Shear bond strength of ceramic orthodontic brackets to enamel

Objective: To compare rebonding of orthodontic brackets based on the hypothesis that no difference would be found between the adhesive systems with respect to shear bond strength, mode of failure, and clinical failure rates. Materials and Methods: The three adhesive systems included two self-etch primers (Transbond and M-Bond) and a conventional phosphoric acid etch (Rely-a-Bond). The sample size was 20 premolars for each adhesive system. The shear bond strength was tested 24 hours after bracket bonding with the bonding/debonding procedures repeated two times after the first debonding. Bond strength, adhesive remnant index (ARI), and failure sites were evaluated for each debonding. Statistical analysis consisted of a two-way analysis of variance (ANOVA) followed by Scheffè analysis. The clinical portion evaluated 15 patients over a 12-month period. Results: The mean shear bond strengths after the first, second, and third debondings for Relya-Bond were 8.4 Ϯ 1.8, 10.3 Ϯ 2.4, and 14.1 Ϯ 3.3 MPa, respectively; for Transbond 11.1 Ϯ 4.6, 13.6 Ϯ 4.5, and 12.9 Ϯ 4.4 MPa, respectively; and for M-Bond 8.7 Ϯ 2.7, 10.4 Ϯ 2.4, and 12.4 Ϯ 3.4 MPa, respectively. After the three debondings the mean shear bond strength increased significantly from the first to the third debonding for Rely-a-Bond and M-bond (P Յ .001), but did not change for Transbond (P ϭ .199). Conclusions:The original hypothesis is not rejected. The two self-etching primers showing higher or comparable bond strength to the conventional phosphoric etch with less adhesive remnant on the enamel surface after the first debonding. With repeated bonding/debonding, the differences in the bond strength, ARI, and failure site were not significantly different. There was no difference in the clinical performance of the three adhesive systems (P ϭ .667).

Section: Introductionmentioning

confidence: 99%

Rebonding of Orthodontic Brackets

Montasser

Drummond

Evans

2008

“…15 Although many researchers have studied the effect of etching time on bond strengths, most of these studies were conducted using phosphoric acid as the enamel etchant. [6][7][8][9][10][11] More recently, the effect of SEP application time on bonding strength has also been tested. It was determined that increasing SEP application time resulted in a more pronounced etch pattern on ground enamel as well as greater tensile bonding strengths.…”

Section: Discussionmentioning

confidence: 99%

“…[3][4][5] While manufacturers of bonding systems typically recommend specific conditioning protocols, the effect of changing the conditioning time on the etching pattern has been investigated previously, yielding differ-ing results. Some studies have shown that a reduced etching time does not result in lower bond strengths [6][7][8] ; other authors have reported significant reductions in bond strengths when decreasing etching time. 9,10 In addition, Olsen et al 11 specifically investigated the effect of enamel etching time on the shear bond strength (SBS) of orthodontic brackets.…”

Section: Introductionmentioning

confidence: 99%

Influence of Self-etchant Application Time on Bracket Shear Bond Strength

Ostby

Bishara

Laffoon

et al. 2007

Objective: To determine the influence of self-etching primer (SEP) application time on the shear bond strength of orthodontic brackets. Materials and Methods: Forty human molars were cleaned, mounted, and randomly divided into two groups. The same SEP, adhesive, and brackets were used in both groups. Twenty teeth were conditioned following the manufacturers' recommendations by rubbing the SEP on the enamel surface for 3 to 5 seconds. The remaining 20 teeth were conditioned using the same SEP, but the application time was increased to 15 seconds. The teeth were debonded within half an hour following initial bonding using a universal testing machine. After debonding, the amount of residual adhesive remaining on the tooth was determined. Student's t-test was used to compare the shear bond strength (SBS) of the two groups, and the 2 test was used to compare the Adhesive Remnant Index (ARI) scores for the two adhesive systems. Results: The mean SBS of the brackets bonded to the teeth subjected to the SEP for 3 to 5 seconds was 8.0 Ϯ 4.6 MPa and was not significantly different (t ϭ Ϫ0.69, P ϭ .494) from the SBS of the brackets bonded using a 15-second SEP application time (x ϭ 8.9 Ϯ 3.4 MPa). The comparisons of the ARI scores between the two groups ( 2 ϭ 2.16) indicated that bracket failure mode was not significantly different (P ϭ .340) for both groups, and most failures were at the bracket-adhesive interface. Conclusion:The present findings indicate that increasing the SEP application from 3 to 5 seconds to 15 seconds does not result in a significant increase in SBS.

“…46 On the other hand, when brackets fail at the enamel-adhesive interface, less residual adhesive remains, but the probability of damage to the enamel surface is increased when failure occurs in this mode. 47 In summary, RMGIs provide the advantages of sustained fluoride release and can be used in a moist environment to bond brackets. In addition, the new self-etch conditioner tested offers the added benefit of not needing to be rinsed off following application.…”

Section: Discussionmentioning

confidence: 99%

A Self-Conditioner for Resin-Modified Glass Ionomers in Bonding Orthodontic Brackets

Bishara

Ostby

Laffoon

et al. 2007

Objective: To evaluate a new self-etch conditioner used with resin-modified glass ionomers (RMGIs) in bonding orthodontic brackets. Materials and Methods: Sixty human molars were cleaned, mounted, and randomly divided into three groups. In group 1 (control), 20 orthodontic brackets were bonded to teeth using Transbond Plus Self-etching Primer; in group 2, 20 brackets were bonded using an RMGI with a 10% polyacrylic acid conditioner. In group 3, 20 brackets were bonded using Fuji Ortho LC with a new norinse self-conditioner for RMGIs. The same bracket type was used on all groups. The teeth were debonded in shear mode using a universal testing machine, and the amount of residual adhesive remaining on each tooth was evaluated. Analysis of variance was used to compare the shear bond strength (SBS), and the 2 test was used to compare the Adhesive Remnant Index (ARI) scores. Results: There were no significant differences in the SBS (P ϭ .556) between the groups. The mean SBS for Transbond Plus was 8.6 Ϯ 2.6 MPa, for Fuji Ortho LC using 10% polyacrylic acid 9.1 Ϯ 4.6 MPa, and for Fuji Ortho LC using GC Self-conditioner 9.9 Ϯ 4.1 MPa. The comparisons of the ARI scores between the three groups ( 2 ϭ 35.5) indicated that bracket failure mode was significantly different (P Ͻ .001), with more adhesive remaining on the teeth bonded using Transbond. Conclusions:The new self-etch conditioner can be used with an RMGI to successfully bond brackets. In addition, brackets bonded with Fuji Ortho LC resulted in less residual adhesive remaining on the teeth.