Microbiology and Clinical Efficacy of Professional Topical Fluoride on Streptococcus Mutans and Selemonas Sputigena in Orthodontic Patients: a Randomized Clinical Trial

This study was born from the need to improve caries prevention in orthodontic patients, a group particularly at risk. Fixed orthodontic appliances make daily oral hygiene more difficult, leading to increased plaque accumulation and the proliferation of cariogenic bacteria such as Streptococcus mutans and, more recently, Selenomonas sputigena. Although the latter does not cause cavities on its own, it enhances the action of Streptococcus mutans, making the caries process more aggressive.

The aim of the research was to evaluate the effectiveness of two different types of professional topical fluoride-gel and varnish-in reducing the presence of these bacteria and improving certain clinical parameters, such as salivary pH, the DMFT index (which measures decayed, missing, and filled teeth), and the Plaque Control Record (PCR%).

The study involved 45 patients, all between 8 and 17 years old and wearing fixed orthodontic appliances. They were divided into three groups: one received fluoride gel, another received fluoride varnish, and the third group underwent only a professional oral hygiene session, without any fluoride application. All patients were evaluated at the beginning of the study (T0) and again after four months (T1), both clinically and microbiologically, through saliva and plaque analysis.

The results showed that in the fluoride-treated groups-especially the varnish group-there was a significant reduction in plaque, an improvement in salivary pH (mainly in the gel group), and a decrease in the presence of S. mutans and S. sputigena. Furthermore, there was a reduction in oral Streptococci and Lactobacilli levels in the treated groups, whereas these levels increased in the control group. Interestingly, although not all differences were statistically significant, the improvements observed in the treatment groups suggest a clinically relevant benefit of topical fluoride, especially in varnish form.

In conclusion, professional application of fluoride-whether in gel or varnish form-proved effective in counteracting key bacteria responsible for dental caries in orthodontic patients and in improving several relevant clinical parameters. This confirms the importance of combining professional oral hygiene with specific fluoride treatments in patients wearing orthodontic appliances.