Tensile bond strength of ceramic orthodontic brackets bonded to porcelain surfaces

The aim of this study was to compare various surface treatment methods to define the procedure that produces adequate bond strength between ceramic brackets and porcelain. The specimens used in this study, 60 porcelain tabs, were produced by duplication of the labial surface of a maxillary first premolar. The 6 different preparation procedures tested were: (1) sandblasting with 50 microm aluminum oxide in a sandblasting device, (2) application of silane to the porcelain and the bracket base, (3) sandblasting followed by application of silane, (4) acid etching with 9.6% hydrofluoric acid, (5) acid etching with 9.6% hydrofluoric acid followed by application of silane, and (6) sandblasting followed by application of 4-Meta adhesive. The ceramic brackets were bonded with no-mix orthodontic bonding material. A bonding force testing machine was used to determine tensile bond strengths at a crosshead speed of 0.5 mm per second. The results of the study showed that porcelain surface preparation with acid etching followed by silane application resulted in a statistically significant higher tensile bond strength (P < .05). Sandblasting the porcelain surface before silane treatment provided similar bond strengths, but sandblasting or acid etching alone were less effective. Silane application was recommended to bond a ceramic bracket to the porcelain surface to achieve bond strengths that are clinically acceptable.     

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.     

A study to investigate the bond strengths of orthodontic brackets bonded to prosthetic acrylic teeth

Abstract

Introduction:

In this study, we compared the shear bond strengths of five different adhesive techniques for attaching metal orthodontic brackets onto acrylic pontics.

Materials and Methods:

Two hundred upper left lateral incisor acrylic teeth with bonded brackets were divided into five groups — composite alone (control), composite following sandblasting, composite held with a mechanical undercut, cyanoacrylate adhesive and Panavia^®. The initial bond strength was tested using the Instron Universal Testing Machine. The fatigue bond strength was tested by subjecting each bracket to 5000 repetitive low-load cycles at 50% of the mean shear bond strength using the Dartec machine at 2?Hz.

Results:

Cyanoacrylate adhesive statistically exhibited the highest mean bond strength (19·82?MPa). This was followed by the mechanical undercut group (17·69?MPa) and the sandblasted group (17·18?MPa). There was no statistically significant difference when considering the effect of fatiguing (p?=?0·238) as well as the interaction between the adhesive technique and the effect of fatiguing on the bond strength (p?=?0·440).

Conclusion:

The initial and fatigue bond strengths of the cyanoacrylate adhesive, sandblasted and undercut groups were significantly higher than the control and Panavia^® groups when tested under laboratory conditions.     

Bond strengths of lingual orthodontic brackets bonded with light-cured composite resins cured by transillumination

A method of curing light-cured composite resins by transillumination to cement acid-etched fixed partial dentures was adapted to bond solid mesh-backed lingual orthodontic brackets. Results of this investigation showed that the bond strengths of the orthodontic brackets bonded with light-cured composite resins were significantly less (P less than 0.05) than the bond strengths of the orthodontic brackets cemented with traditional adhesives and orthodontic composite resins. Notwithstanding, the bond strengths achieved with the transilluminated light-cured composite resins should be adequate to withstand the forces of mastication and orthodontic movements. There was no correlation of bond strengths of the brackets cemented with the transilluminated light-cured composite resins when compared to the faciolingual widths of the teeth.     

The shear bond strengths of stainless steel orthodontic brackets bonded to teeth with orthodontic composite resin and various fissure sealants

Enamel decalcification (whitened areas) around orthodontic brackets during therapy is a well-recognized problem. If a fissure sealant could be used to isolate the enamel and yet withstand debonding of the bracket during therapy, this problem might be overcome. The objective of this in vitro study was to determine (1) the shear bond strengths of stainless steel orthodontic brackets bonded to teeth with an orthodontic bonding resin together with a primary coating of various fissure sealants and (2) the fracture sites of these debonded samples. Forty noncarious human canine teeth were divided into four groups of 10 teeth each. In group A, the brackets were bonded to the buccal surfaces of the prepared teeth with a macrofilled orthodontic composite resin only. In groups B, C, and D, the brackets were similarly bonded, except that the teeth were first treated with a fissure sealant--group B having a light-cured unfilled clear fissure sealant, group C having a light-cured microfilled fissure sealant, and group D having a chemically cured opaque fissure sealant. After storage at 37 degrees C for 24 hours, the brackets were subjected to a shear force in an instron machine, and the fracture strengths were recorded, together with the sites of fracture.(ABSTRACT TRUNCATED AT 250 WORDS)     

Push-out bond strengths of tooth-colored posts bonded with different adhesive systems

PURPOSE: To evaluate the effect of luting systems and root region on the push-out bond strengths of a glass fiber-reinforced post and a zirconia post. METHODS: Thirty-two extracted human anterior teeth (central incisors and canines) were endodontically treated with lateral condensation of gutta percha and AH26 sealer. Teeth were randomly assigned to eight groups (n = 4 per group). Two post systems from the same manufacturer (Cosmopost, a zirconia post; or FRC Postec, a glass fiber-reinforced post) were placed with a luting system (bonding agent and resin luting agent). C-Post was cemented with One-Step and Post Cement Hi-X was used as the light-polymerized adhesive control. ParaPost Fiber White cemented with ParaPost Adhesive and ParaPost Resin Cement was used as an auto-polymerized adhesive control. The roots were sectioned in equal thirds (apical, middle and cervical). A push-out test was performed in each section to measure regional bond strengths in MPa. Means were analyzed with two-way ANOVA and Duncan's post-hoc test (alpha = 0.05). RESULTS: The fiber posts ranked in the highest statistical subset regardless of the luting system: ParaPost Fiber White (self-cure control), FRC Postec bonded with Excite DSC/Variolink II, FRC Postec bonded with Syntac/Variolink II, FRC Postec bonded with Excite DSC/Experimental Self Cure Cement, and C-Post bonded with One Step/Hi-X. The zirconia post Cosmopost ranked in the lowest subsets regardless of the adhesive system used at P < 0.05. Means for the medium region of the root (5.0 +/- 0.8 MPa) were not statistically different from those obtained either in the cervical or in the apical region. Means for the cervical root region (6.2 +/- 0.9 MPa) were statistically higher than those of the apical region (4.5 +/- 1.1 MPa) at P < 0.001.     

Direct bonding of orthodontic brackets to porcelain veneer laminates

The forces required to debond orthodontic attachments from porcelain veneer laminates were studied in vitro. Brackets were bonded to 160 veneered bovine incisor teeth before the determination of the debond force. The independent variables studied were resin type, priming agent, porcelain surface preparation, and debonding time. The average debond forces were compared with those obtained by debonding brackets bonded to natural teeth by means of the acid-etch technique. The bond between the resin and the porcelain surface was found to be satisfactory for direct bonding of orthodontic attachments. Roughening the porcelain surface and using a silane primer required an average debond force comparable to that of the acid-etched enamel bond at 24 hours. However, it increased the risk for porcelain fracture during debonding. Roughened surfaces and surfaces with micro-fractures could be satisfactorily finished and polished with either a series of graded Ceramiste points or a diamond-impregnated polishing wheel followed by a diamond polishing paste.     

正畸粘接剂与瓷面粘接剪切强度的实验研究

目的研究三种不同釉质粘接剂在两种瓷表面处理方式作用下对正畸托槽与瓷粘接剪切强度的影响。方法使用两种不同的瓷表面处理方式处理瓷面,再分别使用三种不同釉质粘接剂粘接金属和陶瓷托槽,在37℃水浴条件下24小时后冷热循环500次(5℃-55℃),测量其粘接剪切强度,并统计粘接剂残留指数。结果瓷表而处理方式与粘接剂种类对粘接强度均有影响,光固化和双组分型化学固化粘接剂粘接强度优于非混合型化学固化粘接剂。结论三种粘接剂在两种不同瓷表面处理方式下均可用于托槽与瓷面的粘接。     

Shear bond strengths of 2 intraoral porcelain repair systems to porcelain or metal substrates.

STATEMENT OF PROBLEM: When clinical fractures of the ceramic veneer on ceramometal can be repaired, the need for remake can be eliminated or postponed. A number of ceramic repair materials are available; bond strength data would be useful for predicting the success of a given repair system. PURPOSE: This in vitro study evaluated shear bond strengths of 2 porcelain repair systems intended for intraoral bonding of resin to porcelain and metal. MATERIAL AND METHODS: Sixty cylindrical specimens were fabricated with feldspathic porcelain and/or a high noble alloy: 20 porcelain (P), 20 porcelain and metal (PM), and 20 metal (M). Specimens were divided into subgroups of 10, and resin composite cylinders were bonded with 1 of 2 systems: CoJet-System (CJ) or Ceramic Repair (CR). Bonded specimens were stored in 37 degrees C distilled water for 24 hours before being thermocycled at 5 degrees C to 55 degrees C for 300 cycles with a 30-second dwell time. The specimens then were stored for an additional 8 days before being subjected to shear force in a universal testing machine at a crosshead speed of 5 mm/min. Stress at failure was calculated in MPa, and mode of failure was recorded. Analysis of variance (ANOVA) was applied to the data. Comparisons between substrates were made with the Duncan multiple range test (P <.05), and differences between the 2 repair systems within like substrate groups were examined with the Student t test. RESULTS: Bonding groups exhibited the following values in megapascals: PM-CR = 19.3 +/- 4.1; PM-CJ = 25.0 +/- 3.1; M-CR = 14.3 +/- 4.9; M-CJ = 23.0 +/- 2.3; P-CR = 18.3 +/- 4.2; P-CJ = 22.4 +/- 5.6. The ANOVA results showed significant differences between the CJ and CR groups. The Student t test revealed that the mean data for the CJ groups were significantly higher than for the CR groups (P <.05). The Duncan multiple range test demonstrated significant differences between the PM and M groups (P <.05) for the CR system only. CONCLUSION: Under the conditions of this study, CJ achieved significantly higher bond strengths to PM and M substrates. Significant differences in strength were found between PM and M, but only within the CR system.     

Bond strengths of orthodontic brackets to restorative resin composite surfaces

In orthodontic practice, it is not uncommon to bond brackets to resin composite restorations. With this in mind, this study was designed to compare first the shear/peel strengths of metal, ceramic and polycarbonate brackets bonded to microfilled resin composite (RC), using either a light-cured resin-modified glass ionomer cement (Fuji Ortho LC), a chemical-cured composite (System 1+) or a light-cured composite adhesive (Transbond XT); and then to examine the effects of thermocycling on the shear/peel strengths of these systems. Four different brackets were used: two stainless steel (Victory and Optimesh), one ceramic (Transcend 6000) and one polycarbonate (Spirit MB). Seventy-two specimens of each bracket were divided into three groups for bonding with one of the three adhesives. Half the specimens from each group were also thermocycled. Mean shear/peel bond strengths were found to be significantly different for the four different brackets, although not influenced by the three adhesives used within each group. All groups were found to have clinically-acceptable mean bond strengths, except for Spirit MB-System 1+. After thermocycling, both Optimesh-Transbond XT and Victory-System 1+ groups showed superior mean bond strengths (26.8 and 24.4 MPa, respectively) when compared with all other groups (p < 0.05). Applying the Weibull survival analysis for groups utilising Victory, Transcend 6000 and Spirit MB brackets, those with 90 per cent or greater probabilities of survival included Victory-System 1+, Transcend 6000-Fuji Ortho LC, Victory-Fuji Ortho LC and Spirit MB-Transbond XT groups. In all groups, bond failure was mainly (64 per cent) cohesive within the RC restorative surface. The thermocycled Spirit MB-Transbond XT group had the highest frequency of undamaged RC failure interfaces. Despite the focus of this study being on bond strength and the potential for surface damage, it was noted that these properties should always be considered alongside other factors such as the strength of the bracket itself, friction within the bracket slot, patients' wishes, cost of the materials and the presenting malocclusion.     

Shear, torsional, and tensile bond strengths of ceramic brackets using three adhesive filler concentrations

The effect of changes in adhesive filler concentration on the shear, torsional, and tensile bond strength of a chemical, a mechanical, and a chemical/mechanical retained ceramic bracket was evaluated. Two hundred ten bovine teeth were bonded with one of three ceramic brackets using a 30%, 55%, or 80% filled adhesive. The brackets were debonded with a shear, torsional, or tensile force to test the bond strength and the site of bond failure. No significant difference was found in the shear, torsional, or tensile bond strength of each ceramic bracket type in relation to changes in the adhesive filler concentration. However, there was a trend toward increased bond strength with increasing filler concentration. Combining the data according to adhesive type revealed that the 80% filled adhesive displayed a significantly greater shear bond strength than the 30% or 55% filled adhesive and a greater torsional bond strength than the 30% filled adhesive. This supports the hypothesis of increased bond strength with increased adhesive filler concentration. The mechanically retained ceramic bracket showed greater shear bond strength and maximum shear bond strength in torsion than the chemical or chemical/mechanical retained ceramic bracket. The tensile bond strength of the mechanically retained ceramic bracket was similar to that of metal brackets reported in other studies, and the failure site was at the bracket-adhesive interface.