THE JOURNAL OF - Dentsply

More documents

Recommendations

Info

Raffaelli et al Table 1 Groups of materials and techniques Groups Adhesive Activator Adhesive Cement Ceramic disk thickness (mm) 1 Prime & Bond NT no LC DC 3 2 XP BOND no LC DC 3 3 XP BOND yes NC DC 2 4 XP BOND yes NC DC 3 5 XP BOND yes NC DC 4 6 XP BOND yes NC CC 2 7 Syntac* - NC CC 2 NC: not cured (mix with SCA is applied, but not light cured); LC: light cured (light cured before placement); DC: dual curing (Light is applied on the mixed cement); CC: chemically cured (no light is used at all). *According to the directions for use, application and light curing of Heliobond is mandatory when combined with self curing materials. MATERIALS AND METHODS Bonding was performed on 70 noncarious human third molars that were extracted after informed consent had been obtained. They were stored in a 1% chloramine T solution at 4°C and used within one month following extraction. Prior to the bonding experiments, the teeth were retrieved from the disinfectant solution and stored in distilled water, with four changes of the latter within 48 h to remove the disinfectant. Tooth Preparation – Bonding to Deep Dentin Bonding was performed on the occlusal surfaces of deep coronal dentin. The occlusal enamel and the superficial dentin of each tooth were removed using a slow-speed saw (Isomet, Buehler; Lake Bluff, IL, USA) under water cooling. The tooth surfaces were polished with wet 180-grit SiC papers. The teeth were divided into 7 experimental groups of 10 teeth each. The experimental dentin groups are listed in Table 1. Coupling of Processed Ceramic Empress 2 blocks (shade A2) were reduced with the Isomet saw under water cooling to produce blocks with dimensions similar to those of the teeth to be bonded. Each reduced block was then sectioned with the Isomet saw to produce 2-, 3-, or 4-mm-thick, parallel-sided ceramic onlays. The inner surface of each ceramic onlay was sandblasted with 50- μm alumina, etched with a hydrofluoric acid gel for 90 s, washed, air dried, and silanized using Calibra silane (<strong>Dentsply</strong>). To bond the ceramic disks to the dentin surface, the bonding systems and the resin cement were used following manufacturer’s instructions. As a curing device, a QTH light (<strong>Dentsply</strong> DeTrey) was used (power output: 800 mW/cm 2 ). The intensity of the curing light was tested before and after curing with a radiometer. The bonded specimens were stored in distilled water at 37°C for 24 h before further laboratory processing. TBS Evaluation and SEM Fractographic Analysis Each tooth was sectioned occluso-gingivally into serial slabs using an Isomet saw under water cooling. The two slabs from each tooth were further sectioned into 0.9 x 0.9 mm ceramic-dentin beams, according to the technique for the nontrimming version of the microtensile test. 6 Each group provided 37 to 53 beams for bond strength evaluation. Premature failures that occurred during sectioning were recorded. The specimens were stressed to failure under tension using a universal testing machine (Model 4440, Instron; Canton, MA, USA) at a crosshead speed of 1 mm/min. The data were analyzed using one-way ANOVA and Tukey’s multiple comparison tests at α = 0.05. Representative fractured beams from each of the 7 groups were air dried and sputter coated with gold/palladium for examination with a conventional SEM (Jeol; Tokyo, Japan). Statistical Analysis Three different one-way ANOVAs were performed, each involving different groups (Tables 2 to 4). The first two analyses were performed in the groups with 3-mm and 2-mm ceramic disks, respectively. The last analysis was performed on groups with 3 different ceramic thicknesses (2, 3, and 4 mm) when samples were luted with XP+SCA+Calibra DC. Premature failures were excluded from the statistical analysis. It was also verified that the tooth of origin was not a significant factor for bond strength. As the bond strength data were normally distributed (Kolmogorov-Smirnov test) and groups had homogeneous variances (Levene test), one-way ANOVA was applied to test for significance of differences among the tested groups, followed by Tukey’s test for post-hoc comparisons. In all the analyses, the level of significance was set at α = 95%. RESULTS The bond strength values found in this investigation are reported in Fig 1 and Tables 2 to 4. 276 The Journal of Adhesive Dentistry
Raffaelli et al Table 2 Bond strength values obtained luting 3-mm-thick porcelain disks. n=sample size (in parentheses, number of premature failures), mean, and standard deviation (SD) values excluding premature failures. Premature failures were excluded from the statistical analysis Group N Mean (MPa) SD 1. (control): 42 (7) 20.9 BC 10 PBNT LC + Calibra DC 2. XP LC + 53 (8) 24.9 AB 10.7 Calibra DC 4. XP + SCA + 37 (4) 29.8 A 12.9 Calibra DC According to the post-hoc test, XP+SCA+Calibra DC achieved a significantly higher bond strength than group 1. Groups with the same uppercase letter are not statistically significantly different. Table 3 Bond strength values obtained luting 2-mm-thick porcelain disks. n=sample size (number of premature failures in parentheses), mean and standard deviation (SD) values excluding premature failures. Premature failures were excluded from the statistical analysis Group N Mean (MPa) SD 3. XP+ SCA + 35 (4) 23.6 AB 11.1 Calibra DC 6. XP + SCA + 37 (6) 28.6 A 10.4 Calibra CC 7. Syntac No LC 20 (17) 17.1 B 6.6 + Calibra CC According to the post-hoc test, XP+SCA (No LC)+Calibra CC achieved a significantly higher bond strength than Syntac No LC+Calibra CC. Groups with the same uppercase letter are not statistically significantly different. Table 4 Bond strength values recorded using 3 different porcelain thicknesses. n=sample size (number of premature failures in parentheses), mean and standard deviation values excluding premature failures. Premature failures were excluded from the statistical analysis Ceramic Adhesive/ n Mean (MPa) SD thickness resin cement Group 3: XP+SCA+Calibra 35 (4) 23.6 B 11.1 2 mm DC Group 4: 3 mm 33 (4) 29.8 AB 12.1 Group 5: 4 mm 43 (10) 30.3 A 12.3 According to the post-hoc test, the bond strengths measured with 4-mm-thick disks were significantly higher than those measured with 2-mm-thick disks. Groups with the same uppercase letter are not statistically significantly different. Groups 4, 5, and 6 showed the highest bond strength values. In these three groups, the XP BOND was not light cured before seating the ceramic onlay, and in group 6 Calibra was chemically cured. When comparing the groups that differed in ceramic onlay thickness, it was noted that the specimens obtained from 4-mm-thick onlays (group 5) showed the highest bond strength but also a higher percentage of pretest failure. SEM observations showed that adhesive fracture was the most common failure type in groups 2 to 7. Only in group 1 were two cohesive failures in dentin and two mixed failures recorded. DISCUSSION The microtensile evaluation performed in this study was used in order to standardize the bond strength test and evaluate two different variables, the restorative material thickness and the curing mode of the adhesive-luting agent combinations. In order to properly apply the statistical analysis, it was decided to report the number of premature failures in the tables without including them in the analysis. Only in group 7 was the number of premature failures rather high (45%). In the other groups, the percentage of premature failures was 10% to 19%. The occurrence of premature failures may be due to the stress transmitted at the bonding interface during the specimen reparation procedure. Vol 9, Supplement 2, 2007 277
Page 1 and 2:
THE JOURNAL OF ADHESIVE DENTISTRY V
Page 3 and 4:
Guest Editorial Satellite Symposium
Page 5 and 6: THE JOURNAL OF ADHESIVE DENTISTRY C
Page 7 and 8: Dental Adhesives …. How it All St
Page 9 and 10: Söderholm resulted in a new genera
Page 11 and 12: Effectiveness of All-in-one Adhesiv
Page 13 and 14: Blunck/Zaslansky composites were us
Page 15 and 16: Blunck/Zaslansky 0 20 40 60 80 100
Page 17 and 18: Blunck/Zaslansky Table 3 Slopes of
Page 19 and 20: Blunk/Zaslansky many of the product
Page 21 and 22: Clinical Bonding of a Single-step S
Page 23 and 24: van Dijken et al DISCUSSION The rap
Page 25 and 26: Shear Bond Strength and Physicochem
Page 27 and 28: Latta Fig 1 Representative spectra
Page 29 and 30: Microshear Fatigue Testing of Tooth
Page 31 and 32: Braem Fig 1 Positioning of the dent
Page 33 and 34: Braem the number of steps but also
Page 35 and 36: Microleakage of Class V Composite R
Page 37 and 38: Rosales-Leal Fig 1 Percentage of ca
Page 39 and 40: Rosales-Leal fect the occlusal seal
Page 41 and 42: Microleakage of XP Bond in Class II
Page 43 and 44: Manhart/Trumm heim, Germany), resul
Page 45 and 46: Six-month Clinical Evaluation of XP
Page 47 and 48: Blunck et al Table 2 Results of the
Page 49 and 50: Adhesive Luting Revisited: Influenc
Page 51 and 52: Frankenberger et al Table 2 Results
Page 53 and 54: Frankenberger et al or resin coatin
Page 55: XP BOND in Self-curing Mode used fo
Page 59 and 60: XP BOND in Self-curing mode used fo
Page 61 and 62: Ferrari et al Table 2 Performance c
Page 63: Sarrett Vol 9, Supplement 1, 2007 2
show all

THE JOURNAL OF - Dentsply

Create successful ePaper yourself

Delete template?

Save as template?