The shear bond strength test was performed in an 4444 Instron machine (0.5 mm / min.), after 24 hours of storage in water at 37°C. RESULTS AND CONCLUSION: The data were analyzed by ANOVA and Tukey’s Test (5%). The means (MPa) were: G1: 7.15 (2.74); G2: 4.15 (1.87) and G3: 9.69 (3.02), with significant differences among the three groups evaluated. The conventional resin cement has shown superior adhesion property over the self etching cement, which presented statistical differences between them.

Class I and Class V composite restorations: Influence of light-curing techniques on microleakage / Restaurações de Classes I e V: influência das técnicas de fotoativação na microinfiltração

Purpose: To evaluate the effect of light-curing techniques on in vitro microleakage of class I and class V composite restorations. Methods: Sixty human premolars were used to prepare 30 class I and 30 class V cavities, which were cleaned and treated with one step self-etching adhesive (Xeno III - Dentsply). A resin composite (TPH 3 - Dentsply) was inserted in two layers and light-cured using two protocols (n=15 each): conventional curing (500 mW/cm ² , 30 s each increment) and pulse delay technique (first increment similar to the conventional technique and the last increment initially cured with 200 mW/cm ² for 3s and after 5 min light-cured again with 500 W/cm² for 30 s). The specimens were polished, submitted to 800 thermal cycles, sealed, and immersed in a 2% basic fuchsin solution. The teeth were cleaned, sliced, and scored according to the dye penetration. Data were analyzed by Mann-Whitney U test. Results: In class I cavities the pulse delay light-curing technique showed statistically significant better sealing than the conventional technique. In class V restorations no difference was detected between the two techniques in enamel and dentin.Conclusion: Light-curing technique affected the microleakage in class I composite restorations but not in class V.

Objetivo: Avaliar o efeito da técnica de fotoativação na microinfiltração in vitro em cavidades de classes I e V restauradas com resina composta. Metodologia: Em 60 pré-molares humanos, foram confeccionadas cavidades de classe I em 30 dentes e de classe V nos demais 30 dentes. As cavidades foram limpas e tratadas com o sistema adesivo autocondicionante de um passo (Xeno III - Dentsply). A resina composta (TPH 3 - Dentsply) foi inserida em dois incrementos e fotoativada de dois modos (n=15 cada): A) Convencional, sendo cada incremento fotoativado com intensidade de 500mW/cm ² por 30 s; B) Pulso tardio, sendo o primeiro incremento fotoativado da mesma forma que o grupo convencional e o último incremento inicialmente fotoativado com 200mW/cm ² , durante 3 s, 5 min de espera e fotoativação final com 500 mW/cm ² por 30 s. Os espécimes foram polidos, submetidos a 800 ciclos térmicos, impermeabilizados e imersos em fucsina básica a 2%. Os dentes foram limpos, seccionados e avaliados quanto à penetração do corante usando-se escores de 0 a 5. Os dados foram analisados por teste U de Mann-Whitney. Resultados: Nas cavidades de classe I houve diferença estatisticamente significativa entre os grupos. Nas cavidades de classe V não houve diferença entre os dois métodos de fotoativação, tanto em margem de esmalte quanto em dentina. Conclusão: Em cavidades de classe I a fotoativação por pulso tardio proporcionou maior vedamento marginal que a fotoativação convencional. Em cavidades de classe V não houve diferença de penetração do corante.

Biological compatibility of the endodontic paste prepared with tetracycline, thiamphenicol and zinc oxide implanted on the subcutaneous tissue of rats / Compatibilidad biológica de pasta endodóntica preparada con tetraciclina,tiamfenicol y óxido de zinc, implantado en el tejido subcutáneo de ratas

An important requirement for endodontic paste with antibiotics placed in direct contact with living tissues is biocompatibility. The aim of this study was to evaluate the paste biocompatibility prepared with zinc oxide (1.25mg), tetracycline (8mg) and thiamphenicol (26.67mg). The paste and its components were implanted separately through polyethylene sterile tubes of 10mm in length and 1.3mm in diameter, in the subcutaneous tissue of rats with the experiment control at intervals of 3, 7, 15 and 30 days. Each day 6 rats were used, being 3 of them with implant of the substances in four sites placed on the back of the animals and 3 sham animals where it was implanted the polyethylene empty tubes. The experimental animals were anesthetized in an intra-peritoneal way with ketamina and xilazina (0.75ml / g body weight). After the experimental periods, the animals were anesthetized with the same anesthetic overdose. It was held an excision biopsy of the implant area with 10 mm to the security limit included in paraffin following a plan of random histological cut and uniformlyisotropic or oriented cuts according to stereological principles, getting a statistical estimative of the relative amount of inflammatory cells or not on the test system, getting as a result the paste biocompatibility, being the zinc oxide the most toxic element for the cell quality found.

Un requisito importante para la pasta endodóntica preparada con antibióticos, que es colocada en contacto directo con los tejidos vivos es la biocompatibilidad. El objetivo de este estudio fue evaluar la biocompatibilidad de la pasta preparada con óxido del zinc (1,25mg), tetraciclina (8mg) y el tiamfenicol (26,67mg). La pasta y sus componentes fueron implantados por separado a través de tubos estériles de polietileno de 10 mm de longitud y de 1,3mm de diámetro en el tejido subcutáneo de ratas en intervalos de 3, 7, 15 y 30 días. Cada día, 6 ratas fueron implantadas en cuatro sitios ubicados en la parte posterior de los animales, 3 de ellas con el implante de las sustancias y 3 fueron implantados con los tubos de polietileno vacíos. Los animales del experimento fueron anestesiados intraperitteonealmen, con ketamina y xilasina (0,75 ml/g peso corporal). Después de los periodos experimentales, los animales fueron anestesiados con la misma sobredosis anestésica. Fue realizada una biopsia exisional del área del implante con 10 mm de límite de seguridad, luego se realizaron cortes histológico al azar uniformemente isotrópicos o orientados según los principios esteriológicos, consiguiendo un estimativo estadístico de la cantidad relativa de células inflamatorias en el sistema de prueba. Se obtuvieron resultados de la biocompatibilidad de la pasta, siendo el óxido del zinc el elemento mas tóxico según la cualidad de las células que fueron encontradas.

Eficácia dos sistemas adesivos autocondicionantes na adesão entre compósitos e superfície dentinária / Efficacy of self-etching primers in the adhesion between composite and dentine surface

O propósito deste estudo foi avaliar in vitro três sistemas adesivos de última geração, porém com mecanismos diferentes: Excite (Vivadent), Prompt-L-Pop (3M ESPE) e Ariston Liner (Vivadent). Tais sistemas são monocomponentes, sendo que dois deles (Prompt-L-Pop e Ariston Liner) não utilizam condicionamento ácido previamente à aplicação do adesivo, sendo chamados, portanto, de adesivos autocondicionantes. Todos os espécimes foram tratados conforme as instruções dos respectivos fabricantes de cada sistema. Alguns espécimes foram analisados ao microscópio eletrônico de varredura Phillips XL30, em outros espécimes analisou-se a resistência de união em uma máquina de testes universal Instron 4444. Confrontando-se os resultados dos três grupos pesquisados, verificou-se uma excelente adesão dentinária do sistema adesivo Excite, com formação de uma consistente camada híbrida e longos tags resinosos, apresentando como força de união 33,99 MPa. Os sistemas autocondicionantes (Prompt-L-Pop e Ariston Liner) mostraram inconsistência no processo de adesão, gerando frequentes áreas de falha (gaps) na união resina-dentina, apresentando como força de união respectivamente 9,63 e 10,75 MPa. Avaliando o resultado pela estatística, concluiu-se que entre os sistemas adesivos Prompt-L-Pop (3M ESPE) e Ariston Liner (Vivadent) não houve diferença estatística t=0.3752509 (p=0.3548). Logo entre aos sistemas adesivos Prompt-L-Pop (3M ESPE) e Excite (Vivadent), obtivemos diferença estatística t=-8.364292 (p<0.0001). Assim como, entre os sistemas adesivos Ariston Liner (Vivadent) e Excite (Vivadent) também obtivemos diferença estatística t=-7.832686 (p<0.0001)

Avaliação in vitro da resistência da união de sistemas adesivos autocondicionantes à dentina / In vitro shear bond strength of self etching primers to dentin

O objetivo deste trabalho foi avaliar a resistência de união sob cisalhamento de sistemas adesivos autocondicionantes à dentina, assim como avaliar a interface dentina/sistema adesivo. Terceiros molares humanos recém-extraídos por razões diversas foram utilizados. Os espécimes foram divididos aleatoriamente em cinco grupos (n=15), de acordo com o sistema adesivo utilizado: Grupo I (controle): Optibond Solo Plus (Sybron Kerr), Grupo II: Optibond Solo Plus SE (Sybron Kerr), Grupo III: Tyrian SPE (Bisco), Grupo IV: Clearfil SE Bond (Kuraray) e Grupo V: Adper Prompt (3M/ESPE). Os corpos-de-prova foram armazenados a 37°C, em água destilada, durante um período de 30 dias. Em seguida, o ensaio de cisalhamento foi realizado em uma máquina de testes universal INSTRON (Modelo 4444), com uma velocidade de 0.75 mm/min. As interfaces dentina/sistema adesivo foram analisadas em Microscopia Eletrônica de Varredura e o material representativo foi fotografado. A análise estatística revelou diferenças significativas entre as médias, que foram comparadas entre si pelo teste ANOVA e comparativo de Tukey. Os valores médios de resistência ao cisalhamento foram de 34,3 MPa (Optibond Solo Plus), 25 MPa (Optibond Solo Plus SE), 14,8 MPa (Tyrian SPE), 30,2 MPa (Clearfil SE Bond) e 20,2 MPa (Adper Prompt). Concluiu-se que os sistemas adesivos autocondicionantes testados apresentaram a seguinte ordem decrescente de resistência de união: Clearfil SE Bond -> Optibond Solo Plus SE -> Adper Prompt -> Tyrian SPE, sendo todas as médias menores que o grupo controle. Não houve diferença estatística entre o Optibond Solo Plus (controle) e Clearfil SE Bond

Tensile bond strength of intracanal posts in primary anterior teeth: an in vitro study.

The aim of this study was to measure in vitro; the tensile bond strength of three intracanal posts used in anterior primary teeth. A total of 45 single rooted primary anterior teeth were selected for the study and the crowns sectioned leaving 1mm above the cement-enamel junction. The roots were then assigned to three groups according the type of retention used. All roots were endodonticaly treated, a 4-mm of the canal was cleansed and a base of glass ionomer cement was put at the bottom of the prepared canal. The roots were then prepared to receive intracanal posts using a # 4137 diamond bur (KG Sorensen) used in a depth of 3-mm of the length of the canal All the prepared roots were acid etched with a 37% phosphoric acid gel for 15 seconds, rinsed, dried and the dentin adhesive Single Bond (3M) was applied. Group I received intracanal posts and cores made of composite resin (Filtek Z 250, 3M). Group II intracanal posts were made from a 0.6mm orthodontic wire bent as a Greek letter type (gamma), fixed with the Z 250 composite resin and cores were built with the same composite. Finally Group III received intracanal retention made of a fiber glass post (Fibrekor Post, Generic/Pentron) with 1.25 mm diameter, fixed with Z 250 and cores were made like the other groups. The samples were submitted to tension in a universal-testing machine (Instron, model 4444). Statistical analysis (ANOVA) revealed that there were no statistically significant differences between the groups. On the basis of the results of this in vitro study it was concluded that the type of intracanal post did not interfere with the tensile strength and the most frequent type of failure was of adhesive type, corresponding to 74% of the sample.