Shear bond strength of precoated and uncoated brackets using a self-etching primer

OBJECTIVE: To test the hypothesis that there are no significant differences in the shear bond strength or the adhesive remaining on the tooth after debonding between precoated and uncoated brackets using a self-etching primer. MATERIALS AND METHODS: APC Plus precoated brackets and uncoated brackets were bonded with Transbond XT adhesive using the self-etching primer Transbond Plus Self-Etching Primer (TPSEP). The brackets were bonded to extracted human premolars and categorized into two groups: (1) TPSEP/Transbond XT and (2) TPSEP/APC Plus. Shear bond strength was measured with a universal testing machine. The adhesive remnant on each tooth after debonding was quantified with image analysis equipment. Scanning electron microscope (SEM) observations of enamel surfaces treated with TPSEP were also carried out. RESULTS: No significant differences were observed in the shear bond strengths for the two groups evaluated (P < .05). TPSEP/APC Plus left significantly less adhesive on the tooth after debonding than did TPSEP/Transbond XT (P < .05). It was observed that SEM left a porous and potentially retentive surface. CONCLUSIONS: There was no significant difference in the bond strength of the two systems tested, but there was a significant difference in the percentage of area of adhesive remaining on the tooth.     

Clinical evaluation of the failure rates of metallic brackets

Objectives

The aim of this study was to evaluate in vivo the bonding of metallic orthodontic brackets with different adhesive systems.

Material and Methods

Twenty patients (10.5-15.1 years old) who had sought corrective orthodontic treatment at a University Orthodontic Clinic were evaluated. Brackets were bonded from the right second premolar to the left second premolar in the upper and lower arches using: Orthodontic Concise, conventional Transbond XT, Transbond XT without primer, and Transbond XT associated with Transbond Plus Self-etching Primer (TPSEP). The 4 adhesive systems were used in all patients using a split-mouth design; each adhesive system was used in one quadrant of each dental arch, so that each group of 5 patients received the same bonding sequence. Initial archwires were inserted 1 week after bracket bonding. The number of bracket failures for each adhesive system was quantified over a 6-month period.

Results

The number of debonded brackets was: 8- Orthodontic Concise, 2- conventional Transbond XT, 9- Transbond XT without primer, and 1- Transbond XT + TPSEP. By using the Kaplan-Meier methods, statistically significant differences were found between the materials (p=0.0198), and the Logrank test identified these differences. Conventional Transbond XT and Transbond XT + TPSEP adhesive systems were statistically superior to Orthodontic Concise and Transbond XT without primer (p<0.05). There was no statistically significant difference between the dental arches (upper and lower), between the dental arch sides (right and left), and among the quadrants.

Conclusions

The largest number of bracket failures occurred with Orthodontic Concise and Transbond XT without primer systems and few bracket failures occurred with conventional Transbond XT and Transbond XT+TPSEP. More bracket failures were observed in the posterior region compared with the anterior region.     

Shear bond strength of orthodontic resins after caries infiltrant preconditioning

Objective:To investigate the influence of caries infiltrant preconditioning on the shear bond strength of orthodontic resin cements on sound and demineralized enamel.Materials and Methods:Stainless-steel brackets were bonded to sound or artificially demineralized (14 d, acidic buffer, pH 5.0) bovine enamel specimens using a resin cement or a combination of caries infiltrant preconditioning (Icon, DMG) and the respective resin cement (light-curing composite: Heliosit Orthodontic, Transbond XT, using either Transbond XT Primer or Transbond Plus Self Etching Primer; light-curing resin-modified glass ionomer cement: Fuji Ortho; or self-curing composite: Concise Orthodontic Bonding System). Each group consisted of 15 specimens. Shear bond strength was evaluated after thermo-cycling (10,000×, 5°C to 55°C) at a crosshead speed of 1 mm/min, and data were statistically analyzed by analysis of variance, Mann-Whitney test, and Weibull statistics. Adhesive Remnant Index (ARI) scores and enamel fractures were determined at 25× magnification and were statistically analyzed by regression analyses (P < .05).Results:The caries infiltrant system significantly increased the shear bond strength of Transbond XT Primer, Transbond Plus Self Etching Primer, and Fuji Ortho in sound specimens, and of all resin cements except for the Concise Orthodontic Bonding System in demineralized enamel. Overall, caries infiltrant preconditioning decreased significantly the number of enamel fractures, but it did not affect ARI scores.Conclusion:Preconditioning of sound and demineralized enamel with the caries infiltrant system did not impair but rather increased the shear bond strength of most orthodontic resin cements while decreasing the risk of enamel fracture at debonding.     

Shear bond strength of orthodontic brackets with newly developed antibacterial self-etch adhesive

Because the enamel adjacent to brackets may be affected by microorganisms, an antibacterial adhesive may be a useful choice to prevent and reduce demineralization. The purpose of this in vitro study was to determine the (1) shear bond strength of a self-etch and an antibacterial self-etch adhesive for orthodontic metal brackets and (2) bond failure interface of a self-etch and an antibacterial self-etch adhesive using a modified adhesive remnant index (ARI). Twenty-four defect-free premolars were randomly assigned into two groups. The teeth received the following treatments-group 1: Transbond Plus Self-Etching Primer + Transbond XT; group 2: antibacterial dentin bonding system (ABF) + Transbond XT. All samples were stored in deionized water at 37 degrees C for 48 hours. Shear debonding tests were performed at a crosshead speed of five mm/min. The results in megapascals were (median, minimum, maximum) group 1: 8.53, 4.59, 12.63; group 2: 9.79, 4.01, 22.10, respectively. Mann-Whitney test revealed that the difference between the groups was not statistically significant (P = .2, P > .05). Failed brackets were examined by an optical microscope at 16x magnification to determine the bond failure interface using a modified ARI. The predominant mode of failure for both groups was at the bracket-adhesive interface. ABF may have sufficient mechanical properties and also an antibacterial effect that makes it a good choice for orthodontic bonding.     

Metallic brackets bonded with resin-reinforced glass ionomer cements under different enamel conditions

OBJECTIVE: To assess the shear bond strength of metallic orthodontic brackets bonded with either Fuji Ortho or Ortho Glass LC resin-reinforced glass ionomer cements to enamel surfaces under different conditions, namely, enamel without etching, enamel conditioned with 37% phosphoric acid and enamel conditioned with Transbond Plus Self Etching Primer (TPSEP). MATERIALS AND METHODS: One hundred and five bovine inferior incisors were divided into seven groups (n = 15). In group 1 (control) Transbond XT was used according to the manufacturer's recommendations. In groups 2, 3, and 4 all using Fuji Ortho LC, the brackets were bonded, respectively, to enamel nonetched, enamel etched with 37% phosphoric acid, and enamel etched with TPSEP. In groups 5, 6, and 7, the bonding was performed using Ortho Glass LC under the same enamel conditions observed in the other experimental groups. After 24 hours, shear bond strength tests were performed for all samples at a crosshead speed of 0.5 mm/min. RESULTS: The results (MPa) showed no statistically significant difference between groups 1, 3, and 4 (P > .05). However, such groups were statistically superior to the others (P < .05). No statistically significant difference was observed between groups 2, 6, and 7 (P > .05). Group 5 showed the lowest shear strength value, which was also statistically inferior to the other groups (P < .05). CONCLUSIONS: Regardless of the enamel treatment, Fuji Ortho LC yielded shear strength values superior to those from Ortho Glass LC.     

Bonding characteristics of a self-etching primer and precoated brackets: an in vitro study

Little is known about the performance of Transbond Plus Self-Etching Primer (TPSEP), especially when used with Adhesive Precoated Brackets (APC 1 and APC 2). The aim of this study was to compare the shear bond and rebond strengths and failure sites of APC 1 and APC 2 with a non-coated bracket system [Victory Series (V)] using Transbond XT light-cured adhesive and TPSEP or 37 percent phosphoric acid as the conditioner. The results demonstrated that on dry testing of 120 brackets when applying an occluso-gingival load to produce a shear force at the bracket-tooth interface, there was no statistically significant difference in the shear bond strength (SBS) of APC 1 (68.4 N), APC 2 (74.9 N), and V brackets (75.4 N, control group). There was also no significant difference in bond failure sites of the APC 1 and APC 2 when compared with the non-coated bracket system using Transbond XT light-cured adhesive and TPSEP, with bond failure for all groups occurring mainly at the adhesive-enamel interface. There was a significant difference in the SBS of the V brackets when using TPSEP and 37 percent phosphoric acid as the conditioners. The latter was lower (60.6 N) and the bond failure site changed from the enamel-adhesive interface to the bracket-adhesive interface. The shear rebond strengths of all bracket types were statistically significantly lower (P < 0.05) than their initial SBS (APC 1, APC 2, and V: 35.9, 36.7, and 34.1 N, respectively) and the locus of bond failure altered from the adhesive-enamel interface to the bracket-adhesive interface. A clinical trial using TPSEP as a conditioner would be useful as the time taken to remove the adhesive from the enamel surface may be reduced following debond.     

Bond strength of disinfected metal and ceramic brackets: an in vitro study

The aim of this in vitro investigation was to test whether disinfecting with Chlorhexamed fluid had an influence on the shear bond strength of metal and ceramic orthodontic brackets. Metal and ceramic brackets were fixed by the composite adhesives Transbond XT (light curing) and Concise (chemical curing) to 224 bovine permanent mandibular incisors. Bovine teeth were divided into eight groups of 28 each as group 1: metal bracket/Transbond XT, group 2: disinfected metal bracket/Transbond XT, group 3: metal bracket/Concise, group 4: disinfected metal bracket/Concise, group 5: ceramic bracket/Transbond XT, group 6: disinfected ceramic bracket/Transbond XT, group 7: ceramic bracket/Concise, and group 8: disinfected ceramic bracket/Concise. Adhesive bonding was done according to the manufacturers' instructions. As shown by group comparison (Kruskal-Wallis test, univariate analysis of variance, P < .001), the disinfection of metal brackets had no statistically relevant influence on shear bond strength (P = .454). However, disinfecting ceramic brackets with either adhesive led to a significant reduction in shear bond strength compared with the untreated ceramic bracket group (P < .001). The Fisher's exact test of the Adhesive Remnant Index (ARI) scores showed a significant difference within the metal group bonded with different adhesives (P = .0003). The ARI scores 1 and 2 were not reached by the ceramic bracket groups. The disinfection of the ceramic brackets is a suitable procedure for clinical use because the measured shear bond strength values were higher than 6-8 MPa required in orthodontics.     

两种光固化正畸黏结剂的黏结性能评价

目的:研究光固化树脂加强型玻璃离子黏结剂与自酸蚀光固化正畸黏结剂对金属托槽-牙面黏结的特点。方法:60颗离体前磨牙随机分成6组,每组10颗牙,3组用光固化树脂加强型玻璃离子黏结剂,另3组用自酸蚀光固化复合树脂黏结剂黏结正畸托槽,分别于0.5、24h及冷热循环实验后测试其抗剪强度及黏结剂残留指数,并通过扫描电镜观察树脂—牙釉质面形态。结果:2种材料黏结强度均能超过5MPa。但是,24h自酸蚀光固化正畸黏结剂的强度高于光固化树脂加强型玻璃离子黏结剂的强度(P<0.05)。结论:2种光固化正畸黏结剂能提供正畸临床黏结金属托槽足够的黏结力。     

Effects of a fluoride-containing casein phosphopeptide-amorphous calcium phosphate complex on the shear bond strength of orthodontic brackets

The purpose of this study was to investigate the effects of enamel pre-treatment with a new fluoride-containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) complex on the shear bond strength (SBS) of brackets bonded with etch-and-rinse or self-etching adhesive systems. The material comprised 66 extracted human premolars randomly divided into six equal groups with respect to the enamel pre-treatment and adhesive system employed: 1. No pre-treatment and brackets bonded with the etch-and-rinse adhesive system (Transbond XT). 2. Pre-treatment with fluoride-containing CPP-ACP paste (MI Paste Plus) and Transbond XT. 3. Pre-treatment with non-fluoride CPP-ACP paste (MI Paste) and Transbond XT.4. No pre-treatment and brackets bonded with the self-etching adhesive system (Transbond Plus). 5 and 6. Enamel pre-treated as for groups 2 and 3, respectively, and the Transbond Plus. Bonded specimens were subjected to thermal cycling (×1000) before SBS testing. The residual adhesive on the enamel surface was evaluated after debonding with the adhesive remnant index (ARI). Data evaluation was made using one-way analysis of variance and Tukey test for SBS results, and Kruskal-Wallis test for ARI results. The results showed that enamel pre-treatment with either fluoride or non-fluoride CPP-ACP paste had no significant effect on the SBS of the self-etching adhesive system (P > 0.05). Enamel pre-treatment with non-fluoride CPP-ACP in group 3 significantly reduced the SBS of the etch-and-rinse adhesive (P < 0.001), while pre-treatment with fluoride-containing CPP-ACP paste (groups 2 and 5) did not affect debonding values (P > 0.05). The fluoride-containing CPP-ACP did not compromise the SBS of brackets bonded with the tested etch-and-rinse and self-etching systems, but its non-fluoride version significantly decreased the SBS of the etch-and-rinse adhesive system.     

Direct bonding with precoated brackets and self-etching primers

PURPOSE: To evaluate the shear bond strength and the adhesive remnant on the tooth after the debonding of APC Plus precoated brackets, when conditioning the enamel with phosphoric acid and Transbond Plus Self Etching Primer (TSEP), in comparison with uncoated brackets bonded with Transbond XT. METHODS: The brackets were bonded to extracted premolars, which were divided into three groups: (1) Acid/Transbond XT, (2) Acid/ APC Plus and (3) TSEP/APC Plus. Shear bond strength was measured using a universal test machine. The crosshead speed was 1 mm/minute. The adhesive remnant on the tooth was quantified using an image analysis equipment. RESULTS: No significant differences were found in the bond strengths of the three groups evaluated (P> 0.05). The two groups in which APC Plus system was used left significantly less adhesive on the tooth than Transbond XT. TSEP/APC Plus left significantly less adhesive than Acid/APC Plus (P< 0.017).     

Comparison of shear bond strengths of orthodontic brackets bonded with flowable composites

This study evaluated the shear bond strengths of orthodontic brackets bonded to human premolars using five different combinations of flowable composites and one-step self-etching adhesives (n=12): (1) Adper Easy Bond+Filtek Supreme XT Flow; (2) Futurabond NR+Grandio Flow; (3) Clearfil S3 Bond+Clearfil Majesty Flow; (4) AdheSE One+Tetric EvoFlow; and (5) Transbond Plus Self Etching Primer+Transbond XT Light Cure Adhesive. After shear bond strength testing, adhesive remnant index (ARI) scores were given according to the amount of adhesive and resin remaining on the brackets. On shear bond strength, there were no statistically significant differences between Groups 2 and 4 and between Groups 3 and 5 (p>0.05). On ARI scores, the predominant ARI scores in Groups 1, 2, 3, and 5 were 4, 2, 5, and 4 respectively; in Group 4, they were 0 and 4. Results showed that some combinations of flowable composites and self-etching adhesives might not be suitable for orthodontic use due to their low shear bond strengths and high ARI scores -with the latter signaling the risk of damaging the enamel surface during debonding.     

Bond strengths and adhesive remnant index of self-etching adhesives used to bond brackets to instrumented and uninstrumented enamel

PURPOSE: This study evaluated bond strengths of orthodontic brackets to instrumented and uninstrumented enamel using self-etching adhesive systems when compared to a total-etch adhesive system. The adhesive remnant index (ARI) was also determined after debonding. METHODS: 140 bovine incisors were included in acrylic resin, and divided randomly in two groups: instrumented vs. uninstrumented enamel. For the instrumented enamel, specimens had their facial enamel ground flat to 600-grit. In each group, specimens were subdivided into four experimental subgroups according to the adhesive technique used: Transbond Plus, Adper Prompt L-Pop, iBond, and Adper Single Bond, applied following manufacturers' instructions. Orthodontic brackets were bonded to the treated instrumented or uninstrumented enamel with Transbond XT light-cured resin-based composite cement, and the bond strength was tested in shear mode after 7 days. One group where no etch and no adhesive were used served as a control. ARI scores were determined after debonding. RESULTS: There was no statistically significant difference in mean bond strengths between instrumented and uninstrumented enamel for any of the adhesive systems (P > or = 0.05). No significant differences were observed for bond strengths among the adhesives tested (P = 0.308), and all experimental groups resulted in mean bond strengths significantly higher than the controls (P < 0.05). Statistically significant differences were identified when ARI scores were compared, with less adhesive remnants being observed for iBond (uninstrumented enamel) and the control groups (P < 0.05).     

Shear bond strength of a new fluoride-releasing orthodontic adhesive

This study evaluated the shear bond strength of stainless steel brackets bonded to enamel with a new fluoride-releasing orthodontic adhesive system. A total of 140 extracted human bicuspids were randomly divided into four groups. Group I (Transbond XT) was a control group in which enamel was etched with phosphoric acid. For the remaining groups, enamel was conditioned with a self-etching primer (SEP): Group II (Transbond Plus), Group III (BeautyOrtho Bond), and Group IV (BeautyOrtho Bond + Salivatect). Stainless steel brackets were bonded to all tooth samples. After which, the samples were stored, thermocycled, tested, and statistically analyzed. Besides bond strength evaluation, the adhesive remnant index (ARI) was also evaluated. The shear bond strengths of Groups II, III, and IV were significantly lower than Group I, and Group II was significantly greater than that of Group III. Concerning ARI scores, no significant differences were found between the groups. Further, no enamel fracture was observed during shear bond test with the new SEP. In conclusion, when enamel was conditioned with the new SEP, the mean values of shear bond strength yielded were lower than when it was etched with 37% phosphoric acid. Nonetheless, these mean values were higher than the average suggested by Reynolds as optimum for clinical treatment.     

Effect of blood contamination on shear bond strength of brackets bonded with conventional and self-etching primers.

This study assessed the effect of blood contamination on the shear bond strength and bond failure site of 2 different orthodontic primers (Transbond XT and Transbond Plus Self-Etching Primer, both from 3M Unitek, Monrovia, Calif) used with adhesive-precoated brackets. Four different enamel surface conditions were tested: (1) dry, (2) blood contamination before priming, (3) blood contamination after priming, and (4) blood contamination before and after priming. Noncontaminated enamel surfaces had the highest bond strengths for both conventional and self-etching primers, which produced almost the same strength values. Under blood-contaminated conditions, both primers showed significantly reduced shear bond strengths. For the conventional primer, no significant differences were reported among the blood-contaminated groups, whereas when the self-etching primer was used, condition 4 reduced significantly the bond strength values. Significant differences in debond locations were found among the groups bonded with the 2 primers under the various enamel surface conditions.     

Effect of saliva on shear bond strength of an orthodontic adhesive used with moisture-insensitive and self-etching primers.

The purpose of this study was to investigate the effect of saliva contamination on the shear bond strength of an orthodontic adhesive used with Transbond Moisture-Insensitive Primer (MIP, 3M Unitek, Monrovia, Calif) and Transbond Plus Self-Etching Primer (SEP, 3M Unitek). Hydrophobic Transbond XT primer (XT, 3M Unitek) was used as a control. A total of 162 extracted premolars were collected and divided equally into 9 groups of 18 teeth each, and brackets were bonded with Transbond XT adhesive (3M Unitek) under different experimental conditions: (1) control: etch/dry/XT, (2) etch/dry/MIP, (3) etch/dry/MIP/wet (saliva)/MIP, (4) etch/wet/MIP, (5) etch/wet/MIP/wet/MIP, (6) dry/SEP, (7) dry/SEP/wet/SEP, (8) wet/SEP, and (9) wet/SEP/wet/SEP. Shear bond strength of each sample was examined with a testing machine. The results showed that the control group had the highest mean shear bond strength (group 1, 21.3 +/- 6.8 MPa), followed by the MIP group in a dry field (group 2, 20.7 +/- 5.0 MPa). No significant difference was found between groups 1 and 2. Groups 3 through 9 had similar mean strengths, ranging from 12.7 to 15.0 MPa (P >.05), which were significantly lower than in groups 1 and 2 (P <.05). There was no significant difference in bond-failure site among the 9 groups. It was concluded that (1) Transbond XT adhesive with Transbond XT primer and MIP in a dry field yields similar bond strengths, which are greater than all other groups, (2) saliva contamination significantly lowers the bond strength of Transbond MIP, (3) saliva has no effect on the bond strength of Transbond SEP, (4) Transbond XT adhesive with Transbond MIP and SEP might have clinically acceptable bond strengths in either dry or wet fields.     

An evaluation and comparison of orthodontic bracket bond strengths achieved with self-etching primer.

The bonding of orthodontic brackets to enamel is a multistep process. To simplify bonding and decrease chair time, Transbond Plus Self-Etching Primer (3M Unitek, Monrovia, Calif) has been introduced; the primer combines the etching, rinsing, and priming steps. This in vitro study evaluated the shear bond strengths and interoperator variability of self-etching primer, as compared with conventional phosphoric acid etching with 2 common orthodontic resins. A total of 214 teeth were bonded, according to the following protocols: group A: self-etching primer plus Transbond XT light-cured resin (3M Unitek); group B: 35% phosphoric acid (15 seconds) plus Transbond XT resin; and group C: 37% phosphoric acid (15 seconds) plus Enlight bonding resin (Ormco, Glendora, Calif). Significantly higher bond strengths were seen in group B than in group A (P =.004) and group C (P =.002). The mean shear bond strengths of group A were not significantly different from those of group C (P =.99). When 3 orthodontists bonded a total of 60 premolars using the protocols of groups A and B, significant differences in shear bond strengths and strength ranking were found. The mean values they obtained using the self-etching primer were not significantly different, but significant differences in mean values were found between operators when the phosphoric acid-etching technique was used.     

Effect of water and saliva contamination on shear bond strength of brackets bonded with conventional, hydrophilic, and self-etching primers

This study assessed the effect of water and saliva contamination on the shear bond strength and bond failure site of 3 different orthodontic primers (Transbond XT, Transbond Moisture Insensitive Primer, and Transbond Plus Self Etching Primer; 3M Unitek, Monrovia, Calif) used with a light-cured composite resin (Transbond XT). Bovine permanent mandibular incisors (315) were randomly divided into 21 groups (15 in each group). Each primer-adhesive combination was tested under 7 different enamel surface conditions: (1) dry, (2) water application before priming, (3) water application after priming, (4) water application before and after priming, (5) saliva application before priming, (6) saliva application after priming, and (7) saliva application before and after priming. Stainless steel brackets were bonded in each test group with composite resin. After bonding, all samples were stored in distilled water at room temperature for 24 hours and then tested for shear bond strength. Noncontaminated enamel surfaces had the highest bond strengths for conventional, hydrophilic, and self-etching primers, which produced the same strength values. In most contaminated conditions, the self-etching primer had higher strength values than either the hydrophilic or conventional primers. The self-etching primer was the least influenced by water and saliva contamination, except when moistening occurred after the recommended 3-second air burst. No significant differences in debond locations were found among the groups bonded with the self-etching primer under the various enamel conditions.     

A New Generation of Self-etching Adhesives: Comparison with Traditional Acid Etch Technique

OBJECTIVE: The aim of this study was to determine the shear bond strength (SBS), etching pattern and depth, and debonding performance of several market-leading, self-etching (SE) adhesives primarily used in restorative dentistry (iBond, Clearfil S(3) Bond, Clearfil Protect Bond, AdheSE, XenoIII), two experimental self-etching adhesives (exp. Bond 1, exp. Bond 2) and one experimental self-etching cement (SE Zement) used with and without prior phosphoric acid-etching, and to compare them to an orthodontic self-etching product (Transbond Plus SE Primer) and to traditional acid-etch technique (Transbond XT Primer, phosphoric acid) MATERIALS AND METHODS: All adhesives were applied on pumiced and embedded bovine incisors following the manufacturers' instructions. Then one bracket each (coated with Transbond XT composite) was bonded (n = 20). Transbond XT was polymerized for 20 s from the incisal and gingival sides using a halogen device positioned at a constant 5 mm from and a 45 degrees angle to the specimen. The specimens were stored in distilled water for 24 h at 37 degrees C before measuring SBS. The ARI (adhesive remnant index) for all specimens was determined from the sheared-off brackets of each. After conditioning, the surface texture was morphologically evaluated from scanning electron microscope (SEM) images, while the etching depth was determined using a confocal laser-scanning microscope (CLSM). All groups were tested for normal distribution and analyzed by applying ANOVA, Kruskal-Wallis or the t test. In addition, a Bonferroni correction was used. RESULTS: The median values of the SBS tests were: SE Zement 3.0 MPa, SE Zement preceded by phosphoric acid etching 11.2 MPa, experimental bond 1: 7.4 MPa, experimental bond 2: 5.6 MPa, iBond 8.1 MPa, Clearfil S(3) Bond 14.1 MPa, Clearfil Protect Bond 16.6 MPa, Clearfil SE Bond 15.9 MPa, AdheSE 16.0 MPa, XenoIII 16.1 MPa, Transbond SE Primer 20.7 MPa, acid-etching+Transbond XT Primer 21.0 MPa. With the exception of iBond, we observed no significant differences among the self-etching adhesives used in Restorative Dentistry or in comparison to the Transbond Plus SE Primer. No significant differences were apparent even when compared to the Transbond XT Primer after phosphoric acid-etching. Both experimental bonding agents and SE Zement without acid etching performed significantly worse than the products mentioned above, failing to demonstrate sufficient adhesive strength. SEM examination revealed less distinctive enamel-etching patterns for self-etching products than for phosphoric acid-etching. CLSM analysis revealed etching depths between 0.5 and 20 microm depending on the product. When self-etching products were used, less residual composite remained on the enamel surface than after phosphoric acid-etching. CONCLUSIONS: All the adhesives tested are suitable for bonding orthodontic brackets and to reduce the risk of enamel fracture while minimizing etching depth, which in turns means less conditioning-related enamel loss. More development is needed to improve the etching performance of both experimental bonding agents and SE Zement.     

Six-month bracket survival with a self-etch adhesive

OBJECTIVE: To evaluate, over a 6-month period, the clinical performance of a self-etch adhesive (Transbond Plus Self-Etching) compared with a conventional adhesive that uses the etch and rinse approach (Transbond XT). MATERIALS AND METHODS: One operator, using the straight-wire technique, placed 567 metallic brackets in 30 patients (age range 12-18 years) such that homologous teeth from the same arch received different materials. The brackets were bonded following the manufacturer's instruction except for the fact that the self-etch system was brushed for a longer time than recommended (10-15 seconds). The failure modes were visually classified into three modes: adhesive-enamel, adhesive-bracket, and cohesive failure. The survival rate of the brackets was estimated by Kaplan-Meier and log-rank test (P < .05). RESULTS: The failure rates of the conventional and self-etch [corrected] adhesives were 10.6% and 7.4%, respectively. The failure rate of the conventional system was 0.43 [corrected] times greater than that of the self-etch system. The self-etch adhesive showed a higher survival rate compared with the conventional system (P < .05). Most of the failures were cohesive and at the adhesive-enamel surface. No difference in the fracture debonding mode was observed for the materials. CONCLUSIONS: These findings indicate that the self-etch Transbond Plus Self-Etching can be safely used for orthodontic brackets because it provides higher survival rates than does the conventional Transbond XT.     

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.