Do Applicator Residues Remain on the Cavity Surface During the Adhesive Application Process?

Abstract Objectives: This in vitro study aimed to examine two different application brushes used to apply an adhesive to dentin surfaces using scanning electron microscopy (SEM) for the possible presence of brush residues. Materials and Methods: Class I cavities with a width of 2 mm and a depth of 3 mm were prepared in 30 human molars using diamond and steel burs under water cooling. These teeth were then divided into two groups of 15 teeth each. According to the manufacturer’s instructions, a universal bonding agent (Scotch Bond Universal) was applied to one group using a microbrush and to the other group using a bristle brush applicator. The bonding agent was then polymerized for 20 s. The prepared cavities were coated with gold-palladium for SEM analysis and photographed at different magnifications. Results: The SEM analysis showed that only the samples from the microbrush group had fibre residues on the adhesive surface, while the samples from the bristle brush group were free of residues. Conclusions: The microbrush used left residues on the adhesive-applied surfaces, while no residues were found on the bristle brush-applied surfaces. The microfibres or bristles at the tip of the brush, which help to apply the adhesive, and the condition of their connection to the brush are important factors in terms of residue on the application surface. Clinical Significance: The possibility that microbrush fibres may interfere with dental adhesion underscores the need for further research on long-term effects, alternative application methods and careful selection of applicators.