Effect of different adhesives combined with two resin composite cements on shear bond strength to polymeric CAD/CAM materials.
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This study tested the impact of different adhesives and resin composite cements on shear bond strength (SBS) to polymethyl methacrylate (PMMA)- and composite-based CAD/CAM materials. SBS specimens were fabricated and divided into five main groups (n=30/group) subject to conditioning: 1. Monobond Plus/Heliobond (MH), 2. Visio.link (VL), 3. Ambarino P60 (AM), 4. exp. VP connect (VP), and 5. no conditioning-control group (CG). All cemented specimens using a. Clearfil SA Cement and b. Variolink II were stored in distilled water for 24 h at 37 degrees C. Additionally, one half of the specimens were thermocycled for 5,000 cycles (5 degrees C/55 degrees C, dwell time 20 s). SBS was measured; data were analyzed using descriptive statistics, four- and one-way ANOVA, unpaired two-sample t-test and Chi(2)-test. CAD/CAM materials without additional adhesives showed no bond to resin composite cements. Highest SBS showed VL with Variolink II on composite-based material, before and after thermocycling. (+info)
Microleakage in Class II composite restorations with margins below the CEJ: in vitro evaluation of different restorative techniques.
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OBJECTIVES: The purpose of this in vitro study was to evaluate the microleakage in "deep" Class II composite restorations with gingival cavosurface margin below the CEJ (cemento-enamel junction) and restored with different techniques. STUDY DESIGN: Fifty human teeth were used. In each tooth two standardized Class II slot cavities (on mesial and on distal surfaces) were prepared: the buccolingual extension of the cavities was 4 mm; the gingival wall was located in dentin/cementum (2 mm beyond the CEJ). The prepared teeth were randomly assigned to 5 experimental groups (of 10 specimens and 20 cavities each) and restored. Group 1: Filtek TM Supreme XTE Flowable (3MESPE) + Universal Filtek Supreme XTE (3MESPE), Group 2: GrandioSO Heavy Flow (Voco) + GrandioSo (Voco), Group 3: SDR (Dentsply Caulk) + Esthet-X(R) HD (Dentsply Caulk), Group 4: SonicFill (Kerr), Group 5: Grandio (Voco). After thermocycling, the specimens were immersed in a 0.5% basic fuchsine dye solution and incubated at 37 degrees C for 24 hours. The teeth were subsequently sectioned mesiodistally. All specimens were examined at 25 in a stereomicroscope and standardized digital images were obtained. Dye penetration was measured from gingival margins. RESULTS: The results demonstrated no significant leakage differences between Group 4 and Group 5, that both showed significantly higher frequency distribution of Score 0. Group 2 and Group 3 showed a significant prevalence of Score 1, whereas Group 1 showed significantly higher frequency of Score 2. CONCLUSIONS: None of the restorative techniques tested completely eliminated microleakage dye penetration in dentin margins; marginal adaptation in Class II composite restorations with gingival wall below the CEJ varied in both substrates and from different restorative techniques used. (+info)
Characterization of enamel and dentin surfaces after removal of temporary cement--effect of temporary cement on tensile bond strength of resin luting cement.
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This study was performed to investigate the effect of temporary sealing with cement on the tensile bond strength of resin luting cement to tooth substrate. Five temporary cements and five resin luting cements were used. Six hundred bovine incisor teeth were randomly divided between each group. Effect of temporary sealing on the tensile bond strength of resin luting cement varied in accordance with the temporary cement used. Temporary sealing with both the eugenol-containing and the eugenol-free temporary cements decreased the tensile bond strength of resin luting cement. The tensile bond strength with one of the resin luting cements was most stable on both enamel and dentin pretreated with all temporary cements tested. (+info)
In vivo wear pattern of experimental composite resins based on different resin monomers.
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This study investigated the effects of various monomer systems on composite resin wear in vivo. Experimental light-cured composite resins were prepared employing four different monomer systems: (1) Bis-GMA type, (2) D-2. 6E type, (3) UDMA type, (4) UTMA type. The resin monomers consisted of 70wt% main monomer and 30wt% TEGDMA. These composites contained 80wt% fine quartz. The resins were placed in 2 mm diameter cylindrical cavities located in the occlusal contact area or the contact free area in cast crowns, temporarily set in a mouth. The crowns were removed at monthly intervals, for longitudinal SEM observation. Two months after setting, wear was analyzed, using an electron probe surface roughness analyzer. Microabrasion of the resin matrix and loss of filler particles were observed for all types of monomer systems. The effect of matrix resin systems on occlusal wear was smaller than that of filler systems. (+info)
Characterization of enamel and dentin surfaces after removal of temporary cement--study on removal of temporary cement.
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Enamel and dentin surfaces of bovine teeth were characterized after mechanical and chemical removal of temporary cements. The surfaces were examined by scanning electron microscopy and X-ray microanalysis. Contact angles of distilled water were measured to monitor surface wettability. Mechanical removal with a dental probe did not completely remove all of the temporary cement from both enamel and dentin surfaces. These surfaces usually produced contact angles of distilled water greater than that on polished surfaces. Etching with thirty-seven percent phosphoric acid effectively removed the temporary cement that remained on enamel surfaces after mechanical removal but the etchant was not effective on dentin surfaces. Acid etching after mechanical removal of cement significantly decreased the contact angles of distilled water on enamel surfaces but the etchant only slightly improved contact angles of distilled water on dentin surfaces. (+info)
Effect of resinous temporary material on tensile bond strength of resin luting cement to tooth substrate.
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We investigated the effect of resinous temporary material on the tensile bond strength of resin luting cement to enamel and to dentin. Four hundred bovine incisor teeth were randomly divided into groups. Four resinous temporary materials and four resin luting cements were used. On enamel, none of the resinous temporary materials decreased the tensile bond strength of the cements. On dentin, all the resinous temporary materials decreased the tensile bond strength of the cements except one containing 4-META/MMA-TBB. (+info)