Résumé
Fiber-reinforced composite(FRC) was developed as a structural component for dental appliances such as prosthodontic framework. FRC provides the potential for fabrication of a metal-free, excellent esthetic prostheses. It has demonstrated success as a result of its simple fabrication, natural colour, and marginal integrity, and fracture resistance of veneering composite resin and the FRC material. Although it has lots of merits, clinical and objective data are insufficient. The purpose of this study was to evaluate the fracture strength and marginal fitness of fiber-reinforced composite bridge in the posterior region for clinical application. Sixteen bridges of each group, Targis/Vectris(R), Sculpture-fibrekor(R)and In-Ceram, were fabricated. All specimens were cemented with Panavia 21 to the master dies. Strength evaluation was accomplished by a universal testing machine (Instron). The marginal fitness was measured by using the stereoscope (X50). The results were as follows. : 1.The fracture strength according to the materials was significantly decreaed in order In-Ceram(238.81+/-82). Targis Vectris(176.25+/-18.93), Sculpture-Fibrekor(120.35 +/-20.08) bridges. 2.FRC resin bridges were not completely fractured, while In-Ceram bridges were completely fractured in the pontic joint. 3.The marginal accuracy was significantly decreased in order Targis/Vectris (60.71micrometer), Sculpture-Fibrekor(73.10micrometer). In-Cream Bridge(83.81micrometer). 4.The fitness of occlusal sites had a lower value than the marginal sites(P<0.001), and the marginal gaps of inner site of the pontic were greater than that of outer sites of the pontic. Fiber reinforced composite bridges are new, esthetic prosthesis and can be clinically used in anterior regions and short span bridges. However, caution must be exercised when extrapolating laboratory data to the clinical situation because there are no long term clinical data regarding the overall success of the FRC.
Sujets)
Prothèse partielle fixe , Articulations , Prothèses et implants , ProsthodontieRésumé
Indirect composite resin are used as an popular effective esthetic material in prosthetic dentistry, often with metallic substructure that provides support for restorations. Recently, new indirect composite resins as a substitute of ceramic have been developed. These resins provide good esthetics, with a wide range of hue and chroma. And the flexural strength of those is in the range of 120-150MPa, which is higher than that of feldspathic ceramic, and similar tot hat of Dicor. Although it has many merits, one of the major clinical problems of composite resins is the bond failure between metal and resin due to insufficient interfacial bond strength. The purpose of this study was to evaluate shear bond strength of the reinforced indirect composite resin to dental alloys. Three different composite resin systems(Artglass . Sculpture , Targis ) as test groups and ceramic(VMK 68 ) as control group were bonded to Ni-Cr-Be alloy(Rexillium III ) and gold alloy(Dave 4). All specimens were stored at 37degrees C distilled water for 24 hours and the half of specimens were thermocycled 2000 times at temperature from 5degrees C to 60degrees C. The shear bond strengths of reinforced indirect composite resins to dental alloys were measured by using the universal testing machine, and modes of debonding were observed by stereoscope and scanning electron microscope. The results were as follows : 1. The shear bond strengths of reinforced indirect composit resins to dental alloys were approximately half those of ceramic to dental alloys(P<0.01). 2. There was no significant difference between the shear bond strength of several reinforced indirect composite resins to metal. 3. Alloy type did not affect on the shear bond strengths of resin to metal, but the shear bond strengths of ceramic to gold alloys were higher than those of ceramic to Ni-Cr alloys(P<0.05). 4. The shear bond strenghts of Artglass and Targis to gold alloys were significantly decreased after thermocycling treatment(P<0.01). 5. Sculpture showed cohesive, adhesive, and mixed failure modes, but Artglass and Targis showed adhesive or mixed failures. And ceramic showed cohesive and mixed failures.
Sujets)
Adhésifs , Alliages , Céramiques , Résines composites , Alliage dentaire , Odontologie , Esthétique , Alliages d'or , Sculpture , EauRésumé
The purpose of this study was to evaluate effects of time on shear bond strengths of a light-cured glass ionomer cement and chemically cured resin cement to enamel, and to observe the failure patterns of bracket bondings. Shear bond strength of a light-cured glass ionomer cement were compared with that of a resin cement Metal brackets were bonded on the extracted human bicuspids. Specimens were subjected to a shear load(in an Instron machine) after storage at room temperature for 5 and 15 minutes, after storage in distilled water at 37degrees C for 1 and 35 days. The deboned specimens were measured m respect of adhesive remnant index. The data were evaluated and tested by ANOVA, Duncan's multiple range test, and t-test, and those results were as follows. 1. The shear bond strength of light-cured glass ionomer cement is higher than that of resin cement at 5 and 15 minutes. 2. The shear bond strengths of both light-cured glass ionomer cement and resin cement increase with time. There was no significant difference in those of both 1 day group and 35 day group. 3. LIght-cured glass ionomer cement is suitable as orthodontic bracket adhesives.
Sujets)
Humains , Adhésifs , Prémolaire , Émail dentaire , Ciment ionomère au verre , Verre , Brackets orthodontiques , Céments résine , EauRésumé
No abstract available.