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38 ◦ C (G38), 80 ◦ C (G80) or 100 ◦ C (G100) for 60 s. Half of the specimens of each group were rinsed with water at 80 ◦ C for 15 s (B). ATR-FTIR was performed using a spectrometer and zinc selenide crystal. Results ATR-FTIR analyses showed a band at 1637 cm −1 in G20 referring to �(O–H), which disappeared in other IR spectra, and changes in Si–O peaks with an enlarged band around 940 cm −1 and a decrease in the band at 1296 cm −1 , assigned to the ester group, after heat treatment (G38, G79, G100). The spectra of silane submitted to rising with 80 ◦ C water (G20b, G38b, G79b and G100b) showed a pattern of bands with intensity variation only, without wave-number shifts. Conclusions The results suggested that heat treatments or rinse with water at 80 ◦ C after silane application could improve the silane layer network. doi:10.1016/j.dental.2010.08.129 122 Clinical follow-up of direct adhesive bridges up to 7 years M. Özcan University of Zurich, Dental Materials Unit, Clinic for Fixed and Removable Prosthodontics, Zurich, Switzerland Objectives: This study evaluated the clinical performance of direct, one-pontic, inlay-retained, fiber-reinforcedcomposite restorations (DOI-FRC) up to 7 years. Materials and methods: Between June 2002 and June 2009, 55 patients (39 females, 16 males, 23–83 years old) received a total number of 75 posterior DOI-FRCs (n = 43 mandible, n = 32 maxilla). Box preparations were made on the abutments. Teeth were conditioned using a three-step adhesive system (Quadrant Unibond Primer and Sealer, Cavex). All restorations were made under rubber-dam directly. Restorations were constructed with unidirectional, preimpregnated E-glass fibers (everStick C&B, StickTech) using one type of resin composite (Clearfil Photo Posterior, Kuraray). Colour was improved using flowable composites (Sinfony, 3M ESPE). After baseline recordings, patients were followed at 6 months and at annual recalls. Patients were instructed to call upon experience of a failure or any kind of intervention. The evaluation criteria involved technical failures such as chipping or fracture (tooth/restoration) and caries. Results: During the observation period, a total of 3 debondings in the inlay cavities, and 3 chippings were observed on the buccal surfaces of pontics within 1 and 2 years’ recall. Chippings were repaired using CoJet system (3M ESPE) and remained functional until the last follow up date. Two restorations could not be observed after 1 year and 2 years, respectively due to caries and subsequent bridge construction. Based on the life-tables calculated from the data, estimated survival rate up to 7 years was 95.3% [Kaplan–Meier, Log Rank (Mantel–Cox) 95% CI]. Conclusions: Direct, one-pontic, inlay-retained, FRC restorations with the adhesive system, veneering composite and the technique used, offer acceptable clinical survival rate. doi:10.1016/j.dental.2010.08.130 dental materials 26S (2010) e1–e84 e57 123 Adhesive behaviour of resin-based sealer cements in thin and thick layers E.S. Pane 1 , J.E.A. Palamara 2 , H.H. Messer 2 1 University of Melbourne, Australia and University of Sumatera Utara, Medan, Indonesia 2 University of Melbourne, Australia Objectives: In root canal treatment, a thin layer of sealer cement is recommended for obturation. However, with resinbased sealers, lower bond strength has been shown in thin layer compared to thick (Jainaen et al., IEJ 2007 40:882). This contradicted the finding with resin composite restorative materials which showed that tensile strength decreased gradually with increasing thickness (Alster et al., J Dent Res 1995 74:1745). The aim of this study was to evaluate tensile and shear strength of thin and thick layers of three resin-based sealers (methacrylate-based: EndoREZ, Ultradent; RealSeal, SybronEndo; and epoxy-based: AH Plus, Dentsply). Materials and methods: Thin and thick layers of sealer cements were prepared between metal-to-metal joints of plano-parallel stainless steel aligned rods with diameter 4.7 mm. Ten samples of thin layers averaged 0.1 mm and thick layers 1.0 mm were prepared for each group of sealer, measured from the layer images by Image Tool (UTHSCSA). Tensile and shear strength were tested after 48 h for the methacrylate-based and 7 days for the epoxy-based material using a universal testing machine (Instron model 5544) with a crosshead speed of 1 mm/s. Force data were used to calculate the bond strength (MPa). Modes of failure were examined under magnification and replicas of the fractured surfaces were examined with SEM (Quanta FEG SEM, FEI Co.). Data were analyzed using two-way ANOVA (SPSS Statistics 17.0). Results: Higher mean tensile and shear strength of thin layers than the thick were found in the methacrylate-based sealers (statistically significant, p < 0.05). For the epoxy-based sealer, similar behaviour was found for the shear strength (not statistically significant), and the opposite tendency in the tensile strength (p < 0.05) with higher values in thick layers. There was no association between thicknesses and mode of failure. However, numerous voids were noted with thin layer of AH Plus. Conclusions: The behaviour of resin-based sealers was influenced by layer thickness. Further study regarding the behaviour of resin-based sealer in different thicknesses applied to root dentin will be undertaken. doi:10.1016/j.dental.2010.08.131
e58 dental materials 26S (2010) e1–e84 124 Zirconium oxy-fluoride surface activation for improved bonding to zirconia substrates J.R. Piascik 1 , S.D. Wolter 2 , B.R. Stoner 1,2 1 RTI International, Durham, NC, USA 2 Duke University, Durham, NC, USA Objectives: The purpose of this study was to compare an oxy-fluoride surface activation process to other techniques used to enhance adhesion of dental materials to zirconia surfaces. The effect of this novel pre-treatment on the adhesive strength to both as-received and mechanically roughened surfaces will be presented along with a discussion of bonding mechanisms, their advantages and limitations. Materials and methods: The study leverages a novel gasphase fluorination process that creates a thin oxy-fluoride conversion layer on the surface of zirconia, making it more reactive to conventional adhesive bonding protocols. Zirconia specimens, polished and roughened, were pre-treated and both composite and zirconia cylinders were bonded to them using conventional adhesive techniques. All specimens were subjected to a shear force at a crosshead speed of 0.5 mm/min in an electro-mechanical testing device. Single factor analysis of variance (ANOVA) at a 5% confidence level was performed for the bonding strength data. Optical and scanning electron microscopy was used to evaluate and quantify failure surfaces. Results: Data for composite-to-zirconia shear bond tests, comparing the oxy-fluoride activation to other surface treatments, conventional and recently reported. The fluorinated roughened zirconia surfaces resulted in the highest shear bond stress to fracture, while demonstrating the highest (90%) occurrence of mixed mode (adhesive/cohesive) failures (Table 1). Conclusions: Simple shear bond mechanical tests demonstrated that a fluorination pre-treatment is a viable method to chemically activate zirconia surfaces for improved adhesive bonding. Data show that even on polished zirconia, the oxy-fluoride activation is as-good, or better than conventional pre-treatments. doi:10.1016/j.dental.2010.08.132 125 Adhesion between zirconia and luting cements: Effect of surface treatments M. Querzè 1 , P. Baldissara 1 , N. Scotti 2 , L.F. Valandro 3 ,R. Scotti 1 1 University of Bologna, Italy 2 University of Turin, Italy 3 University of Santa Maria, Brazil Objectives: To compare the bond strength values of two luting cements to Y-TZP ceramics having different surface treatments: feldsphatic liner application and tribochemical silica coating. Materials and methods: Zirconia tablets made of Lava and IPS e.max ZirCAD were surface treated with two feldsphatic liners (Framework Modifier and Intensive Zirliner Brown) or tribochemical silica coating (CoJet) and bonded to resin composite cylinders using two chemically different cements (Panavia F 2.0 and RelyX UniCem). Specimens with untreated surface served as controls. The specimens were thermally cycled at 5–55 ◦ C, then shear bond strength (SBS) test was used to evaluate the bonding. Twelve specimens were tested for each group (n = 12). Data were analyzed with one-way ANOVA and Tukey’s test (˛ = 0.05). Failure pattern analysis was performed using a stereomicroscope and SEM. Results: Mean (SD) PANAVIA F 2.0 RelyX UNICEM Mean and standard deviation SBS (MPa) Lava No treatment 7.569 (3.575) a12 4.757 (3.191) a1 Silica-coating 8.025 (2.264) a12 13.46 (1.651) b23 Liner 12.86 (3.247) a3 12 (2.271) a234 ZirCAD No treatment 5.08 (2.559) a2 2.103 (1.735) a1 Silica-coating 9.515 (2.376) a14 14.08 (1.148) b2 Liner 12.23 (1.482) a34 10.73 (1.536) a34 For each horizontal row: values with identical letters indicate no statistically significant differences (p > 0.05). For each vertical column: values with identical numbers indicate no statistically significant differences (p > 0.05). Conclusions: Within the limits of this study, tribochemical treatment with CoJet may represent the method of Table 1 – Shear bond stress (MPa) with standard deviation of the different test groups. Columns with A shows the percent of samples displaying adhesive failure; A/C a mixed mode of adhesive and cohesive failure. Sample group (with surface finish) Shear bond stress (MPa) Standard deviation A (%) A/C (%) Fluorination (rough) a 32.7 6.4 10 90 Fluorination (polished) b 26.3 6.4 30 70 Co-JetTM (rough) b 24.4 4.9 30 70 3nmSixOy (rough) b 22.9 4.7 40 60 3nmSixOy (polished) c 18.6 2.8 80 20 Untreated (rough) c 15.6 2.0 90 10 Untreated (polished) d 10.1 3.8 100 0 a,b,c,dValues followed by the same letter are statistically similar (p > 0.05).
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