Estudo comparativo da eficacia de dois adesivos dentinarios e um cimento de ionomero de vidro empregados na adesão do amalgama a dentina

Pós-graduação em Odontologia Restauradora - ICT

Avaliação laboratorial da resistência ao cisalhamento de discos de porcelana e de um polímero de vidro cimentados à dentina bovina com o emprego de cimentos adesivos

Pós-graduação em Odontologia Restauradora - ICT

Dentina humana e bovina: estudo comparativo das propriedades físicas e características da hibridização de sistemas adesivos convencionais ou grander modificados: análise em mev

A adesão longitudinal continua a representar um dos maiores desafios da Odontologia moderna. Uma nova proposta para o estabelecimento do equilíbrio da adesão aos tecidos dentários surge, baseada na observação dos resultados obtidos com a tecnologia Grander para revitalização da água. Objetiva-se com o estudo verificar a influência dessa tecnologia nas propriedades físicas de dois sistemas adesivos (convencional e autocondicionante) à partir da medição da tensão superficial e do ângulo de contato; e avaliar a formação e a qualidade da camada híbrida em dentina humana e bovina. A tensão superficial de quatro diferentes líquidos (água, Single Bond- 3M, Primer do Clearfil SE Bond -Kuraray, e Bond do Clearfil SE-Kuraray), foi medida antes e após a modificação pelo procedimento Grander em aparelho goniômetro (Ramé-hart). O ângulo de contato com três substratos distintos (placa de titânio, dentina humana e dentina bovina), foi medido para os quatro líquidos também antes e após a modificação pelo procedimento Grander, também em goniômetro. A formação e qualidade da camada híbrida, foi avaliada em MEV, a partir da confecção de corpos de prova dos substratos humano e bovino, devidamente embutidos, preparados em lixas de variada granulação até a exposição de dentina, submetidos ao procedimento adesivo (SB ou CSEB) normal ou grander modificado, recebendo ao final dupla camada de resina composta Z250-3M, fotopolimerizada por 40s. Após armazenamento em estufa bacteriológica por 24h, os procedimentos para análise ao MEV foram realizados (fixação, desidratação, secagem e metalização). A estatística de Análise de Variância ANOVA e Teste de Tukey 5% revelou que: houve redução estatisticamente significante da tensão superficial para todos os líquidos Grander modificados; houve redução estatisticamente... (Resumo completo, clicar acesso eletrônico abaixo)

Influência da clorexidina na capacidade de umectabilidade da dentina hígida e afetada por cárie por um sistema adesivo

To evaluate the effect of chlorhexidine (CHX) on the wettability of sound and caries affected dentin by a simplified adhesive system. Material and Methods: Flat coronal dentin surfaces were produced on 60 sound molars, 30 of which were artificially decayed. The teeth were divided randomly into 3 groups (n = 10) with smear layer (SL), without SL impregnated with water and without SL impregnated with chlorhexidine. The SL removal was performed by phosphoric acid etching for 15 s. 20 uL of distilled water or 2% chlorhexidine digluconate were applied on the demineralized dentin for 60 s. Then, a drop of Single Bond 2 was deposited on each surface. Contact angles between dentin surface and adhesive was measured by means of a goniometer and data were submitted to ANOVA and Tukey tests (α = 0.05). Results: Higher contact angles were obtained on sound versus caries affected dentin (p <0.05), regardeless of the surface treatment. For both substrates, contact angles statistically higher were obtained for dentin covered with SL (P <0.05). The SL removal resulted in significant reduction of the angles (P <0.05) and no difference was found among angles produced on demineralized dentin impregnated with water or chlorhexidine (p> 0.05). Conclusion: Caries affected dentin wettability was higher than sound dentin and that characteristic was not influenced by chlorhexidine application.

Efeitos da aplicação de resina hidrofóbica sobre a resistência de união de adesivos autocondicionantes de frasco único

Introduction: It is known that self-etching adhesive systems can act as semi-permeable membranes. Objective: Evaluate the effects of additional layer of hydrophobic resin on the microtensile bond strength of self-etching one-bottle adhesives. Material and method: Sixty bovine incisors were used in this study. The facial enamel surfaces of the crowns were abraded with silicon carbide paper to expose flat, mid-coronal dentin surfaces. The following adhesives were used: Clearfil Tri S Bond (CTSB), AdheSE One (ADH) and One Coat  7.0 (OC). Each material was tested with and without applying an additional layer of hydrophobic material from the same manufacturer. Z-350 composite resin was inserted in three 1 mm increments. All adhesive restorative procedure was performed under simulated pulpal pressure and the microtensile test was performed immediately after curing the composite resin. Data were submitted to ANOVA and Tukey test (p < 0.05). Result: For all adhesives tested, the worst results were observed in groups which the additional layer of hydrophobic resin was not applied. Conclusion: The application of additional layer of hydrophobic material can improve the adhesion of self-etching all-in-one adhesive systems.

Influencia de diferentes intensidades de luz en la resistencia de unión de un sistema adhesivo utilizando un colorante fluorescente para su observación

The purpose of this study was to use a fluorescent dye and CLSM microscope to observe the effect of different light intensities on dentin tensile bond strength. Flat dentin surfaces were created on 16 intact human third molars and divided in 4 groups: Group G1 - halogen - KM -200R®; Group G2 - LED - Ultraled®; Group G3 - LED - UltraLume LED5® and Group G4 - LED - Biolux Single V®. For all the groups, the restoration procedure used Single Bond® adhesive, mixed with rodamin B and InTen-S® composite resin. Then, they were cut on serial sections to obtain 1 mm2 area and submitted to micro tensile test and after words, the fractures were analyzed with a digital microscope and CLSM. The statistical analysis showed that all in all groups, except Group G2, which had a significant smaller tensile bond strength ratio. The fracture mode analysis showed that there were significant differences when comparing groups G1 / G2, and G2 / G4. There is no evidence of relevant differences among the other groups. With these results, we conclude that the use of fluorescent dye and CLSM demonstrated to be a simple and nondestructive technique, and that there are evidences that light intensities influenced the dentine tensile.

Avaliação in vitro da resistência de união de dois sistemas adesivos dentinários à dentina bovina antes e após a termociclagem: teste de cisalhamento e análise estereomicroscópia

Pós-graduação em Odontologia Restauradora - ICT

Periapical Tissue Response After Use of Intermediate Restorative Material, Gutta-Percha, Reinforced Zinc Oxide Cement, and Mineral Trioxide Aggregate as Retrograde Root-End Filling Materials: A Histologic Study in Dogs

Purpose: To investigate the periapical tissue response of 4 different retrograde root-filling materials, ie, intermediate restorative material, thermoplasticized gutta-percha, reinforced zinc oxide cement (Super-EBA), and mineral trioxide aggregate (MTA), in conjunction with an ultrasonic root-end preparation technique in an animal model. Materials and Methods: Vital roots of the third and fourth right mandibular premolars in 6 healthy mongrel dogs were apicectomized and sealed with 1 of the materials using a standardized surgical procedure. After 120 days, the animals were sacrificed and the specimens were analyzed radiologically, histologically, and scanning electron microscopically. The Fisher exact test was performed on the 2 outcome values. Results: Twenty-three sections were analyzed histologically. Evaluation showed better re-establishment of the periapical tissues and generally lower inflammatory infiltration in the sections from teeth treated with the intermediate restorative material and the MTA. New root cement on the resected dentin surfaces was seen on all sections regardless of the used material. New hard tissue formation, directly on the surface of the material, was seen only in the MTA sections. There was no statistical difference in outcome among the tested materials. Conclusions: The results from this dog model favor the intermediate restorative material and MTA as retrograde fillings when evaluating the bone defect regeneration. MTA has the most favorable periapical tissue response when comparing the biocompatibility of the materials tested. (C) 2012 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 70:2041-2047, 2012

Shear bond strength of self-etch and total-etch bonding systems at different dentin depths

The purpose of this study was to evaluate the dentin shear bond strength of four adhesive systems (Adper Single Bond 2, Adper Prompt L-Pop, Magic Bond DE and Self Etch Bond) in regards to buccal and lingual surfaces and dentin depth. Forty extracted third molars had roots removed and crowns bisected in the mesiodistal direction. The buccal and lingual surfaces were fixed in a PVC/acrylic resin ring and were divided into buccal and lingual groups assigned to each selected adhesive. The same specimens prepared for the evaluation of superficial dentin shear resistance were used to evaluate the different depths of dentin. The specimens were identified and abraded at depths of 0.5, 1.0, 1.5 and 2.0 mm. Each depth was evaluated by ISO TR 11405 using an EMIC-2000 machine regulated at 0.5 mm/min with a 200 Kgf load cell. We performed statistical analyses on the results (ANOVA, Tukey and Scheffé tests). Data revealed statistical differences (p < 0.01) in the adhesive and depth variation as well as adhesive/depth interactions. The Adper Single Bond 2 demonstrated the highest mean values of shear bond strength. The Prompt L-Pop product, a self-etching adhesive, revealed higher mean values compared with Magic Bond DE and Self Etch Bond adhesives, a total and self-etching adhesive respectively. It may be concluded that the shear bond strength of dentin is dependent on material (adhesive system), substrate depth and adhesive/depth interaction.

Adhesion of an endodontic sealer to dentin and gutta-percha: shear and push-out bond strength measurements and SEM analysis

The use of an adequate method for evaluation of the adhesion of root canal filling materials provides more reliable results to allow comparison of the materials and substantiate their clinical choice. The aims of this study were to compare the shear bond strength (SBS) test and push-out test for evaluation of the adhesion of an epoxy-based endodontic sealer (AH Plus) to dentin and gutta-percha, and to assess the failure modes on the debonded surfaces by means of scanning electron microscopy (SEM). Three groups were established (n=7): in group 1, root cylinders obtained from human canines were embedded in acrylic resin and had their canals prepared and filled with sealer; in group 2, longitudinal sections of dentin cylinders were embedded in resin with the canal surface smoothed and turned upwards; in group 3, gutta-percha cylinders were embedded in resin. Polyethylene tubes filled with sealer were positioned on the polished surface of the specimens (groups 2 and 3). The push-out test (group 1) and the SBS test (groups 2 and 3) were performed in an Instron universal testing machine running at crosshead speed of 1 mm/min. Means (±SD) in MPa were: G1 (8.8±1.13), G2 (5.9±1.05) and G3 (3.8±0.55). Statistical analysis by ANOVA and Student's t-test (a=0.05) revealed statistically significant differences (p<0.01) among the groups. SEM analysis showed a predominance of adhesive and mixed failures of AH Plus sealer. The tested surface affected significantly the results with the sealer reaching higher bond strength to dentin than to gutta-percha with the SBS test. The comparison of the employed methodologies showed that the SBS test produced significantly lower bond strength values than the push-out test, was skilful in determining the adhesion of AH Plus sealer to dentin and gutta-percha, and required specimens that could be easily prepared for SEM, presenting as a viable alternative for further experiments.

Er : YAG laser, ultrasonic system, and curette produce different profiles on dentine root surfaces: An in vitro study

Objective: The aim of the present study was to compare the in vitro effects of the Er:YAG laser, an ultrasonic system, and manual curette on dentine root surface by roughness and micro-morphological analysis. Materials and Methods: Thirty-six flattened bovine roots were randomly assigned to one of the following groups: group 1 (n = 12): Er: YAG laser ( 2940 nm), 120 mJ/pulse, 10 Hz, 8.4 J/cm(2); group 2 ( n = 12): ultrasonic system; and group 3 ( n = 12): manual curette. The mean surface roughness (Ra) of each sample was measured using a profilometer before and after the treatments. The micro-morphology of the treated and untreated ( control) root surfaces was evaluated with scanning electron microscopy (SEM) at 50 x and 1000 x magnification. Results: Analysis with the profilometer showed that for equal times of instrumentation, the smoothest surfaces were produced by the Er: YAG laser and the ultrasonic system, followed by the curette ( p < 0.05). Morphological analyses demonstrated that treatment with the Er: YAG laser produced some areas with an irregular surface, craters, and ablation of the intertubular dentin. The smear layer was removed and dentine tubules were opened by both curettes and the ultrasonic system. The micro-morphology of the dentine root surface after ultrasonic treatment, however, demonstrated randomly distributed areas cratering. Conclusion: All instruments increased the roughness of the dentine root surface after treatment; however, the curette produced rougher surfaces than the other devices. SEM analysis revealed distinct root surface profiles produced by the three devices.

Effect of Titanium Tetrafluoride and Amine Fluoride Treatment Combined with Carbon Dioxide Laser Irradiation on Enamel and Dentin Erosion

Objective: This in vitro study aimed to analyze the influence of carbon dioxide (CO(2)) laser irradiation on the efficacy of titanium tetrafluoride (TiF(4)) and amine fluoride (AmF) in protecting enamel and dentin against erosion. Methods: Bovine enamel and dentin samples were pretreated with carbon dioxide (CO(2)) laser irradiation only (group I), TiF(4) only (1% F, group II), CO(2) laser irradiation before (group III) or through (group IV) TiF(4) application, AmF only (1% F, group V), or CO(2) laser irradiation before (group VI) or through (group VII) AmF application. Controls remained untreated. Ten samples of each group were then subjected to an erosive demineralization and remineralization cycling for 5 days. Enamel and dentin loss were measured profilometrically after pretreatment, 4 cycles (1 day), and 20 cycles (5 days) and statistically analyzed using analysis of variance and Scheffe's post hoc tests. Scanning electron microscopy (SEM) analysis was performed in pretreated but not cycled samples (two samples each group). Results: After 20 cycles, there was significantly less enamel loss in groups V and IV and significantly less dentin loss in group V only. All other groups were not significantly different from the controls. Lased surfaces (group I) appeared unchanged in the SEM images, although SEM images of enamel but not of dentin showed that CO(2) laser irradiation affected the formation of fluoride precipitates. Conclusion: AmF decreased enamel and dentin erosion, but CO(2) laser irradiation did not improve its efficacy. TiF(4) showed only a limited capacity to prevent erosion, but CO(2) laser irradiation significantly enhanced its ability to reduce enamel erosion.

Influence of etching time on bond strength in dentin irradiated with erbium lasers

The purpose of this in vitro study was to evaluate the effect of etching time on the tensile bond strength (TBS) of a conventional adhesive bonded to dentin previously irradiated with erbium:yttrium-aluminum-garnet (Er:YAG) and erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers. Buccal and lingual surfaces of 45 third molars were flattened until the dentin was exposed and randomly assigned to three groups (n = 30) according to the dentin treatment: control (not irradiated), irradiated with Er:YAG (1 W; 250 mJ; 4 Hz; 80.6 J/cm(2)) laser or Er,Cr:YSGG (4 W; 200 mJ; 20 Hz; 71.4 J/cm(2)) laser, and into three subgroups (n = 10) according to acid etching time (15 s, 30 s or 60 s) for each experimental group. After acid etching, the adhesive was applied, followed by the construction of an inverted cone of composite resin. The samples were immersed in distilled water (37A degrees C for 24 h) and subjected to TBS test [50 kilogram-force (kgf), 0.5 mm/min]. Data were analyzed by analysis of variance (ANOVA) and Tukey statistical tests (P a parts per thousand currency signaEuro parts per thousand 0.05). Control group samples presented significant higher TBS values than those of all lased groups. Both irradiated groups exhibited similar TBS values. Samples subjected to the different etching times in each experimental group presented similar TBS. Based on the conditions of this in vitro study we concluded that Er:YAG and Er,Cr:YSGG laser irradiation of the dentin weakens the bond strength of the adhesive. Moreover, increased etching time is not able to modify the bonding strength of the adhesive to irradiated dentin.

Micro-shear bond strength of Er : YAG-laser-treated dentin

This study tested if dentin adhesion is affected by Er:YAG laser. Ninety dentin disks were divided in groups (n=10): G1, control; G2, Er:YAG laser 150 mJ, 90 degrees contact, 38.8 J/cm(2); G3, Er:YAG laser 70 mJ, 90 degrees contact, 18.1 J/cm(2); G4, Er:YAG laser 150 mJ, 90 degrees non-contact, 1.44 J/cm(2); G5, Er:YAG laser 70 mJ, 90 degrees non-contact, 0.67 J/cm(2); G6, Er:YAG laser 150 mJ, 45 degrees contact, 37.5 J/cm(2); G7, Er:YAG laser 70 mJ, 45 degrees contact, 17.5 J/cm(2); G8, Er:YAG laser 150 mJ, 45 degrees non-contact, 1.55 J/cm(2); and G9, Er:YAG laser 70 mJ, 45 degrees non-contact, 0.72 J/cm(2). Bonding procedures were carried out and the micro-shear-bond strength (MSBS) test was performed. The adhesive surfaces were analyzed under SEM. Two-way ANOVA and multiple comparison tests revealed that MSBS was significantly influenced by the laser irradiation (p < 0.05). Mean values (MPa) of the MSBS test were: G1 (44.97 +/- 6.36), G2 (23.83 +/- 2.46), G3 (30.26 +/- 2.57), G4 (35.29 +/- 3.74), G5 (41.90 +/- 4.95), G6 (27.48 +/- 2.11), G7 (34.61 +/- 2.91), G8 (37.16 +/- 1.96), and G9 (41.74 +/- 1.60). It was concluded that the Er:YAG laser can constitute an alternative tool for dentin treatment before bonding procedures.

Effect of prolonged application times on the durability of resin-dentin bonds

Objectives. To examine the effect of prolonged application time on the early and 3-year resin-dentin microtensile bond strength. Methods. Water/ethanol (Single Bond [SB]) and acetone-based systems (One Step [OS]) were employed. A flat superficial dentin surface was exposed in third human molars by wet abrasion. The adhesives were applied to a delimited area of 52 mm(2) on wet surfaces, for 40, 90, 150 and 300s. Four teeth were assigned for each experimental condition. Composite build-ups were constructed incrementally After water storage at 37 degrees C for 24 h, teeth were sectioned to obtain sticks with cross-sectional areas of 0.8 mm(2) to be tested in tension (0.5 mm/min) either immediately (IM) or after 3 years (3Y) of water storage. The microtensile bond strength (mu TBS) values were analyzed by two way repeated measures ANOVA and Tukey`s test (alpha = 0.05). Results. The 90- and 150-s groups achieved the highest IM mu TBS for OS (p < 0.01). For SB, the highest IM mu TBS values were observed after 300-s application (p < 0.01). Significant decreases in mu TBS were observed for OS in the 40- and 90-s groups after 3Y, except for the 150-s group. With regard to SB, after 3Y significant drops in mu TBS values were observed for the 40- and 150-s groups, except for the 300-s group. Significance. Prolonged application times can increase the immediate LTBS of two-step etch-and-rinse adhesive systems and make the adhesive layer more stable over time. (c) 2007 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.