Comparison of shear bond strength of brackets bonded with four different bonding protocols at different time intervals; An in vitro study

Abstract

Objective: To test shear bond strength and mode of debonding of brackets bonded using a traditional orthodontic adhesive (Transbond XT), self-adhesive material (Heliosit) and selfetch &self-adhesive resin material (Vertise flow) with and without phosphoric acid etching; after 15 minutes, 24 hours and following aging and thermocycling. Materials and Methods: One hundred and eighty upper first premolar teeth were used in this study. The specimens were equally and randomly allocated into four groups. TXT group (Transbond XT; n=45); HS group (Heliosit group; n=45); VF group (Vertise Flow; n=45) and (VF+P) (Vertise Flow with phosphoric acid etch; n=45). Each group was randomly divided into three equal subgroups; First subgroup (n=15) shear bond strength was tested after 15 minutes of bracket bonding, second subgroup (n=15): shear bond strength was tested after storage in distilled water at 37°C for 24 hours and third subgroup (n=15): shear bond strength was tested after specimens storage in distilled water at 37°C for 6 weeks and subjected to 1000 thermal cycles. Adhesive remnant index (ARI) was recorded for each specimen and its mean was compared between different groups. Results: Vertise flow (either with or without enamel pre-etching) and Transbond had acceptable bond strength at 15minutes debond testing. Heliosit adhesive had a significantly lower SBS at 15 minutes debond. Transbond XT had a significantly higher (SBS) compared to the other 3 groups at 24 hours debond. Thermocycling and aging conditions affected SBS in all the groups except specimens bonded using Transbond XT. Vertise Flow when used without enamel pre-etch resulted in decreased SBS below the clinically acceptable value after thermocycling and aging. Conclusions: Both Vertise Flow (when used with pre-etched enamel) and Heliosit can be used in orthodontic practice, offering simplified bonding procedures associated with clinically acceptable bond strength and minimal amount of remaining adhesive on enamel surface at debond.

Clinical performance of light-cured orthodontic adhesives for bonding brackets – an in-vitro study.

“…However, it has been established that Heliosit’s bond strengths for orthodontic bonding fall within the recommended range for clinical use. 28 – 31 The current study found it less invasive on the teeth, similar to Transbond XT. This was evident from the evenly distributed adhesive remnant index scores between ARI scores of “1” and “2”.…”