Assessing the performance of a methyl methacrylate-based resin cement with self-etching primer for bonding orthodontic brackets

Questions over the usefulness of a self-etching primer with resin adhesive in the bonding of orthodontic brackets remain unsolved. The purpose of this study was to determine the effects of using Multibond, a new methyl methacrylate (MMA)-based resin cement with self-etching primer, on the shear bond strength of orthodontic brackets compared with Superbond C&B, which is a well-known MMA-based resin cement containing phosphoric acid etching. Metal or plastic brackets were bonded to etched or self-etching primed bovine teeth using Superbond C&B or Multibond. The shear bond strengths were measured after immersion in water at 37 degrees C for 24 hours. Data were analyzed by two-way analysis of variance and Scheffe's test. The surface appearances of the teeth after phosphoric acid etching or self-etching priming were observed by field-emission scanning electron microscopy (FE-SEM). Metal brackets bonded with Multibond had a significantly lower shear bond strength than metal brackets bonded with Superbond C&B. No significant differences in shear bond strength were observed between Multibond and Superbond C&B when plastic brackets were bonded to the enamel. The shear bond strength of metal brackets bonded with Multibond was comparable with that of plastic brackets bonded with Superbond C&B. Adhesive remnant index score showed a tendency of more residual resin cement remaining on the teeth when metal brackets were bonded with Multibond. FE-SEM observation revealed less dissolution of the enamel surface resulting from treatment with Multibond self-etching primer as compared with phosphoric acid. Thus, the Multibond system may be a candidate for bonding orthodontic brackets with the advantage of minimizing enamel loss.     

Shear bond strength of orthodontic brackets bonded with a modified 1-step etchant-and-primer technique.

When bonding orthodontic brackets to enamel, most orthodontists use a conventional technique of etching tooth enamel with phosphoric acid, placing a hydrophilic primer on the etched, rinsed, and dried surface, then bonding the bracket with an adhesive resin composite. New systems simultaneously etch and prime the tooth surface in preparation for bonding. The purpose of this study was to compare the shear bond strength of orthodontic brackets bonded to enamel with a conventional, multistep adhesive system and a self-etching primer adhesive system. In addition, a third group was included in which the air dispersion step in the self-etching primer system was omitted. Brackets were bonded to 108 extracted human molars according to 1 of 3 experimental protocols--group 1: conventional multistep adhesive (n = 36); group 2: self-etching primer system (n = 36); group 3: self-etching primer system without air dispersion (n = 36). Specimens were loaded to failure in a universal testing machine (Instron, Canton, Mass). Mean shear bond strengths in megapascals (standard deviation) were 11.3 (2.2), 11.9 (3.2), and 8.2 (2.8) for groups 1, 2, and 3, respectively. Data were subjected to 1-way analysis of variance at alpha =.05. The mean shear bond strength of the self-etching primer group in which the air dispersion step was omitted was significantly less than in the other 2 groups (P <.001). However, there was no difference in mean shear bond strength between the conventional, multistep adhesive system and the self-etching primer system when the primer was dispersed correctly (P =.34).     

牙齿漂白剂对正畸托槽粘接强度的影响

目的:评价三种牙齿漂白剂对自酸蚀粘接系统粘接正畸托槽粘接强度的影响。方法:将100颗人前磨牙均分为四组:空白对照组(组1)、38%过氧化氢漂白组(组2)、10%过氧化脲漂白组(组3)和20%过氧化脲漂白组(组4),漂白牙齿后即刻使用自酸蚀正畸粘接系统Transbond Plus SEP将托槽粘接在牙面上,测量各组的抗剪切粘接强度,评价其剩余粘接剂指数,对结果进行统计学分析。结果:空白对照组的抗剪切粘接强度高于各漂白组,组2的抗剪切粘接强度高于组3和组4,而组4的抗剪切粘接强度最低,其差异均具有统计学意义(P<0.05)。各组的剩余粘接剂指数差异均有统计学意义(P<0.05),剩余粘接剂指数最低者为空白对照组,最高者为20%过氧化脲组。结论:在使用自酸蚀粘接系统粘接正畸托槽前应禁止使用过氧化物漂白牙齿,特别是高浓度的过氧化脲。     

Bonding durability of using self-etching primer with 4-META/ MMA-TBB resin cement to bond orthodontic brackets

This study determines the bonding durability when a self-etching primer is used with Superbond C&B (a 4-methacryloxyethyl trimellitate anhydride/methyl methacrylate-tri-n-butyl borane resin) to bond orthodontic brackets to enamel. Thermocycling test was used to assess bonding durability. Metal brackets were bonded to the phosphoric acid-etched or Megabond self-etching primer-treated enamel surface of human premolars using Superbond C&B. The shear bond strengths were measured after immersion in water at 37 degrees C for 24 hours or after 2000 or 5000 cycles of thermocycling between 5 degrees C and 55 degrees C. Data were analyzed using 2-way analysis of variance and Fisher's protected least significant difference test for multiple comparisons. There was no significant difference in shear bond strength between phosphoric acid and Megabond self-etching primer treatment before the thermocycling test. After 2000 and 5000 thermal cycles, significant decreases in shear bond strength were observed with phosphoric acid etching. On the contrary, no significant differences in shear bond strength were observed after 2000 and 5000 thermal cycles with Megabond self-etching primer. The adhesive remnant indices were not significantly different between phosphoric acid etching and Megabond self-etching primer treatment either before or after thermal cycles. This study suggested that when used with Superbond C&B in bonding orthodontic brackets, Megabond self-etching primer is superior to phosphoric acid as an enamel preparation agent in providing durable bond strength.     

Effect of using self-etching primer for bonding orthodontic brackets

Questions over the use of self-etching primers with composite resin adhesives in the bonding of orthodontic brackets remain unsolved. In addition, there are no previous reports on the efficacy of self-etching primers with resin-modified glass ionomer cements for bonding orthodontic brackets in orthodontic dentistry. The purpose of this study was to determine the shear bond strengths of orthodontic brackets bonded with one of four protocols: (1) a composite resin adhesive used with 40% phosphoric acid, (2) the same composite resin used with Megabond self-etching primer, (3) a resin-modified glass ionomer cement adhesive used with 10% polyacrylic acid enamel conditioner, and (4) the same resin-modified glass ionomer cement used with Megabond self-etching primer. The appearance of the tooth surfaces after acid etching or priming was observed with a field-emission scanning electron microscope (FE-SEM). When used with resin-modified glass ionomer cement, Megabond self-etching primer gave no significantly different shear bond strength compared with polyacrylic acid etching. But when used with composite resin adhesive, Megabond self-etching primer gave significantly lower shear bond strength than phosphoric acid etching. However, the shear bond strength of orthodontic brackets bonded with composite resin adhesive after Megabond priming was almost the same as that of brackets bonded with resin-modified glass ionomer cement after polyacrylic acid etching. FE-SEM observation revealed that Megabond self-etching primer produced less dissolution of enamel surface than did phosphoric acid and polyacrylic acid etching. Megabond self-etching primer may be a candidate for bonding orthodontic brackets using the resin-modified glass ionomer cement for minimizing the amount of enamel loss.     

Effect of a self-etch primer/adhesive on the shear bond strength of orthodontic brackets

Conventional adhesive systems use 3 different agents (an enamel conditioner, a primer solution, and an adhesive resin) during the bonding of orthodontic brackets to enamel. A unique characteristic of some new bonding systems in operative dentistry is that they combine the conditioning and priming agents into a single product. Combining conditioning and priming saves time and should be more cost-effective to the clinician and, indirectly, to the patient. The purpose of this study was to determine the effects of the use of a self-etch primer on the shear bond strength of orthodontic brackets and on the bracket/adhesive failure mode. Brackets were bonded to extracted human teeth according to 1 of 2 protocols. In the control group, teeth were etched with 37% phosphoric acid. After the sealant was applied, the brackets were bonded with Transbond XT (3M Unitek, Monrovia, Calif) and light cured for 20 seconds. In the experimental group, a self-etch acidic primer (ESPE Dental AG, Seefeld, Germany) was placed on the enamel for 15 seconds and gently evaporated with air, as suggested by the manufacturer. The brackets were then bonded with Transbond XT as in the first group. The present in vitro findings indicate that the use of a self-etch primer to bond orthodontic brackets to the enamel surface resulted in a significantly (P = .004) lower, but clinically acceptable, shear bond force (mean, 7.1 +/- 4.4 MPa) as compared with the control group (mean, 10.4 +/- 2.8 MPa). The comparison of the adhesive remnant index scores indicated that there was significantly (P = .006) more residual adhesive remaining on the teeth that were treated with the new self-etch primer than on those teeth that were bonded with the use of the conventional adhesive system.     

Effect of a fluoride-releasing self-etch acidic primer on the shear bond strength of orthodontic brackets

Conventional adhesive systems use three different agents--an enamel conditioner, a primer solution, and an adhesive resin--during the bonding of orthodontic brackets to enamel. A unique characteristic of some new bonding systems in operative dentistry is that they combine the conditioning and priming agents into a single application. Combining conditioning and priming saves time and should be more cost-effective to the clinician and indirectly to the patient. The purpose of this study was to assess and compare the effects of self-etching primers, including a fluoride-releasing primer, on the shear bond strength of orthodontic brackets. The brackets were bonded to extracted human teeth according to one of four protocols. In group 1 (control), teeth were etched with 37% phosphoric acid; after the sealant was applied, the brackets were bonded with Transbond XT (3M Unitek, Monrovia, Calif) and light cured for 20 seconds. In group 2, a self-etch acidic primer (3M ESPE, St Paul, Minn) was applied as suggested by the manufacturer, and the brackets were then bonded with Transbond XT as in the first group. In group 3, an experimental self-etch primer EXL #547 (3M ESPE) was applied to the teeth as suggested by the manufacturer, and the brackets were then bonded as in groups 1 and 2. In group 4, a fluoride-releasing self-etch primer, One-Up Bond F (J. Mortia, USA Inc. Irvine, Calif) that also has a novel dye-sensitized photo polymerization initiator system was applied as suggested by the manufacturer, and the brackets were then bonded as in the other groups. The present in vitro findings indicated that the shear bond strengths of the four groups were significantly different (P = .001). Duncan multiple range tests indicated that One-Up Bond F (mean +/- SD strength, 5.1+/-2.5 MPa) and Prompt L-Pop (strength, 7.1+/-4.4 MPa) had significantly lower shear bond strengths than both the EXL #547 self-etch primer (strength, 9.7+/-3.7 MPa) or the phosphoric acid etch and the conventional adhesive system (strength, 10.4+/-2.8 MPa).     

Effect of using a new cyanoacrylate adhesive on the shear bond strength of orthodontic brackets.

During bonding of orthodontic brackets to enamel, conventional adhesive systems use three different agents: an enamel conditioner, a primer solution, and an adhesive resin. A unique characteristic of some new bonding systems is that they need neither a priming agent nor a curing light to bond brackets. Such an approach should be more cost-effective for the clinician and indirectly also for the patient. The purpose of this study was to determine the effects of using a cyanoacrylate adhesive on the shear bond strength of orthodontic brackets and on the bracket/adhesive failure mode. The brackets were bonded to extracted human teeth according to one of two protocols. Group 1: Teeth were etched with 37% phosphoric acid. After applying the primer, the brackets were bonded with Transbond XT (3M Unitek, Monrovia, Calif) and were light-cured for 20 seconds. Group 2: Teeth were etched with 35% phosphoric acid. The brackets were then bonded with Smartbond (Gestenco International, G?thenburg, Sweden). The present in vitro findings indicated that the use of the cyanoacrylate adhesive to bond orthodontic brackets to the enamel surface did not result in a significantly different (P = .24) shear bond force (mean = 5.8 +/- 2.4 MPa) as compared to the control group (mean = 5.2 +/- 2.9 MPa). The comparison of the Adhesive Remnant Index scores indicated that there was significantly (P = .006) less residual adhesive remaining on the tooth with the cyanoacrylate than on the tooth with the conventional adhesive system. In conclusion, the new adhesive has the potential to be used to bond orthodontic brackets while reducing the total bonding time.     

Effect of antimicrobial monomer-containing adhesive on shear bond strength of orthodontic brackets

A new antibacterial and fluoride-releasing bonding system consists of a self-etching primer that contains an antibacterial monomer and a bonding agent that contains sodium fluoride. This study was to determine the effect of using this new adhesive on the shear bond strength of orthodontic brackets. Forty molar teeth were randomly divided into two groups. Group 1 consisted of 20 teeth that were etched for 15 seconds with 35% phosphoric acid, washed with a water spray for 10 seconds, and dried to a chalky white appearance, and the sealant was applied to the etched surface. The precoated brackets were placed on the teeth and light cured. Group 2 consisted of 20 teeth that were etched with 35% phosphoric acid for 15 seconds as suggested by the manufacturer when bonding to intact enamel. The teeth were washed with a water spray for 10 seconds and dried to a chalky white appearance, and the primer containing antibacterial monomer was applied to the etched surface, left for 20 seconds, and sprayed with a mild airstream. The adhesive was applied to each tooth, and the precoated bracket was placed and light cured. There were no significant differences (P = .220) in the shear bond strengths of the two groups. The mean shear bond strength for the antibacterial fluoride-releasing adhesive was 11.7 +/- 5.6 MPa and for the control was 9.6 +/- 5.0 MPa. The use of an antibacterial fluoride-releasing adhesive system did not affect the shear bond strength of the orthodontic brackets within the first half hour after initial bonding.     

Effects of a chlorhexidine varnish on shear bond strength in indirect bonding

The purpose of this study was to evaluate the effects of an antimicrobial varnish on the shear bond strength (SBS) of metallic orthodontic brackets bonded with an indirect bonding resin. For this purpose, 60 noncarious human premolars were divided into three equal groups. Group 1 was an indirect bonding control group and, after acid etching of the enamel, the brackets were indirectly bonded to the teeth with an indirect bonding resin. In group 2, before bonding, an antimicrobial varnish was painted on the etched enamel and indirect bonding was carried out as in group 1. In group 3, Transbond MIP primer and the antimicrobial varnish were thoroughly mixed in a 1:2 proportion, applied to the enamel surface, light cured for 20 seconds, and the brackets were direct bonded. A universal testing machine was used to determine the maximum load necessary to debond the brackets, the SBS values recorded, and the adhesive remnant index scores determined. Data were analyzed using analysis of variance (ANOVA), Tukey HSD, and chi-square tests. Results of ANOVA revealed statistically significant differences in the SBS among the various groups tested (P < .05). Indirect bonding of brackets with Sondhi Rapid Set after the application of the antimicrobial varnish showed significantly lower SBS when compared with both the group 2, indirect bonding control group, and the group 3, direct bonded-antimicrobial varnish group.     

Effect of self-etching primers on bond strength--are they reliable?

Currently introduced self-etching primers combine conditioning and priming agents into a single product. The purpose of this study was to determine the effects of using three self-etching primers on the shear bond strength (SBS) of orthodontic brackets and on the bracket/adhesive failure mode. Brackets were bonded to extracted human teeth according to one of four protocols. In the control group, teeth were etched with 37% phosphoric acid. In the experimental groups, the enamel was conditioned with three different self-etching primers, Clearfil SE Bond (CSE), Etch & Prime 3.0 (EP3), or Transbond Plus (TBP), as suggested by the manufacturer. The brackets were then bonded with Transbond XT in all groups. The present in vitro findings indicate that conditioning with TBP before bonding orthodontic brackets to the enamel surface resulted in a significantly (P < or = .001) higher SBS (mean, 16.0 +/- 4.5 MPa) than that found in CSE, EP3, and the control (acid-etched [AE]) groups. CSE produced bond strength values (mean 11.5 +/- 3.3 MPa) that are statistically comparable to those produced by acid etching (mean 13.1 +/- 3.1 MPa). The use of EP3 for enamel conditioning resulted in the lowest mean SBS value (mean 9.9 +/- 4.0 MPa). A comparison of the adhesive remnant index scores indicated that there was more residual adhesive remaining on the teeth that were treated with conventional acid etching than in the CSE and EP3 groups. In the TBP group, the failure sites were similar to those of the AE group but different from those of the CSE group.     

喷磨预处理对离体氟斑牙正畸托槽粘接强度的影响

目的筛选一种使氟斑牙与托槽有较高粘接强度的临床可行的粘接方法。方法选择15例氟斑牙正畸患者拔除的60颗第一前磨牙为研究对象,采用随机区组设计方法分为15个区组,每区组包括每位患者的4颗牙齿,区组内采用随机排列表法分为A、B、C、D 4小组,每小组即包括每位患者的1颗牙齿,共计15颗。4小组采用不同方法粘接托槽,分别为常规酸蚀后用釉质粘接剂粘接、喷磨预处理后用釉质粘接剂粘接、自酸蚀后用Bond粘接剂和光固化复合树脂粘接、喷磨预处理和自酸蚀后用树脂粘接剂和光固化复合树脂粘接;然后测定4小组的粘接强度和托槽底面粘接剂的余留情况。结果A、B、C、D 4小组的托槽/牙面剪切强度测试结果分别为（2.247±0.261）MPa、（5.374±0.469）MPa、（4.345±0.401）MPa、（5.791±0.636）MPa,4组间存在统计学差异（P<0.01）,D组剪切强度最大,其次为B、C组,A组最小。4组样本在去除托槽时残留粘接剂的情况无统计学差异（P>0.05）。结论氟斑牙面先用空气喷磨机喷磨,然后进行自酸蚀和树脂粘接托槽是一种较为可行的方法。     

An investigation into the use of a single component self-etching primer adhesive system for orthodontic bonding: a randomized controlled clinical trial

OBJECTIVE: This study assessed the in vivo bond failure of the single component orthodontic self-etching primer system, Ideal 1 (GAC Orthodontic Products) and compared it with the conventional acid etching using a conventional 37% o-phosphoric acid, rinsing and drying regimen when bonding stainless steel orthodontic brackets to enamel. DESIGN: Prospective randomized, controlled clinical trial. SETTING: Orthodontic Department, Bristol Dental School. MATERIAL AND METHODS: Twenty consecutive patients undergoing upper and lower fixed orthodontic treatment entered this cross-mouth control study. Diagonally opposite quadrants were randomly allocated to either the self-etching primer group or the conventional etching group. A total of 339 teeth were bonded with Ideal 1 light-cured adhesive. Bond failures and locus of bond failure were then recorded at 1, 6 and 12 months. RESULTS: Significantly more bond failures occurred at each of the 3 time intervals, 1, 6 and 12 months, where the enamel was pretreated with the Ideal I self-etching primer, than when the enamel was treated with the conventional etchant, 37% o-phosphoric acid. With the latter the cumulative bond failure rates were 3.0, 5.3 and 14.8%, respectively. With the self-etching primer the cumulative failure rates were 29.4, 56.5 and 72.4%. CONCLUSION: The study found that enamel pre-treatment with the Ideal 1 self-etching primer system prior to orthodontic bonding results in an unacceptably high bond failure rate when compared with conventional enamel acid etching.     

The effect of porcelain surface conditioning on bonding orthodontic brackets

The purpose of this study was to evaluate the effects of a new self-etching primer/ adhesive used to enhance the shear strength of orthodontic brackets bonded to porcelain surfaces. Forty-five porcelain maxillary central incisor teeth were used in the study. The teeth were divided randomly into three groups: group I (control), the porcelain teeth were etched with 37% phosphoric acid followed by a sealant and the brackets were bonded with a composite adhesive; group II, the porcelain teeth were microetched and hydrofluoric acid and silane applied and metal brackets were then bonded with the composite adhesive; and group III, the porcelain teeth were etched with phosphoric acid and a self-etching primer/adhesive applied before bonding. Brackets precoated with the adhesive were used on all three groups of teeth. All teeth were stored for 24 hours at 37 degrees C before debonding. The results of the analysis of variance (F = 10.7) indicated that there was a significant difference (P = .001) between the three groups. The mean shear bond strengths of conventional bonding using a 37% phosphoric acid and sealant was 4.4 +/- 2.7 MPa, whereas that of microetching followed by the application of hydrofluoric acid and silane was 11.2 +/- 4.7 MPa, and for the new self-etching primer/adhesive it was 10.3 +/- 5.3 MPa. The last two groups had the highest bond strength values and were not significantly different from each other.     

Comparison of the shear bond strength of 2 self-etch primer/adhesive systems.

Conventional adhesive systems use 3 different agents-an enamel conditioner, a primer solution, and an adhesive resin for bonding orthodontic brackets to enamel. A unique characteristic of some new bonding systems in operative dentistry is that they combine the conditioning and priming agents into a single application. Combining conditioning and priming saves time and should be more cost-effective to the clinician and indirectly to the patient. The purpose of this study was to assess and compare the effects of mix and no-mix self-etch primers/bonding systems on the shear bond strengths of orthodontic brackets. The brackets were bonded to extracted human molars according to the following protocols. In group I, a self-etch acidic primer/adhesive system, Transbond Plus (3M Unitek, Monrovia, Calif), was applied on the enamel surface as suggested by the manufacturer; it has 2 components that must be mixed before use. The brackets were then bonded with Transbond XT and light-cured for 20 seconds. In group II, a no-mix self-etch bracket adhesive system, Ideal 1 (GAG International, Islandia, NY), was applied to the teeth as suggested by the manufacturer. The self-etch primer has 1 component that does not need to be mixed before use. The brackets were then bonded with the adhesive and light-cured for 20 seconds. The in vitro findings indicated that the shear bond strength comparisons (t = 0.681) of the 2 adhesive systems were not significantly different (P =.501). The mean shear bond strength of the 2-component acid etch primer was 5.9 +/- 2.7 MPa, and the mean for the 1-component system was 6.6 +/- 3.2 MPa. The clinician should consider the bond strength and the ease of application of the various components of the bracket bonding systems available on the market.     

Can previously bleached teeth be bonded safely using self-etching primer systems?

OBJECTIVE: To test the null hypothesis that there is no statistical significance in (1) bond strength and (2) failure site location with bleached and unbleached enamel prepared with Transbond Plus Self-etching Primer between different time intervals. MATERIALS AND METHODS: Sixty freshly extracted human premolar teeth were randomly divided into three groups of 20 teeth each. Bleaching treatment was performed at two different time intervals (bleaching immediately before bonding and bleaching 30 days before bonding). All brackets were bonded with a self-etching primer system. The shear bond strength of these brackets was measured and recorded in MPa. Adhesive remnant index (ARI) scores were determined after the brackets failed. Data were analyzed with analysis of variance, Tukey, and chi2 tests. RESULTS: The bond strengths of group 1 (no bleaching, mean: 17.60 +/- 7.93 MPa) and group 3 (bleaching 30 days before bonding, mean: 13.95 +/- 5.23 MPa) were significantly higher (P < .05) than that of group 2 (bleaching immediately before bonding, mean: 11.45 +/- 5.25 MPa). No statistically significant differences were found between groups 1 and 3 (P > .05). ARI scores were significantly different among the three groups. In groups 1 and 2, there was a higher frequency of ARI scores of 2 to 4, indicating cohesive failures within the resin. In group 3, the failures were shown to be adhesive (resin/enamel interface) and cohesive characteristics. CONCLUSION: The use of a carbamide peroxide bleaching agent immediately before bonding significantly reduces the shear bond strength values of self-etching primer systems.     

Treated enamel surface patterns associated with five orthodontic adhesive systems--surface morphology and shear bond strength

The chief aim of this study was to evaluate the influence of three different types of pretreatment solutions (phosphoric acid, self-etching primers, and polyacrylic acid) on enamel surfaced when used in association with one of the five orthodontic adhesive systems. In the same vein, the shear bond strength of orthodontic metal brackets was also measured to evaluate the influence of bonding procedure. After the enamel surfaces of extracted human maxillary incisors were pretreated with the five adhesive systems, scanning electron microscopy (SEM) was used to observe the effects of pretreatment on enamel. Additionally, the shear bond strength of metal brackets bonded with the five adhesives was measured (n=6). SEM observation revealed different etching patterns on the enamel surface after pretreatment. As for shear bond strength, no statistically significant differences were observed among the five different adhesives (p>0.05). It was found that self-etching primers and polyacrylic acid produced a less aggressive etching pattern than phosphoric acid. Nonetheless, all the five adhesive systems provided acceptable bond strength and attachment of orthodontic brackets.     

两种正畸粘接系统对金属和陶瓷托槽粘接强度的影响

目的:评价传统正畸粘接系统和自酸蚀粘接系统分别对金属托槽和陶瓷托槽的粘接强度。方法:将100颗人前磨牙均分为4组:金属托槽/传统粘接系统组(1组)、金属托槽/自酸蚀粘接系统组(2组)、陶瓷托槽/传统粘接系统组(3组)、陶瓷托槽/自酸蚀粘接系统组(4组),使用Transbond XT树脂糊剂将托槽粘接在牙面上,测量各组的抗剪切粘接强度,并评价其剩余粘接剂指数,对结果进行单因素方差分析。结果:统计学分析表明金属托槽的抗剪切粘接强度高于陶瓷托槽,其差异具有统计学意义(P<0.05);1组和2组平均抗剪切粘接强度的差异无统计学意义(P>0.05),3组和4组间的差异也无统计学意义(P>0.05);各组剩余粘接剂指数的差异无统计学意义(P>0.05),但各组的粘接强度与剩余粘接剂指数有平行相关性(P<0.05)。结论:金属托槽的粘接强度高于陶瓷托槽;自酸蚀粘接系统与传统粘接系统都可满足正畸临床粘接托槽的需求;大部分样本的粘接失败发生在托槽/粘接剂界面或粘接剂内部破坏,表明牙釉质受损的几率较低,且粘接强度和剩余粘接剂指数之间存在统计学相关性。     

Evaluation of a new self-etching primer on bracket bond strength in vitro

The purpose of this in vitro study was to evaluate the influence of a new self-etching primer (Adper Prompt L-pop; 3M ESPE, St Paul, Minn) on shear bond strength of orthodontic brackets. Forty extracted human premolars were obtained and randomly divided into two groups of 20 each: group 1 (control), phosphoric acid + Transbond XT primer (3M Unitek, Monróvia, Calif) and group 2, Adper Prompt L-pop. Transbond XT adhesive paste (3M Unitek) was used in both groups for bracket bonding. All products were used according to the manufacturer's instructions. Instron Universal Testing Machine was used to apply an occlusal shear force directly onto the enamel-bracket interface at a speed of 0.5 mm/min. The groups were compared using Student's t-test. Mean results and standard deviation for the groups were: group 1 = 16.23 MPa (4.77), group 2 = 13.56 MPa (4.31). No significant difference was observed in the bond strengths of the two groups evaluated (P = .069). However, the adhesive remnant index was significantly less when conditioning the enamel with Adper Prompt L-pop compared with phosphoric acid (P = .0003). The results suggest no difference in bond strength whether a conventional etching and primer or Adper Prompt L-pop is used. The amount of adhesive on the enamel after debonding was significantly less when using Adper Prompt than when using phosphoric acid. These results indicated that Adper Prompt is potentially adequate for orthodontic bonding needs.     

Comparison of bonding time and shear bond strength between a conventional and a new integrated bonding system

Conventional adhesive systems use 3 different agents, an enamel conditioner, a primer solution, and an adhesive resin during the bonding of orthodontic brackets to enamel. A characteristic of some new bonding systems is that they combine the conditioning and priming agents into a single application as well as precoat the bracket with the adhesive in an attempt to save time during the bonding procedure. This study compared the total bonding time and shear bond strength (SBS) of 2 bracket-bonding systems: (1) an integrated system that incorporates a self-etching primer and precoated brackets and (2) a conventional system in which the etchant and primer are applied separately and the adhesive applied to the bracket by the clinician. The results of the SBS and the total bonding time comparisons (t = 3.451) of the 2 adhesive systems showed a significant difference (P = .0001). The mean SBS was 9.4+/-3.7 MPa for the new bonding system and 6.2+/-4.4 MPa for the conventional system. The mean total bonding time was 36.5 s/tooth for the new system and 46.7 s/tooth for the conventional system. The clinician has to decide whether the increase in bond strength, the decrease in the total bonding time, and the steps saved during the bonding procedure with the new bonding system balance the increased cost incurred.