Effect of surface conditioning methods on the bond strength of luting cement to ceramics

Objectives. This study evaluated the effect of three different surface conditioning methods on the bond strength of a Bis-GMA based luting cement to six commercial dental ceramics. Methods. Six disc shaped ceramic specimens (glass ceramics, glass infiltrated alumina, glass infiltrated zirconium dioxide reinforced alumina) were used for each test group yielding a total number of 216 specimens. The specimens in each group were randomly assigned to one of the each following treatment conditions: (1) hydrofluoric acid etching, (2) airborne particle abrasion, (3) tribochemical silica coating. The resin composite luting cement was bonded to the conditioned and silanized ceramics using polyethylene molds. All specimens were tested at dry and thermocycled (6.000, 5-55degreesC, 30 s) conditions. The shear bond strength of luting cement to ceramics was measured in a universal testing machine (2 mm/min). Results. In dry conditions, acid etched glass ceramics exhibited significantly higher results (26.4-29.4 MPa) than those of glass infiltrated alumina ceramics (5.3-18.1 MPa) or zirconium dioxide (8.1 MPa) (ANOVA, P <0.001). Silica coating with silanization increased the bond strength significantly for high-alumina ceramics (8.5-21.8 MPa) and glass infiltrated zirconium dioxide ceramic (17.4 MPa) compared to that of airborne particle abrasion (ANOVA, P <0.001). Thermocycling decreased the bond strengths significantly after all of the conditioning methods tested. Significance. Bond strengths of the luting cement tested on the dental ceramics following surface conditioning methods varied in accordance with the ceramic types. Hydrofluoric acid gel was effective mostly on the ceramics having glassy matrix in their structures. Roughening the ceramic surfaces with air particle abrasion provided higher bond strengths for high-alumina ceramics and the values increased more significantly after silica coating/silanization. 2003 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved

Fiber-Reinforced Composites - New Alternatives for Fixed Prosthodontics

Development of oral biomaterials has been focused on composites of various kinds. From the prosthodotic point of view, the most promising composites are fibre-reinforced composites (FRC). The use of FRCs in prosthodontics is rapidly growing at the moment and their applications are in FRC full coverage crown bridges, surface retained bridges, inlay retained bridges and in root canal posts. Interestingly, the currently available data of biomechanics and preliminary clinical findings suggest that combination of retentive / adhesive elements of different kind of bridges can now be combined to a single FRC bridge/restoration. By this, odontological and subjective needs of the patient toward fixed prosthetic therapy can better be taken into consideration. This treatment philosophy is called “the dynamic treatment approach”. Successful use of FRC in the dynamic treatment approach put some demands on FRC material. The use of FRC should be easy to use for dental technician and for dentist, the adhesional behaviour of FRC to composite resin luting cement should be good enough, and finally, the biomechanical properties of the FRC should correspond the needs of the masticatory system. Recent development in the field of dental FRC materials have been able to resolve many of the aforementioned questions. These aspects with clinical examples will be demonstrated in the lecture

Experimental novel silane system in adhesion promotion between dental resin and pretreated titanium

Five silane blends were evaluated as experimental adhesion-promoter primers. First, five organosilane monomers (silicon esters), 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, tetrakis-(2-ethyloxyethoxy)silane and bis-[3-(triethoxysilyl)propyl]tetrasulfide, were diluted to 1% (v/v) and blended with a non-functional cross-linking silane, 1,2-bis-(triethoxysilyl)ethane (1%), in 95% ethanol. After activation, each blend was applied to silica-coated Ti coupons. A resin based on bis-phenol-A-diglycidyldimethacrylate was then bonded and photo-polymerized as stubs to the pretreated Ti coupons. Half of the specimens were stored in dry conditions and half were artificially aged by thermo-cycling. The primers containing 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane produced significantly higher shear bond strength values than the control silane, a standard pre-activated product used in clinical dentistry. © Springer Science+Business Media B.V. 2010.published_or_final_versionSpringer Open Choice, 01 Dec 201

A new approach to cure and reinforce cold-cured acrylics

Purpose: The low degree of polymerization of cold-cured acrylics has resulted in inferior mechanical properties and fracture vulnerability in orthodontics removable appliances. Methods: In this study, the effect of reinforcement by various concentrations of chopped E-glass fibers (0%, 1%, 2%, 3% and 5% by weight of resin powder) and post-curing microwave irradiation (800 W for 3 min) on the flexural strength of cold-cured acrylics was evaluated at various storage conditions (at room temperature for 1 day and 7 days; at water storage for 7, 14 and 30 days). Results: The data was analyzed by using 1-way and 2-way ANOVA, and a Tukey post hoc test (α = .05). The specimens with chopped E-glass fibers treated with post-curing microwave irradiation significantly increased the flexural strength of cold-cured PMMA. The optimal concentration might be 2% fibers under irradiation. Conclusions: The exhibited reinforcement effect lasted in a consistent trend for 14 days in water storage. A new fiber-acrylic mixing method was also developed. © 2012 The Author(s).published_or_final_versio

Effects of different silane coupling agent monomers on flexural strength of an experimental filled resin composite

The hydrolytic stability of various silane combinations and their effects on biomechanical properties and water sorption of an experimental dental composite made of bis-GMA and TEGDMA and silane-treated fillers were evaluated. Four silane coupling agents and their blends with a cross-linker silane were used as coupling agents for the 0.7-μm BaSiO 3 fillers. The silanization was carried out in toluene containing 1% (v/v) of one of the four following organofunctional silane coupling agents: 3- acryloxypropyltrimethoxysilane, 3methacryloxypropyltrimethoxysilane, 3-styrylethyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane. Blends of these functional silanes with 1% (v/v) of a cross-linker silane, 1,2- bis -(triethoxysilyl)ethane were also used for silanization. Composites were prepared by mixing 5.00 g Ba-glass filler with 2.00 g of a resin mixture consisting of bis-GMA (58.8 wt%) and TEGDMA (39.2 wt%) in a high-speed mixer. Threepoint bending test specimens (2.0 mm × 2.0 mm × 25.0 mm) were fabricated (n= 8) in a mould and photo-polymerized. The degree of conversion was measured with FT-IR. Biomechanical testing was carried out according to the ISO 10477 standard. Specimens were tested (flexural strength) after 30 days of water storage (37° C, distilled water). Water sorption and solubility (in wt%) were also measured on 1, 2, 3, 5, 7, 14, 21 and 30 days in water storage. Statistical analysis with ANOVA showed that the highest flexural strength was obtained when 3-acryloxypropyltrimethoxysilane + 1,2- bis -(triethoxysilyl) ethane (100.5 MPa; SD, 25.7 MPa) was used in the silanization step, and the lowest was obtained when 3isocyanatopropyltriethoxysilane + 1,2- bis-(triethoxysilyl)ethane (28.9 MPa; SD, 8.8 MPa) was used. The three-point bending strength was significantly affected by the functionality of the main silane tested (p 0.05). The composite that had been silanized with 3- isocyanatopropyltriethoxysilane had the greatest amount of water uptake (1.75%), and the composite silanized with 3-methacryloxypropyltrimethoxysilane + 1,2- bis-(triethoxysilyl)ethane had the least (1.08%). In conclusion, selection of the functional silane monomer can be a significant factor in developing filled resin composites in dentistry. © 2011 VSP.postprin

Chairside fabricated fiber-reinforced composite fixed partial denture

The advances in the materials and techniques for adhesive dentistry have allowed the development of non-invasive or minimally invasive approaches for replacing a missing tooth in those clinical situations when conservation of adjacent teeth is needed. Good mechanical and cosmetic/aesthetic properties of fiber-reinforced composite (FRC), with good bonding properties with composite resin cement and veneering composite are needed in FRC devices. Some recent studies have shown that adhesives of composite resins and luting cements allow diffusion of the adhesives to the FRC framework of the bridges. By this so-called interdiffusion bonding is formed [1]. FRC bridges can be made in dental laboratories or chairside. This article describes a clinical case of chairside (directly) made FRC Bridge, which was used according to the principles of minimal invasive approach. Treatment was performed by Professor Vallittu from the University of Turku, Finland

Telechelic macromer-based polymer-matrix reinforced with E-glass fibers

Oral Session: Dental Materials 6: Polymer-based Materials-Chemistry and Composition - 38. Keynote Address; New Approaches in Materials Development, Processing and Analysis: no. 148OBJECTIVE: Water sorption and flexural properties of fiber reinforced composites (FRC) prepared from extended urethane dimethacrylate (PEG-400-EUEDMA), hydroxypropyl methacrylate (HPMA) and E-glass fibers were investigated. METHOD: The resins contained 72, 50, or 28 wt% PEG-400-E-UEDMA (Esstech Inc., USA) and 28, 50, or 72 wt% HPMA (Esstech Inc., USA), respectively, and camphorquinone (1 wt%)/N,N-cyanoethyl methylaniline (1 wt%) (Accu-Chem Industries Inc., USA). Resin preimpregnated E-glass fibers were placed unidirectionally in a rectangular mold (2×2×20mm3) incorporating ~42 vol% of fibers. The specimens were light-cured (λ=400−500 nm) for 20s with a light curing unit (Elipar™ 2500, 3M ESPE, Germany). In the water sorption tests (based ...postprin

Thermocycling effects on resin bond to silicatized and silanized zirconia

Various techniques have been introduced to create a durable resin composite bond to sintered zirconia (Y-TZP). Shear bond strength values achieved through tribochemical treatment have been investigated in numerous studies, but less is reported about long-term durability. The objective here was to evaluate the effects of thermocycling and silane on shear bond strength of a composite luting cement to silicatized Y-TZP. Two groups of Y-TZP (Procera Zirconia, Nobel Biocare), both consisting of 40 specimens were prepared. The specimen surfaces were air particle abraded with silica-coated aluminum trioxide particles (particle size 110 μm, duration 15 s, air pressure 300 kPa, nozzle distance 10 mm). The silica-coated surfaces in group ZA were silanized with an acrylate-functional silane (Experimental laboratory-made acrylate silane, Toray Dow Corning Silicone) and in the other group ZM with a pre-activated methacrylate silane (ESPE Sil, 3M ESPE). The surfaces were coated with adhesive system (Scotchbond 1, 3M ESPE) and photo-polymerized for 10 s. Resin composite luting cement (RelyX ARC, 3M ESPE) stubs were bonded to substrates and photo-polymerized for 40 s. The test specimens were thermocycled for 0, 1000, 3000, 8000 or 15 000 times (temperature 5-55°C, exposure time 20 s). The shear bond strengths of luting cement to ceramics were measured with a crosshead speed of 1.0 mm/min. ANOVA was used for statistical analysis. ANOVA revealed that both silane and thermocycling affected significantly (p < 0.001) the shear bond strength. Short term hydrolytic stability of acrylate silane was superior. It was concluded that evaluation of bonding requires extended thermocycling. © 2009 VSP.postprin

Effect of primers and resins on the shear bond strength of resin composite to zirconia

Objective. To evaluate the effects of various surface conditioning methods and agents. Methods. The intaglio zirconia substrates were air particle abraded with Al2O3 (Ø 50 μm) for 10 s. An air pressure of 450 kPa and a nozzle distance of 10 mm were used. Surface conditioning by groups: A = silane coupling agent  + organophosphate adhesive; B = organophosphate primer + silane coupling agent + organophosphate adhesive; C = organophosphate primer; D = methacrylate adhesive; E = thiophosphate primer + methacrylate adhesive. Composite stubs were bonded to substrates and photo-polymerized. The specimens were thermocycled 8000 times 55±1∘C and 5±1∘C and kept in distilled water for 14 d. The shear bond strengths were measured with a universal testing machine. Results. Shear bond strengths (MPa ± SD): Group A 25.8±6.7, Group B 26.5±8.6, Group C 16.7±8.5, Group D 2.6±0.7, and Group E 4.2±1.2. ANOVA: significant differences among groups (P<.05). Groups A and B: mainly cohesive fractures, Group C: mixed or adhesive fractures, Groups D and E: adhesive fractures. Conclusions. A value of 10–13 MPa is the minimum acceptable shear bond strength. Groups A, B, and C exceeded this limit, Groups D and E could not achieve the limit.published_or_final_versio

Adsorption of parotid saliva proteins and adhesion of Streptococcus mutans ATCC 21752 to dental fiber-reinforced composites.

The use of fiber-reinforced composites (FRC) in dentistry has increased during recent years. In marginal areas of crowns and removable partial dentures the fibers may become exposed and come into contact with oral tissues, saliva, and microbes. To date, few articles have been published on oral microbial adhesion to FRCs. The aim of this study was to compare different FRCs, their components, and conventional restorative materials with respect to S. mutans ATCC 21752 adhesion and adsorption of specific S. mutans binding proteins. Surface roughness of the materials was also determined. Four different FRCs, a restorative composite, and a high-leucite ceramic material were studied. Polyethylene FRC was found to be significantly rougher than all other materials. Aramid FRC also showed higher surface roughness in comparison with all materials but polyethylene FRC. Without a saliva pellicle, adhesion of S. mutans coincided with surface roughness and polyethylene and aramid FRC promoted S. mutans adhesion better than the other smoother materials. In the presence of salivary pellicle, ceramic and polyethylene FRC bound more bacteria than the other materials studied. Higher quantities of S. mutans binding proteins in the pellicles may in part account for the higher S. mutans adhesion to saliva-coated ceramic and polyethylene FRC.</div