Post-thermocycling shear bond strength of a gingiva-colored indirect composite layering material to three implant framework materials

Abstract

Objective. To evaluate shear bond strength of a gingiva-colored indirect composite to three implant framework materials, before and after thermocycling, and verify the effect of surface pre-treatment for each framework. Materials and methods. Commercially pure titanium (CP-Ti), American Dental Association (ADA) type 4 casting gold alloy (Type IV) and zirconia ceramics (Zirconia) were assessed. For each substrate, 96 disks were divided into six groups and primed with one of the following primers: Alloy Primer (ALP), Clearfil Photo Bond (CPB), Clearfil Photo Bond with Clearfil Porcelain Bond Activator (CPB+Activator), Estenia Opaque Primer (EOP), Metal Link (MLP) and V-Primer (VPR). The specimens were then bonded to a gingiva-colored indirect composite (Ceramage Concentrate GUM-D). Shear bond strengths were measured at 0 and 20 000 thermocycles and data were analyzed with the Steel-Dwass test and Mann-Whitney U-test. Results. Shear bond strengths were significantly lower after thermocycling, with the exception of Type IV specimens primed with CPB (p = 0.092) or MLP (p = 0.112). For CP-Ti and Zirconia specimens, priming with CPB or CPB+Activator produced significantly higher bond strengths at 0 and 20 000 thermocycles, as compared with the other groups. For Type IV specimens, priming with ALP or MLP produced higher bond strengths at 0 and 20 000 thermocycles. Conclusions. Shear bond strength of a gingiva-colored indirect composite to CP-Ti, gold alloy and zirconia ceramics was generally lower after thermocycling. Application of a hydrophobic phosphate monomer and polymerization initiator was effective in maintaining bond strength of CP-Ti and zirconia ceramics. Combined use of a thione monomer and phosphoric monomer enhanced the durable bond strength of gold alloy.     

Shear bond strength between an indirect composite layering material and feldspathic porcelain-coated zirconia ceramics

Objectives

This study aims to evaluate the effect of both feldspathic porcelain coating of zirconia frameworks and priming agents on shear bond strength between an indirect composite material and zirconia frameworks.

Materials and methods

A total of 462 airborne-particle-abraded zirconia disks were divided into three groups: untreated disks (ZR–AB), airborne-particle-abraded zirconia disks coated with feldspathic porcelain, (ZR–PO–AB), and hydrofluoric acid-etched zirconia disks coated with feldspathic porcelain (ZR–PO–HF). Indirect composite (Estenia C&;B) was bonded to zirconia specimens with no (CON) or one of four priming agents—Clearfil Photo Bond (CPB), Clearfil Photo Bond with Clearfil Porcelain Bond Activator (CPB?+?activator), Estenia Opaque primer, or Porcelain Liner M Liquid B (PLB)—with or without an opaque material (Estenia C&;B Opaque). All specimens were tested for shear bond strength before and after 20,000 thermocycles. The Steel–Dwass test and Mann–Whitney U test were used to compare shear bond strength.

Results

In ZR–AB specimens, the initial bond strength of the CPB and CPB?+?Activator groups was significantly higher as compared with the other three groups (P?P?Conclusion Feldspathic porcelain coating of a Katana zirconia framework enhanced the bond strength of Estenia C&;B indirect composite to zirconia independent of surface treatment. The use of a silane coupling agent and opaque material yields durable bond strength between the indirect composite and feldspathic-porcelain-coated zirconia.

Clinical relevance

The results of the present study suggest that feldspathic porcelain coating of zirconia frameworks is an effective method to obtain clinically acceptable bond strengths of a layering indirect composite material to a zirconia framework.     

Twenty-four hour bond strength between layers of a highly loaded indirect composite

This study evaluated the repair bond strength of Estenia composite. Disk specimens of a dentin material were conditioned with varying combinations of silane primer (Add-on Primer, Clearfil Porcelain Bond Activator, Clearfil Porcelain Bond Activator + Clearfil Mega Bond-Primer, Porcelain Liner M, and unprimed) and bonding agent (Clearfil Mega Bond-Bond, Modeling Liquid, Stain Diluent, and no bonding agent). After photopolymerization of the enamel material placed on each surface, the specimens were either wet- or dry-stored at 37 degrees C for 24 hours. Average shear bond strength varied from 24.9 to 61.4 MPa, where the Clearfil Porcelain Bond Activator + Clearfil Mega Bond-Bond group and the Add-on Primer + Modeling Liquid group showed the greatest bond strength for dry and wet conditions respectively. To achieve reliable bond strength between layers of Estenia composite, it is highly recommended to use specific combinations of silane primer and bonding agent.     

Bonding between resin luting cement and glass infiltrated alumina-reinforced ceramics with silane coupling agent

The purpose of this study was to evaluate the shear bond strengths of three dual-cured resin luting cements (Linkmax HV, Panavia Fluoro Cement, and RelyX ARC) to glass-infiltrated alumina-reinforced ceramic material and the effect of four silane coupling agents (Clearfil Porcelain Bond, GC Ceramic Primer, Porcelain LinerM, and Tokuso Ceramic Primer) on the bond strength. The two type-shaped of In-Ceram alumina ceramic glass-infiltrated specimens were untreated or treated with one of the four ceramic primers and then cemented together with one of the three dual-cured resin luting cements. Half of the specimens were stored in water at 37 degrees C for 24 h and the other half thermocycled 20,000 times before shear bond strength testing. Surface treatment by all silane coupling agents improved the shear bond strength compared with non-treatment. The specimens treated with Clearfil Porcelain Bond showed significantly greater shear bond strength than any of the other three silane coupling agents regardless of resin luting cements and thermocycling except for the use of Panavia Fluoro Cement at 20,000 thermocycles. When the alumina-reinforced ceramic material was treated with any silane coupling agent except GC Ceramic Primer and cemented with Linkmax HV, no significant differences in bond strength were noted between after water storage and after 20,000 thermocycles. After 20,000 thermocycles, all specimens except for the combined use of Clearfil Porcelain Bond or GC Ceramic Primer and Linkmax HV and GC Ceramic Primer and Panavia Fluoro Cement showed adhesive failures at the ceramic-resin luting cement interface.     

Bond strength between machinable glass-ceramic and dual-cured resin luting cements using silane coupling agents

PURPOSE: To evaluate the shear bond strength of two dual-cured resin luting cements (Linkmax HV and Panavia Fluoro Cement) to machinable glass-ceramics (Decsy Machinable Ceramic) and the effect of three silane coupling agents (Clearfil Porcelain Activator, Ceramic Primer, and Porcelain Liner M) on the bond strength. METHODS: Disk-shaped specimens fabricated from machinable glass-ceramic blocks using a low-speed cutting saw were either treated or not treated with one of three silane coupling agents and then bonded together with one of two dual-cured resin luting cements. Specimens were stored in water at 37degrees C for 24 hours and/or thermal cycled 50,000 times before shear bond strength testing. RESULTS: Regardless of the resin luting cement and thermal cycling, specimens treated with the Clearfil Porcelain Activator showed the highest shear bond strength among all the treatments. Surface treatment of the Clearfil Porcelain Activator showed significantly greater shear bond strength after 50,000 thermocycles compared with other treatments. However, significant differences in bond strength were observed between 0 and 50,000 thermocycles for all treatments.     

Comparative evaluation of metal priming agents applied for bonding of magnetic stainless steel with acrylic repair resin

The purpose of this study was to evaluate the effect of acidic priming agents on adhesive bonding to SUS XM27 stainless steel. Disk steel specimens were primed with one of the following materials; Acryl Bond, All-Bond 2 Primer B, Alloy Primer, Estenia Opaque Primer, Eye Sight Opaque Primer, Metal Primer II, M.L. Primer, MR Bond, and Super-Bond Liquid. The specimens were then bonded with an acrylic resin designed for denture repair (Repairsin), and bond strengths were determined. Unprimed specimen was used as control. The average bond strengths before thermocycling varied from 21.3 to 51.0 MPa, whereas post-thermocycling bond strengths ranged from 3.0 to 37.0 MPa. Of the nine priming agents, the Acryl Bond, All-Bond 2 Primer B, Estenia Opaque Primer, and MR Bond materials showed significantly higher bond strength after application of thermocycling. Within the limitation of the current experimental settings, it can be concluded that the use of the four acidic priming agents is recommended for bonding SUS XM27 stainless steel with Repairsin self-polymerizing repair material.     

Bond strength of composite to porcelain treated with new porcelain repair agents.

In vitro tensile bond strengths of composite to porcelain were evaluated using three pretreatments (HF etching, sandblasting, diamond abrasion) of the porcelain, four bonding agents (Clearfil Porcelain Bond, Porcelain Liner M, Porcelain Liner M with Super-Bond C&B, and Scotchprime) and two storage conditions (24 h and thermocycling). The overall coefficient of variation was 27%. Significant differences among bond strengths were observed, with storage condition being the most important factor, followed by bonding agent and then pretreatment. Thermocycling decreased the bond strength of all samples, but samples treated with Scotchprime were affected least. For 24 h storage, Clearfil Porcelain Bond and Scotchprime had bond strengths above 23 MN/m2 to sandblasted porcelain.     

Effect of acidic primers on adhesive bonding of tri-n-butylborane initiated adhesive resin to alumina

The present study was conducted to evaluate the effect of acidic primers on adhesive bonding to sintered alumina. Alumina disk specimens were primed with one of the following acidic materials: Acryl Bond, All Bond II Primer B, Alloy Primer, Estenia Opaque Primer, Eye Sight Opaque Primer, M.L. Primer, MR. Bond, and Super-Bond Liquid. The disks were bonded with an adhesive resin (Super-Bond) initiated with a tri-n-butylborane (TBB) derivative, and bond strengths were determined. Average bond strength before thermocycling varied from 42.9 to 44.3 MPa, whereas post-thermocycling bond strength ranged from 22.0 to 42.8 MPa. Of the nine groups assessed, reduction of bond strength after thermocycling was not significant in three: Alloy Primer, Estenia Opaque Primer, and Eye Sight Opaque Primer. It can be concluded that phosphate-based primers are recommended for bonding sintered alumina with Super-Bond resin.     

Effect of single-liquid priming agents on adhesive bonding to aluminum oxide of a methacrylic resin

The purpose of this study was to evaluate the effects of acidic primers on adhesive bonding to sintered aluminum oxide (alumina). Alumina disks were primed with one of the following materials: Acryl Bond, All Bond 2 Primer B, Alloy Primer, Estenia Opaque Primer, Eye Sight Opaque Primer, M.L. Primer, MR. Bond, and Super-Bond Liquid. Specimens were then bonded with an acrylic resin initiated with partially oxidized tri-n-butylborane (TBBO), and bond strengths were determined. Unprimed specimen was employed as the control. Average bond strength before thermocycling ranged from 20.5 to 41.9 MPa, whereas post-thermocycling bond strength ranged from 0.0 to 40.0 MPa. Of the eight primers, Estenia Opaque Primer and Alloy Primer showed better adhesive performance than the other materials. It could thus be concluded that either Estenia Opaque Primer or Alloy Primer--which contained an adhesive monomer, 10-methacryloyloxydecyl dihydrogen phosphate (MDP)--was recommended for bonding alumina with TBBO-initiated resin.     

A method for communication analysis in prosthodontics

Abstract

Objective. To evaluate the effect of different primers on the bond strength of adhesive resin cement to zirconia ceramic surface in vitro. Material and methods. Thirty zirconia disk-shaped ceramic specimens (10×2 mm²) were divided into three equal groups for the application of different primers: Monobons-S, Clearfil Ceramic Primer and Signum Zirconia Bond. A further 10 specimens served as a control group. Forty composite resin blocks (6×2 mm²) were cemented (Panavia F 2.0) to zirconia ceramic specimens. Shear bond strengths were measured. Treated zirconia ceramic surfaces were examined using scanning electron microscopy. Results. One-way ANOVA showed that the application of different primers affected the shear bond strength of adhesive resin cement to zirconia ceramic. The highest test values were obtained with application of Signum Zirconia Bond, and the lowest values were obtained in the control group. Conclusion. Signum Zirconia Bond is effective for increasing the bond strength of adhesive resin cement to zirconia ceramic.     

Effect of priming agents on shear bond strengths of resin-based luting agents to a translucent zirconia material

Purpose

The purpose of the present study was to evaluate the effect of priming agents and artificial aging with thermocycling on shear bond strengths of two resin-based luting agents to a translucent zirconia material.

Three different adhesive systems; three different bond strength test methods

Abstract

Objective. The aim of this study was to evaluate the efficacy of the microtensile, microshear and shear bond strength test methods to assess the bond strength of two self-etch adhesives and one etch&rinse adhesive on dentin. Materials and methods: Seventy-five extracted human molars were ground to expose their flat dentin surfaces and randomly assigned to one of three groups according to the type of test method (15 for microtensile, 15 for microshear, 45 for shear). Each of these groups was then assigned to three sub-groups according to the bonding systems (Clearfil SE Bond, Kuraray; G Bond, GC; Prime&Bond NT, Dentsply) used. Then, 15 specimens were prepared for each sub-group according to the test method employed (n = 15). After being stored in distilled water at 37°C for 24 h, the specimens were placed in a universal testing machine for three test methods and stressed at a crosshead speed of 0.5 mm/min. Mean bond strengths were analyzed using Kruskall-Wallis and Mann-Whitney U-tests at a significance level of p < 0.05. Results. The microtensile test had the highest bond strength (p = 0.046). Clearfil SE Bond and Prime&Bond NT produced significantly higher values than the G Bond in the microtensile bond test (p < 0.05), whereas no significant differences were found among the adhesives in the microshear bond test (p > 0.05). For the shear test, Clearfil SE Bond showed higher bond strength than Prime&Bond NT and G Bond (p < 0.05). Conclusion: Bond strength to dentin depends on the material and the test method used.     

Bonding effectiveness to different chemically pre-treated dental zirconia

Objective

The objective of this study was to evaluate the effect of different chemical pre-treatments on the bond durability to dental zirconia.

Methods

Fully sintered IPS e.max ZirCAD (Ivoclar Vivadent) blocks were subjected to tribochemical silica sandblasting (CoJet, 3M ESPE). The zirconia samples were additionally pre-treated using one of four zirconia primers/adhesives (Clearfil Ceramic Primer, Kuraray Noritake; Monobond Plus, Ivoclar Vivadent; Scotchbond Universal, 3M ESPE; Z-PRIME Plus, Bisco). Finally, two identically pre-treated zirconia blocks were bonded together using composite cement (RelyX Ultimate, 3M ESPE). The specimens were trimmed at the interface to a cylindrical hourglass and stored in distilled water (7 days, 37 °C), after which they were randomly tested as is or subjected to mechanical ageing involving cyclic tensile stress (10 N, 10 Hz, 10,000 cycles). Subsequently, the micro-tensile bond strength was determined, and SEM fractographic analysis performed.

Results

Weibull analysis revealed the highest Weibull scale and shape parameters for the ‘Clearfil Ceramic Primer/mechanical ageing’ combination. Chemical pre-treatment of CoJet (3M ESPE) sandblasted zirconia using Clearfil Ceramic Primer (Kuraray Noritake) and Monobond Plus (Ivoclar Vivadent) revealed a significantly higher bond strength than when Scotchbond Universal (3M ESPE) and Z-PRIME Plus (Bisco) were used. After ageing, Clearfil Ceramic Primer (Kuraray Noritake) revealed the most stable bond durability.

Conclusion

Combined mechanical/chemical pre-treatment, the latter with either Clearfil Ceramic Primer (Kuraray Noritake) or Monobond Plus (Ivoclar Vivadent), resulted in the most durable bond to zirconia.

Clinical relevance

As a standard procedure to durably bond zirconia to tooth tissue, the application of a combined 10-methacryloyloxydecyl dihydrogen phosphate/silane ceramic primer to zirconia is clinically highly recommended.     

冷热循环对牙本质粘结系统与牙釉质粘结强度的影响

目的评价冷热循环对牙本质粘结系统与牙釉质粘结强度的影响。方法选取人离体下颌第三磨牙20颗,使用600目砂纸打磨颊面釉质,分别使用全酸蚀粘结系统AdperTM Single Bond2（SB2）、两步法自酸蚀粘结系统Clearfil SE Bond（CSE）、一步法自酸蚀粘结系统ClearfilS3Bond（CS3）和iBondGI（IB）进行粘结。实验组冷热循环3000次后测定微拉伸粘结强度,对照组不做冷热循环处理直接测试。结果实验组冷热循环后,各粘结系统粘结强度均有所下降,但与对照组相比,仅IB有显著性差异（P〈0.05）。对照组中SB2和CSE的粘结强度相近,明显高于CS3和IB。结论不同牙本质粘结系统与牙釉质的粘结强度存在差异。冷热循环3000次可导致一步法自酸蚀粘结系统IB与牙釉质粘结强度显著性下降。     

In vitro comparative bond strength of contemporary self-adhesive resin cements to zirconium oxide ceramic with and without air-particle abrasion

This study compared shear bond strengths of six self-adhesive resin cements to zirconium oxide ceramic with and without air-particle abrasion. One hundred twenty zirconia samples were air-abraded (group SB; n = 60) or left untreated (group NO). Composite cylinders were bonded to the zirconia samples with either BisCem (BC), Maxcem (MC), G-Cem (GC), RelyX Unicem Clicker (RUC), RelyX Unicem Applicator (RUA), or Clearfil SA Cement (CSA). Shear bond strength was tested after thermocycling, and data were analyzed with analysis of variance and Holm–Sidak pairwise comparisons. Without abrasion, RUA (8.0 MPa), GC (7.9 MPa), and CSA (7.6 MPa) revealed significantly higher bond strengths than the other cements. Air-particle abrasion increased bond strengths for all test cements (p < 0.001). GC (22.4 MPa) and CSA (18.4 MPa) revealed the highest bond strengths in group SB. Bond strengths of self-adhesive resin cements to zirconia were increased by air-particle abrasion. Cements containing adhesive monomers (MDP/4-META) were superior to other compositions.     

Effect of silanization on bond strengths of fiber posts to various resin cements.

OBJECTIVES: To investigate the effects of pretreatment (silanization) on bond strengths between 3 different types of fiber posts and 4 resin cements, respectively. METHOD AND MATERIALS: Prefabricated quartz-fiber (Unicore Post, Ultradent) and prefabricated glass-fiber (FRC Postec, Ivoclar Vivadent) posts with a cross-linked polymer matrix and individually formed glass-fiber posts with an interpenetrating polymer network (IPN Post, Stick Tech) (n = 160 each) were inserted into resin composite disks (2 mm thick) using the following resin cements and silane solutions: Panavia F/Porcelain Bond Activator (Kuraray), PermaFlo DC/Silane (Ultradent), Variolink II/Monobond S (Ivoclar Vivadent) and RelyX Unicem/Espe Sil (3M Espe). Nonsilanated posts served as controls. The push-out bond strengths were determined before (n = 10) and after (n = 10) thermocycling (2,000 cycles, 5 degrees C to 55 degrees C, dwelling time 30 seconds). RESULTS: Bond strengths (mean [SD]) were significantly affected by the resin cement (P < .001), the pretreatment (P < .001), and the type of post (P < .001), but not by thermocycling (P = .955, 4-way ANOVA). The IPN post demonstrated significantly higher bond strengths compared to the other posts (P < .05; Tukey B). Silanization significantly increased bond strengths (15.2 [5.2] MPa) compared to those of the control groups (13.9 [4.9] MPa). CONCLUSION: The type of fiber post revealed a significant influence on bond strengths, whereas the effects of silanization appeared to be clinically negligible.     

Adhesive performance of silver-palladium-copper-gold alloy and component metals bonded with organic sulfur-based priming agents and a tri-n-butylborane initiated luting material

Abstract

Objective. The purpose of the current study was to evaluate the effect of thione-based metal priming agents on the adhesive behavior of a Ag-Pd-Cu-Au alloy and component metals bonded with an acrylic resin. Materials and methods. Disk specimens (10 mm in diameter by 3 mm thick) were prepared from a silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy (Castwell M.C.12), high-purity silver, palladium, copper and gold. Four single-liquid priming agents containing organic sulfur compound (Alloy Primer, Metaltite, M.L. Primer and V-Primer) and three acidic priming agents (All Bond II Primer B, Estenia Opaque Primer and Super-Bond Liquid) were assessed. The metal specimens were flat-ground with abrasive papers, primed with one of the agents and bonded with a tri-n-butylborane initiated resin. The shear bond strengths were determined both before and after repeated thermocycling (5°C and 55°C, 1 min each, 20,000 cycles). The results were statistically analyzed with a non-parametric procedure (p = 0.05 level). Results. The post-thermocycling bond strengths in MPa (median; n = 11) associated with the Alloy Primer, Metaltite, M.L. Primer and V-Primer materials were, respectively, 20.8, 22.8, 17.8 and 18.4 for the Ag-Pd-Cu-Au alloy; 19.6, 21.9, 14.4 and 20.1 for silver; 5.4, 4.5, 12.8 and 5.3 for palladium; 17.1, 19.2, 0.7 and 6.6 for copper; and 18.5, 17.7, 22.8 and 15.4 for gold. Conclusions. It can be concluded that the use of the four priming agents, which are based on organic sulfur compounds, effectively enhanced bonding to the Ag-Pd-Cu-Au alloy and the component metals, although the bonding performance varied among the priming agents and metal elements. The priming agents appeared to have more of an effect on the alloy, silver and gold than on the palladium and copper.     

Effect of physicochemical aging conditions on the composite-composite repair bond strength

PURPOSE: This study evaluated the effect of different physicochemical aging methods and surface conditioning techniques on the repair bond strength of composite. It was hypothesized that the aging conditions would decrease the repair bond strength and surface conditioning methods would perform similarly for the repair of resin composites. MATERIALS AND METHODS: Disk-shaped resin composite specimens (Clearfil Photo Bright, Kuraray) were randomly assigned to one of the three aging conditions (N=120, n = 12/per group): (1) immersion in deionized water (37 degrees C, 1 week), (2) immersion in citric acid (pH: 3.0, 1 week), (3) boiling in water (8 h), (4) thermocycling (5000 times, 5 degrees C to 55 degreesC), (5) immersion in water (37 degrees C, 2 months). After aging procedures, the specimens were subjected to one of the following surface conditioning methods: (1) chairside silica coating (30-microm SiOx) (CoJet, 3M ESPE) + silane (ESPE-Sil) (SC method), (2) silane (Clearfil SE Bond Primer and Clearfil Porcelain Bond Activator) + bonding agent (Clearfil SE Bond) (SB method). The fresh and aged composite surfaces were also examined using SEM (n=6, 1/group). Resin composite (Quadrant Anterior Shine) was bonded to the conditioned substrates using polyethylene molds and then light polymerized. Shear force was applied to the adhesive interface in a universal testing machine (1 mm/min). The failure types were categorized as: (A) cohesive in the substrate, (B) adhesive at the interface, or C) cohesive in the adherend. Bond strength values were statistically analyzed using two-way ANOVA and Tukey's test (alpha < 0.05). RESULTS: A significant influence of the conditioning method (p < 0.0001) and aging method was observed (p < 0.01) (two-way ANOVA, Tukey-Kramer). The SC method showed significantly higher bond values (7.8 +/- 1.2 to 11.6 +/- 5 MPa) than those of SB method (4.6 +/- 2.3 to 7.6 +/- 3.9 MPa) in all groups (p < 0.0001). While the SC method showed 96% cohesive (A type), the SB method demonstrated 92% adhesive failures (B type). SEM images showed distinct pattern of microcracks in the boiled specimens and filler dissolution with disorganized matrix resin in the other aged specimens. Aging the composite substrates through water storage for 2 months produced significantly lower bond strengths than those of water or acid storage for 1 week (p = 0.011). CONCLUSION: Chairside silica coating and silanization provided the highest bond strength values with almost exclusively cohesive failures on aged composites. Aging methods showed significant differences on the composite-composite repair strength.     

Microtensile bond strength of one- and two-step self-etching adhesives on sclerotic dentin: the effects of thermocycling

This study evaluated the effects of thermocycling on the microtensile bond strength (microTBS) of one- and two-step self-etch adhesives (SEAs) to sclerotic dentin. Two adhesives, Clearfil S3 Bond (S3), a one-step self-etch adhesive (1-SEA), and Clearfil SE Bond (SE), a two-step self-etch adhesive (2-SEA), were applied on cervical lesions in human premolars with sclerotic or normal dentin. After adhesive application, the lesions were restored and built up using a resin composite (Clearfil AP-X). After 24 hours in water storage, the restored teeth were sectioned into 0.7 x 0.7 mm composite-dentin beams. The beams were then aged with 0, 5,000 or 10,000 thermocycles. The use of two adhesives, two substrate types and three thermocycling regimens yielded 12 experimental groups of 14-19 beams each. The beams were subsequently subjected to microTBS testing at a crosshead speed of 1 mm/minute and statistical analyses were computed with three-way ANOVA and Tukey's post hoc test at p < 0.05. Three-way ANOVA showed statistically significant effects on bonding effectiveness by lesion type, adhesive system, thermocycling or combinations of the adhesive system and thermocycling (p < 0.05). With sclerotic dentin, although S3 and SE provided comparable microTBS after 24 hours of water storage, S3 showed significantly lower microTBS than SE after thermocycling (p < 0.05). Regardless of lesion type, the microTBS for S3 decreased significantly after 5,000 or 10,000 thermocycles, while the microTBS for SE showed a significant decrease only after 10,000 thermocycles. Regardless of the extent of thermocycling, the microTBS values for either SE or S3 bonded to sclerotic dentin were significantly lower than to normal dentin (p < 0.05). The results suggested that thermocycling had a significant negative effect on the bond strength of the two SEAs tested. In contrast to 2-SEA, 1-SEA might not be a good choice for sclerotic dentin when seeking durability of the resin-dentin bond.     

Shear bond strength of different adhesives to Er:YAG laser-prepared dentin

PURPOSE: The aim of this study was to examine the influence of Er:YAG laser on the shear bond strength of three different adhesives to lased dentin. MATERIALS AND METHODS: Seventy specimens obtained from 35 extracted human molars were embedded in polyester resin and ground with silicon carbide papers. The samples were divided into seven groups. 1. Er:YAG laser (Key Laser 3, KaVo) + Clearfil Protect Bond (Kuraray); 2. Er:YAG laser + Clearfil tri-S Bond (Kuraray); 3. Er:YAG laser + 37% H3PO4 + Single Bond 2 (3M-ESPE); 4. Er:YAG laser + Single Bond 2; 5. conventional method + Clearfil Protect Bond; 6. conventional method + Clearfil tri-S Bond; 7. conventional method + 37% H3PO4 + Single Bond 2. The samples were subjected to shear bond testing 24 h after bonding. Statistical analyses were carried out by two-way ANOVA, t-test, one-way ANOVA, post-hoc Tukey's and Dunnett C test (p = 0.05). RESULTS: Only the Er:YAG laser + Clearfil tri-S Bond group demonstrated significantly higher bond strengths vs conventionally prepared specimens (p < 0.05). There were no significant differences between the shear bond strengths of Single Bond 2 adhesive applied to laser- vs bur-treated specimens (p > 0.05). In laser prepared samples, Clearfil Protect Bond showed the highest scores (p < 0.05), whereas in conventionally prepared groups, no statistical differences were observed between Clearfil Protect Bond and Clearfil tri-S Bond (p > 0.05). CONCLUSION: Er:YAG laser irradiation did not adversely affect the shear bond strength of Single Bond 2 and Clearfil Protect Bond to dentin, whereas it increased the shear bond strength values of Clearfil tri-S Bond.