Streptococcus mutans colonization around orthodontic brackets bonded with flash-free versus conventional adhesives: an in-vitro study

Streptococcus mutans colonization around orthodontic brackets is a major risk factor for white spot lesions and dental caries due to the bacteria’s ability to form plaque in hard-to-clean areas. This study aimed to compare Streptococcus mutans colonization around orthodontic brackets bonded with a flash-free and a conventional adhesive. Ten intact extracted human premolars were divided into two equal-sized groups and bonded with orthodontic brackets using either a flash-free (3M APC Flash-Free Adhesive Coated Appliance System, Solventum) or a conventional adhesive (3M APCII Adhesive Coated Appliance System, Solventum) as a control. The teeth were then incubated in a Streptococcus mutans suspension at 37 °C for 48 h. Bacterial colonization was evaluated using scanning electron and confocal microscopy in three areas of interest: on the brackets, on the tooth surface, and on the adhesive. Differences between groups were tested for statistical significance. The bacterial colonization on both the brackets and on the tooth surface did not differ statistically significantly between groups (p = 0.6991). In contrast, the bacterial colonization on the adhesive was statistically significantly (p = 0.0004) higher for the conventional adhesive group, indicating decreased bacterial biofilm presence around the brackets bonded with the flash-free adhesive. The flash-free adhesive may offer some advantages in reducing bacteria in certain areas, providing a less favorable environment for bacterial growth and potentially reducing the risk of white spot lesions.