ABSTRACT
STATEMENT OF PROBLEM: Recently, presintered metal blocks for nonprecious and precious metal implant-supported restorations have gained popularity in computer-aided design and computer-aided manufacturing (CAD-CAM) systems. However, few studies have evaluated the marginal discrepancy of implant-supported restorations made with these new alloy systems. PURPOSE: The purpose of this in vitro study was to compare the milling-sintering method with the lost-wax and milling methods in terms of the marginal fit of implant-supported metal-ceramic restorations. MATERIAL AND METHODS: Thirty implant abutments screwed to implant analogs were embedded into acrylic resin to investigate marginal fit and then divided according to fabrication methods into the following 3 groups (n=10): lost-wax (LW; control group), milling (M), and milling-sintering (MS). Porcelain material was applied to all specimens after completion of the fabrication process. Subsequently, all specimens were cemented to implant abutments for the measurement of marginal discrepancies. Twelve marginal discrepancy measurements were recorded on each implant abutment by using a stereomicroscope. The arithmetic mean of these 12 measurements was considered the mean marginal discrepancy value of each abutment. Data were statistically analyzed by using 1-way ANOVA and Tukey honest significant difference tests (α=.05). RESULTS: The lowest mean marginal discrepancy values (81 ±2 µm) were observed in the M group, which was significantly different (P<.001) from the other methods. The highest mean marginal discrepancy values (99 ±2 µm) were observed in the MS group. CONCLUSIONS: The results revealed that restorations prepared by the milling-sintering method provided clinically acceptable results (<120 µm); however, this new technique was not found to be as precise as the milling method in terms of marginal fit.
Subject(s)
Crowns , Dental Prosthesis, Implant-Supported , Metal Ceramic Alloys , Computer-Aided Design , Dental Marginal Adaptation , Dental Prosthesis Design , Humans , In Vitro TechniquesABSTRACT
This study evaluated the effect of surface treatments on the repair strength of composite resin on a feldspathic ceramic. Ninety ceramic specimens were divided into six groups. In the experimental groups, 4% hydrofluoric acid etching, Er:YAG laser irradiation, CO2 laser irradiation, airborne-particle abrasion, and silica coating were used as surface treatments. After the application of a porcelain repair kit, composite resin was placed on the treated surfaces. After a shear bond strength test, data were statistically analyzed (α = .05). Surface treatments increased the repair bond strength values (P < .05). Airborne particle abrasion and silica coating were found to be the most effective. CO2 laser showed higher repair strength values than Er:YAG laser.
Subject(s)
Dental Bonding , Dental Porcelain/chemistry , Dental Prosthesis Repair , Acid Etching, Dental/methods , Aluminum Oxide/chemistry , Aluminum Silicates/chemistry , Aluminum Silicates/radiation effects , Composite Resins/chemistry , Dental Etching/methods , Dental Materials/chemistry , Dental Porcelain/radiation effects , Dental Stress Analysis/instrumentation , Dentin-Bonding Agents/chemistry , Humans , Hydrofluoric Acid/chemistry , Lasers, Gas , Lasers, Solid-State , Materials Testing , Methacrylates/chemistry , Microscopy, Electron, Scanning , Potassium Compounds/chemistry , Potassium Compounds/radiation effects , Shear Strength , Silicon Dioxide/chemistry , Stress, Mechanical , Surface Properties , Temperature , Time Factors , Water/chemistry , Zirconium/chemistry , Zirconium/radiation effectsABSTRACT
OBJECTIVES: This study evaluated the effects of various pre-processing methods on the bond strength between resin and denture teeth. BACKGROUNDS: Debonding of acrylic resin teeth from denture base material is a problem for patients wearing complete dentures. MATERIALS AND METHODS: Four experimental groups (n = 30) were investigated by subjecting tooth-resin bonding to tensile loading. Specimens were prepared and tested according to the methods of the International Standards Organization (ISO 22112:2005) using a special assembly. Four pre-processing surface treatments of teeth were applied: (i) ST(1), no treatment applied (control); (ii) ST(2) , wax solvent (Dewaks, Faber Kimya & Ilaç, Turkey); (iii) ST(3), boiling water followed by conditioning with methyl methacrylate (MMA) monomer (Meliodent, Bayer Dental, Germany); (iv) ST(4), boiling water followed by wax solvent agent and finally MMA monomer application. Bond strength test was performed using a universal testing machine. RESULTS: All the strength values of the test groups were within clinically acceptable limits. The lowest values were from the ST(1) group and the highest values were in the ST(4) group. CONCLUSIONS: Wax elimination methods affected bonding strength. Application of wax solvent and MMA monomer to the ridge lap surfaces of the teeth gave the best results. In clinical practice, this application procedure may decrease the bonding failure of denture teeth.
