Purpose: Latest improvements in the formulation of dentin
bonding systems involved the addition of chlorhexidine (CHX)
within the adhesive blends. Despite its possible antibacterial
role, no information is available on CHX elution from the polymerized adhesive. Aim of this preliminary studywas to assess elution of CHX in water. The tested hypothesis was that no release of active material occurs over time.
Methods and materials: Two universal adhesive systems
were selected for the study: Peak Universal (Ultradent), and
Scotchbond Universal (3M ESPE; control). Adhesive disks
(1mm thick and 6mm in diameter) were prepared, fully
cured using a LED lamp (VALO, Ultradent) for 3min and
immersed in water for 72 h. Elution of CHX was monitored
by an optimized and validated high-performance liquid chromatographic (HPLC) method. In details, the mobile phase was a binary mixture of a pH 3.0 triethylamine phosphate buffer and acetonitrile under gradient elution; the stationary phase was a Kinetex PFP column (5m, 150mm×4.6mm) and the detection wavelength was 254 nm.
Results: The results of the study revealed that under the
tested conditions, the selective analysis of chlorhexidine could
be performed with limit of quantification (LOQ) of 0.1 ppm.
Interestingly, no CHX was found in the eluates, despite the
high sensitivity of the tested HPLC system.
Conclusion: Further studies are needed to clarify the role of
active compounds blended within the adhesive formulations.
