Effect of two commercial energy drinks on enamel surface characteristics and orthodontic bracket shear bond strength: an in vitro study

Background Energy drinks are acidic beverages with recognized erosive potential, but their effect on enamel characteristics relevant to orthodontic bonding remains incompletely described. This in vitro study evaluated the effect of continuous 24-hour immersion in two commercial energy drinks, Red Bull and Code Red, on enamel surface morphology, elemental profile, surface roughness, and orthodontic bracket shear bond strength (SBS). Methods Thirty sound human lower premolars were randomly allocated to three groups ( n = 10): distilled water (control), Red Bull, and Code Red. After 24 h of immersion at 37 °C, enamel was assessed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and SEM-derived surface roughness analysis. Stainless-steel premolar brackets were then bonded, and SBS was measured using a universal testing machine. Results Under the accelerated laboratory exposure conditions used, both energy drinks produced evident enamel surface alterations compared with the control group. The control group showed the lowest roughness (Ra = 3.04), whereas Red Bull and Code Red increased roughness, with the highest values observed for Code Red (Ra = 24.9). Mean SBS decreased from 24.1 MPa in the control group to 17.7 MPa after Red Bull exposure and 12.7 MPa after Code Red exposure. EDX demonstrated lower calcium values after exposure to both drinks than in the control group. Conclusions Within the limitations of this acute in vitro immersion model, both tested energy drinks showed erosive potential and were associated with altered enamel surface characteristics and lower orthodontic bracket SBS compared with distilled water. These findings should be interpreted as laboratory evidence under accelerated exposure conditions rather than as direct evidence of the risk of clinical bracket failure.