Surface properties and biocompatibility of acid-etched titanium

The purpose of this study was to evaluate the effects of acid-etched titanium on the biological responses of osteoblast-like MC3T3-E1 cells. Four types of treatments (polishing, sandblasting, concentrated H2SO4 etching, and concentrated H2SO4 etching with vacuum firing) were carried out on the surfaces of commercially pure titanium (cpTi) disks. MC3T3-E1 cells were then cultured on the treated cpTi surfaces. Through surface roughness measurement and SEM analysis, it was found that the acid-etched surfaces showed higher roughness values than the sandblasted ones. Scanning electron microscope analysis showed that the cells on the disks treated with acid-etching and acid-etching with vacuum firing spread as well as the sandblasted ones. There were no significant differences in cell proliferation and collagen production on cpTi among the four different surface treatments. Based on the results of this study, it was concluded that etching with concentrated sulfuric acid was a simple and effective way to roughen the surface of titanium without compromising its biocompatibility.     

Surface modification of titanium by etching in concentrated sulfuric acid

OBJECTIVE: The purpose of this study was to characterize the etching behavior of titanium in concentrated sulfuric acid and discuss its application on surface modification of titanium for biological use. METHODS: Commercially pure titanium (cpTi) plate was etched in 48% H2SO4 at RT -90 degrees C for 0.25-8 h. The weight loss was derived from the weight differences before and after etching. The surfaces after etching were characterized by surface roughness, X-ray diffractometry, and scannning electron spectroscopy. The apparent activation energy of the dissolution of cpTi into acid was derived from an Arrhenius plot of the rate of weight loss versus the acid temperature. RESULTS: The surface roughness of cpTi increased with the acid temperature and etching time. The surface roughness was strongly related to the weight loss. The weight loss increased drastically with the acid temperature after an initial period, which shortened with increasing acid temperature. The apparent activation energy for the dissolution of cpTi in H2SO4 was derived as 67.8 kJ/mol. SIGNIFICANCE: This study indicates that etching with concentrated sulfuric acid is an effective way to modify the surface of titanium for biological applications.     

Bonding strength and durability of alkaline-treated titanium to veneering resin

The shear bonding strengths of a veneering resin to polished, sandblasted, and retention bead-cast commercially pure titanium (cpTi) plates with and without alkaline treatment were measured before and after thermal cycling. The bonding strengths to polished cpTi with and without alkaline treatment decreased remarkably with thermal cycling (p<0.01). The bonding strength to sandblasted cpTi with alkaline treatment at 5,000 thermal cycles showed no significant differences from those before thermal cycling (p>0.05), and those at 20,000 thermal cycles showed values which were quite small (p<0.01). On the other hand, there were no significant differences in the bonding strengths of veneering resin to retention bead-cast cpTi in all conditions (p>0.05). These results suggested that although alkaline treatment is a simple and effective surface modification technique for titanium improving adhesion to resin due to formation of tight-fine rutile particles, it does not provide sufficient bonding durability for long-period restorations.     

铸钛的不同表面处理对钛-聚合瓷结合强度影响的实验研究

目的 研究铸钛的不同表面处理方法对钛-聚合瓷结合强度的影响。方法 将24个铸钛试件随机分为光 滑组、粗糙组、酸蚀光滑组和酸蚀粗糙组,每组6个。根据分组不同分别采用不同的表面处理方式,粗糙组进行喷 砂处理,酸蚀光滑组进行酸蚀处理,酸蚀粗糙组喷砂后进行酸蚀,光滑组表面不做处理。表面处理后的钛试件与 聚合瓷制备成钛-聚合瓷试件,测试其剪切结合强度,并在扫描电镜下观察钛表面形貌和剪切试验后钛与聚合瓷断 裂面的形貌。结果 光滑组、粗糙组、酸蚀光滑组和酸蚀粗糙组的剪切结合强度分别为（3.08±0.45）、（6.05±0.74）、（6.27±0.80）、（10.16±0.82）MPa。粗糙组、酸蚀光滑组和酸蚀粗糙组的剪切结合强度高于光滑组（P<0.01）,其中酸 蚀粗糙组的剪切结合强度最高,粗糙组和酸蚀光滑组间的剪切结合强度无统计学差异（P>0.05）。各组的钛表面形
貌和剪切试验后钛与聚合瓷断裂面的形貌均有一定的差异。结论 钛表面酸蚀处理和喷砂处理可提高钛-聚合瓷的剪切结合强度,喷砂后酸蚀处理是一种有效地提高钛-聚合瓷剪切结合强度的表面处理方法。     

Evaluation of 24-hour shear bond strength of resin composite to porcelain according to surface treatment

PURPOSE: The purpose of the present in vitro study was to examine shear bond strengths of resin composite to porcelain according to surface treatment. MATERIALS AND METHODS: One hundred eight feldspathic porcelain blocks were prepared. Specimens were divided into nine surface treatment groups: sandblasting with 50- or 110-microm Al2O3, acid etching with hydrofluoric acid, applying silane agent, and combinations of these treatments. Microhybrid resin composite was condensed and light cured for 40 seconds on the porcelain specimens, which were then stored in distilled water at 37 degrees C for 24 hours before mechanical testing. RESULTS: The bond strengths were significantly different according to one-way ANOVA. The lowest bond strength was observed in the silane group (4.09 MPa); the highest bond strengths were observed with acid etching + silane (11.97 MPa) and sandblasting with 50-microm Al2O3 + acid etching + silane (12.34 MPa) (no significant difference between groups). CONCLUSION: Acid etching with 9.6% hydrofluoric acid gel or sandblasting with 50- or 110-microm Al2O3 particles alone did not provide adequate bond strength. Silane agent was effective in increasing the shear bond strength of resin composite to porcelain after sandblasting or acid etching. Porcelain treatment with a combination of 50-microm Al2O3 air abrasion, 9.6% hydrofluoric acid, and silane agent provided higher bond strengths than treatment with any of these procedures alone.     

热酸溶液蚀刻对氧化锆粘接强度的影响

目的 研究牙科氧化锆经3种酸溶液加热处理后与树脂的初期粘接强度和粘接耐久性。方法 将80枚氧化锆瓷片分为5组,进行不同的表面处理,随后制作陶瓷/树脂粘接试样。其中,A组：经H2SO4/（NH4）2SO4混合液热处理,使用氧化锆底涂剂;B组：HF/HNO3混合液热处理,使用氧化锆底涂剂;C组：经H2SO4/HF/HNO3混合液热处理,使用氧化锆底涂剂;D组：氧化铝喷砂,使用氧化锆底涂剂;E组：摩擦化学法硅涂层,使用硅烷偶联剂。将粘接试样分为两部分,分别于水储24 h和40 d后进行剪切粘接强度（SBS）测试。扫描电镜（SEM）下观察3种酸处理和氧化铝喷砂处理氧化锆瓷片的表面形态。结果 老化前E组SBS最高,其余4组间差异无统计学意义;老化后A、B、E组显示了较高的SBS。水储老化40 d后A组和B组的SBS值较水储24 h时有显著性增加,剩余3组老化前后差异均无统计学意义。结论 热酸溶液蚀刻相对于喷砂的粗化方法能够显著提高氧化锆与树脂的初期粘接强度和粘接耐久性。     

Comparative study of chemical and mechanical retentive systems for bonding of indirect composite resin to commercially pure titanium

This study evaluated the effect of chemical and mechanical surface treatments for cast metal alloys on the bond strength of an indirect composite resin (Artglass) to commercially pure titanium (cpTi). Thirty cylindrical metal rods (3 mm diameter x 60 mm long) were cast in grade-1 cpTi and randomly assigned to 6 groups (n=5) according to the received surface treatment: sandblasting; chemical treatment; mechanical treatment - 0.4 mm beads; mechanical treatment - 0.6 mm beads; chemical/mechanical treatment - 0.4 mm; and chemical/mechanical treatment - 0.6 mm beads. Artglass rings (6.0 mm diameter x 2.0 mm thick) were light cured around the cpTi rods, according manufacturer's specifications. The specimens were invested in hard gypsum and their bond strength (in MPa) to the rods was measured at fracture with a universal testing machine at a crosshead speed of 2.0 mm/min and 500 kgf load cell. Data were analyzed statistically by one-way ANOVA and Tukey test (a=5%). The surface treatments differed significantly from each other (p<0.05) regarding the recorded bond strengths. Chemical retention and sandblasting showed statistically similar results to each other (p=0.139) and both had significantly lower bond strengths (p<0.05) than the other treatments. In conclusion, mechanical retention, either associated or not to chemical treatment, provided higher bond strength of the indirect composite resin to cpTi.     

聚合后热压处理对不同表面处理的铸钛与聚合瓷结合强度的影响

目的 研究聚合后热压处理对不同表面处理的铸钛与聚合瓷结合强度的影响。方法 将30个金属试件随机分为5组：光滑组（A组）、喷砂组（B组）、酸蚀喷砂组（C组）、喷砂热压组（D组）、酸蚀喷砂热压组（E组）,根据分组对试件进行相应处理并涂布聚合瓷,测试其剪切结合强度及表面显微硬度,并对钛与聚合瓷断裂面的形貌进行扫描电镜观察。结果 A、B、C、D、E组的剪切结合强度分别为（5.92±0.54）、（10.25±0.55）、（14.97±0.88）、（14.41±0.63）、（19.95±0.52） MPa,除C组与D组间无统计学差异外,其余两组之间均有统计学差异（P<0.01）。B、C、D和E组的钛表面可见部分聚合瓷残留于金属表面。D、E组的显微硬度值高于B、C组（P<0.05）。结论 聚合后热压处理可以显著提高钛与Ceramage聚合瓷的结合强度及聚合瓷的表面显微硬度。     

纯钛种植体表面多孔结构的制备与分析

目的：利用喷砂、双重酸蚀和H2O2法构建粗化、改性种植体表面并对其形貌进行分析。方法：商业纯钛片经磨平、喷砂、清洗后分为6组,分别采用不同方法进行处理,从而得到不同的表面形貌。用扫描电镜（FSEM）观察表面形貌,能谱分析表面元素组成,X射线衍射（XRD）分析表面成分。结果：钛片表面经喷砂、超声清洗后．表面嵌有大量的喷砂颗粒,经低浓度HF／HNO3酸蚀后,仍有部分残留;同时,钛片表面形成大量纳米级孔洞。经高浓度HF／HNO3酸蚀后完全去除喷砂颗粒,钛片表面形成大量微米级孔洞。钛片再经HCl和H2SO4混合液酸蚀后,可以完全去除喷砂颗粒,同时得到多级孔洞结构。H2O2法处理,可使粗化表面得到锐钛矿晶相结构的TiO2层。结论：通过改变HF／HNO3浓度,可以得到不同孔径的孔洞;双重酸蚀处理,可以完全去除喷砂颗粒,并得到多级孔洞结构。H2O2法可将粗化表面的非晶态TiO2结晶转变为锐钛矿晶相结构。     

HF酸蚀对氧化锆陶瓷与树脂短期粘接性能的影响

目的评价常温下使用HF对Y-TZP陶瓷进行蚀刻提高其与树脂短期粘接强度的效果。方法制作Y-TZP瓷片48枚,分别进行氧化铝喷砂、室温下以40%HF酸蚀90 min和室温下以40%HF酸在超声环境下振荡15 min的方式进行表面粗化,随后在处理表面分别使用2种通用型粘接剂,制作树脂粘接试件,测试24 h水储后的剪切粘接强度。原子力显微镜测试3种粗化方式获得的表面粗糙度,并以扫描电镜观察表明微观形态。结果 2种酸蚀方法获得的表面粗糙度和粘接强度较喷砂处理显著提高。结论室温下以40%HF酸蚀可以取代氧化铝喷砂作为粗化Y-TZP陶瓷的方法。     

The effect of different etching times of acidulated phosphate fluoride gel on the shear bond strength of high-leucite ceramics bonded to composite resin

STATEMENT OF PROBLEM: A 10-minute treatment with acidulated phosphate fluoride (APF) gel has been used as an alternative in ceramic surface etching before repairing with composite resin. However, the optimal etching time for APF gel is still unknown. PURPOSE: The purpose of this study was to determine the in vitro shear bond strengths of composite resin on high-leucite ceramics after APF gel treatment over different time periods. MATERIAL AND METHODS: One hundred and twenty high-leucite ceramic (Empress 1) specimens (12 mm in diameter and 1.5 mm thick) were prepared and divided into 12 groups (n=10). Ten experimental groups were surface treated with 1.23% APF gel, each group receiving 1 to 10 minutes of etching time in 1 minute increments. One group was treated with 9.6% hydrofluoric acid for 4 minutes and the final group received no treatment and served as a control. The surface condition of the treated specimens was analyzed under a scanning electron microscope (SEM). All specimens received a silane application and were bonded to a composite resin Filtek (Z250) cylinder with an adhesive system (Scotchbond Multi-Purpose Plus adhesive) and then stored in 100% humidity at 37 degrees C for 24 hours before shear bond strength testing in a universal testing machine. Mean bond strengths (MPa) were analyzed with 1-way ANOVA and the Tukey HSD test (alpha=.05). RESULTS: Hydrofluoric acid etching produced the highest mean shear bond strength (SD) between composite resin and the ceramic (17.64 (1.48) MPa). Overall, APF gel etching produced lower bond strengths. No significant difference in mean bond strength (SD) was observed between etching with hydrofluoric acid and etching with APF gel for 7 to 10 minutes (15.21 (1.93) to 17.33 (1.43)). The lowest mean shear bond strengths (SD) were recorded in the untreated group (7.61 (1.03) MPa) (P<.05). CONCLUSIONS: Within the limitations of this study, shear bond strength values between composite resin and high-leucite ceramics after etching with 1.23% APF gel for 7 to 10 minutes were not significantly different than that after etching with 9.6% hydrofluoric acid for 4 minutes.     

酸蚀处理对纯钛-Solidex黏结强度的影响

目的：研究用酸蚀法提高钛与瓷聚合体剪切黏结强度的可行性。方法：采用不同浓度的酸蚀剂对钛铸件表面进行酸蚀，并与Solidex瓷聚合体进行黏结，以单纯喷砂组为对照，比较剪切黏结强度的差异。将酸蚀后及剪切试验后的金属表面进行扫描电镜观察。结果：用酸蚀法可以显著提高钛与复合树脂的黏结强度，HF浓度为4％时黏结强度最高。结论：纯钛铸件用酸蚀法处理后可以获得较高的黏结强度，HF酸浓度以4％为宜。     

The influence of internal surface treatments on tensile bond strength for two ceramic systems

STATEMENT OF THE PROBLEM: The ceramic composition and surface microstructure of all-ceramic restorations are important components of an effective bonding substrate. Hydrofluoric acid and sandblasting are well-known procedures for surface treatment; however, surface treatment for high alumina-containing and lithium disilicate ceramics have not been fully investigated. PURPOSE: This in vitro study evaluated the tensile bond strength of resin cement to two types of ceramic systems with different surface treatments. METHODS AND MATERIALS: Thirty specimens of each ceramic system were made according to the manufacturer's instructions and embedded in polyester resin. Specimens of In-Ceram Alumina [I] and IPS Empress 2 [E] were distributed to three groups with differing surface treatments (n = 10): sandblasting with 50 microm aluminum oxide (APA); sandblasting with 110 microm aluminum oxide modified with silica particles (ROCATEC System-RS); a combination of sandblasting with APA and 10% hydrofluoric acid etching (HA) for two minutes on In-Ceram and for 20 seconds for IPS Empress 2. After the respective surface treatments, all the specimens were silanated, and Rely-X resin cement was injected onto the ceramic surface and light polymerized. The specimens were stored in distilled water at 37 degrees C for 24 hours and thermally cycled 1,100 times (5 degrees C/55 degrees C). The tensile bond strength test was performed in a universal testing machine at a 0.5 mm/minute crosshead speed. RESULTS: The mean bond strength values (MPa) for IPS Empress 2 were 12.01 +/- 5.93 (EAPA), 10.34 +/- 1.77 (ERS) and 14.49 +/- 3.04 (EHA). The mean bond strength values for In-Ceram Alumina were 9.87 +/- 2.40 (IAPA) and 20.40 +/- 6.27 (IRS). All In-Ceram specimens treated with 10% hydrofluoric acid failed during thermal cycling. CONCLUSION: The Rocatec system was the most effective surface treatment for In-Ceram Alumina ceramics; whereas, the combination of aluminum oxide sandblasting and hydrofluoric acid etching for 20 seconds worked more effectively for Empress 2 ceramics.     

Effects of thermocycling on the bond strength of a resin-modified glass ionomer cement: an in vitro comparative study

This study investigated the effects of thermally induced stresses (thermocycling) on the shear bond strength of resin-modified, chemically cured, glass ionomer cement for use as an orthodontic bonding agent. A conventional no-mix composite resin was also used as a control. Mesh-based metal orthodontic brackets were bonded to extracted human premolars using either the resin-modified glass ionomer cement or the no-mix composite resin. Specimens were stored either in water at 37 degrees C for 24 hours for baseline data or thermocycled between 5 degrees C and 55 degrees C for 200 and 20,000 cycles before testing the in vitro shear bond strengths. Thermocycling reduced shear bond strengths for all specimens. The resin-modified glass ionomer cement showed a 11.1% decrease after 200 thermocycles and 26.5% decrease after 20,000 thermocycles, whereas the no-mix adhesive resin showed only 5.7% and 17.9% reductions, respectively. Analysis of variance showed statistically significant differences between the mean shear bond strengths of the groups at the P < .001 level of significance. For the resin-modified glass ionomer cement groups, the predominant bond failure site was at the bracket-adhesive interface. The results of this study suggest strongly that resin-modified glass ionomer cements offer a viable alternative to conventional no-mix composite resins, with satisfactory in vitro shear bond strength even after 20,000 thermocycles.     

Influence of surface conditions and silane agent on the bond of resin to IPS Empress 2 ceramic

PURPOSE: The aim of this study was to evaluate the effect of different ceramic surface treatments on the tensile bond strength between IPS Empress 2 ceramic framework and Rely X adhesive resin cement, with or without the application of a silane coupling agent. MATERIALS AND METHODS: One hundred twenty disks were made, embedded in resin, and randomly divided into six groups: group 1 = sandblasting (100 microm), no silanation; group 2 = sandblasting (100 microm), silane treatment; group 3 = sandblasting (50 microm), no silanation; group 4 = sandblasting (50 microm), silane treatment; group 5 = hydrofluoric acid etching, no silanation; and group 6 = hydrofluoric acid etching, silane treatment. The disks were bonded into pairs with adhesive resin cement. All samples were stored in distilled water at 37 degrees C for 24 hours and then thermocycled. The samples were submitted to tensile testing. RESULTS: The use of silane improved the bond strength in relation to the groups in which silane was not applied (P < .05). The most effective surface treatment was etching with 10% hydrofluoric acid, both with (25.6 MPa) and without silane application (16.4 MPa); these values showed a statistically significant difference compared to sandblasting with 50- and 100-microm Al2O3. Sandblasting with 50-microm Al2O3, with (11.8 MPa) and without silane (5.4 MPa), demonstrated significantly higher tensile bond strength than sandblasting with 100-microm Al2O3, with (8.3 MPa) and without silane (3.8 MPa). CONCLUSION: Combined application of 10% hydrofluoric acid and silane enhanced the bond strength between the IPS Empress 2 ceramic framework and resin agent.     

Investigation into the Effect of Use of Metal Primer on Adhesion of Heat Cure Acrylic Resin to Cast Titanium: An In Vitro Study

The availability of adhesive primers capable of bonding chemically to base metal alloys without well defined passive oxide surface film has been improved significantly over the last decade. Therefore, the purpose of the study was to compare and evaluate the effect of metal primer on adhesion of heat cure acrylic resin to cast titanium. Shear bond strength test was conducted on 80 commercially pure titanium cast metal heat-cure acrylic resin discs treated with different surface treatments. The first group received no surface treatment (group I); the second group was subjected to sandblasting (group II); the third group was treated with bonding agent (alloy primer) (group III) and the fourth was treated with sandblasting and alloy primer (group IV). After the samples were surface treated, acrylic resin was mixed, packed and processed over the test area of cast titanium. Ten specimens of each group were immersed in distilled water for 24 h followed by thermocycling for 20,000 cycles. Shear bond-strength between the heat cure acrylic resin and titanium was evaluated using Instron universal testing machine. Debonded specimens of all the groups were subjected to SEM analysis. The bond failure (MPa) was analyzed by ANOVA and Duncan’s multiple comparison tests. Surface treatment with sandblasting, followed by the application of alloy primer showed maximum shear bond strength before and after thermocycling (24.50 ± 0.59 and 17.39 ± 1.56 MPa respectively).The bond strength values are found to be in decreasing magnitudes as group IV > group III > group II > group I. The following pretreatment to improve the shear bond strength of heat cure acrylic resin to titanium is recommended in order to attain the maximum bond strength in cast titanium frameworks for various prostheses: sandblasting, cleaning in an ultrasonic bath for 10 min and air drying followed by application of a bonding agent uniformly on the sandblasted cast titanium surface before packing with heat cure acrylic resin.     

Influence of thermal cycling on dentin bond strengths of single-step self-etch adhesive systems

This study investigated the influence of thermal cycling on the dentin bond strengths of single-step self-etch adhesive systems. The Absolute, Clearfil Tri-S Bond, G-Bond and One-Up Bond F Plus systems were used. Bovine mandibular incisors were mounted in self-curing resin, and the facial surfaces were wet ground with #600 SiC paper. Adhesives were applied to the prepared dentin surfaces, and they were light irradiated according to each manufacturer's instructions. Resin composites were condensed into a mold (4 mm in diameter and 2 mm in height) and light irradiated for 30 seconds. Bonded specimens were divided into three groups and subjected to different storage conditions as follows: 37 degrees C water for 24 hours; 37 degrees C water for 24 hours followed by 10,000 thermal cycles between 5 degrees C and 60 degrees C or 37 degrees C water for 24 hours followed by 20,000 thermal cycles between 5 degrees C and 60 degrees C. Ten samples per group were tested in a shear mode at a crosshead speed of 1.0 mm/minute. Analysis of variance and Tukey's HSD test at the 0.05 significance level were used to compare the three storage conditions for each adhesive system. After 24 hours storage in water, the mean dentin bond strengths ranged from 11.4 MPa to 17.1 MPa. The Clearfil Tri-S Bond system showed the highest bond strength. After 10,000 thermal cycles, the mean bond strengths remained unchanged except for those of the Clearfil Tri-S Bond system, which significantly increased. Significant decreases in bond strength were observed for the Absolute and One-Up Bond F Plus systems after 20,000 thermal cycles. Failure mode was commonly due to adhesive breakdown associated with partial cohesive failure of the adhesive resin. From the results of this study, in terms of simplifying the clinical procedure, the benefit of using single-step self-etch systems might be acceptable.     

Adhesive strength of paint-on resins to crown and bridge composites

This paper examined the adhesive strength of paint-on resin to crown and bridge composites after soaking in water and thermal-cycling. Three shades of paint-on resin were coated on three kinds of crown and bridge composite under four surface treatment conditions (a combination of sandblaster and pretreatment liquid). These specimens were soaked in water at 37 degrees C for 1 day, 1 month, and 1 year, and at 4 degrees C and 60 degrees C alternatively for 1-minute periods for 10,000 cycles by thermal-cycling machine. The adhesive strengths were obtained by shear test. There were no significant differences among the adhesive strengths of three shades of paint-on resin to three composites after storage (p > 0.05). The adhesive strengths to composites with sandblasting showed higher values than those without it (p < 0.01).     

Effects of phosphoric acid concentration and etch duration on the shear bond strength of an orthodontic bonding resin to enamel : An in vitro study

The purpose of this in vitro study was to determine the effects of phosphoric acid (H3PO4) concentration and duration of etching on the shear bond strength of an orthodontic bonding resin to enamel. Nine bonding procedures, each involving 18 extracted human maxillary permanent canines, were used. Ground enamel surfaces were etched with a 37% H3PO4 solution, a 15% H3PO4 gel, or a 5% H3PO4 solution for 60, 30, and 15 seconds, respectively. Cylinders of an orthodontic bonding resin, Concise, were prepared in a special device. The test specimens were disassembled 15 minutes after preparation and stored in distilled water at 37 degrees C for 24 hours. A shear load was applied to the bonded cylinders at a crosshead speed of 0.02 in.min-1 in an Instron testing machine, and the shear bond strengths were calculated and expressed in MN.m-2. A two-factor analysis of the data showed that the H3PO4 concentration had no significant effect on the shear bond strength, but the duration of etching affected shear bond strength significantly. The enamel aspects of the fractured test specimens were examined microscopically and the percent failure within the bonding resin at the bonding sites estimated. The correlation between shear bond strength and percentage failure within the bonding resin was not significant. The effects of the nine etching procedures on ground and unground enamel surfaces were studied by scanning electron microscopy. The etching procedures produced well-defined etching patterns on both ground and unground enamel surfaces.     

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.