Abstract The objective of this study was to evaluate the occlusion potential of in-office desensitizing agents, and characterize the human dentin elements after acid exposure. Twelve human dentin discs were sectioned into four specimens each, and randomized into treatments (n = 20): no treatment (negative control); no treatment and 6% citric acid exposure (positive control); application of Gluma desensitizer (Heraeus Kulzer) or PRG Barrier Coat (Shofu), followed by 6% citric acid exposure. Occlusion and dentin surface characteristics were determined by scanning electron microscopy (SEM, n = 10), and elemental composition (at%), by energy-dispersive X-ray spectroscopy (EDS, n = 10). Three calibrated, blinded evaluators used SEM to categorize the occlusion potential: 1 = occluded, 2 = partially unoccluded, 3 = equally occluded/unoccluded, 4 = partially occluded, 5 = unoccluded. Data were analyzed by weighted kappa, Friedman, and Nemenyi tests (α = 0.05). For SEM, mean occlusion scores were higher for the PRG Barrier Coat than the positive control (p = 0.0235). Most specimens in the controls scored 4 or 5. The most frequent scores for PRG Barrier Coat were 1(60%) and 2(20%), while 30% of Gluma specimens scored 1 and 2. Gluma showed intratubular precipitation, while PRG Barrier Coat covered dentinal tubules totally or partially. For EDS, the K% was lower for Gluma than the negative control (p = 0.0046), with Si peaks in dentin treated with PRG Barrier Coat. The bioactive in-office desensitizing agent with S-PRG filler (PRG Barrier Coat) promoted dentin tubule occlusion, and persisted after exposure to acid.

Aim This study assessed the activity of neuron/odontoblast receptors and neuropeptide release, under an animal model of dentin hypersensitivity (DH). Methods Wistar rats were allocated in two groups (n=10): in test group DH was induced by a validated protocol in which a sports drink (pH 3.08) was ingested for 45d, while in control group, the animals ingested filtered water instead. Animals were euthanized and blood samples were collected to measure plasma corticosterone levels. Dental pulp samples (n=6) were processed for Western Blot and ELISA analysis of TRPV1 (mechano-, thermo- and chemoreceptor), P2X7 (adenosine triphosphate (ATP)-mechanosensitive receptor), TRPM8 (cold-sensitive receptor) and substance P (neurogenic peptide released by neuron activation and due to TRPV1 expression). Data were analyzed using Student’s t tests (α=0.05). Results DH significantly increased expression of TRPV1 (p=0.002), P2X7 (p=0.007) and substance P (p<0.001) but did not significantly affect the activity of TRPM8 (p=0.079). Conclusion Under DH condition, neurons and odontoblasts expressed TRPV1 and P2X7 receptors as well as increased substance P release, demonstrating cellular and molecular mechanisms underlying DH.

Aim The aim of this study was to investigate the impact of pre-treatment with ethanolic solutions of caffeic acid phenethyl ester (CAPE) at varying concentrations on the dentin collagen matrix, specifically focusing on its biomodification potential. This was assessed through evaluations of the modulus of elasticity and changes in mass. Methods Seventy dentin collagen matrices (demineralized sticks) were prepared to receive treatments with ethanolic solutions of CAPE at concentrations of 0.05%, 0.1%, 0.5%, or 2.5%, or with control treatment solutions (distilled water or ethanol) for one hour. The dentin matrices were evaluated for modulus of elasticity and mass before (baseline), immediately after treatment (immediately), and after storage in Simulated Body Fluid (SBF) for time intervals of 1 and 3 months. Results Generalized linear models for repeated measures over time indicated no significant differences between groups (p=0.7530) or between different time points (p=0.4780) in terms of the modulus of elasticity. Regarding mass variation, no differences were observed in the time interval between 1 month and the immediate time (p=0.0935). However, at the 3-month mark compared to the immediate time, the 0.1% CAPE group exhibited less mass loss compared to the water group (p=0.0134). Conclusion This study concludes that various concentrations of CAPE in an ethanolic solution did not affect the modulus of elasticity of dentin, suggesting that CAPE lacks biomodifying potential in this context. However, it was observed that 0.1% CAPE positively influenced the variation in mass over different evaluation time intervals.

Aim To evaluate dentin permeability after pretreatment with 2.5% aqueous solution of titanium tetrafluoride (TiF4), followed by a self-etching universal adhesive system. Methods Forty dentin discs (1.5 mm thick) were randomly divided into groups according to the application or non-application of a pretreatment, and the type of adhesive system to be tested (two-step self-etching/ Clearfil SE Bond/ Kuraray Medical, or universal adhesive system/ Single Bond Universal/ 3M ESPE). Both sides of the discs were conditioned with 37% phosphoric acid to remove the smear layer. The first hydraulic conductivity measurement (L1) was performed in a permeability machine, under 5 PSI pressure. The samples were sanded again to form a standardized smear layer. The teeth designated for pre-treatment with TiF4 received the TiF4 solutions applied actively for 60 seconds, and the adhesive systems were applied according to the manufacturer’s instructions. Then, a new hydraulic conductivity measurement (L2) was performed for the purpose of calculating the hydraulic conductance at a later time, considering the water viscosity and the thickness of the specimen. The percentage (L) of dentin permeability after application of the adhesive system was obtained (L (%) = [(L1-L2) x100] / L1). The Mann-Whitney non-parametric test was applied. Results There was no difference between the two adhesive systems, or between the groups with or without pretreatment, as regards dentin permeability (p>0.05). Conclusion Pretreatment with 2.5% TiF4 did not influence dentin permeability, irrespective of the adhesive system used. 25 2 2.5 TiF4, TiF , (TiF4) selfetching self etching 1.5 15 1 (1. thick nonapplication non twostep step selfetching/ etching/ Medical Universal M ESPE. ESPE . ESPE) 37 layer L1 L (L1 machine pressure pre treatment 6 seconds manufacturers manufacturer s instructions Then L2 (L2 time specimen % (% L1L2 LL [(L1-L2 x100 x L1. L1) MannWhitney Mann Whitney nonparametric parametric p>0.05. p005 p p>0.05 0 05 (p>0.05) used 2. (TiF4 1. (1 3 ( L1L [(L1-L x10 p00 p>0.0 (p>0.05 (TiF x1 p0 p>0. (p>0.0 p>0 (p>0. p> (p>0 (p> (p

Abstract This study aimed to evaluate the effect of endodontic sealer (ES) on bond strength (BS) of prefabricated or milled-CAD-CAM (computer-aided design and computer-aided manufacturing) glass-fiber-posts (GFP). Canals of 90 single-rooted teeth were prepared for filling by the single-cone technique with gutta-percha and one of the following ES: AH Plus (epoxy resin), Endofill (zinc-oxide and eugenol), and Bio-C Sealer (calcium-silicate). After post-space preparation, tooth-specimens were equally divided in half according to type of GFP to be used. In the half to receive milled-CAD-CAM posts, tooth specimens were molded with acrylic resin to obtain replicas. These were scanned to enable the laboratory to produce the milled-CAD-CAM GFPs (Fiber CAD Lab, Angelus) by the subtractive technique. The other half of samples received prefabricated GFPs (Exacto, Angelus) (n=15). The GFPs were cemented with dual-cure resin cement (Panavia F2.0, Kuraray). Each root was sectioned into two slices per root region (cervical, middle, apical) that were subjected to the push-out BS test, in a universal testing machine. Failure mode (FM) was classified by scores. The BS data were submitted to generalized linear model analyses, while FM was analyzed using the chi-square test (a=0.05). BS showed no significant difference among the three ES (p > 0.05). BS was significantly higher for prefabricated (mean 10.84 MPa) versus milled-CAD-CAM GFPs (mean 6.94 MPa) (p <0.0001), irrespective of ES. The majority showed mixed failures. It could be concluded that type of ES did not affect BS of GFPs to dentin, and prefabricated-GFPs had higher bond-strength than customized-milled-CAD-CAM GFPs. (ES (BS milledCADCAM milled CAM computeraided computer aided manufacturing glassfiberposts glass fiber posts GFP. . (GFP) 9 singlerooted single rooted singlecone cone guttapercha gutta percha epoxy resin, , resin) zincoxide zinc oxide eugenol, eugenol eugenol) BioC Bio C calciumsilicate. calciumsilicate calcium silicate (calcium-silicate) postspace post space preparation toothspecimens used replicas Fiber Lab Angelus Exacto, Exacto (Exacto n=15. n15 n n=15 15 (n=15) dualcure dual cure Panavia F20 F F2 0 F2.0 Kuraray. Kuraray Kuraray) cervical, cervical (cervical middle apical pushout push out machine (FM scores analyses chisquare chi square a=0.05. a005 a=0.05 05 (a=0.05) p 0.05. 005 0.05 0.05) mean 1084 10 84 10.8 MPa 694 6 94 6.9 <0.0001, 00001 <0.0001 0001 <0.0001) failures dentin prefabricatedGFPs bondstrength customizedmilledCADCAM customized (GFP (calcium-silicate n1 n=1 1 (n=15 F2. a00 a=0.0 (a=0.05 00 0.0 108 8 10. 69 6. 0000 <0.000 000 n= (n=1 a0 a=0. (a=0.0 0. <0.00 (n= a=0 (a=0. <0.0 (n a= (a=0 <0. (a= <0 (a <

Aim This study assessed the effect of thermal aging on the interfacial strength of resin cements to surface-treated PEEK. Methods Ninety-six PEEK blocks were allocated into 4 groups (n=24), according to following surface treatments: SB - sandblasting with aluminum oxide; SA - acid etched with 98% sulfuric acid; CA – coupling agent (Visio.link, Bredent) and CO - control group (untreated). Surface roughness (Ra) was measured and one cylinder (1-mm diameter and height) of Rely-X Ultimate - ULT (3M/ESPE) and another one of Panavia V5 - PAN (Kuraray) were constructed on the treated or untreated PEEK surfaces. Half of the samples of each group were thermal aged (1,000 cycles). Samples were tested at a crosshead speed of 1 mm/min in shear mode (µSBS). Ra and µSBS data were compared using one- and three-way ANOVA, respectively, and Tukey’s tests. Results SA and SB samples had the roughest surfaces, while CA the smoother (p<0.001). Thermal aging reduced µSBS regardless the surface treatment and resin cement used. There was interaction between surface treatment and resin cement (p <0.001), with ULT showing higher µSBS values than PAN. SA provided higher µSBS than SB for both resin cements, while for CA µSBS was higher (PAN) or lower than SB (ULT). Conclusion Aging inadvertently reduces interfacial strength between PEEK and the resin cements. If ULT is the resin cement of choice, reliable interfacial strength is reached after any PEEK surface treatment. However, if PAN is going to be used only SA and CA are recommended as PEEK treatment.

RESUMO Objetivo: O objetivo deste estudo foi comparar métodos para diagnóstico in vitro de sulcos pigmentados em superfície oclusal. Métodos: Foram utilizados 41 molares e pré-molares humanos extraídos com pigmentação em sulcos e fissuras. Os dentes foram avaliados com iluminação artificial para classificação quanto ao critério ICDAS, seguida por avaliação com laser fluorescente. Para a avaliação radiográfica, os dentes foram posicionados para obtenção de imagens interproximais, adotando-se o critério de Rodrigues et al. (2008) para diagnóstico. Para avaliação histológica, os dentes foram seccionados no sentido mésio-distal na região de sulco oclusal e avaliados em lupa estereoscópica com aumento de 20 vezes, adotando-se o critério de Ekstrand et al. (1997). Os métodos foram comparados com a avaliação histológica, obtendo-se valores de acurácia, sensibilidade e especificidade quanto às variáveis de resposta “presença/ausência” de lesão de cárie em esmalte. Resultados: Ao comparar a inspeção visual com a análise histológica, observou-se acurácia de 65,85%, sensibilidade de 40% e especificidade de 90,48%. Ao comparar o laser fluorescente com a análise histológica, a acurácia foi de 58,54%, sensibilidade de 70% e especificidade de 47,62%. Na comparação da análise radiográfica com a histológica, obteve-se acurácia de 53,66%, sensibilidade de 42,11% e especificidade de 73,68%. Conclusão: A curva ROC mostrou que a inspeção visual apresentou a melhor combinação de sensibilidade e especificidade que o laser fluorescente e que a análise radiográfica para o diagnóstico, representando o melhor método para detecção de cárie em lesões com sulcos pigmentados em esmalte

ABSTRACT Objective: The aim of this study was to compare methods for in vitro diagnosis of pigmented pits and fissures on the occlusal surface. Methods: Forty-one human molars and premolars extracted with pigmentation in pits and fissures were used. The teeth were evaluated with artificial illumination for classification according to ICDAS, followed by fluorescent laser evaluation. For the radiographic evaluation, the teeth were positioned to obtain interproximal images, adopting the criterion of Rodrigues et al. 2008 for diagnosis of lesions. For histological evaluation, the teeth were sectioned in the mesiodistal direction in the occlusal sulcus region and evaluated in a 20-fold stereoscopic magnifying glass, using the criterion of Ekstrand et al. (1997) for evaluation. The methods were compared with the histological evaluation, obtaining values of accuracy, sensitivity and specificity regarding the response variables “presence / absence” of enamel caries. Results: When comparing visual inspection with histological analysis, 65.85% accuracy, 40% sensitivity and 90.48% specificity were observed with false positive and negative probability of 20% and 38.71%. When comparing the fluorescent laser with the histological analysis, the accuracy was 58.54%, sensitivity 70% and specificity 47.62%. Comparing the radiographic analysis with the histological analysis, it was obtained 53.66% accuracy, sensitivity of 42.11% and specificity of 73.68%. Conclusion: The ROC curve and the Yuden index showed that visual inspection presented the best combination of sensitivity and specificity than fluorescent laser and radiographic analysis for diagnosis, which represented the best method for detecting inactive carious lesions in enamel.

Abstract The aim of this in vitro study was to evaluate the color stability of a bulk-fill (Filtek One Bulk Fill, 3M ESPE) and a conventional (Filtek Z350 XT, 3M ESPE) composite resin light-cured at different distances, before and after being submitted to staining with a coffee solution. Sixty specimens of each composite resin were prepared and light-cured at distances of 0, 2 and 4 mm, using a LED light-curing unit (Valo, Ultradent). The specimens were separated (n = 10) for immersion in either distilled water or coffee solution (10 minutes a day for 8 days) to stimulate staining. Color evaluations were performed before and after immersion in the solutions, according to CIELab (△Eab), CIEDE2000 (△E00) and the Whiteness Index for Dentistry (△WID). Kruskal Wallis and Dunn tests, Mann-Whitney tests and Wilcoxon test were applied (α = 5 %). The a* value for conventional composite resin showed a significant increase after immersion in coffee and distilled water (p < 0.05). Both composite resins showed greater b* values when immersed in coffee than in distilled water, with no significant difference among the light-activation distances (p > 0.05). There was no significant difference for L* among the light-activation distances; both resins showed significant decrease in L* after immersion in coffee (p < 0.05). Color change (△Eab, △E00) and difference in whiteness (△WID) were higher for conventional resin when immersed in the coffee solution at all the light-activation distances. Conventional composite resin presented a higher staining value than bulk-fill composite resin, regardless of the light-activation distance.

Abstract Titanium dioxide nanotubes are nanostructures that can accelerate the oxidation reaction of bleaching procedures and promote a more effective whitening effect. Objective This study evaluated physicochemical properties of bleaching agents incorporated with titanium dioxide (TiO2) nanotubes, and the effects on tooth color change at different periods. Methodology 40 premolars were treated according to the following groups (n=10): CP - 10% carbamide peroxide (1 hour daily/21 days); CPN - CP incorporated into TiO2; HP - 40% hydrogen peroxide (three 40-minute sessions/7 days apart); HPN - HP incorporated into TiO2. Color shade was evaluated at five different periods (baseline, after 7, 14 and 21 days of bleaching, and 7 days after end of treatment) according to Vita Classical, CIELab and CIEDE2000 scales. Mean particle size (P), polydispersity (PO) and zeta potential (ZP) were evaluated using dynamic light scattering. Data on the different variables were analyzed by mixed model tests for measures repeated in time (ZP e L*), generalized linear models for measures repeated in time (P, PO, Vita Classical and b*), and Friedman and Mann-Whitney tests (a* and color change/ΔE and ΔE00). Results CP and CPN presented higher P, higher PO and lower ZP than HP and HPN (p≤0.05). All groups showed a significant decrease in Vita Classical color scores after 7 days of bleaching (p<0.05), and HPN presented a greater significant reduction than the other groups. L* increased in TiO2 presence, in all groups, without any differences (p>0.05) in bleaching time. A significant reduction occurred in the a* and b* values for all the groups, and HPN presented lower a* and b* values (p<0.05) than CPN. ΔE was clinically noticeable after 7 days, in all groups, and all groups resulted in a perceptible color change according to ΔE00. Conclusion TiO2 did not influence physicochemical properties of the bleaching agents. HPN presented more effective tooth bleaching than CPN.

Resumo Objetivo: este estudo investigou o efeito das condições de lubrificação no atrito entre braquetes e fios de NiTi de diferentes secções transversais. Métodos: os braquetes (Roth, GAC) foram fixados a um dispositivo conectado a uma máquina de ensaio universal, que recebeu segmentos de fio de NiTi (Nitinol, GAC) com secções de 0,012”; 0,016” ou 0,020”. Após o fio ter sido instalado no slot do braquete, aplicou-se um dos seguintes lubrificantes: saliva humana (SH: controle positivo), água destilada (AD) ou saliva artificial à base de mucina (MUC) ou de carboximetilcelulose (CMC). No grupo controle negativo, nenhum lubrificante foi utilizado. As combinações entre as secções dos fios e as condições de lubrificação geraram 15 grupos, com 15 amostras cada. Os dados foram submetidos à análise de variância a dois critérios e ao teste de Tukey. Resultados: não houve interação significativa entre a secção do fio e a condição de lubrificação (p = 0,901). Independentemente de ter sido utilizado ou não lubrificante, observou-se elevação significativa do atrito com o aumento da secção transversal do fio (p < 0,001). Para qualquer um dos fios, o grupo testado na presença de MUC não diferiu daquele em que se aplicou SH. Por outro lado, quando suprimiu-se os lubrificantes, constatou-se atrito significativamente mais elevado. Os grupos CMC e AD demonstraram comportamento intermediário. Conclusões: o atrito se elevou com o aumento da secção transversal dos fios de NiTi, mas a despeito do fio, o atrito com a saliva à base de MUC foi similar àquele com a SH e menor do que sob condição a seco.

Abstract Objective: This study investigated the effect of the condition of lubrication on the friction between brackets and NiTi archwires of different rounded cross-sections. Methods: Brackets (Roth, GAC) were affixed to a device connected to a universal testing machine into which segments of archwire were placed (NiTi, Nitinol, GAC) with cross-sections of 0.012-in, 0.016-in and 0.020-in. Once the wire was in the bracket slot, the following lubricants were applied: human saliva (HS: positive control), distilled water (DI), mucin-based (MUC) or carboxymethylcellulose-based (CMC) artificial saliva. In the negative control group, no lubricant was used. The combination between the wire cross-sections and the lubrication condition generated 15 groups with 15 samples each. Data were submitted to two-way analysis of variance and Tukey’s test. Results: There was no significant interaction between the wire cross-section and the condition of lubrication (p= 0.901). Irrespective of whether lubricants were used or not, there was a significant increase in friction with an increase in the cross-section of the wire (p< 0.001). For any wire, the group tested in the presence of MUC was not different from that in which HS was applied. On the other hand, when the application of lubricants was suppressed, significantly higher friction values were observed. The CMC group and the DI group demonstrated intermediate behavior. Conclusions: Friction increased with the increase of the cross-section of the NiTi archwire, but regardless of the archwire, friction with MUC artificial saliva was similar to that of HS and lower than in dry conditions.

RESUMO Objetivo: Este estudo investigou a presença de resposta inflamatória na polpa dentária de ratos apresentando hipersensibilidade dentinária induzida por episódios erosivos. Métodos: Dezesseis ratos Wistar foram alimentados com ração peletizada isenta de sacarose por 12 horas; enquanto a dieta estava ausente no restante do período diário, os animais receberam água mineral ou um refrigerante dietético à base de limão, de acordo com o grupo ao qual pertenciam. Oito animais consumiram o refrigerante para a indução do quadro de hipersensibilidade, enquanto os demais receberam água mineral (controle). Após seis semanas, realizou-se a eutanásia dos animais, os quais tiveram suas mandíbulas removidas e seccionadas medialmente no plano sagital, a fim de serem obtidas hemimandíbulas direita e esquerda. Lâminas coradas com hematoxilina-eosina foram analisadas sob microscopia óptica. Resultados: A avaliação histológica dos grupos controle e experimental revelou ausência de processo inflamatório no tecido pulpar e também não foi observada a presença de células inflamatórias como linfócitos, plasmócitos, eosinófilos ou macrófagos. Em adição, não houve edema ou vasos sanguíneos dilatados e congestos. O teste de Mann-Whitney demonstrou inexistência de diferença significativa (p = 1,000) entre os grupos experimental e controle. Conclusão: No modelo animal adotado, a hipersensibilidade dentinária não desencadeou resposta inflamatória na polpa dentária.

ABSTRACT Objective: This study investigated the presence of inflammatory response in the dental pulp of rats showing hypersensitive dentin, induced by erosive episodes. Methods: Sixteen Wistar rats were fed with commercial sucrose-free pellet diet for 12 hours; whereas the food was removed during the remainder of the day, and the animals received mineral water or a lemon-based sucrose-free soft drink, according to the group to which they belonged. Eight animals consumed the soft drink to induce hypersensitivity, while the other 8 animals received mineral water (control). After six weeks, the animals were euthanized, the mandible was removed and subjected to a median incision in the sagittal plane, to obtain right and left hemimandibles. The slides stained with hematoxylin-eosin were analyzed using light microscopy. Results: Histological evaluation of the control and experimental groups revealed no inflammatory process in the pulp tissue, and the presence of inflammatory cells, such as lymphocytes, plasma cells, eosinophils and macrophages, was not observed. In addition, there was no edema or dilated and congested blood vessels. The Mann-Whitney test showed no significant difference (p = 1.000) between the experimental and the control groups. Conclusion: In the animal model used, dentin hypersensitivity does not trigger dental pulp inflammatory response.

Abstract: The aim of this study was to evaluate soluble and insoluble fluoride concentrations in commercial varnishes, and their remineralization effect on artificial caries enamel lesions using surface and cross-sectional microhardness evaluations. Forty bovine enamel blocks were separated into four groups (n=10): control (no treatment), Enamelast (Ultradent Products), Duraphat (Colgate-Palmolive) and Clinpro White Varnish (3M ESPE). Surface enamel microhardness evaluations were obtained, artificial enamel caries lesions were developed by dynamic pH-cycling, and the varnishes were then applied every 6 days, after which the enamel blocks were submitted to dynamic remineralization by pH cycles. After removal of the varnishes, the enamel surfaces were reassessed for microhardness. The blocks were sectioned longitudinally, and cross-sectional microhardness measurements were performed at different surface depths (up to 300 μm depth). Polarized light microscopy images (PLMI) were made to analyze subsurface caries lesions. The fluoride concentration in whole (soluble and insoluble fluoride) and centrifuged (soluble fluoride) varnishes was determined using an extraction method with acetone. The data were analyzed to evaluate the surface microhardness, making adjustments for generalized linear models. There was a significant decrease in enamel surface microhardness after performing all the treatments (p<0.0001). Enamelast and Duraphat showed significantly higher enamel microhardness values than the control and the Clinpro groups (p = 0.0002). Microhardness loss percentage was significantly lower for Enamelast (p = 0.071; One-way ANOVA). PLMI showed that subsurface caries lesions were not remineralized with the varnish treatments. No significant differences in the in-depth microhardness levels (p = 0.7536; ANOVA) were observed among the treatments. Enamelast presented higher soluble and insoluble fluoride concentrations than the other varnishes (p < 0.0001; Kruskal-Wallis and Dunn tests). Enamelast and Duraphat varnishes promoted enamel surface remineralization, but no varnish remineralized the subsurface lesion body. Although insoluble and soluble fluoride concentration values did not correspond to those declared by the manufacturer, Enamelast presented higher fluoride concentration than the others.

Resumo O objetivo deste estudo foi comparar a resistência de união (RU) de pinos de fibra de vidro (PFV), cimentados a condutos com secção transversal ovalada ou circular reabilitados com diferentes técnicas de restauração com PFVs, em função do nível intrarradicular. Noventa raízes de pré-molares inferiores humanos, com 16 mm de altura, classificadas como possuindo canais ovais ou circulares, foram tratadas endodonticamente e preparadas para serem reabilitadas com uma das três técnicas de restauração com PFVs (n=15): 1) PFV único, 2) PFV reembasado com resina composta, e 3) PFV principal associado a pinos acessórios. Os PFVs foram cimentados com um agente resinoso de polimerização dupla (RelyX ARC), após o canal ter sido tratado com um sistema adesivo de condicionamento total de três passos (Adper Scothbond Multiuso). As amostras foram seccionadas em três fatias de 1 mm de espessura, de acordo com o nível da raiz (cervical, médio e apical)e foram submetidas ao teste de RU por push-out. A análise do modo de falha foi realizada com auxílio de um estereomicroscópio. Os dados foram analisados utilizando-se a ANOVA a três critérios para medidas repetidas e o teste de Tukey. A secção do conduto apresentou influência na RU (p<0,001), com os menores valores sendo observados nos condutos ovalados. A técnica de restauração com PFVs afetou significativamente a RU (p=0,018), tendo o PFV reembasado proporcionado os maiores valores de RU, tanto em condutos ovais quanto circulares. Independentemente da secção transversal do conduto radicular e da técnica de restauração com PFV, não houve diferença significativa na RU nos terços cervical, médio e apical (p=0,084). Nos canais de secção transversal ovalada, a RU à dentina intrarradicular nos níveis cervical, médio ou apical aumentou com o emprego de PFVs reembasados.

Abstract The aim of this study was to compare the bond strength (BS) of glass fiber posts (GFP) luted to oval and circular-shaped root canals rehabilitated using varying post techniques, at different intraradicular levels. Ninety 16-mm-long roots of human mandibular premolars, classified either as having oval or circular-shaped canals, were endodontically treated and prepared for restoration using one of three different post techniques (n=15): 1) single GFP; 2) resin-relined GFP; 3) main GFP associated with accessory posts. GFPs were luted with a dual polymerizing resin cement (RelyX ARC) after the canal had been treated with a 3-step etch-and-rinse adhesive system (Adper Scothbond Multipurpose). The samples were sectioned into three 1-mm-thick sections, which were differentiated by the root level (cervical, middle and apical) and tested for push-out BS. Assessment of failure mode was made under a stereomicroscope. Data were analyzed using repeated measures three-way ANOVA and Tukey’s test. The root canal cross-section had a significant influence on BS (p<0.001), with the lowest values being observed in oval-shaped canals. The post technique also significantly affected the BS (p=0.018), with the resin-relined GFPs providing the highest BS values in both oval and circular-shaped canals. Irrespective of the cross-section of the root canal and post technique, there was no significant difference in BS in the cervical, middle and apical third of the root canal (p=0.084). In oval-shaped canals, the BS to intraradicular dentin at cervical, middle or apical level could be increased when the GFPs posts were relined.

Resumo A incidência da erosão tem aumentado e o seu controle ainda é um desafio na prática clínica. Este estudo avaliou os efeitos do gel de TiF4 a 4% sobre a dentina humana erodida submetida a episódios erosivos/abrasivos in situ. Setenta e dois fragmentos de dentina previamente erodida (ácido cítrico 0,05 M, pH 2,3, 20 min) foram distribuídas em 6 grupos (n=12) de acordo com o tratamento a ser realizado durante a fase in situ e o número de ciclos erosivos/abrasivos, como descrito a seguir: gel de TiF4 a 4% aplicado uma (TiF41), duas (TiF42) ou três vezes (TiF43) seguido de 1, 2 e 3 ciclos erosivos/abrasivos, respectivamente. As aplicações dos géis foram realizadas antes do início do ciclo erosivo seguinte. Grupos controle foram submetidos a 1 (C1), 2 (C2) e 3 (C3) ciclos erosivos/abrasivos apenas. Um sétimo grupo (n=12) compreendia amostras sem erosão in vitro (UN) submetidas a 3 ciclos erosivos/abrasivos. Cada ciclo correspondia a 2 dias de desafios erosivos (ácido cítrico a 0,5%, pH 2,6, 6x/dia) e abrasivos (escova de dentes elétrica, 10 s/amostra, 1x/dia). As amostras foram avaliadas em perfilômetro e Microscopia Eletrônica de Varredura Ambiental (MEV). Imagens de microscopia de força atômica (AFM) também foram capturadas (n=3). ANOVA a 2-fatores para medidas repetidas e o teste de Tukey (p<0,001) demonstraram que TiF42, que não diferiu do TiF41 e TiF43, revelou redução significativa na perda de superfície quando comparado a todos os grupos controle. TiF41 e TiF43 não apresentaram diferença estatisticamente significativa em relação ao C1, mas ambos os grupos demonstraram perda de superfície significativamente menor que C2 e C3. Micrografias de MEV e AFM sugeriram alterações nas superfícies tratadas quando comparadas a amostras dos grupos controle, apresentando redução no diâmetro das luzes dos túbulos dentinários. Portanto, o TiF4 foi capaz de reduzir a progressão das lesões erosivas/abrasivas.

Abstract Erosion incidence is increasing and its control is still a challenge in clinical practice. This study evaluated 4% TiF4-gel effects on eroded human dentin subjected to in situ erosive/abrasive episodes. Seventy-two previously eroded dentin slabs (0.05 M citric acid, pH 2.3, 20 min) were allocated to 6 groups (n=12) according to the treatment to be performed during the in situ phase and number of erosive/abrasive cycles, as follows: 4% TiF4-gel applied once (TiF41), twice (TiF42) or three times (TiF43) followed by 1, 2 and 3 erosive/abrasive cycles, respectively. Gel was applied before the beginning of the next cycle. Control groups were subjected to 1 (C1), 2 (C2) and 3 (C3) erosive/abrasive cycles only. A seventh group (n=12) comprised in vitro uneroded samples (UN) subjected to 3 erosive/abrasive cycles. Each cycle corresponded to 2 days of erosive (citric acid 0.5%, pH 2.6, 6x/day) and abrasive (electric toothbrush, 10 s/sample, 1 x/day) challenges. Samples were evaluated under profilometry and environmental scanning electron microscopy (ESEM). Atomic force microscopy images (AFM) were also made (n=3). Repeated measures 2-way ANOVA and Tukey test (p<0.001) showed that TiF42, which did not differ from TiF41 and TiF43, revealed a significant reduction in surface loss compared to all control groups. TiF41 and TiF43 showed no significant difference from C1, but both groups demonstrated significantly smaller surface loss than C2 and C3. ESEM and AFM micrographs suggested alterations on treated surfaces compared to samples from control groups, showing reduced diameters of dentinal tubules lumens. Therefore, TiF4 was able to reduce the progression of erosive/abrasive lesions.

RESUMO Objetivo Avaliar a resistência de união por cisalhamento (RU) de uma cerâmica de dissilicato de lítio (CDL) à zircônia (Y-TZP) utilizando diferentes estratégias de cimentação. Métodos Cilindros de CDL foram cimentados à estrutura de Y-TZP de acordo com os seguintes sistemas adesivos (SA)/ Cimentos resinosos (CR) (n=15): U: CR autoadesivo de cura dual; AMBAR: SA contendo monômeros fosfatados (MF) + CR convencional de cura dual; SBU: SA contendo MF/silano + RC de cura fotoativada; ALLB: SA contendo MF/silano + CR de cura dual. Os corpos de prova foram submetidos ao teste de cisalhamento em máquina universal de ensaios (0.5 mm/min). Os dados (MPa) foram submetidos a ANOVA a um critério e teste de Tukey (α = 0,05). Resultados Observou-se que os grupos SBU e ALLB promoveram valores de RU estatisticamente superiores ao grupo U, no qual observou-se a menor média de RU. Para o grupo AMBAR, valores de RU intermediários foram encontrados, os quais não diferiram dos demais grupos. Conclusão Independente do cimento resinoso, o uso de sistemas adesivos contendo monômeros fosfatados em sua composição promoveram resistência de união superior ao cimento resinoso autoadesivo.

ABSTRACT Objective This study evaluated the shear bond strength (SBS) of lithium disilicate glass (LDG) ceramic bonded to a zirconia (Y-TZP), using different cementation strategies. Methods LDG ceramic cylinders were cemented to Y-TZP structure according to the following adhesive system (AS)/resin cement (RC) (n = 15): U- self-adhesive dual-cure RC; AMBAR- AS containing phosphate monomers (PM) + dual-cure RC; group SBU: PM+Silane/AS + light-cure RC; group ALLB: PM/AS + dual-cure RC. Specimens were subjected to SBS in a universal testing machine (0.5 mm/min). Data (MPa) were subjected to one-way ANOVA and Tukey's test (α = 0,05). Results The groups SBU and ALLB had significantly higher SBS than those provided by the group U, in which the lowest values were observed. For the AMBAR group, intermediate SBS values were found, which did not differ significantly from the values observed in the other groups. Conclusion Regardless of resins cement, the use of adhesives containing phosphate monomers provided superior bond strength than self-adhesive cement.