The effect of delayed light exposure on bond strength: light-cured resin-reinforced glass ionomer cement vs light-cured resin.

Under clinical situations, the intervals between material mixing and light exposure during bracket bonding using light-cured resin-reinforced glass ionomer cement may vary for each individual bracket. This study evaluates the bond strength of light-cured resin-reinforced glass ionomer cement subjected to various time intervals between material mixing and subsequent light exposure. This investigation was conducted in two parts. The first part consisted of measuring the enamel surface temperature to define the conditions under which the second part of the study was carried out. One hundred fifteen subjects, 63 males and 52 females, participated in this study. The over-all mean temperature as measured with a noncontact infrared thermometer was 31.9 degrees C. The second part of this study assessed tensile and shear bond strengths of light-cured resin-reinforced glass ionomer cement subjected to immediate light exposure (time interval, 5 minutes) and bond strengths subjected to light exposure at 10, 20, and 40 minutes after material mixing. Light-cured resin-reinforced glass ionomer cement was then compared with light-cured composite resin. Mean tensile and shear bond strengths of light-cured resin-reinforced glass ionomer cement exposed after 40 minutes were 4.5 MPa and 20.5 MPa, respectively. This represented a reduction of approximately 20% when compared with the 5-minute group. Scheffé test showed no statistically significant differences between any two time intervals. Mean bond strengths of the light-cured resin decreased with time. Tensile and shear bond strengths of light-cured resin indicated high statistical significance within groups across time. It could therefore be concluded that the bond strength of light-cured resin-reinforced glass ionomer cement was not affected by the timing of visible light exposure; whereas, the bond strength of light-cured resin decreased as time intervals increased. Light-cured resin-reinforced glass ionomer cement may thus serve as an advantageous alternative to composite resin for bracket bonding.     

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.     

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。     

Laboratory evaluation of a compomer and a resin-modified glass ionomer cement for orthodontic bonding

The mean shear debonding force of stainless steel orthodontic brackets with microetched bases bonded with either a compomer or a resin-modified glass ionomer cement was assessed. In addition, the amount of cement remaining on the enamel surface following bracket removal was evaluated. Finally, survival time of orthodontic brackets bonded with these materials was assessed following simulated mechanical stress in a ball mill. Debonding force and survival time data were compared with those obtained for brackets bonded with a chemically cured resin adhesive, a light-cured resin adhesive, and a conventional glass ionomer cement. There were no significant differences in mean shear debonding force of brackets bonded with the compomer, resin-modified glass ionomer, chemically cured resin adhesive, or the light-cured resin adhesive. Brackets bonded with a conventional glass ionomer cement had a significantly lower mean shear debonding force than that recorded for the other materials. The Adhesive Remnant Index (ARI) mode score indicated that significantly less cement remained on the enamel following debonding of brackets cemented with resin-modified or conventional glass ionomers compared with other adhesives. The median survival time for brackets cemented with the compomer, resin-modified glass ionomer, chemically cured resin, or light-cured resin were significantly longer than for brackets cemented with conventional glass ionomer. The compomer and the resin-modified glass ionomer adhesive appear to offer viable alternatives to the more commonly used resin adhesives for bracket bonding.     

Bond strength for orthodontic brackets contaminated by blood: composite versus resin-modified glass ionomer cements.

PURPOSE: The purpose of this study was to evaluate and compare the shear bond strengths of a self-cured glass ionomer versus composite cement for bonding of stainless steel buttons with various enamel surface and setting conditions. MATERIALS AND METHODS: Stainless steel orthodontic buttons were bonded using composite material under 3 different enamel and setting conditions: 1) conditioned and dry enamel surface, 2) conditioned and precontamination of the enamel surface with blood before bonding, 3) conditioned and immediate blood contamination postbonding and were compared with 3 different enamel conditions and setting for bonding with the glass ionomer cement: 1) nonconditioned and wet enamel surfaces, 2) nonconditioned and blood contamination of enamel before bonding, and 3) nonconditioned and immediate blood contamination postbonding. The brackets were bonded to 109 recently extracted teeth and allowed to set in a moist plastic container for 24 hours. They were subsequently tested in shear mode with a universal testing machine. The maximum bond strength and the site of bond failure were recorded. In addition, the location of the bond failure was studied. RESULTS: Composite was capable of sustaining greater forces than the resin-modified glass ionomer materials. Hence, it took more force to debond a bracket cemented with composite than with resin-modified glass ionomer. The effect of contamination was similar in both of the materials, and the magnitude of the decrease in bond strength was nearly of the same proportion. The postcontamination values were not significantly different from the uncontaminated bond strength for either material. The type of bond failure was significantly different for the different materials, and there were significant differences among the treatment conditions. CONCLUSION: Composite resin had significantly greater shear strength than resin-reinforced glass ionomer cement. Both materials showed a significant decrease in bond strength when precontaminated with blood. The postcontamination values were not significantly different from the uncontaminated bond strength for either material.     

Effect of altering the type of enamel conditioner on the shear bond strength of a resin-reinforced glass ionomer adhesive.

The purpose of this study was to determine the effects of changing the type of enamel conditioner on the shear bond strength of a resin-reinforced glass ionomer within half an hour after bonding the bracket to the tooth. Freshly extracted human molars were collected and stored in a solution of 0.1% (weight/volume) thymol. The teeth were cleaned and polished. The teeth were randomly separated into 4 groups according to the enamel conditioner/etchant and adhesive used: group I, teeth were conditioned with 10% polyacrylic acid and brackets were bonded with a resin-reinforced glass ionomer adhesive; group II, teeth were conditioned with 20% polyacrylic acid and brackets were bonded with a resin-reinforced glass ionomer adhesive; group III, teeth were etched with 37% phosphoric acid and the brackets were bonded with a resin-reinforced glass ionomer adhesive; group IV, teeth were etched with 37% phosphoric acid and the brackets were bonded with a composite adhesive. The results of the analysis of variance comparing the 4 experimental groups (F = 24.87) indicated the presence of significant differences between the groups (P =.0001). In general, the shear bond strengths were significantly greater in the 2 groups etched with 37% phosphoric acid. This was true for both the resin-reinforced glass ionomer (X = 6.1 +/- 2.7 MPa) and the composite (X = 5.2 +/- 2.9 MPa) adhesives. On the other hand, the shear bond strengths were significantly lower in the two groups conditioned with polyacrylic acid. The bond strength of the resin-reinforced glass ionomer adhesive conditioned with 10% polyacrylic acid (X = 0.4 +/- 1.0 MPa) was significantly lower than the group conditioned with 20% polyacrylic acid (&xmacr; = 3.3 +/- 2.6 MPa). The present findings indicated that the bond strength of the resin-reinforced glass ionomer adhesive can be significantly increased in the initial half hour after bonding if the enamel is etched with 37% phosphoric acid instead of being conditioned with either 10% or 20% polyacrylic acid. The clinician needs to take these properties into consideration when ligating the initial archwires.     

An in vitro study of the bond strength of a glass ionomer cement in the direct bonding of orthodontic brackets

The shear/peel bond strength of a 'no-mix' composite orthodontic bonding resin was compared in vitro with that of a glass ionomer cement. The effect of pre-treatment of the enamel, with either phosphoric acid or polyacrylic acid, prior to using the glass ionomer cement was also assessed. The composite resin had a significantly higher bond strength than the glass ionomer cement. Simple prophylaxis and drying of the enamel achieved the best results when using the glass ionomer cement, whilst etching the tooth surface with phosphoric acid produced a significantly poorer bond to the enamel. Investigation of the site of failure showed the composite resin bonded very well to the tooth and less well to the bracket, whilst the glass ionomer adhered significantly better to the bracket base than to the tooth surface.     

Demineralization around orthodontic brackets bonded with resin-modified glass ionomer cement and fluoride-releasing resin composite.

PURPOSE: Enamel demineralization adjacent to orthodontic brackets is one of the risks associated with orthodontic treatment. Glass ionomer cements have been shown to decrease enamel demineralization adjacent to brackets and bands but do not exhibit bond strengths comparable to resin composites. The purpose of this in vitro study was to compare a fluoride-releasing resin composite versus a resin-modified glass ionomer cement for inhibition of enamel demineralization surrounding orthodontic brackets. METHODS: Forty-five teeth were randomly assigned to 3 groups of 15 teeth. Fifteen were bonded with Concise (3M), a non-fluoride-releasing resin composite (control); 15 teeth were bonded with Light Bond (Reliance), a fluoride-releasing resin composite; and 15 teeth were bonded with Fuji Ortho LC (GC Corporation), a resin-modified glass ionomer cement. The teeth were placed in an artificial caries solution to create lesions. Following sectioning of the teeth in a buccolingual direction, polarized light microscopy was utilized to evaluate enamel demineralization adjacent to the orthodontic bracket. The area of the lesion was measured 100 microns from the orthodontic bracket and bonding agent. RESULTS: MANOVA (P < .0001) and Duncan's test (P < .05) indicated the resin-modified glass ionomer cement (Fuji Ortho LC) and the fluoride-releasing resin composite (Light Bond) had significantly less adjacent enamel demineralization than the non-fluoride-releasing resin composite control. However, there was no significant difference between the resin-modified glass ionomer cement and the fluoride-releasing resin composite. CONCLUSIONS: Based on the results of this in vitro study, it can be concluded that Fuji Ortho LC and Light Bond exhibit significant inhibition of adjacent demineralization compared to the non-fluoride-releasing control.     

Bond strength of orthodontic brackets using different light and self-curing cements

The purpose of the study was to evaluate the shear bond strength of stainless steel orthodontic brackets directly bonded to extracted human premolar teeth. Fifty teeth were randomly divided into five groups: (1) System One (chemically cured composite resin), (2) Light Bond (light-cured composite resin), (3) Vivaglass Cem (self-curing glass ionomer cement), (4) Fuji Ortho LC (light-cured glass ionomer cement) used after 37% orthophosphoric acid-etching of enamel (5) Fuji Ortho LC without orthophosphoric acid-etching. The brackets were placed on the buccal and lingual surfaces of each tooth, and the specimens were stored in distilled water (24 hours) at 37 degrees C and thermocycled. Teeth were mounted on acrylic block frames, and brackets were debonded using an Instron machine. Shear bond strength values at fracture (Nw) were recorded. ANOVA and Student-Newman-Keuls multiple comparison tests were performed (P < .05). Bonding failure site was recorded by stereomicroscope and analyzed by Chi-square test, selected specimens of each group were observed by scanning electron microscope. System One attained the highest bond strength. Light Bond and Fuji Ortho LC, when using an acid-etching technique, obtained bond strengths that were within the range of estimated bond strength values for successful clinical bonding. Fuji Ortho LC and Vivaglass Cem left an almost clean enamel surface after debracketing.     

Increasing the resistance of teeth to fracture: bonded composite resin versus glass ionomer cement

The purpose of this study was to compare the fracture resistance of teeth restored with bonded composite resin to teeth restored with glass ionomer cement. Extracted maxillary premolars prepared with MOD slots were restored with either a light-cured composite resin (P-30) bonded (with Scotchbond) to enamel and dentin or with glass ionomer cement (Ketac Fil) following manufacturers' directions. One group, left unrestored, served as the control. All of the teeth were loaded occlusally by a universal testing machine until fracture. The results suggest that teeth restored with bonded composite resin are significantly more resistant to fracture than teeth restored with glass ionomer cement (P=0.05). cohesive failures occurred frequently within the bulk of the glass ionomer cement. Failures with the bonded composites usually occurred within the bonding agent.     

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)     

Comparison of bracket debonding force between two conventional resin adhesives and a resin-reinforced glass ionomer cement: an in vitro and in vivo study.

The purpose of this study was to compare the debonding force of orthodontic brackets bonded with two conventional resin adhesives (Resilience L3 and Light Bond) and a resin-reinforced glass ionomer cement (Fuji Ortho LC). For the in vitro part of the study, 80 extracted premolars were randomly divided into four groups. In groups A and B, brackets were bonded to unetched enamel using Fuji Ortho LC cement in wet and dry conditions, respectively. In groups C and D, brackets were bonded to etched enamel using Resilience L3 and Light Bond, respectively. Debonding force was determined using a servohydraulic testing machine at a crosshead speed of 1 mm/min. Data was analyzed using the ANOVA and Tukey-Kramer multiple comparison test at p<0.05. A significant difference was found in debonding force between unetched Fuji Ortho LC and the two conventional resins. There was no significant difference between the two conventional resins or between unetched resin-reinforced glass ionomer in the wet and dry conditions. For the in vivo part of the study, 30 patients were randomly assigned to one of the three bonding material groups. Bracket survival rates and distributions were obtained by following these patients for 1.2 years. Data was analyzed using the Kaplan-Meier product-limit estimates of survivorship function. Bond failure interface was determined using a modified adhesive remnant index (ARI). These results showed no significant difference between survival rates and distributions among the three bonding materials with respect to the type of malocclusion, type of orthodontic treatment, or location of bracket. There were significant differences between survival distributions of males and females in the unetched Fuji Ortho LC group and among type of teeth in the conventional resin groups. The predominant mode of bracket failure for the unetched Fuji Ortho LC cement was at the enamel-adhesive interface, and for conventional resins, the enamel-adhesive interface and the bracket-adhesive interface. These results suggest that resin-reinforced glass ionomer cement can withstand occlusal and orthodontic forces despite having a bond strength lower than that of conventional resin adhesives.     

Optimization of a procedure for rebonding dislodged orthodontic brackets.

The purpose of this study was to compare shear bond strength (SBS) of bonded and rebonded orthodontic brackets following a variety of commonly used conditioning treatments and using both light-cured and self-cured composite resin systems. Brackets debonded during the initial determination of SBS were rebonded after the removal of residual resin from enamel surfaces using five different treatments: (1) Remove residual resin using a tungsten carbide bur, re-etch enamel surface, then bond a new bracket; (2) Remove resin from the base mesh with micro-etching then rebond the same bracket, (3) Remove residual resin from the enamel surface using resin-removing pliers, recondition the enamel with an air-powder polisher, then bond a new bracket; (4) Remove residual resin using a rubber cup and pumice, then bond a new bracket; (5) Remove residual resin using pliers alone, then bond a new bracket. The results revealed that the light-cured system produced higher shear bond strength in the initial bond than the self-cured system (p<0.005). Reconditioning the enamel surfaces using a tungsten carbide bur and acid-etching gave the highest SBS (difference 5.8 MPa; p<0.01) and clinically favorable fracture characteristics. The data suggest that the optimal procedure for rebonding dislodged orthodontic brackets is to resurface the enamel using a tungsten carbide bur, acid-etch the enamel, and use a new or re-use an old bracket after microetching.     

In vitro study of 24-hour and 30-day shear bond strengths of three resin–glass ionomer cements used to bond orthodontic brackets

Interest in using composite resin–glass ionomer hybrid cements as orthodontic bracket adhesives has grown because of their potential for fluoride release. The purpose of this pilot study was to compare shear bond strengths of three resin–glass ionomer cements (Advance, Fuji Duet, Fuji Ortho LC) used as bracket adhesives with a composite resin 24 hours and 30 days after bonding. The amount of adhesive remaining on the debonded enamel surface was scored for each adhesive. Mesh-backed stainless-steel brackets were bonded to 100 extracted human premolars, which were stored in artificial saliva at 37° C until being tested to failure in a testing machine. The hybrid cements, with one exception, had bond strengths similar to those of the composite resin at 24 hours and 30 days. Fuji Ortho LC had significantly lower bond strengths (ANOVA p ≤ 0.05) than the other adhesives at 24 hours and 30 days when it was bonded to unetched, water-moistened enamel. Adhesive-remnant scores were similar for all cements, except for cement Fuji Ortho LC when it was bonded to unetched enamel. The resin–glass ionomer cements we tested appear to have bond strengths suitable for routine use as orthodontic bracket–bonding adhesives. (Am J Orthod Dentofacial Orthop 1998;113:620-24.)     

Bond Strength of Various Fluoride-Releasing Orthodontic Bonding Systems Experimental Study

The aim of the study was to compare the shear bond strength of a fluoride-releasing composite resin adhesive (Light Bond, Reliance) and a light-cured resin-reinforced glass ionomer cement (Fuji Ortho LC, GC America) bonded to extracted teeth under different enamel surface conditions. Forty human premolars were divided at random into 4 groups of 10 specimens. Stainless steel brackets were attached to the enamel surface by 1 of the 4 protocols: 1. Fuji Ortho LC, moist non-etched enamel; 2. Fuji Ortho LC, moist etched (37% H3PO4); 3. Light Bond, dry etched (37% H3PO4); 4. Light Bond, dry etched (Etch & Prime 3.0, Degussa). The teeth were stored in deionized water at 37 degrees C for 48 hours. Shear bond strengths was determined at a crosshead speed of 1 mm/min. The residual adhesive on the enamel surface was evaluated with the modified Adhesive Remnant Index (ARI). Analysis of variance (ANOVA) and Duncan's test were used to compare the 4 groups. Significance was predetermined at p = 0.05. Significant inter-group differences were found (p < 0.0001). The mean SBS (and SD), in MPa were: Group 1: 15.9 (4.7); Group 2: 20.3 (2.5); Group 3: 16.7 (2.6); Group 4: 11.7 (2.5). Glass ionomer cement without etching and composite with Etch & Prime showed adhesive failures at the enamel and good enamel integrity after debonding. The other specimens showed mixed or adhesive fractures at the bracket failure sites. Glass ionomer used on wet tooth surfaces without etching shows a clinically acceptable bond strength with clean separation from the enamel after debonding.     

Clinical comparison between a resin-reinforced self-cured glass ionomer cement and a composite resin for direct bonding of orthodontic brackets. Part 2: Bonding on dry enamel and on enamel soaked with saliva

The purposes of this investigation were to compare the clinical performance of a resin-reinforced self-cured glass ionomer cement to a standard composite resin in the direct bonding of orthodontic brackets when bonded onto: a) dry teeth and b) teeth soaked with saliva. The two bonding agents were compared using a split-mouth design. In that, both systems were used for direct bonding of stainless steel brackets in every patient. Thirty-eight consecutive patients with fixed appliances were followed for a period of 12 months. The patients were randomly divided into two groups: group A (11 patients) and group B (27 patients). In group A, the performance of 220 stainless steel brackets was evaluated: 110 brackets were bonded with GC Fuji Ortho glass ionomer cement (GC Industrial Co., Tokyo, Japan) onto dry teeth, and 110 bonded with System 1+ composite resin (Ormco Corp., Glendora, CA). In group B, the performance of 540 stainless steel brackets was evaluated: 270 brackets were bonded with GC Fuji Ortho onto teeth soaked with saliva, and 270 bonded with System 1+. In group A, GC Fuji Ortho recorded an overall failure rate (34.5%) significantly higher (p < 0.05) than System 1+ (9%) when applied onto completely dry teeth. Conversely, in group B, no statistically significant differences (p > 0.05) between the failure rates of the two bonding agents were found when GC Fuji Ortho was used on teeth soaked with saliva. It was concluded, therefore, that GC Fuji Ortho shows clinically acceptable bond strengths when bonded onto moist teeth, but not when used on dry enamel. Both bonding agents failed mostly at the enamel/adhesive interface, without causing any enamel damage.     

A comparison of the shear bond strengths of two glass ionomer cements

The objective of this study was to determine the in vitro shear bond strength (in megapascals) and location of bond failure with two light-cured glass ionomer resin systems. One system was a hybrid glass ionomer cement with resin (GC Orthodontics, Aslip, Ill), and the other system a glass-filled resin system (Reliance Orthodontic Products, Inc, Itasca, Ill). These systems, Fuji Ortho LC (GC Orthodontics) and Ultra Band Lok^{^} (Reliance), respectively, were compared to a light-cured composite resin. Maxillary premolar brackets (n = 200) were bonded to the facial surface of human premolar teeth. The two glass ionomer resin systems were each evaluated by two protocols, one according to the manufacturers’ direction plus a variation of their respective technique. The five distinct groups (n = 40) were stored in 37°C distilled water for 30 days and subjected to thermocycling before shear bond strength testing. The findings indicated that large variations existed between the bond strengths of the materials tested. The laboratory shear bond strength of the glass-filled resin glass ionomer cement (Reliance), whether tested in a dry or moist field, was similar to the composite control with all of the previous materials being significantly (P < .01) higher than both the hybrid glass ionomer cement groups (Fuji Ortho LC). However, the hybrid glass ionomer cement with enamel conditioner demonstrated a clinically acceptable mean megapascal value. The Adhesive Remnant Index values ranged from 0.53 to 1.62. The hybrid glass ionomer cement without enamel conditioning recorded the lowest mean adhesive remnant index score and the lowest mean megapascal score. Although both products are glass ionomer resin systems, their individual chemistries vary; this affects their clinical performance. Clinically, it may be suggested that glass ionomers used in a dry field may be beneficial for orthodontic bonding, and that glass ionomer resin systems used in a moist environment need an enamel conditioner. (Am J Orthod Dentofacial Orthop 1999;115:125-32.)     

Tensile bond force of glass ionomer cements in direct bonding of orthodontic brackets: an in vitro comparative study.

Tensile bond force of three glass ionomers was evaluated in vitro. Ketac-Cem and Aqua-Cem, two conventional cements, and light-cured Vitrabond were used in this study. The results were then compared with the values obtained for a composite resin (Concise) by means of the Mann-Whitney two-sample rank test adjusted for ties. The composite resin had a significantly higher bond force (152.5 N) than any of the other adhesives (5.5 to 27.53 N) used. Tensile bond strength was also calculated and the failure bond site investigated on the enamel surface was evaluated. The composite resin and the two conventional glass ionomers used had high cement percentages (86% to 62%) adhering to the enamel surface. Cement remaining on enamel was lower (20%) for the light-cured glass ionomer. It was concluded that the in vitro bond force of Vitrabond might be adequate for orthodontic bracket bonding.     

树脂加强型玻璃离子水门汀临床初步应用的研究

目的了解树脂加强型玻璃离子水门汀在临床使用的脱落率,探讨树脂加强型玻璃离子水门汀在临床使用的可行性.方法20名正畸初诊患者的上颌左右侧分别使用正畸用树脂加强型玻璃离子水门汀,复合树脂型正畸釉质粘结剂粘结正畸托槽,观察其临床脱落率.结果树脂加强型玻璃离子水门汀粘结托槽的脱落率与临床普遍使用的复合树脂型正畸釉质粘结剂粘结托槽的脱落率相似.结论树脂加强型玻璃离子水门汀可以满足临床需要.