Effect of clinical and laboratory contamination media on the adhesion of luting cement to direct and indirect resin composite materials

Abstract

This study evaluated the effect of contamination media on the adhesion of resin cement to resin composites. Specimens of direct (DRC) (Quadrant Photo Posterior) and indirect resin composite (IRC) (Gradia) (N = 300, n = 15 per group) were prepared. Except the control group (C), the specimens of DRC and IRC were contaminated with one of the following media: (a) saliva (S), (b) silicon (SI), (c) dental stone (D), and (d) isolation medium (I). While one half was only rinsed with water, the other half was silica coated (30 m SiO2, Siljet). All specimens were silanized (Monobond Plus) and coated with adhesive resin (Heliobond). Resin cement (Variolink II) was bonded to the substrates and photopolymerized for 40 s. After thermocycling (x5.000, 5-55°C), composite-cement interface was loaded under shear in a Universal Testing Machine (1 mm/min). Data (MPa) were analyzed using Univariate analysis, Tukey's and Dunnett-T3 tests. Both contamination media (p = 0.000) and surface conditioning (p = 0.005) significantly affected adhesion to DRC and IRC. No significant difference was found between the DRC and IRC (without: p = 0.098; with: p = 0.084). Significantly lower results were obtained after SI (DRC: 0.66 ± 0.6; IRC: 0.8 ± 1.3) followed by I contamination (DRC: 2.1 ± 2.6; IRC: 0.8 ± 1.3) (p < 0.05). Regardless of contamination medium, surface conditioning significantly increased the results for both DRC (15.1 ± 6.1-23.6 ± 3.7) and IRC (20.3 ± 5.4-25.1 ± 3.6) (p < 0.05). Weibull distribution increased after surface conditioning for both DRC (without: 1.33-3.27; with: 2.55-9.34) and This study evaluated the effect of contamination media on the adhesion of resin cement to resin composites. Specimens of direct (DRC) (Quadrant Photo Posterior) and indirect resin composite (IRC) (Gradia) (N = 300, n = 15 per group) were prepared. Except the control group (C), the specimens of DRC and IRC were contaminated with one of the following media: (a) saliva (S), (b) silicon (SI), (c) dental stone (D), and (d) isolation medium (I). While one half was only rinsed with water, the other half was silica coated (30 μm SiO 2 , Siljet). All specimens were silanized (Monobond Plus) and coated with adhesive resin (Heliobond). Resin cement (Variolink II) was bonded to the substrates and photo-polymerized for 40 s. After thermocycling (x5.000, 5-55 °C), composite-cement interface was loaded under shear in a Universal Testing Machine (1 mm/min). Data (MPa) were analyzed using Univariate analysis, Tukey's and Dunnett-T3 tests. Both contamination media (p = 0.000) and surface conditioning (p = 0.005) significantly affected adhesion to DRC and IRC. No significant difference was found between the DRC and IRC (without: p = 0.098; with: p = 0.084). Significantly lower results were obtained after SI (DRC: 0.66 ± 0.6; IRC: 0.8 ± 1.3) followed by I contamination (DRC: 2.1 ± 2.6; IRC: 0.8 ± 1.3) (p < 0.05). Regardless of contamination medium, surface conditioning significantly increased the results for both DRC (15.1 ± 6.1-23.6 ± 3.7) and IRC (20.3 ...

Adhesion of Resin to Lithium Disilicate with Different Surface Treatments before and after Salivary Contamination—An In-Vitro Study

“…Studying this parameter would then be more interesting for this type of restoration where the absence of mechanical retention makes bonding an essential element for its longevity [40]. Moreover, when compared to a microtensile bond strength test, it helps avoiding pre-testing failures since it does not need to be cut before testing, which would be problematic with a brittle material, such as ceramic [6,17]. This research did not include a group of specimens without saliva contamination, since it has already been proved that etching with HF allows one to obtain the same bond strength values as before contamination [9,15,28], so these two groups would lead to identical values.…”

“…However, saliva remains the most relevant from a clinical point of view. The adhesion of saliva to restorations and to the surface of the teeth leads to the formation of a thin pellicle that reaches a thickness of 10 to 20 nm within a few minutes [ 6 ]. This layer is not eliminated by water rinsing [ 16 ] and has a negative influence on the wettability and surface free energy of the substrate [ 9 ].…”

“…The results of the second method were more controversial in the literature; they were identical to the control group on LDS [ 15 ], on feldspathic ceramic [ 30 ], and on zirconia [ 31 ], like in this study, unlike other studies, where it was either fair [ 5 , 16 ] or unsatisfying [ 28 ]. Although it is not entirely clear how phosphoric acid helps in removing saliva, it is suggested that it perhaps penetrates the salivary film and then etches the surface of the ceramic below it, liberating the saliva from the surface [ 6 ].…”

“…Studying this parameter would then be more interesting for this type of restoration where the absence of mechanical retention makes bonding an essential element for its longevity [ 40 ]. Moreover, when compared to a microtensile bond strength test, it helps avoiding pre-testing failures since it does not need to be cut before testing, which would be problematic with a brittle material, such as ceramic [ 6 , 17 ].…”

“…An important step for this success is proper bonding [ 4 ], which includes etching the intaglio with HF and then applying a silane agent. Furthermore, it is essential to find the best way to clean the prosthetic intaglio of the saliva after the intra-oral try-in, since this thin film is known to reduce the bond strength [ 5 , 6 ]. Numerous techniques have been proposed and tested, such as cleaning with ethanol, isopropanol, sodium hypochlorite, water spray, or putting the restoration in an ultrasonic bath, but the results were not satisfying [ 5 , 7 , 8 , 9 ].…”