Tensile bond strength of light-cured resin-reinforced glass ionomer cement with delayed light exposure

In the clinical situations, the time intervals between material mixing and light exposure during bracket bonding, using light-cured resin-reinforced glass ionomer cement (LCGIC), may vary for each individual bracket. This study determined the tensile bond strengths of LCGIC subjected to various time intervals, and evaluated the durability with thermocycling. Comparisons were made between LCGIC and light-cured composite resin (LCR). Two hundred and forty bovine teeth were chosen as specimens. Light exposure was performed 5, 10, 20, and 40 min after the commencement of powder/liquid mixing. The durability was evaluated by thermocycling for 2000 times at temperatures between 5°C and 55°C, with a 30-s dwell time. Tensile bond strengths of LCGIC and LCR after 5 min, representing the general condition in clinical use, equaled 5.7 ± 1.5 MPa and 5.1 ± 2.6 MPa, respectively. For the LCGIC groups, no significant differences were seen between bond strengths with and without thermocycling. Also, no significant differences were noted among any time intervals. For the LCR groups, there were also no significant differences with and without thermocycling. The tensile bond strength of LCR showed highly significant differences within groups across time. Compared with LCR, the failure sites for brackets bonded with LCGIC appeared to be predominantly at the bracket/adhesive interface. The standard deviations of LCR were high when compared with those of LCGIC. The bond strength of LCGIC with or without thermocycling surpassed the clinically required minimum. LCGIC may be an advantageous alternative to LCR for orthodontic bracket bonding. Received: October 3, 2000 / Accepted: June 19, 2001     

光固化树脂加强型玻璃离子水门汀即刻剪切强度的测定

目的研究光固化树脂加强型玻璃离子水门汀黏结正畸托槽的即刻剪切强度。方法收集离体前磨牙30颗,随机均分为3组。第1组(对照组):35%磷酸酸蚀30 s,冲洗、干燥,涂黏结剂,京津釉质黏结剂黏结托槽。第2、3组:35%磷酸酸蚀30 s,冲洗,湿润,光固化型的Fuji Ortho Lc树脂加强型玻璃离子黏结托槽。第1、2组24 h后测剪切强度,第3组30 min内测剪切强度。托槽去除后统计牙面上的黏结剂残留量。结果第2组的剪切强度高于第3组,差异有显著性;第1、3组间剪切强度差异无显著性。结论光固化树脂加强型玻璃离子水门汀的即刻黏结强度能够满足临床要求,但24 h后的黏结强度显著增强。     

酸蚀剂浓度对光固化树脂加强型水门汀粘结强度的影响

目的:比较不同酸蚀浓度下光固化树脂加强型玻璃离子水门汀(RMGIC)与正畸托槽的粘结强度。方法:60颗上颌第一前磨牙,随机分成6组,每组10颗。各组采用不同酸蚀浓度的表面处理,粘结后10min,置于人工唾液室温下保存24h。干燥、固定后,测定各样本的抗剪切强度,并记录托槽脱落后牙釉质粘结界面的粘结材料残留指数(ARI)。采用SPSS11.5统计软件包对结果进行χ2检验。结果:(1)托槽的抗剪粘结强度A组为(14.786±4.940)MPa,B组未检测,C组为(7.002±3.768)MPa,D组为(7.879±3.013)MPa,E组为(7.452±2.561)MPa,F组为(7.406±2.407)MPa。C、D、E、F组托槽的抗剪粘结强度比较,差异无显著性,P>0.05。A组与其他组的剪切强度比较,差异有统计学意义,P<0.01。(2)托槽脱落后,牙釉质粘结界面的粘结材料残留指数(ARI)经χ2分析,P>0.05,ARI计分在各组之间无显著性差异。结论:不同浓度的酸蚀剂对RMGIC粘接的托槽的抗剪切强度无显著影响。用不同浓度的酸蚀剂处理牙釉质后,牙釉质表面粘结剂残留指数ARI值无显著差异。     

Tensile and shear bond strength of resin-reinforced glass ionomer cement to glazed porcelain

The purpose of this study was to measure the tensile and shear bond strength of resin-reinforced glass ionomer cement (RGIC) to glazed porcelain, to evaluate the durability of RGIC by thermal cycling, and to examine the RGIC remaining on the surface of the porcelain after the bond strength test to evaluate bonding conditions. Three adhesives were used in this study: Concise (CO) as a chemically cured composite resin, Fuji ORTHO (FO) as a chemically cured RGIC, and Fuji ORTHO LC (FOLC) as a light-cured RGIC. Tensile and shear bond strengths were measured 24 hours after bonding orthodontic brackets and also after thermal cycling. Tensile bond strength after 24 hours was 6.6 +/- 3.2 MPa in CO, 7.3 +/- 1.4 MPa in FO, and 8.6 +/- 1.9 MPa in FOLC, and the strength significantly decreased after the thermal cycling test. Shear bond strength after 24 hours was 32.5 +/- 8.9 MPa in CO, 23.3 +/- 6.8 MPa in FO, and 24.7 +/- 6.5 MPa in FOLC, and in contrast to tensile bond strength, no decreases in the strength were detected after the thermal cycling test. CO showed significantly higher shear bond strength than did FO and FOLC. When using the shear bond strength test and CO, destruction of porcelain surfaces frequently occurred after 24 hours and was observed in every specimen after the thermal cycling. RGIC was found to be an advantageous alternative to resin adhesive for bracket bonding to porcelain and to enamel.     

Shear bond strength of a resin-reinforced glass ionomer cement: An in vitro comparative study

Shear bond strength of Concise (a composite resin adhesive) and Fuji Ortho LC (a light-cured resin-reinforced glass ionomer cement) bonded to extracted teeth was tested under different bonding conditions: (1) Concise/etched/dry (2) Fuji/etched/dry (3) Fuji/etched/wet (4) Fuji/unetched/dry (5) Fuji/unetched/wet. Concise/etched/dry and Fuji/etched/dry groups showed comparable mean shear bond strength (10.5 and 8.2 MPa, respectively); the other three groups had considerably lower values. The difference between Fuji/etched/dry and Fuji/etched/wet was not statistically significant. The site of bond failure was between bracket and adhesive in all etched groups and between adhesive and enamel in the unetched groups. We conclude that (1) enamel surface etching is required for Fuji Ortho LC to achieve optimum bond strength, (2) moisture does not affect bond strength of Fuji Ortho LC significantly. (Am J Orthod Dentofacial Orthop 1999;115:52-4)     

Adhesive thickness effects on the bond strength of a light-cured resin-modified glass ionomer cement

These in vitro studies investigated the effect of adhesive thickness on the tensile and shear bond strength of a light-cured, resin-modified glass-ionomer cement (FO). A light-cured conventional composite resin (CO) was used as the control material. Mesh-based metal brackets were bonded to extracted human premolars using FO and CO. The adhesive thickness was controlled by a special device and 0, 0.25, and 0.5 mm thicknesses were tested for both bonding agents. All bonded specimens were stored in distilled water at 37 degrees C for 48 hours and thermocycled between 5 degrees C and 55 degrees C for 200 cycles before testing. Analysis of variance showed that bond strength was significantly affected by the adhesive thickness (P < .001) and type of adhesive (P = .001). There were statistically significant differences between the mean bond strengths of the groups at the P < .05 level of significance. For all adhesive thicknesses, CO had higher bond strength values than those of FO in both test modes. The bond strength values were also analyzed using a Weibull analysis, which showed the most favorable adhesive thickness, and the 5% and 90% probabilities of failures was 0.25 mm in the FO groups. Bracket-adhesive interface failure was predominant for all groups in tensile testing, but enamel-adhesive interface failures increased with increased adhesive thickness in shear testing for the FO. This study suggests that adhesive thickness under a bracket could be particularly important when using a FO in direct bonding.     

Shear bond strength of chemical and light-cured glass ionomer cements bonded to resin composites

A bond between glass ionomer cements (GIC) and resin composites is desirable for the success of the ‘sandwich’ restoration. Chemically cured glass ionomer cements have been the traditional materials used in this technique since its development, but etching the GIC was necessary to obtain a bond to the composite facing. Producing a very smooth GIC surface has aided in better determining the magnitude of the chemical bond between glass ionomers and resin composites. Shear testing of bonded specimens has revealed that chemical bonding is minimal (0.21 MPa) in conventional glass ionomers, but does exist (4.92 MPa) between GIC and resin composite regardless of the filler content (microfilled vs hybrid) of the composite. Thermal stressing affects the bond to resin-modified glass ionomers, but has no significant effect on self-cured cements. Of all combinations tested, Vitremer/Scotchbond/Silux Plus showed the highest mean shear bond strength. Based on the clinical need for an adhesive bond between GIC liner/base and resin composite, the resin-modified glass ionomer would appear to be the material of choice.     

Orthodontic bracket bonding with a plasma-arc light and resin-reinforced glass ionomer cement.

Developments in light-curing technology have led to the introduction of a plasma-arc light-curing unit that delivers high-intensity output for faster curing. The purposes of this study were to determine the shear bond strengths of light-cured resin-reinforced glass ionomer cement cured with a plasma-arc light-curing unit and to evaluate the durability of the resultant bond strength with thermal cycling. Comparisons were made between light-cured resin-reinforced glass ionomer cement and light-cured composite resin. Two light-curing units were used in this study: a plasma-arc light-curing unit and a conventional light-curing unit. The mean shear bond strengths of light-cured resin-reinforced glass ionomer cement with the plasma-arc and the conventional light-curing units were 20.3 MPa and 26.0 MPa, respectively. An analysis of variance showed no statistically significant differences between the plasma-arc and the conventional light-curing units. Light-cured resin-reinforced glass ionomer cement and light-cured composite resin demonstrated similar bond strengths and exhibited no statistical differences. There was no statistical difference in bond strength between the teeth that were thermal cycled and those that were not. Failure sites for the brackets bonded with light-cured resin-reinforced glass ionomer cement appeared to be predominantly at the bracket-adhesive interface. The SDs of light-cured composite resin were high for both light-curing units. Whereas the coefficients of variation for light-cured resin-reinforced glass ionomer cement ranged from 20% to 30%, those of light-cured composite resin ranged from 40% to 60%. The bond strength of light-cured resin-reinforced glass ionomer cement cured with either a conventional light-curing unit or a plasma-arc light-curing unit surpassed the clinically required threshold. The plasma-arc light-curing unit may be an advantageous alternative to the conventional light-curing unit for orthodontic bracket bonding with both light-cured resin-reinforced glass ionomer cement and light-cured composite resin.     

Effect of enamel etching on tensile bond strength of brackets bonded in vivo with a resin-reinforced glass ionomer cement

OBJECTIVE: To evaluate the influence of enamel etching on tensile bond strength of orthodontic brackets bonded with resin-reinforced glass ionomer cement. MATERIALS AND METHODS: The sample group consisted of 15 patients who had indications for extraction of four premolars for orthodontic reasons, equally divided into two different groups according to bracket and enamel preparation. Brackets were bonded in vivo, by the same operator, using a split mouth random technique: Group 1 (control), phosphoric acid + Fuji Ortho LC; Group 2, Fuji Ortho LC without acid conditioning. The teeth were extracted after 4 weeks using elevators. An Instron Universal Testing Machine was used to apply a tensile force directly to the enamel-bracket interface at a speed of 0.5 mm/min. The groups were compared using a Mann-Whitney U-test and Weibull analysis. RESULTS: Mean results and standard deviations (in MPa) for the groups were: Group 1, 6.26 (3.21), Group 2, 6.52 (2.73). No significant difference was observed in the bond strengths of the two groups evaluated (P = .599). CONCLUSIONS: Fuji Ortho LC showed adequate shear bond strength and may be suitable for clinical use.     

Bond strength of glass ionomer cement to composite resin.

This report assesses the effect of acid etching, acid etching plus bonding adhesive and bonding adhesive only, on the bond strength of one light curing and two chemical curing glass ionomer cements (GICs) to composite resin. Bonded specimens were fractured using a three point flexural jig. The only bond obtained with the chemically curing cements was after acid etching and bonding adhesive application. The light curing cements produced a bond with all treatments but a true cohesive fracture was only obtained after application of the dentine primer and bonding adhesive of the particular bonding system employed. It is recommended that a bonding adhesive be applied after acid etching chemically curing GICs in order to achieve a bond to composite resin. The light curing GIC should not be etched with phosphoric acid and is the material of choice as it is both stronger and less technique sensitive than the chemically curing GICs. Manufacturers' instructions may not always give the best results.     

Shear bond strength of light-cured glass ionomer to enamel and dentin

The shear bond strengths of a light-cured glass-ionomer cement to enamel and dentin were determined with use of extracted human maxillary permanent canines and molars. Bonding sites on the ground, etched enamel and ground dentin surfaces were demarcated by the punching of a hole, 3 mm in diameter, in an adhesive tape. The mixed glass-ionomer cement was transferred to the demarcated site, cured by exposure to visible light for 30 s, and the cement surface treated with Scotchprep Dentin Primer followed by Scotchbond 2 Light Cure Dental Adhesive. The embedded teeth were positioned in an assembly apparatus, and Silux composite was bonded to the glass-ionomer-cement surfaces. The specimens were disassembled after 15 min and subjected to a shear load (in an Instron machine) immediately after disassembly; after storage in water at 37 degrees C for 24 h, without and with temperature cycling; and after storage in water for four weeks, without and with temperature cycling. The shear bond strength of the glass-ionomer cement to etched enamel was in the order of 12 MN.m-2, and to dentin it was 9 MN.m-2. Temperature cycling and duration of storage had no adverse effect on the shear bond strength. The enamel and dentin aspects of fractured test specimens were examined, and the percentage of the bonding area that failed in the cement was estimated. Most of the test specimens failed partly at the enamel and dentin interfaces and within the glass-ionomer cement.     

影响玻璃离子水门汀粘结强度的因素

玻璃离子水门汀作为牙科充填和粘结材料,以其优良的性能特点在口腔临床被广泛应用,其粘结强度及稳定性对修复体的固位及使用寿命有着较大的影响。本文对水门汀粘结强度的影响因素作一简单的综述。     

树脂加强型玻璃离子水门汀在托槽粘结中的应用

目的探讨两种树脂加强型玻璃离子水门汀对托槽粘结强度的影响。方法收集离体人前磨牙60个,随机分成6组。第1组和第2组(对照组):35%磷酸酸蚀30 s,冲洗、吹干,涂粘结剂,采用光固化复合树脂粘结托槽。第3、4、5、6组:10%聚丙烯酸酸蚀30 s,冲洗,保持潮湿,第3组和第4组采用化学固化型的Fuji Ortho树脂加强型玻璃离子水门汀粘结托槽,第5组和第6组采用光固化型的Fuji Ortho LC树脂加强型玻璃离子水门汀粘结托槽。第1、3、5组进行抗剪强度测定,第24、、6组进行抗张强度测定,测试后观察断面形态。结果光固化复合树脂的抗剪强度高于其他2组,抗张强度各组间差异无显著性。各种材料的抗剪强度均高于抗张强度。在断面形态观察中,第1组与第3组、第5组差异有显著性,其余差异无显著性。结论两种树脂加强型玻璃离子水门汀的抗剪强度低于复合树脂,但能满足临床的需要。     

Effect of argon laser curing on the shear bond strength of metal brackets bonded with light-cured glass ionomer cement

INTRODUCTION: The purpose of this study was to evaluate the shear bond strength and debonding characteristics of glass ionomer cement cured with an argon laser. METHODS: Thirty extracted first premolars were divided into 2 groups of 15. The teeth were cleaned and mounted in resin, and metal brackets were bonded with glass ionomer cement. In the control group, the bond was cured with a halogen light for 40 seconds (20 seconds mesial and 20 seconds distal). In the test group, the specimens were cured with an argon laser for 5 seconds. Brackets were debonded in shear; bond strength was measured, and the adhesive remnant index was scored. RESULTS: The difference in mean shear bond strength was not statistically significant between groups when compared with a t test. More adhesive remained on the enamel surface in the laser group than in the control group. CONCLUSIONS: Argon laser curing produces bond strengths equivalent to those obtained with traditional light curing in much less time, but it leaves more adhesive on the tooth surface.     

Shear bond strength of resin modified glass ionomer cement bonded to different tooth-colored restorative materials

AIM: The aim of this study was to determine in vitro the shear bond strength (MPa) and the type of bond failure when resin-modified glass ionomer cement (RMGIC) was bonded with different tooth-colored restorative materials. METHODS AND MATERIALS: The RMGIC tested was Fuji II LC (FL) and the tooth-colored restorative materials used were composite resin Point-4 (P4), Compomer Dyract AP (DY), and Ormocere Admira (AD). A total number of 60 FL specimens were prepared using Teflon molds. The specimens were divided into six equal groups. Each group of ten specimens was bonded to a tested tooth-colored restorative material as follows: Group I--etched FL bonded to P4; Group II--non-etched FL bonded to P4; Group III--etched FL bonded to DY; Group IV--non-etched FL bonded to DY; Group V--etched FL bonded to AD; and Group VI--non-etched FL bonded to AD. The specimens were stored in distilled water at 37 degrees C for 24 hours. The shear bond strength was measured in a universal testing machine, and the fractured surfaces were examined under a stereomicroscope. RESULTS: The results of the shear bond strength indicated the lowest mean value (14.46 MPa) was in Group III, and this was significantly different from the values of other groups (p<0.05). However, Groups V and VI recorded the highest mean values (24.5 MPa and 28.39 MPa) which were significantly different (p<0.05) when compared to other groups. Groups I, II, and IV showed no significant difference with mean values of 20.06, 19.99, and 20.1 MPa which were significantly different from other groups (p<0.05). CONCLUSION: AD showed the highest shear bond strength to RMGIC. All groups demonstrated a cohesive failure in FL except for Group IV where a cohesive failure in DY was recorded. AD showed good shear bond strength when laminated with FL.     

Bonding of light-cured glass ionomer cement to polycarbonate resin treated with experimental primers

The effect of experimental primers on the shear bond strength of polycarbonate composite resin with light-cured glass ionomer cements was investigated. Mixtures of methylmethacrylate (MMA) with the comonomers 2-hydroxyethyl methacrylate (HEMA), triethyleneglycol methacrylate (TEGDMA), and bisphenol-A-glycidymethacrylate (bisGMA) were used as primers. Polycarbonate composite resin rods of circular cross section and plates were bonded, with and without precured and nonprecured primers, using 2 light-cured glass ionomer cements (commercially available [LC] and experimental [EX]). In addition, commercial polycarbonate composite resin brackets with precured 50% TEGDMA/MMA primer were bonded to etched human enamel with both cements. Shear bond strengths were measured. Results were compared by ANOVA and Scheffe's tests at P = .05. The 30% HEMA/MMA, 50% TEGDMA/ MMA, 10% bisGMA/MMA, and 30% bisGMA/MMA primers produced the higher shear bond strengths (9.5 to 20.8 MPa) with LC and EX to polycarbonate composite resin. The 50% TEGDMA/MMA primer was most effective in improving the shear bond strengths of both LC and EX. Precured 50% TEGDMA/ MMA primer on a commercial resin bracket was effective in providing good shear bond strength to enamel.     

Sealing effectiveness of light-cured glass ionomer cement liners

Glass ionomer materials have been used as liners or bases beneath restorations, but light-cured varieties have recently been introduced. Microleakage at the restoration/tooth interface in cervical cavities was used to test the adhesion to dentin of two new light-cured glass ionomer cement lining materials, XR-Ionomer and Fuji Lining LC. Wedge-shaped cervical cavities were prepared on extracted teeth with a gingival cavosurface margin involving dentin, and the specimens were assigned randomly to three groups. The experimental groups were restored with two light-cured glass ionomer cements, the controls were restored with a chemically cured glass ionomer cement; and marginal leakage was assessed by dye penetration. The two light-cured glass ionomer cements displayed some adhesion to dentin in class V test cavities, but there was no significant difference between the two materials.     

Effect of contamination and etching on enamel bond strength of new light-cured glass ionomer cements.

The effect of water and saliva contamination on the bond strength of metal orthodontic brackets cemented to etched (10% polyacrylic acid) and unetched human premolar enamel was investigated. Two bonding agents were used: one commercially available product (LC) and one experimental (EX) light-cured glass ionomer. Shear bond strength was measured after aging for 5 minutes, 15 minutes, and 24 hours. The results were compared by ANOVA and Scheffe's tests at p = 0.05. For LC, the bond strength of brackets bonded to etched enamel, with and without contamination, was statistically higher than that of brackets bonded to unetched enamel for all aging times. An exception was the bond strength to unetched enamel with saliva contamination after 24 hours; for EX, this value was statistically higher than that measured on unetched enamel with water contamination. Contamination by saliva did not reduce bond strength to unetched enamel. For both etched and unetched enamel, there was no significant difference between LC and EX after 24 hours for all contamination conditions.