Comparison of two self-etch primers and a fluoride sealant on shear bond strength of precoated brackets
Wong, Debby H.
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Introduction. In an attempt to save chair time during bonding, self-etching primers are used along with metal brackets that are precoated with adhesive material. Fluoride releasing sealants has also been used commonly to prevent decalcification during orthodontic treatment. The purpose of this study was to compare the shear bond strength (SBS) of APC(TM) precoated brackets bonded with two different self-etching primers: Transbond Plus(TM) self-etch primer (TPSEP) and Reliance self-etch primer(TM). This study also evaluated the effect of combining TPSEP or the Reliance SEP(TM) with LED Pro Seal®, a fluoride releasing sealant for the enamel surface. Each of the self-etching primers (SEPs) and the combination of SEP combined LED Pro Seal® were evaluated for shear bond strength after 24 hours of storage and thermocycling with 1 week of storage, in order to simulate some of the temperature changes in the oral cavity. Materials and Methods. One hundred and twelve teeth were randomly divided into eight groups as follows: Group 1: Transbond(TM) Plus self-etch primer (TPSEP), Group 2: Reliance self-etch primer(TM) (Reliance), Group 3: TPSEP + LED Pro Seal, Group 4: Reliance + LED Pro Seal, Group 5: TPSEP + thermocycling, Group 6: Reliance + thermocycling, Group 7: TPSEP + LED Pro Seal + thermocycling, Group 8: Reliance + LED Pro Seal + thermocycling. An occlusogingival load was applied to the brackets producing a shear force at the bracket-tooth interface utilizing a Universal Testing Machine. Results. Significant differences in shear bond strengths among the groups containing the TPSEP or Reliance SEP, were detected by two-way ANOVA (p = 0.018). The results of the Newman-Keul's test that compared the test groups at 24 hours show that the shear bond strength of Reliance SEP (3.98 MPa ± 1.30) was not statistically different from TPSEP (4.25 MPa ± 1.16). When each of the SEP is combined with the Pro Seal, a statistical difference in shear bond strength is detected between TPSEP (6.01 MPa ± 3.05) and Reliance SEP (3.76 MPa ± 1.52). Reliance SEP used alone vs. Reliance SEP combined with Pro Seal did not show any statistical difference in shear bond strength. However, when TPSEP was compared to TPSEP combined with Pro Seal, it showed a statistical difference in shear bond strength. Nonetheless, a two-way ANOVA did not detect any statistically significant interaction between the SEPs and the Pro Seal (p = 0.058). None of the groups showed statistically significant differences in shear bond strength when compared at the one week group. Conclusion. The newly introduced Reliance SEP(TM) provides similar shear bond strengths to Transbond(TM) Plus SEP. Reliance SEP(TM) with LED Pro Seal® and Transbond(TM) Plus SEP with LED Pro Seal both provide adequate shear bond strengths. Both SEPs used alone or with LED Pro Seal® maintained its bond strength after thermocycling. LED Pro Seal® is demonstrated to have good bond strength to enamel and can withstand the oral environment.