Enamel Conditioning Research Articles

Evaluation of different enamel conditioning techniques for orthodontic bonding

ObjectiveThe aim of this study was to compare the effects of different enamel conditioning techniques for bracket bonding.MethodsNinety-one human premolars were randomly divided in six groups of 15 specimens each. The enamel surfaces of the teeth were etched with 35% orthophosphoric acid in Group 1, with a self-etching primer in Group 2, sandblasted in Group 3, sandblasted and etched with 35% orthophosphoric acid in Group 4, conditioned by Er:YAG laser in Group 5 and conditioned by Er:YAG laser and etched with 35% phosphoric acid gel respectively in Group 6. After enamel conditioning procedures, brackets were bonded and shear bonding test was performed. After debonding, adhesive remnant index scores were calculated for all groups. One tooth from each group were inspected by scanning electron microscope for evaluating the enamel surface characteristics.ResultsThe laser and acid etched group showed the highest mean shear bond strength (SBS) value (13.61 ± 1.14 MPa) while sandblasted group yielded the lowest value (3.12 ± 0.61 MPa).ConclusionsAlthough the SBS values were higher, the teeth in laser conditioned groups were highly damaged. Therefore, acid etching and self-etching techniques were found to be safer for orthodontic bracket bonding. Sandblasting method was found to generate inadequate bonding strength.

Depth of resin penetration into enamel with 3 types of enamel conditioning methods: A confocal microscopic study

The clinical efficiency of a bonding material relies on its bond strength and debonding characteristics; the depth of resin penetration into enamel affects both of these factors. The depth of resin penetration has been previously studied by researchers using laborious, indirect methods, including the scanning electron microscope and the optical microscope. We used a more direct method, confocal microscopy, to visualize the resin tags in enamel. Thirty maxillary first premolars were selected and divided into 3 groups. In group A, the buccal enamel surfaces were conditioned with 37% phosphoric acid; in group B, a self-etching primer was used; and group C was treated with air abrasion. Transbond XT adhesive (3M Unitek, Monrovia, Calif) was used to bond a modified bracket. Transbond XT primer (3M Unitek) mixed with rhodamine B fluorescent dye (Chennai Chemicals, Chennai, India) was applied in groups A and C. In group B, rhodamine was mixed with self-etching primer. After curing, the brackets were debonded, and the teeth were visualized under the fluorescent channel of the confocal microscope. Maximal resin penetration of 53.9 μm was observed in group A, followed by group B at 40.5 μm and group C at 39.9 μm. Confocal microscope evaluation showed that enamel conditioning with 37% phosphoric acid produced greater depths of resin penetration than did self-etching primer or air abrasion.

Roughness of enamel surfaces after different bonding and debonding procedures

Maintaining an intact enamel surface is an essential aspect of orthodontic therapy; however, various therapeutic measures can affect this surface. The aim of our study was to evaluate roughness of the enamel surface after different conditioning and polishing procedures. 42 bovine incisors were submitted to conventional abrasion (using 37% phosphoric acid), to air abrasion, and a combination of the two. Brackets were put in place and then debonded, and the remaining adhesive removed with a carbide bur or via air abrasion. The enamel surface's roughness was assessed using a confocal laser scanning microscope (CLSM). Mean roughness (R(a)) was 33.1. There were no statistically significant differences among the six groups, or in R(q) values. Under CLSM, the roughness after polishing via air abrasion appeared even. Although it was macroscopically smoother after polishing with a carbide bur, the surface showed a wave-like pattern. The method of enamel conditioning revealed no significant effect on the enamel surface after debonding. Neither polishing via air abrasion nor carbide bur resulted in differences in superficial roughness. However, the carbide bur left a wave-like pattern on the enamel surface.

Bond Strengths of Metal, Ceramic and Polymer Brackets in Combination with Different Enamel Preconditioning Methods

Introduction: Adhesive technology is widely spread throughout the different specialities of dentistry. In orthodontics the bonding of brackets accounts for a significant percentage of time in practice routine. Bond strength is dependent on several factors such as enamel conditioning, adhesive technology and the material and construction of the bracket base. It was the intention of the present study to investigate the bond strength in relation to the above mentioned parameters. Method: Four different brackets (metal, ceramic, polymer, fiber reinforced polymer) were evaluated for their bond strength during tensile testing with a universal testing machine using a conventional composite (Transbond MIP, XT) and in the case of the fiber reinforced bracket additionally a specially designed adhesive (Quick-Bond). Enamel conditioning was achieved with conventional etching, air-abrasion or a combination of both techniques. ARI (adhesive remnant index) scores were evaluated. Results: There were significant differences between the types of enamel conditioning. All brackets showed significantly lower bonding forces when the enamel was prepared with air-abrasion alone. Metal brackets had the highest bonding strength and the fiber reinforced composite brackets with the conventional adhesive the lowest. The ARI scores showed good correlation to the bonding forces, with low bonding forces presenting as a detachment at the enamel-adhesive interface. Conclusion: Air-abrasion alone showed significantly lower bonding forces than enamel conditioning with etching for all bracket types. This finding was independent of the bracket material, base design or adhesive system.

Microtensile bond strength test and failure analysis to assess bonding characteristics of different adhesion approaches to ground versus unground enamel

This study evaluated the bonding characteristics to ground and unground enamel obtained with different strategies. For this purpose, 24 sound third-molars were bisected mesiodistally to obtain tooth halves. A flat enamel area was delimited in the tooth sections, which were randomly distributed into 8 groups (n=6), according to the enamel condition (ground and unground) and adhesive system (Adper Single Bond 2 - SB2; Adper Prompt L-Pop - PLP; Adper Prompt - AD; Clearfil SE Bond - SE). Each system was applied according manufacturers' instructions and a 6-mm-high resin composite "crown" was incrementally built up on bonded surfaces. Hourglass-shaped specimens with 0.8 mm(2) cross-section were produced. Microtensile bond strength (μTBS) was recorded and the failure patterns were classified. Results were analyzed by two-way ANOVA and Tukey's test (α=0.05). There were no statistically significant differences among the μTBS values of SB2, PLP and AD (p>0.05). SE values were significantly lower (p0.05). There was prevalence of cohesive failure within enamel, adhesive system and resin composite for SB2. The self-etch systems produced higher incidence of cohesive failures in the adhesive system. Enamel condition did not determine significant differences on bonding characteristics for the same bonding system. In conclusion, the bonding systems evaluated in this study resulted in specific μTBS and failure patterns due to the particular interaction with enamel.

Laser Conditioning of Enamel with the Erbium YAG and the CO2 Laser.Bond Strength and Surface Structure

Introduction: Acid etching is the standard procedure for enamel conditioning. However it leaves a demineralized surface, which is prone to caries. This is a major disadvantage especially in combination with a fixed orthodontic appliance and reduced oral hygiene. Therefore it was the aim of this study to evaluate the effect of an Erbium:YAG laser as well as a CO2 laser on bond strength and enamel surface structure. Material and methods: 90 freshly extracted bovine incisors were used as substitutes for human enamel. One group of 30 samples was bonded following conventional acid conditioning and served as the control group. The two other groups were conditioned with an Erbium:YAG laser or a CO2 laser. All samples were tested for shear forces with a universal testing machine (Instron 4444). PMMA (polymethylmethacrylate) cylinders were used as shear bodies. SEM (scanning electron microscope) images were taken to compare the effect of the conditioning methods on the enamel surface. Results: There was a significant difference between the shear forces attained with conventional etching (16.5 MPa), the Erbium:YAG laser (6.2 MPa) and the CO2 laser (3.3 MPa). However due to large standard deviations in the groups conditioned with laser, no significant difference was observed between the Erbium:YAG laser and the CO2 laser. The SEM images revealed a micro-retentive relief for both lasers, but the surface treated with the Erbium:YAG laser showed cracks in the enamel. Conclusion: Conventional acid etching showed a superior bond strength in comparison with both the laser conditioning methods. Of concern were the fissures observed in the enamel surface treated with the Erbium:YAG laser.

The impact of fissure depth and enamel conditioning protocols on glass-ionomer and resin-based fissure sealant penetration.

To evaluate the effect that fissure depth and enamel conditioning protocols have on penetration abilities of resin-based and glass-ionomer fissure sealants. Fifty extracted human molars were randomized into 10 experimental groups. Conditioning was performed as follows: groups I and VI, no pretreatment; groups II and VII, 10% polyacrylic acid and 37% phosphoric acid, respectively; groups III and VIII, self-etching adhesive; groups IV and IX, Er:YAG laser; groups V and X, Er:YAG laser/10% polyacrylic acid and laser/37% phosphoric acid, respectively. In groups I to V, teeth were sealed with a glass-ionomer material, and in groups VI to X a resin-based sealant was used. The sealed teeth were sectioned and the penetration ability was evaluated using scanning electron microscopy (SEM). Pretreatment with a suitable acid resulted in superior penetration of glass-ionomer and resin-based sealant when compared with other conditioning protocols (p < 0.0001), except for the teeth treated with both Er:YAG laser and acid. Both conditioning protocol and fissure depth significantly affected the sealant penetration (p < 0.0001), but fissure depth had a greater impact on fissure penetration than did conditioning protocol. Resin-based and glass-ionomer sealing materials show similar potential for pit-and-fissure penetration. Penetration of a fissure sealant is largely influenced by the fissure depth. Regarding the conditioning protocol, a pretreatment with a suitable acid is essential to obtain an adequate penetration of a sealing material.

Effetto della contaminazione ematica sul distacco di tre differenti tipi di brackets autoleganti: studio sperimentale in vitro

Objectives To assess the effect of blood contamination on the bonding and bond-failure site of 3 different types of self-ligating bracket. Materials and methods Two hundred forty bovine permanent mandibular incisors were randomly divided into 12 groups, each containing 20 specimens. Three different self-ligating brackets (Smart Clip - 3 M Unitek, Monrovia, California, USA; Damon - Ormco, Glendora, California, USA; and Quick - Forestadent, Pforzheim, Germania) were bonded to the teeth with Orthosolo primer (Ormco, Glendora, California, USA) and Trasbond XT composite (3 M Unitek, Monrovia, California, USA). Bonding was tested under different surface enamel conditions: dry, contaminated with blood before priming, contaminated with blood after priming, and contaminated with blood before and after priming. After bonding, all samples were stored in distilled water at room temperature for 24 hours. Shear bond strength was then evaluated with a universal testing machine (Mod. 4301, Instron Corp., Canton, Massachussets, USA). After bond failure, the bracket bases and the enamel surfaces were examined under an optical microscope (Stereomicroscope SR, Zeiss, Oberkochen, Germany) at 10 x magnification, and the amount of adhesive left on the enamel surface was rated with the adhesive remnant index (ARI). All the data were statistically analyzed (Chi-square test; level of significance p < 0.05). Results and conclusions ARIs of 2 were more frequent among samples bonded to dry enamel, whereas samples bonded to blood-contaminated enamel (before, after, or before and after priming) exhibited a higher frequency of ARI 0. However, there were no significant differences between the ARI scores for the 3 conditions of contaminated enamel or for those related to the 3 types of self-ligating brackets tested.

Influence of Enamel Conditioning on the Shear Bond Strength of Different Adhesives

Phosphoric acid etching is the gold standard for enamel conditioning. However, it is possible that air abrasion or a combination of air abrasion and etching might result in enhanced adhesion. The aim of this study was to investigate the effect of different enamel conditioning methods on the bond strength of six adhesives. Three different enamel conditioning procedures (phosphoric acid etching, air abrasion, air abrasion + phosphoric acid etching) were evaluated for their influence on the shear bond strength of six different adhesives (Transbond™ XT, Cool-Bond™, Fuji Ortho LC, Ultra Band-Lok, Tetric(®) Flow, Light-Bond™). Each group consisted of 15 specimens. Shear forces were measured with a universal testing machine. The scores of the Adhesive Remnant Index (ARI) were also analyzed. There were no significant differences between phosphoric acid etching and air abrasion + phosphoric acid etching. Air abrasion as a single conditioning technique led to significantly lower shear forces. The ARI scores did not correlate with the shear strengths measured. There were greater variations in shear forces for the different adhesives than for the conditioning techniques. The highest shear forces were found for the conventional composites Transbond™ XT and Cool- Bond™ in combination with conventional etching. Air abrasion alone and in combination with phosphoric acid etching showed no advantages compared with phosphoric acid etching alone and, therefore, cannot be recommended.

Adhesive performance of a caries infiltrant on sound and demineralised enamel

Objective Resin infiltration is considered as a treatment option for initial caries lesions. As cavitated early lesions might require additional restorative intervention, a caries infiltrant might be also used for enamel conditioning prior to composite insertion. This study aimed to analyse the shear bond strength of a flowable composite to sound and demineralised enamel pretreated with a caries infiltrant, a conventional adhesive or a combination of both. Methods Flattened bovine enamel specimens ( n = 120) were either demineralised (14 d, acidic buffer, pH 5) or remained untreated. Sound and demineralised specimens (each n = 20) were then treated with: (1) 35% phosphoric acid, conventional adhesive, (2) 15% hydrochloric acid, caries infiltrant or (3) 15% hydrochloric acid, caries infiltrant, conventional adhesive. Shear bond strength of a flowable composite was tested after 24 h water storage (37 °C) and statistically analysed (ANOVA, p ≤ 0.05). The mode of failure was assessed microscopically at 25× magnification. Results On demineralised enamel, the combination of caries infiltrant and conventional adhesive showed significantly higher shear bond strength values than the conventional adhesive alone, while both being not significantly different from group 2. No significant differences between the groups could be detected on sound specimens. A higher percentage of cohesive failures could be observed in demineralised samples of group 2 (40%) and 3 (65%), while all other specimens presented almost only adhesive failures. Conclusion The use of a caries infiltrant before application of a conventional adhesive did not impair bonding to sound and demineralised enamel and might be beneficial as a pretreatment in demineralised enamel.

Bond strengths of different orthodontic adhesives after enamel conditioning with the same self-etching primer

Abstract Aim To determine the shear bond strengths (SBS) of stainless steel brackets bonded with seven light-cured orthodontic adhesives after the enamel was conditioned with the same self-etching primer. Methods A total of 140 extracted human molars were randomly divided into seven groups (N = 20). In all the groups, the enamel was conditioned with Transbond Plus SEP (TPSEP). Stainless steel brackets were bonded with the following orthodontic adhesives: Group I, Transbond XT; Group II, Blūgloo; Group III, BeautyOrtho Bond; Group IV, Enlight; Group V, Light Bond; Group VI, Transbond CC; Group VII, Xeno Ortho. The teeth were stored in distilled water at 37 °C for 24 hours and debonded with a universal testing machine. The modified adhesive remnant index (ARI) was also recorded. Results There were no significant differences in the SBS values among the groups: I (18.0 ± 7.4 MPa); II (18.3 ± 5.1 MPa); III (14.8 ± 4.3 MPa); IV (18.3 ± 7.0 MPa); V (16.4 ± 4.3 MPa); VI (20.3 ± 5.3 MPa); VII (15.9 ± 6.4 MPa), but significant differences in ARI were found. Conclusions The seven orthodontic adhesives evaluated in this study can be successfully used for bonding stainless steel brackets when the enamel is conditioned with TPSEP, however, the differences among some groups might influence the clinical bond strengths. In addition, the amount of residual adhesive remaining on the teeth after debonding differed among the adhesives. Further studies are required to better understand the differences in SBS and ARI.

Shear Bond Strength of Resin Modified Glass Ionomer Cement Using Different Enamel Conditions

Aims: In an effort to improve the shear bond strength of resin modified glass ionomer cement on orthodontic brackets, various enamel conditioning have been evaluated for use with this cement. Materials and methods: A total of 100 freshly extracted human premolars were subjected to two steps of treatment. The first step of treatment involve dividing the teeth into 5 groups each of 20 teeth: (I) treated with 20 second acid etching with 37% phosphoric acid; (II), treated with micro–etching using 50 μ aluminum oxide; (III), treated with air polisher using 45 μ sodium bicarbonate; (IV), treated with coarse finishing disk for 10 second; (V), left the enamel clean without treatment. In the second step each group then subdivided into two subgroups, ten teeth subjected to wetting with tab water and ten left dry. Following, storage for 24 hours at 37°C in distilled water, shear debonding force was measured using a Universal Testing Machine with a cross–head speed of 10 mm/minute. Results: The result indicated that the highest shear bond strength was for acid etched enamel under wet condition with lowest mean for normal dry enamel. the Mann–Whitney analysis estimated a significant difference between wet and dry condition in general with high probability of bond failure for the dry than that of wet conditions. Conclusions: The suitable enamel conditions regarding the shear bond with the mode of bond failure had been shown to be the wet and dry situation of group III and wet situation of group IV. But, it could be concluded that the most suitable enamel condition may be that treated with a coarse finishing disk under wet condition.

The in vitro effect of repeated bonding on the shear bond strength with different enamel conditioning procedures

The aims of this study were to evaluate the effect on shear bond strength (SBS), adhesive remnant, and enamel surface of repeated bonding of new brackets on the same tooth using different methods of enamel conditioning. One hundred and thirty-five bovine incisors were used. Brackets were bonded to enamel using one of the following conditioning procedures: (1) 37 per cent phosphoric acid, (2) 37 per cent phosphoric acid (prior to first bond but not for further bonds), (3) Transbond Plus Self Etching Primer (TSEP), and (4) non-rinse-conditioner (NRC). Brackets were sequentially bonded and debonded three times following the same conditioning procedure with the exception of group 2 where 37 per cent phosphoric acid was not reapplied prior to the second and third bonding sequences. SBS and adhesive remnant were evaluated for each debond. Scanning electron microscopy observations were made for each conditioning sequence. Statistical analysis was undertaken using ANOVA, Mann-Whitney, and Kruskal-Wallis tests. Bond strength and adhesive remnant values were similar across the four groups for the first and second bonding sequences. At the third sequence, SBS was significantly less (P < 0.008) for group 2 (5.71 +/- 1.56 MPa) than for group 1 (9.42 +/- 2.75 MPa) and the adhesive remnant was significantly lower (P < 0.008) for group 2 (6.93% +/- 3.34) than for the other groups (group 1: 16.95 +/- 4.99 per cent, group 3: 14.40 +/- 5.11 per cent, and group 4: 14.60 +/- 5.33 per cent). When comparing the SBS and adhesive remnant of the three bonding/debonding sequences within each group, both the SBS and adhesive remnant for group 2 (SBS: 5.71 +/- 1.56 MPa and adhesive remnant: 6.93 +/- 3.34%) at the third sequence were significantly less (P < 0.017) than at the first (SBS: 10.44 +/- 3.55 MPa and adhesive remnant: 13.81 +/- 5.59%) and second (SBS: 9.23 +/- 2.69 MPa and adhesive remnant: 15.32 +/- 6.85%) sequences. Enamel changes were similar across all groups. TSEP and NRC produced bonds that were similar to acid etching. When acid etching is used, it is possible to avoid etching for a second bond but not for following bonds.

Surface conditioning of natural enamel caries lesions in deciduous teeth in preparation for resin infiltration

Objectives As a conditioning step for resin infiltration into caries lesions, the relatively impermeable surface layer should be removed using hydrochloric acid gel (15%) to achieve improved infiltration, as it could be shown for permanent teeth. It is unclear whether this etching regimen can be transferred to the deciduous dentition, where differences in surface structure have been reported. Thus, the aim of the present study was to evaluate the effect of phosphoric and hydrochloric acid gels on the surface layer reduction of natural lesions of primary teeth. Methods Thirty-two extracted or exfoliated primary molars with lesions confined to enamel were selected. Paired lesion halves were partially etched with either 37% phosphoric (H 3PO 4) or 15% hydrochloric acid gel (HCl) for 30 s, 60 s, 90 s, or 120 s, respectively. Results Etching with H 3PO 4 resulted in incomplete reduction of the surface layers in all groups [highest percentage reduction (SD) at 120 s: 54 (28)%] as observed with confocal microscopy. In contrast, surface layers could be eroded almost completely [99 (3)%] by etching with HCl for 120 s. Conclusion An effective erosion of the surface layer of natural enamel caries in deciduous teeth can be achieved by etching with 15% hydrochloric acid gel for 90–120 s.

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

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). 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. 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). Regardless of the enamel treatment, Fuji Ortho LC yielded shear strength values superior to those from Ortho Glass LC.

Shear bond strength of metallic brackets: influence of saliva contamination

Objective:To evaluate the influence of saliva contamination on shear bond strength and the bond failure pattern of 3 adhesive systems (Transbond XT, AdheSE and Xeno III) on orthodontic metallic brackets bonded to human enamel.Material and Methods:Seventy-two permanent human molars were cut longitudinally in a mesiodistal direction, producing seventy-two specimens randomly divided into six groups. Each system was tested under 2 different enamel conditions: no contamination and contaminated with saliva. In T, A and X groups, the adhesive systems were applied to the enamel surface in accordance with manufacturer's instructions. In TS, AS and XS groups, saliva was applied to enamel surface followed by adhesive system application. The samples were stored in distilled water at 37°C for 24 h, and then tested for shear bond strength in a universal testing machine (Emic, DL 2000) running at a crosshead speed of 1 mm/min. After bond failure, the enamel surfaces were observed under an optical microscope at 40x magnification.Results:The control and contaminated groups showed no significant difference in shear bond strength for the same adhesive system. However, shear bond strength of T group (17.03±4.91) was significantly higher than that of AS (8.58±1.73) and XS (10.39±4.06) groups (p<0.05). Regarding the bond failure pattern, TS group had significantly higher scores of no adhesive remaining on the tooth in the bonding area than other groups considering the adhesive remnant index (ARI) used to evaluate the amount of adhesive left on the enamel.Conclusion:Saliva contamination showed little influence on the 24-h shear bond strength of orthodontic brackets.

Le micro-sablage amélaire

Enamel conditioning (elimination of dental plaque and creation of an irregular surface) is an essential step before bonding of orthodontic brackets. The most popular procedure in our practice is bonding with resin which requires enamel etching in order to get enough shear bond strength. Many studies have tried to evaluate the effects of enamel bonding using the acid-etching procedure as well as the changes caused by detachment of brackets. Thanks to the development of other adhesives such as glass ionomer cements which chemically bind to the enamel, new enamel conditioning methods appeared, in particular sandblasting with aluminium oxide particles. This technique is a mechanical preparation of the tooth that avoids the harmful effects of acid products. By suitably choosing the parameters of sandblasting (pressure, time and quantity of powder), enamel loss is lower than with the acid-etch procedure and the surface of the enamel seems less affected. However the bond strength remains superior to the values required for treatment. The presented results indicate that enamel sandblasting can be considered as an alternative for the acid-etching technique currently used in orthodontic practice because it creates sufficient strength and respects enamel thickness better.

Editor's Summary, Q & A, Reviewer's Critique: Effects of 6 self-etching primers on shear bond strength of orthodontic brackets

Introduction This study was conducted to compare the effects of 6 self-etching primers (SEPs) on the shear bond strength (SBS) of orthodontic brackets bonded with the same orthodontic composite resin. Methods One hundred forty extracted premolars were randomly divided into 7 groups (20 per group). In group I (control), the enamel was etched with 37% phosphoric acid. In the other groups, it was conditioned with SEPs according to each manufacturer's instructions: group II, Transbond Plus SEP (3M Unitek, Monrovia, Calif); group III, AdheSE (Ivoclar Vivadent AG, Schaan, Liechtenstein); group IV, Primers A and B (Shofu, Kyoto, Japan); group V, Clearfil Mega Bond FA (Kuraray Medical, Tokyo, Japan); group VI, Peak SE and Peak LC Bond (Ultradent Products, South Jordan, Utah); and group VII, Bond Force (Tokuyama, Osaka, Japan). All brackets were bonded with Transbond XT (3M Unitek), and the teeth were then stored (37°C, 24 hours), tested, and statistically analyzed (Scheffé, ANOVA [P <0.05], and Weibull analyses). The adhesive remnant index (ARI) was also recorded. Results Group I (26.5 ± 8.1 MPa) had a significantly higher SBS value than the other groups except group II (21.1 ± 6.2 MPa). There were no significant differences among groups II, V (19.0 ± 4.3 MPa), VI (19.6 ± 5.1 MPa), and VII (18.3 ± 4.4 MPa). The values for groups I, II, and VI were significantly higher than for group III (13.4 ± 4.1 MPa), and the value for group IV (8.8 ± 2.6 MPa) was significantly lower than the values for groups I, II, V, VI, and VII. Significant differences were found in the ARI scores. Conclusions The SBS values of all groups might be clinically acceptable, and orthodontic brackets can be successfully bonded with Transbond XT after enamel conditioning with any of these SEPs. However, since the SEPs used in groups III and IV significantly affected the bond strength negatively, further studies are warranted to evaluate their effectiveness. This study was conducted to compare the effects of 6 self-etching primers (SEPs) on the shear bond strength (SBS) of orthodontic brackets bonded with the same orthodontic composite resin. One hundred forty extracted premolars were randomly divided into 7 groups (20 per group). In group I (control), the enamel was etched with 37% phosphoric acid. In the other groups, it was conditioned with SEPs according to each manufacturer's instructions: group II, Transbond Plus SEP (3M Unitek, Monrovia, Calif); group III, AdheSE (Ivoclar Vivadent AG, Schaan, Liechtenstein); group IV, Primers A and B (Shofu, Kyoto, Japan); group V, Clearfil Mega Bond FA (Kuraray Medical, Tokyo, Japan); group VI, Peak SE and Peak LC Bond (Ultradent Products, South Jordan, Utah); and group VII, Bond Force (Tokuyama, Osaka, Japan). All brackets were bonded with Transbond XT (3M Unitek), and the teeth were then stored (37°C, 24 hours), tested, and statistically analyzed (Scheffé, ANOVA [P <0.05], and Weibull analyses). The adhesive remnant index (ARI) was also recorded. Group I (26.5 ± 8.1 MPa) had a significantly higher SBS value than the other groups except group II (21.1 ± 6.2 MPa). There were no significant differences among groups II, V (19.0 ± 4.3 MPa), VI (19.6 ± 5.1 MPa), and VII (18.3 ± 4.4 MPa). The values for groups I, II, and VI were significantly higher than for group III (13.4 ± 4.1 MPa), and the value for group IV (8.8 ± 2.6 MPa) was significantly lower than the values for groups I, II, V, VI, and VII. Significant differences were found in the ARI scores. The SBS values of all groups might be clinically acceptable, and orthodontic brackets can be successfully bonded with Transbond XT after enamel conditioning with any of these SEPs. However, since the SEPs used in groups III and IV significantly affected the bond strength negatively, further studies are warranted to evaluate their effectiveness.

Effects of 6 self-etching primers on shear bond strength of orthodontic brackets

<h3>Introduction</h3> This study was conducted to compare the effects of 6 self-etching primers (SEPs) on the shear bond strength (SBS) of orthodontic brackets bonded with the same orthodontic composite resin. <h3>Methods</h3> One hundred forty extracted premolars were randomly divided into 7 groups (20 per group). In group I (control), the enamel was etched with 37% phosphoric acid. In the other groups, it was conditioned with SEPs according to each manufacturer's instructions: group II, Transbond Plus SEP (3M Unitek, Monrovia, Calif); group III, AdheSE (Ivoclar Vivadent AG, Schaan, Liechtenstein); group IV, Primers A and B (Shofu, Kyoto, Japan); group V, Clearfil Mega Bond FA (Kuraray Medical, Tokyo, Japan); group VI, Peak SE and Peak LC Bond (Ultradent Products, South Jordan, Utah); and group VII, Bond Force (Tokuyama, Osaka, Japan). All brackets were bonded with Transbond XT (3M Unitek), and the teeth were then stored (37°C, 24 hours), tested, and statistically analyzed (Scheffé, ANOVA [<i>P</i> <0.05], and Weibull analyses). The adhesive remnant index (ARI) was also recorded. <h3>Results</h3> Group I (26.5 ± 8.1 MPa) had a significantly higher SBS value than the other groups except group II (21.1 ± 6.2 MPa). There were no significant differences among groups II, V (19.0 ± 4.3 MPa), VI (19.6 ± 5.1 MPa), and VII (18.3 ± 4.4 MPa). The values for groups I, II, and VI were significantly higher than for group III (13.4 ± 4.1 MPa), and the value for group IV (8.8 ± 2.6 MPa) was significantly lower than the values for groups I, II, V, VI, and VII. Significant differences were found in the ARI scores. <h3>Conclusions</h3> The SBS values of all groups might be clinically acceptable, and orthodontic brackets can be successfully bonded with Transbond XT after enamel conditioning with any of these SEPs. However, since the SEPs used in groups III and IV significantly affected the bond strength negatively, further studies are warranted to evaluate their effectiveness.

Enamel Deproteinization and Its Effect on Acid Etching: An in vitro Study

The goal of this in vitro study was to identify the topographical features of the enamel surface deproteinized and etched with phosphoric acid (H3PO4) compared to phosphoric acid alone. Ten extracted lower first and second permanent molars were polished with pumice and water, and then divided into 4 equal buccal sections having similar physical and chemical properties. The enamel surfaces of each group were subjected to the following treatments: Group A: Acid Etching with H3PO4 37% for 15 seconds. Group AH1: Sodium Hypochlorite (NaOCl) 5.25% for 30 seconds followed by Acid Etching with H3PO4 37% for 15 seconds. Group AH2; Sodium Hypochlorite (NaOCl) 5.25% for 60 seconds followed by Acid Etching with H3PO4 37% for 15 seconds. Results showed that group AH2 etching technique reached an area of 76.6 mm2 of the total surface, with a 71.8 mm2 (94.47%), type 1 and 2 etching pattern, followed by group AH1 with 55.9 mm2 out of 75.12 mm2 (74.1%), and finally group A with only 36.8 mm2 (48.83%) out of an area of 72.7 mm2. A significant statistical difference (P < 0.05) existed between all groups, leading to the conclusion that enamel deproteinization with 5.25% NaOCl for 1 minute before H3PO4, etching increases the enamel conditioning surface as well as the quality of the etching pattern.