Effects of silica coating and silane surface conditioning on the bond strength of metal and ceramic brackets to enamel

OBJECTIVE: To evaluate the effect of tribochemical silica coating and silane surface conditioning on the bond strength of metal and ceramic brackets bonded to enamel surfaces with light-cured composite resin. MATERIALS AND METHODS: Twenty metal and 20 ceramic brackets were divided into four groups (n = 10 for each group). The specimens were randomly assigned to one of the following treatment conditions of the metal and ceramic brackets' surface: (1) tribochemical silica coating combined with silane and (2) no treatment. Brackets were bonded to the enamel surface on the labial and lingual sides of human maxillary premolars (20 total) with a light-polymerized resin composite. All specimens were stored in water for 1 week at 37 degrees C and then thermocycled (5000 cycles, 5 degrees C to 55 degrees C, 30 seconds). The shear bond strength values were measured on a universal testing machine. Student's t-test was used to compare the data (alpha = 0.05). The types of failures were observed using a stereomicroscope. RESULTS: Metal and ceramic brackets treated with silica coating with silanization had significantly greater bond strength values (metal brackets: 14.2 +/- 1.7 MPa, P < .01; ceramic brackets: 25.9 +/- 4.4 MPa, P < .0001) than the control groups (metal brackets: 11.9 +/- 1.3 MPa; ceramic brackets: 15.6 +/- 4.2 MPa). Treated specimens of metal and ceramic exhibited cohesive failures in resin and adhesive failures at the enamel-adhesive interface, whereas control specimens showed mixed types of failures. CONCLUSIONS: Silica coating with aluminum trioxide particles coated with silica followed by silanization gave higher bond strengths in both metal and ceramic brackets than in the control group.     

Heat treatment following surface silanization in rebonded tribochemical silica-coated ceramic brackets: shear bond strength analysis

Objective

This study aimed to evaluate the effects of heat treatment on the tribochemical silica coating and silane surface conditioning and the bond strength of rebonded alumina monocrystalline brackets.

Material and Methods

Sixty alumina monocrystalline brackets were randomly divided according to adhesive base surface treatments (n=20): Gc, no treatment (control); Gt, tribochemical silica coating + silane application; Gh, as per Gt + post-heat treatment (air flux at 100ºC for 60 s). Brackets were bonded to the enamel premolars surface with a light-polymerized resin and stored in distilled water at 37ºC for 100 days. Additionally, half the specimens of each group were thermocycled (6,000 cycles between 5-55ºC) (TC). The specimens were submitted to the shear bond strength (SBS) test using a universal testing machine (1 mm/min). Failure mode was assessed using optical and scanning electron microscopy (SEM), together with the surface roughness (Ra) of the resin cement in the bracket using interference microscopy (IM). 2-way ANOVA and the Tukey test were used to compare the data (p>0.05).

Results

The strategies used to treat the bracket surface had an effect on the SBS results (p=0.0), but thermocycling did not (p=0.6974). Considering the SBS results (MPa), Gh-TC and Gc showed the highest values (27.59±6.4 and 27.18±2.9) and Gt-TC showed the lowest (8.45±6.7). For the Ra parameter, ANOVA revealed that the aging method had an effect (p=0.0157) but the surface treatments did not (p=0.458). For the thermocycled and non-thermocycled groups, Ra (µm) was 0.69±0.16 and 1.12±0.52, respectively. The most frequent failure mode exhibited was mixed failure involving the enamel-resin-bracket interfaces.

Conclusion

Regardless of the aging method, Gh promoted similar SBS results to Gc, suggesting that rebonded ceramic brackets are a more effective strategy.     

不同处理方法对脱落托槽再粘接抗剪切强度的影响

目的：比较三种不同处理方法去除脱落正畸托槽底板残留粘接剂,对托槽再次粘接时抗剪切强度大小的影响。方法：挑选因正畸需要而拔除的完整前磨牙80颗,随机分成4组,每组20个样本,分别按常规方法粘接网底型直丝弓正畸托槽,通过万能材料测试仪测试并记录其脱落时的抗剪切强度后,第一组更换新托槽,第二组采用喷砂法、第三组采用燃烧法、第四组采用磨除法去除托槽底板残留粘接剂,再次粘接托槽,在同样条件下测试并记录其脱落时的抗剪切强度。结果：更换新托槽组、喷砂组再次粘接时其抗剪切强度与初次粘接无显著性差异（P＞0.05）,燃烧组、磨除组再次粘接时其抗剪切强度与初次粘接相比明显减小（P＜0.05）。喷砂组再次粘接的抗剪切强度与更换新托槽组无显著性差异（P＞0.05）。燃烧组、磨除组再次粘接的抗剪切强度比更换新托槽组明显减小（P＜0.05）。结论：为了获得理想的粘接强度,脱落托槽再利用时宜采用喷砂法进行处理,不宜采用燃烧法和磨除法进行处理。     

喷砂处理对不同底面设计陶瓷托槽再粘接影响的实验研究

目的：探讨喷砂处理对不同底面设计的陶瓷托槽再粘接抗剪切强度的影响。方法：选取90颗因正畸拔除的健康前磨牙,随机抽取30颗用于制备脱落陶瓷托槽,其余60颗用于粘接实验。将60颗牙根据不同底面设计分成3大组：微隐窝底面组（A组）、微晶体底面组（B组）、树脂底面组（C组）,每大组分成2小组：新托槽组（n）、喷砂组（sb）,每组10颗牙。陶瓷托槽粘接于未经酸蚀处理的微湿的离体牙上,然后用去托槽钳小心取下,形成脱落托槽,对托槽底面进行喷砂处理,并在底面常规涂硅烷偶联剂。离体牙经常规牙面处理后,分别粘接新托槽及处理后的托槽,测定并比较各组抗剪切强度。结果：三组托槽初次粘接及再次粘接抗剪切强度分别为（12．4733±3．4326）Mpa和（9．1612±1．3261） Mpa;（12．7374±3．8999）Mpa和（6．7152±3．1876）Mpa;（9．5022±1．8801）Mpa和（6．6281±2．1187）Mpa,其中A组的抗剪切强度大于B组和C组的抗剪切强度,差别有统计学意义（P＜0．05）;B组和C组两者的抗剪切强度有差别,但无统计学意义（P＞0．05）。结论：三组陶瓷托槽再粘接抗剪切强度明显下降,但高于正畸临床所需的最低抗剪切强度值。其中微隐窝底面与微晶底面和聚合体网底相比,抗剪切强度下降最少,更适合喷砂处理。     

Effects of surface treatment and artificial aging on the shear bond strength of orthodontic brackets bonded to four different provisional restorations

Objective:To evaluate the combined effects of material type, surface treatment, and thermocycling on the bond strength of orthodontic brackets to materials used for the fabrication of provisional crowns.Materials and Methods:Four materials were included in this study (ProTemp, Trim Plus, Trim II, and Superpont C+B). Sixty cylindrical specimens (1 × 3 cm) were prepared from each material and equally divided into three groups. The first group was ground with silica carbide paper, the second was polished with pumice, and the last group was sandblasted with 50-µm aluminum oxide particles. Stainless-steel maxillary central incisor brackets (Victory Series, 3M) were bonded to the provisional material specimens with Transbond XT light-cured composite resin, and half of the specimens from each group were thermocycled 500 times in 5°C and 55°C water baths. Then the brackets were debonded with shear testing, and the results were statistically analyzed by three-way analysis of variance and Tukey''s multiple-comparison tests at α  =  0.05. Adhesive Remnant Index (ARI) was also identified.Results:Before and after thermocycling, ProTemp materials showed the highest shear bond strength with orthodontic brackets (10.3 and 13.1 MPa, respectively). The statistical analysis indicated an interaction among the three independent variables (P < .05) and statistically significant differences in bond strength among provisional materials (P < .001), surface treatments (P < .001), and thermocycling (P < .05). According to the ARI, most groups demonstrated adhesive failure.Conclusions:The provisional material type, surface treatment, and artificial aging have a significant effect on bond strength. Sandblasting treatment exerts a beneficial effect on shear bond strength.     

Effects of different etching methods and bonding procedures on shear bond strength of orthodontic metal brackets applied to different CAD/CAM ceramic materials

Objective:To investigate the shear bond strength (SBS) of orthodontic metal brackets applied to different types of ceramic surfaces treated with different etching procedures and bonding agents.Materials and Methods:Monolithic CAD/CAM ceramic specimens (N = 120; n = 40 each group) of feldspathic ceramic Vita Mark II, resin nanoceramic Lava Ultimate, and hybrid ceramic Vita Enamic were fabricated (14 × 12 × 3 mm). Ceramic specimens were separated into four subgroups (n = 10) according to type of surface treatment and bonding onto the ceramic surface. Within each group, four subgroups were prepared by phosphoric acid, hydrofluoric acid, Transbond XT primer, and Clearfill Ceramic primer. Mandibular central incisor metal brackets were bonded with light-cure composite. The SBS data were analyzed using three-way analysis of variance (ANOVA) and Tukey HSD tests.Results:The highest SBS was found in the Vita Enamic group, which is a hybrid ceramic, etched with hydrofluoric acid and applied Transbond XT Adhesive primer (7.28 ± 2.49 MPa). The lowest SBS was found in the Lava Ultimate group, which is a resin nano-ceramic etched with hydrofluoric acid and applied Clearfill ceramic primer (2.20 ± 1.21 MPa).Conclusions:CAD/CAM material types and bonding procedures affected bond strength (P < .05), but the etching procedure did not (P > .05). The use of Transbond XT as a primer bonding agent resulted in higher SBS.     

Effect of blood contamination on shear bond strength of orthodontic brackets and disinclusion buttons

Our aim was to assess the effect of blood contamination on the shear bonding strength and sites of failure of orthodontic brackets and bondable buttons. We randomly divided 160 bovine permanent mandibular incisors into 8 groups of 20 specimens each. Both orthodontic brackets (Step brackets, Leone, Sesto Fiorentino, Italy) and bondable buttons (Flat orthodontic buttons, Leone, Sesto Fiorentino, Italy) were tested on four different enamel surfaces: dry; contamination with blood before priming; after priming; and before and after priming. Brackets and buttons were bonded to the teeth and subsequently tested using a Instron universal testing machine. Shear bonding strength and the rate of adhesive failures were recorded. Data were analysed using the analysis of variance (ANOVA), Scheffè tests, and the chi-square test. Uncontaminated enamel surfaces showed the highest bonding strengths for both brackets and buttons. When they were contaminated with blood, orthodontic brackets had significantly lower shear strengths than bondable buttons (P = 0.0001). There were significant differences in sites of failure among the groups for the various enamel surfaces (P = 0.001). Contamination of enamel by blood during bonding lowers the strength of the bond, more so with orthodontic brackets than with bondable buttons.     

两种底板设计的国产陶瓷托槽剪切粘接强度的研究

目的评价两种不同底板设计的国产多晶体氧化铝陶瓷托槽的剪切粘接强度。方法实验组为国产沟槽底板和网格底板陶瓷托槽,对照组为临床常用的多晶体氧化铝陶瓷托槽Crystaline IV。30颗离体上颌双尖牙随机分为3组,每组10颗,使用37%液体磷酸和京津釉质粘接剂分别粘接上述三种托槽,在0.9%生理盐水中室温保存24h。使用WDW3050型微机控制电子万能试验机检测剪切粘接强度。托槽脱落后记录粘接剂残留指数、陶瓷托槽的折断数目和釉质表面出现肉眼可见缺损的牙齿数目。结果国产沟槽底板、网格底板陶瓷托槽及Crystaline IV的剪切粘接强度分别为12.10±2.69MPa、10.17±2.55MPa及14.66±2.39MPa。Crystaline IV和国产网格底板陶瓷托槽剪切粘接强度的差异有显著性意义。三种陶瓷托槽的主要脱开部位均在粘接剂内,所有样本未出现陶瓷托槽折断和肉眼可见的釉质缺损。结论两种国产陶瓷托槽均能够获得足够的剪切粘接强度。     

Effects of different bleaching methods on shear bond strengths of orthodontic brackets

Objective:To evaluate the effects of different bleaching methods on the shear bond strength (SBS) of orthodontic brackets.Materials and Methods:Forty-five freshly extracted premolars were randomly divided into three groups (n  =  15 per group). In group I, bleaching was performed with the office bleaching method. In group II, bleaching was performed with the home bleaching method. Group III served as the control. Orthodontic brackets were bonded with a light cure composite resin and cured with an LED light. After bonding, the SBS of the brackets were tested with a Universal testing machine.Results:Analysis of variance indicated a significant difference between groups (P < .001). The highest values for SBS were measured in group III (20.99 ± 2.32 MPa). The SBS was significantly lower in groups I and II than in group III (P < .001). The lowest values for SBS were measured in group II (6.42 ± 0.81 MPa). SBS was significantly higher in group I than in group II (P < .001).Conclusions:Both of the bleaching methods significantly affected the SBS of orthodontic brackets on human enamel. Bleaching with the home bleaching method affected SBS more adversely than did bleaching with the office bleaching method.     

不同处理方法对托槽再黏结强度的影响

目的:比较不同处理方法对金属托槽再黏结强度的影响。方法:选择40颗离体前磨牙为实验对象,随机分为4组。粘结托槽后,选择3组剥离托槽,采用磨除、烧灼、喷砂3种不同托槽底板处理后予以再次黏结,经体外pH循环30 d后,测定托槽的抗剪切强度。采用SPSS 13.0软件包对所得数据进行单因素方差分析。另选取试样通过扫描电镜观察托槽底板的形态及结构。结果:4组间有显著差异,托槽烧灼再黏结组与其他各组间有显著差异,其余各组两两相比,均无显著性差异。结论:托槽底板残留黏结剂经磨除或喷砂处理,可获得与初次黏结相近的黏结强度。     

瓷表面处理对正畸托槽与瓷黏结抗剪强度的影响

目的:探讨不同瓷表面处理技术对正畸托槽与瓷黏结抗剪强度的影响。方法:采用4组不同的瓷表面处理方式,使用光固化正畸黏结剂将瓷面分别与金属和陶瓷托槽黏结,每组再平均分为2组分别在37℃水浴24h和7d后冷热循环500次(5～55℃),测量黏结抗剪强度,并统计其黏结剂残留指数,在扫描电镜下观察其瓷面显微结构的变化。结果:4种瓷表面处理技术对2种不同材料托槽处理的结果近似,均可达到有效正畸黏结强度。结论:磷酸酸蚀结合硅烷偶联剂是正畸托槽与瓷黏结的较佳方式之一。