Effects of cyclic loading on the bond strength of metal orthodontic brackets bonded to a porcelain surface using different conditioning protocols

Abstract

Objective: To evaluate cyclic and static shear bond strengths (SSBSs) of metal orthodontic brackets bonded to a porcelain surface using different conditioning protocols. Materials and Methods: A total of 100 feldspathic porcelain disks were fabricated. The specimens were divided into four equal groups. Porcelain surfaces were conditioned with different protocols. In group 1, hydrofluoric acid and Embrace First-Coat primer were used. In group 2, hydrofluoric acid and silane were utilized. In groups 3 and 4, sandblasting with aluminum oxide powder was done instead of etching. Metal brackets were bonded to the porcelain surfaces using Transbond XT adhesive. SSBS testing was carried out in 10 specimens, while cyclic shear bond strength (CSBS) testing was done in 15 specimens from each group. The data were subjected to analysis of variance, least significant difference post hoc, and Student's t-tests. Results: Embrace First-Coat and silane exhibited a comparable SSBS. The sandblasting process significantly increased SSBS. No significant difference was found in bond SSBS utilizing either hydrofluoric acid and Embrace First-Coat or sandblasting and silane. With regard to CSBS, the use of sandblasting and Embrace First-Coat revealed the highest significant CSBS value, followed by sandblasting and silane. Etching with hydrofluoric acid prior to application of either primer exhibited the least CSBS values; however, no significant difference was found between them. The SSBS was significantly higher than CSBS. Conclusion: Embrace First-Coat could be used successfully as an alternative to silane. Sandblasting provides higher bond strength than did hydrofluoric acid. Cyclic loading significantly decreased bond strength. (Angle Orthod. 2011;81:1064-1069

Comparison of marginal fit of cemented zirconia copings manufactured after digital impression with lava™ C.O.S and conventional impression technique

“…Nevertheless this is in accordance with studies by Rahme et al, showing that the marginal fit was similar after using the replica technique and after cementation with glass-ionomer cement [28]. Another study investigating inter alia the marginal fit after using the replica technique compared to cemented samples also showed no significant differences, reporting values of about 100 μm independent of the technique, which is also in accordance with the values of the present study [29]. …”

Comparison of Shear Bond Strength of Metal Brackets Bonded to Porcelain Surface using Different Surface Conditioning Methods: An in vitro Study

“…The present study shows that sandblasting with silane combination to condition the ceramic surface gives the highest shear bond strength among all the groups which is similar to the results obtained by Abdelnavy YL. 7 The second highest shear bond strength was seen in the group conditioned with hydrofluoric acid and silane combination. This result is concurrent with the results of a study conducted by Schmage P et al 5 Zachrisson Y, Zachrisson B and Buyukyilmaz T 2 had conducted a study, in which he concluded that silane application after sandblasting the ceramic surface significantly increases the bond strength of metal brackets bonded to ceramic surface, which is concurrent to the results obtained in our study.…”

Effect of Femtosecond Laser Treatment on the Shear Bond Strength of a Metal Bracket to Prepared Porcelain Surface

“…This finding is concurrent with results from the current study, because thermocycle can decrease the SBS value. However, Abdelnaby 28 reported that 50 lm Al 2 O 3 SB porcelain surface with thermocycling provided a 6.95 MPa SBS value. In the current study, the SBS values of the HF and SB groups showed no significant difference, and similar bond failure modes.…”

“…17 Aluminum oxide sandblasting has been widely used to promote micromechanical retention of ceramics (madani 2000). Many studies 27,28 have shown that Al 2 O 3 sandblasting, combined with silane, significantly increased the bond strength of bracket-to-porcelain surface. Girish et al 27 showed that 50 lm Al 2 O 3 SB for 10 sec without thermocycling enhanced to SBS value (15.18 MPa).…”