Biomedical subjects

M Atsuta

Publications and source records attributed to M Atsuta.

At least 37 records · Page 2Linked to original sources

PubMed2001

Effects of filler composition and surface treatment on the characteristics of opaque resin composites.

The effects of filler composition and surface treatment of titanium dioxide (TiO2) on the shear bond strength to noble metal and mechanical properties of opaque dental resin composites were assessed. A series of fillers for resin composites were prepared with untreated TiO2 or treated silica/alumina-coated TiO2 with silane coupling agent; these fillers were replaced with silanized SiO2 in increasing amounts. Each of various powder compositions were mixed with the liquid and applied to the surface of a silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy and light cured. A light-activated resin-veneering composite material was placed on top with the use of a brass ring mold and light cured. Specimens were stored at 37 degrees C in water for a period of 24 h. Additionally some specimens were thermocycled at 4 degrees C and 60 degrees C in water baths for 1 min each for 5000 cycles before shear mode testing was performed. Light-activated opaque resin composites containing filler with specific filler compositions of 50 wt% of untreated TiO2-50 wt% of silanized SiO2 (untreated TiO2(50)) and 40 wt% of untreated TiO2-60 wt% of silanized SiO2 (untreated TiO2(40)) showed higher shear bond strengths to the Ag-Pd-Cu-Au alloy than any other specific compositions when no thermocycling was involved. Surface treatment of TiO2 filler and TiO2(50)- and TiO2(40)-opaque resin composites prepared thereof showed significantly higher shear bond strengths than untreated TiO2(50)- and TiO2(40)-opaque resin composites when subjected to thermocycling. Surface-treated opaque resin composite had significantly higher compressive and flexural strength than untreated opaque resin composite after immersion in water for 1 month. Scanning electron microscopy of the fractured opaque resin composite surface showed an interface failure between TiO2 and the matrix resin for untreated composite, and cohesive failure within the resin for surface-treated composite. Surface-treated TiO2(50) and TiO2(40) may be clinically useful as the filler for light-activated opaque dental resin composites.

Adhesiveness↗

PubMed2001

Attractive force of castable iron-platinum magnetic alloys.

OBJECTIVE: The objective of this study was to examine the attractive force of cast Fe-Pt alloys of varying compositions to dental iron-neodymium-boron magnets. METHODS: Ingots of Fe-40 at%Pt, Fe-38 at%Pt, Fe-37 at%Pt and Fe-36 at%Pt alloys were cast in pattern molds for dental magnetic attachment keepers. The attractive forces of the cast Fe-Pt alloy keepers and magnetic stainless steel keepers to dental Fe(14)Nd(2)B magnets (MAGFIT and HICOREX) were measured and statistically evaluated. The saturation magnetization of each Fe-Pt alloy was determined by recording the hysteresis loop using a vibrating sample magnetometer under a magnetic field of 1.6 MA/m. RESULTS: Decreasing the Pt percentage increased the saturation magnetization value and resulted in an increase of the attractive force to each magnet. There was no statistical difference (p>0.05) in attractive force between the Fe-36 at%Pt alloy specimens and the stainless steel keepers for both magnets. A definite correlation between Pt percentage and the value of saturation magnetization was also found (r(2)=-1.000). SIGNIFICANCE: The Fe-Pt alloys with less than Fe-39.5 at%Pt produced high saturation magnetization values and great attractive force to the magnet, and thus, they have the potential to serve as magnetic attachment keepers. Of the Fe-Pt alloys tested, Fe-36 at%Pt seemed to be the best composition for making magnetic attachment keepers.

Analysis of Variance↗

PubMed2001

In vitro corrosion behavior of cast iron-platinum magnetic alloys.

OBJECTIVE: The objective of this study was to investigate the corrosion resistance of cast Fe-Pt alloys of varying compositions for use as attachment keepers and to make a comparison with the corrosion resistance of magnetic stainless steel. METHODS: The corrosion behavior of cast Fe-Pt alloy keepers (Fe-40 at%Pt, Fe-38 at%Pt, Fe-37 at%Pt and Fe-36 at%Pt) was evaluated by means of an immersion test and an anodic polarization test. The solutions used were a 1.0% lactic acid aqueous solution (pH=2.3) (10 ml) and 0.9% NaCl solution (pH=7.3) (10 ml). As a control, the corrosion resistance of a magnetic stainless steel keeper (SUS 447J1: HICOREX) was also measured. RESULTS: Chromium and platinum ions were not detected in either the 1.0% lactic acid or 0.9% NaCl solutions. The only released ions detected were the Fe ions in the 1.0% lactic acid solution. The amounts of Fe ions released from the Fe-40 at%Pt and Fe-38 at%Pt alloys were significantly (p<0.05) lower than from the Fe-37at%Pt, Fe-36 at%Pt and SUS 447J1 alloys. In the anodic polarization test, the potentials at the beginning of passivation for the four Fe-Pt alloys were higher than for the SUS 447J1 alloy in both solutions. SIGNIFICANCE: The Fe-Pt alloys, especially the alloys with higher Pt percentages (Fe-40 and 38 at%Pt), indicated a high corrosion resistance compared to the magnetic stainless steel keeper. A reduction in the Pt percentage may decrease the corrosion resistance in the oral environment.

Chromium↗

PubMed2001

Effect of heat treatment on mechanical properties of age-hardenable gold alloy at intraoral temperature.

OBJECTIVE: The aim of this study was to investigate the effect of various heat treatments on the mechanical properties of gold alloys capable of age-hardening at intraoral temperature. METHODS: Dumbbell-shaped patterns (ISO 6871) were cast with three gold alloys (Sofard; NC Type-IV; Aurum Cast, NihombashiTokuriki Co.). The Sofard alloy is age-hardenable at intraoral temperature. The castings underwent various heat treatments [as-cast (AC); solution treatment (ST); high-temperature aging (HA); intraoral aging (IA)]. After these heat treatments, ultimate tensile strength (UTS), 0.2% offset yield strength (YS), and elongation (EL) were measured at a strain rate of 1.7x10(-4)/s. Fracture surfaces of the specimens after tensile testing were observed using SEM. Vickers hardness was also measured after heat treating. RESULTS: After IA, the hardness values of the Sofard alloy increased and reached values similar to the hardness of the Sofard specimens aged at high temperature (HA). The hardness values of the NC Type-IV and Aurum Cast specimens slightly increased after IA, but did not reach the values of the specimens after HA. All the Sofard, NC Type-IV and Aurum Cast specimens showed significantly (P<0.05) greater hardness values after HA, compared with the values after any other heat treatments (AC, ST and IA). The UTS and YS of the specimens indicated a tendency similar to the results obtained for hardness. The Sofard specimens with ST showed the greatest elongation compared to the corresponding NC Type-IV and Aurum Cast specimens. However, the elongation of the Sofard specimens was abruptly reduced after intraoral aging. CONCLUSION: Intraoral aging significantly improved the mechanical properties and hardness of the Sofard alloy.

Analysis of Variance↗

PubMed2001

Adhesive bonding of titanium nitride-plated stainless steel for magnetic attachments.

The purpose of this study was to evaluate adhesive bonding of resin to titanium nitride ion-plated stainless steel in order for magnetic attachments to survive in the oral environment. Two primers, Cesead II Opaque Primer (CPII) and Metal Primer II (MPII), and one bonding agent, Super-Bond C&B (SB), were used. The surfaces of stainless steel disks were ground and then plated with titanium nitride. After the primer and SB resin were applied, a self-curing resin was bonded to the metal surfaces. Shear bond strengths were determined after 24 h of water storage and after 2,000 thermocycles. Titanium nitride ion-plated stainless steel showed bond strength comparable to the non-plated material. After thermocycling, all specimens of the group no primer/no SB were debonded. The bond strengths of groups CPII/no SB, MPII/no SB and no primer/SB were significantly lower bond strengths than groups CPII/SB and MPII/SB. An appropriate combination of primer and bonding agent should be selected when bonding a magnetic attachment to the denture base.

Adhesiveness↗

PubMed2001

Effect of three adhesive primers for a noble metal on the shear bond strengths of three resin cements.

The purpose of this study was to evaluate the durability and shear bond strengths of the different combinations of three adhesive primers and three resin cements to a silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy. The adhesive primers Alloy Primer (AP), Metal PrimerII (MPII) and Metaltite (MT), and the resin cements BistiteII (BRII), Panavia Fluoro Cement (PFC) and Super-Bond C&B (SB) were used. Two sizes of casting alloy disks were either non-primed or primed and cemented with each of the three resin cements. The specimens were stored in a 37 degrees C water bath for 24 h and then immersed alternately in 4 and 60 degrees C water baths for 1 min each for up to 100,000 thermal cycles. Shear mode testing at a crosshead speed of 0.5 mm/min was then performed. The application of MPII or MT was effective for improving the shear bond strength between each of the three resin cements and the Ag-Pd-Cu-Au alloy compared with non-primed specimens. However, when primed with MPII or MT and cemented with SB, the bond strength at 100,000 thermal cycles was significantly lower than that at thermal cycle 0. When primed with AP, the specimens cemented with BRII or PFC showed lower bond strength than non-primed specimens and failed at the metal-resin cement interface at 100,000 thermal cycles. On the other hand, AP was effective in enhancing the shear bond strength of SB to the Ag-Pd-Cu-Au alloy. The five combined uses of an adhesive metal primer and resin cement (combinations of MPII or MT and BRII or PFC and AP and SB) are applicable to the cementation of prosthodontic restorations without complicated surface modification of the noble alloy.

Adhesives↗

PubMed2001

Improved bonding of adhesive resin to sintered porcelain with the combination of acid etching and a two-liquid silane conditioner.

This study determined the bond strengths of adhesive resins joined to a feldspathic porcelain (VMK 68) for the purpose of developing the most durable surface preparation for the porcelain. Three porcelain surfaces-ground, air-abraded with alumina, and etched with hydrofluoric acid-were prepared. A two-liquid porcelain conditioner that contained both 4-methacryloyloxyethyl trimellitate anhydride (4-META) and a silane coupler (Porcelain Liner M) was used as the priming agent. Each of the two liquid components of the conditioner was also used individually in order to examine the effects of the respective chemical ingredients on adhesive bonding. Two methyl methacrylate (MMA)-based resins initiated with tri-n-butylborane (TBB) either with or without 4-META (MMA-TBB and 4-META/MMA-TBB resins) were used as the luting agents. Shear bond strengths were determined both before and after thermocycling. Shear testing results indicated that thermocycling was effective for disclosing poor bonding systems, and that both mechanical and chemical retention were indispensable for bonding the porcelain. Of the combinations assessed, etching with hydrofluoric acid followed by two-liquid priming with the Porcelain Liner M material generated the most durable bond strength (33.3 MPa) for the porcelain bonded with the 4-META/MMA-TBB resin (Super-Bond C&B).

Acid Etching, Dental↗

PubMed2001

Effect of three adhesive primers on the bond strengths of four light-activated opaque resins to noble alloy.

The effect of commercial adhesive primers for noble metals on the bond strength of light-activated opaque resin has not been determined. This study evaluated the effect of three adhesive primers on the shear bond strengths of each of the four light-activated opaque resins to silver--palladium--copper--gold (Ag--Pd--Cu--Au) alloy. The adhesive primers Alloy Primer (AP), Metal Primer II (MPII) and Metaltite(MT) were used. Four commercial light-activated opaque resins (Axis (AX), Cesead II (CEII), Dentacolor(DE) and Solidex (SO) were used to bond a light-activated resin-veneered composite to Ag--Pd--Cu--Au alloy. The specimens were stored in water at 37 degrees C for 24 h and then immersed alternatively in water baths at 4 and 60 degrees C for 1 min each for up to 20,000 thermal cycles before shear mode testing at a cross-head speed of 0.5 mm min(-1). All the primers examined improved the shear bond strength between opaque resin and Ag--Pd--Cu--Au alloy compared with non-primed specimens prior to thermal cycling. After 20,000 thermal cycles, the bond strengths of combined use of AP and DE and that of MT and each of AX, CE or DE were significantly greater than any other groups. Significant difference was observed between the bond strengths at thermal cycles 0 and 20,000, with the combined use of MT and DE. With the combination of appropriate adhesive metal primers and light-activated opaque resins, complicated surface preparations of metal frameworks of resin-veneered prostheses that are composed of casting Ag-Pd-Cu-Au alloy may be negligible.

Adhesives↗

PubMed2001

Curing depth of different shades of a photo-activated prosthetic composite material.

This study determined the depth of cure of different shades of a prosthetic composite material with the aim of evaluating the influence of shade variation on post-curing material properties. Four light shades having small tabs (A1, B1, C1 and D2) and four dark shades having higher tabs (A4, B4, C4 and D4) of a prosthetic composite (Artglass) for body paste based on the Vita Lumin Shade guide were selected. Specimens of each shade were exposed with the proprietary photo-curing unit (UniXS) for periods 20, 30, 60 and 90 s. The curing depth of the material for each shade was determined with a scraping technique described by the International Organization for Standardization (ISO 4049), and average values of groups of five specimens were compared using analysis of variance (ANOVA) and Scheffe's S intervals (P < 0.05). The L*a*b* colour parameters of five specimens after 90 s exposure were measured using a small-area dental colorimeter (ShadeEye) in order to determine the colorimetric differences. Three-factor ANOVA revealed that the depth of cure was influenced by shade letter (A, B, C or D) and shade tab (1 and 2, or 4) as well as by the exposure period (P=0.05). Curing depth of the light shades was consistently greater than that of the dark shades. Among the eight shades selected, B1 shade demonstrated the greatest curing depth, while A4 shade exhibited the lowest curing depth. For all shades, longer exposure increased the depth of cure. All of the light shades exhibited higher L* values than any of the four dark shades. Curing depth of the composite material was found to be related to the Vita shade variation and the exposure period.

Analysis of Variance↗

PubMed2001

Clinical evaluation of a chemically cured hard denture relining material.

The purpose of the current study was to evaluate the clinical performance of a chemically cured denture relining material after 1-year service period. A powder-liquid material designed for denture base relining (Tokuso Rebase Normal-set, Tokuyama Corp., Tokyo, Japan.) was assessed. Fifty adult patients, who required denture reline treatment, participated in the current project. Adaptation of each denture was examined with a silicone elastomeric material, and the surface to be relined was reduced by means of a rotary cutting instrument, then conditioned with dichloromethane. The relining material was spatulated, poured into the relining area, inserted and adjusted after setting. Each relined denture was subjected to base line evaluation immediately after relining and end evaluation after 1 year. Standardized criteria were used for direct evaluation of the material. After an observation period of 1 year, the rate of the relining cases considered to be in clinically ideal condition (Alfa) was 90% for staining, 90% for discoloration, 94% for peeling, 96% for adaptation and 100% for irritation to oral tissue. Only one case was judged as clinically unacceptable (Charlie), and this was for staining. On the basis of a 1-year observation, the Tokuso Rebase material is considered to be a clinically reliable hard denture relining agent.

Adult↗

PubMed2001

Colour reproducibility of a photo-activated prosthetic composite with different thicknesses.

This study determined the colour accuracy of a photo-activated prosthetic composite with various thicknesses and shades for the purpose of evaluating the relationship between material thickness variation and colour reproducibility. Four light shades (A1, B1, C1 and D2) and four dark shades (A4, B4, C4 and D4) of a representative photo-activated prosthetic composite (Artglass) for body paste were assessed. The specimens were prepared with thicknesses of 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mm. The L*a*b* colour parameter of each shade was measured using a dental colorimeter (ShadeEye) connected to a computer. The overall colour accuracy of groups of five specimens was compared by means of analysis of variance (ANOVA) and Scheffe's S multiple range test (P=0;05). In addition, L*a*b* colour difference (Delta E*) values between the 3.0 mm thickness and the other thicknesses were calculated. Three-factor ANOVA revealed that all colour parameters were influenced by the thickness as well as by the shade letter and shade tab (P < 0.05). The L* value consistently decreased for all shades as thickness increased, although there was no obvious correlation between the thickness of the material and either the a* or b* values. Among the Delta E* values, the values between the 2.5 and 3.0 mm thicknesses were the lowest, and values were found to be lower than 2.0 for all shades. The colour accuracy of the photo-activated prosthetic composite was related to the thickness of the material regardless of the shade. For acceptable colour reproducibility, a composite material thickness of at least 2.5 mm was found to be required.

Color↗

PubMed2001

Effect of desensitizers on bond strength of adhesive luting agents to dentin.

The current study investigates the influence of three dentin hypersensitivity treating agents (Gluma CPS, MS Coat and Saforide) on bond strength to dentin of two luting agents (Panavia Fluoro Cement and Super-Bond C & B). Sixty bovine dentin substrates were divided into 12 combinations of four treatment conditions (Gluma CPS, MS Coat, Saforide and control) and three adhesive systems (AD Gel sodium hypochlorite + Panavia Fluoro Cement, Panavia Fluoro Cement without AD Gel and Super-Bond C & B). After bonding the treated teeth to steel rods, 24-h tensile bond strengths were determined, and average values (n=5) were compared by analysis of variance (ANOVA). Without application of the desensitizers, bond strengths of the two groups (Super-Bond C & B, 10.2 MPa; AD Gel + Panavia, 11.5 MPa) were comparable, and they were greater than the group bonded with the Panavia material with no AD Gel conditioning (7.1 MPa). Application of the Saforide ammoniated silver fluoride desensitizer reduced bond strength of both the Super-Bond and Panavia luting agents, whereas the MS Coat polymeric agent negatively affected bond strength of the Panavia cement only. The use of the Gluma desensitizer did not affect bond strength of any of the three adhesive systems, and the bond strength of the Panavia cement with the AD Gel conditioning was not reduced by application of any of the three desensitizers. The four combinations of two desensitizers (MS Coat and Gluma CPS) and two adhesive systems (Super-Bond C & B and AD Gel + Panavia) are deemed to be applicable to fixed prosthodontic treatment.

Acid Etching, Dental↗

PubMed2001

Effects of two silane coupling agents, a bonding agent, and thermal cycling on the bond strength of a CAD/CAM composite material cemented with two resin luting agents.

STATEMENT OF PROBLEM: Surface treatment of CAD/CAM-generated composite material is important for a strong bond of resin luting agents to composite material. Purpose. This study evaluated the shear bond strengths of 2 dual-cured resin luting agents to a CAD/CAM composite material and the effect of silane coupling agent and bonding resin on the bond strength. MATERIAL AND METHODS: Rectangular- and disk-shaped CAD/CAM composite materials were untreated or treated with 1 of the 2 silane coupling agents or bonding resin and then cemented together with 1 of the 2 dual-cured resin luting agents. Half of the specimens were stored in water at 37 degrees C for 24 hours, the other half thermocycled 50,000 times before shear bond strength testing. Shear bond strengths were measured with a servohydraulic mechanical testing machine, and results were analyzed with 2-way analysis of variance. RESULTS: Surface treatment by silane coupling agent improved the shear bond strength when compared with nontreatment. Specimens treated with bonding resin showed significantly greater shear bond strength than the untreated groups. However, all specimens had the same adhesive failures at the composite-luting agent interface as untreated groups. When the CAD/CAM composite material was treated with 1 of the 2 silane coupling agents, no significant differences in bond strength were noted between water storage alone and after 50,000 thermocycles. For the 2 groups treated with bonding resin or silane coupling agent and cemented with 1 of the 2 dual-cured resin luting agents, there were significant increases in bond strength after 50,000 thermocycles, compared with specimens that were not subjected to thermal cycling. On the other hand, for the 2 untreated groups, there were significant decreases in bond strength after thermocycling. After 50,000 thermocycles, all specimens treated with silane coupling agent and then cemented with 1 of the 2 resin luting agents showed cohesive failures within the composite material. CONCLUSION: The application of a silane coupling agent to the CAD/CAM composite surface provided the highest bond strength between the resin luting agent and composite after long-term thermal cycling.

Adhesiveness↗

PubMed2001

Shear bond strength of resin composite veneering material to gold alloy with varying metal surface preparations.

STATEMENT OF PROBLEM: Although adequate surface preparation is indispensable to achieve a consistent and durable bond between resin composite materials and the metal substructures of veneered restorations, information on the bonding performance of current metal adhesive systems is limited. PURPOSE: The purpose of this study was to evaluate the surface preparation effects of 4 metal conditioners and 1 adhesive system on bonding between a prosthetic resin composite veneering material and a gold casting alloy. MATERIAL AND METHODS: Four primers containing sulfur derivative monomer and designed for conditioning noble metal alloys (Alloy Primer, Infis Opaque Primer, Metal Primer II, and Metaltite) and a surface modification technique (Siloc) were assessed. Cast disk specimens made of gold alloy (Pontor LFC) were either primed with 1 of the 4 primers or treated with the Siloc system and bonded with a light-activated prosthetic resin composite material (New Metacolor Infis). Control specimens were also prepared without the use of a bonding agent. Shear bond strengths were determined before and after thermocycling (20,000 cycles) for evaluation of bond durability. RESULTS: All of the primed and Siloc-treated groups showed improved 24-hour shear bond strengths compared with the control group. After thermocycling, the groups either primed with the Metaltite conditioner or treated with the Siloc system exhibited the highest mean shear bond strengths. CONCLUSION: The Metaltite conditioner and Siloc system each represent a useful method for improving the bond between the gold alloy and resin composite material tested.

Adhesives↗

PubMed2001

Properties of opaque resin composite containing coated and silanized titanium dioxide.

Titanium dioxide (TiO2) is mainly used as a pigment in opaque resin composites for application to the surface of a metal framework. The hypothesis in this paper is that particles of silica/alumina (SiO2/Al2O3)-coated TiO2 treated with a silane coupling agent could bond effectively with resin monomers of opaque resin composites. Untreated TiO2 was used as the control filler. Compressive and flexural strength specimens were prepared by the heat-curing method, because these bulk specimens could not be made by the typical photo-curing method. The treated composite had significantly higher compressive and flexural strengths than the untreated composite after 6 months' immersion in water. Scanning electron microscopy of the fractured composite surfaces showed an interface failure between TiO2 and resin for the untreated composite and cohesive failure within the resin for the treated composite after 6 months' immersion. The light-activated opaque resin composite containing treated TiO2 exhibited significantly higher bond strength to a noble dental alloy after 5000 thermal cycles than that containing untreated TiO2. Thus, silanized SiO2/Al2O3-coated TiO2 appears to be clinically useful as a filler of opaque resin composites.

Aluminum Oxide↗

PubMed2001

Effects of heat treatments on mechanical strength of laser-welded equi-atomic AuCu-6at%Ga alloy.

There is little information available on the mechanical strengthening of laser-welded gold alloys to achieve reliable dental prostheses. This study examined the hypothesis that heat treatments increase the mechanical strength of a laser-welded equi-atomic AuCu-6at%Ga alloy with age "hardenability" at intra-oral temperature. Cut cast gold alloy plates were laser-welded. The specimens were given one of three heat treatments: (1) solution treatment, (2) high-temperature aging after solution treatment, and (3) simulated intra-oral aging after solution treatment. As-cast and uncut specimens were also prepared. Tensile testing was conducted, and the breaking stress and yield strength were recorded. The yield strength values of all the heat-treated specimens nearly reached the values of the corresponding heat-treated control specimens. The results of this study indicated that, for high mechanical strength to be achieved, the laser-welded alloy tested should be aged at a high temperature or be intraorally aged after being laser-welded.

Dental Soldering↗

PubMed2001

Wear of luting materials with titanium retainer.

PURPOSE: The purpose of this study was to investigate the wear resistance of prosthodontic luting materials with a titanium framework by means of an in vitro three-bodied wear-testing device. MATERIALS AND METHODS: The surfaces of flat cast titanium disks were blasted with 50 microns alumina. Placing a 50 microns masking tape on the plane surface, the disks were bonded with five luting materials. The axial surfaces of the bonded disks were ground flat with 600 grit silicon-carbide paper, and then cyclically loaded (75.6 N, 1.2 Hz) by a chewing simulator for 400,000 cycles. The distance between titanium and cement surfaces was measured in micrometers by means of a profilometer to determine delta wear, and the surface texture was evaluated with a scanning electron microscope. RESULTS: The delta wear measurement showed that the resistance of Super-Bond Opaque adhesive was significantly higher than Panavia Fluoro adhesive and Fuji I cement after 400,000 wear cycles. No significant differences were detected among Super-Bond Opaque adhesive, Super-Bond adhesive, and All-Bond adhesive. Visually, continuity with the titanium framework was observed when the titanium disks were luted with resin systems.

Analysis of Variance↗

PubMed2001

Early bond strength and durability of bond between a ceramic material and chemically-cured or dual-cured resin luting agent.

PURPOSE: To evaluate the influence of the different polymerization types of two chemically-cured (Panavia 21 and Super-Bond C&B) and three dual-cured (Panavia Fluoro Cement, Clapearl DC, and Vita Cerec Duo Cement) resin luting agents on the early bond strengths and durability of bond to a Cerec 2 ceramic material. MATERIALS AND METHODS: The Cerec 2 ceramic specimens were prepared with No. 600 silicon carbide paper and their surfaces were etched with phosphoric acid gel, and applied with silane coupling agent. Two sizes of specimens were then bonded together with each of the five luting agents. Shear bond tests were performed 10 mins or 20 mins after preparing specimens, storage in water at 37 degrees C for 24 hrs, and/or 20,000 thermocycles between 4 degrees C and 60 degrees C water baths. RESULTS: The specimens bonded with one of the three dual-cured resin luting agents showed almost the same shear bond strengths for all four storage conditions. However, two chemically-cured resin luting agents exhibited much lower shear bond strengths at 10- and 20-min intervals than at 0 and 20,000 thermocycles. Three dual-cured resin luting agents showed significantly higher bond strengths than two chemically-cured resin luting agents at 10- and 20-min intervals.

Analysis of Variance↗