Antibacterial properties of orthodontic cements combined with fluoride mouth rinse

Objectives: Orthodontic patients are at high risk for developing initial carious lesions. Daily rinse with a 0.05% sodium fluoride mouth rinse was suggested. Anticariogenic mechanisms of fluoride are :reduction of demineralization, enhancement of remineralization, and inhibition of microbial growth. Due to the fact that fluoride levels decrease over time, “recharging” with fluoride has been suggested. Methods: Four orthodontic cements were tested: composite resin based materials – Transbond XT , and Transbond Plus, a conventional glass ionomer cement- CX-Plus and a dual cured resin-reinforced glass ionomer cement - Fuji ORTHO LC were placed on the sidewalls of wells of a 96-microtiter plate. After polymerization and 30 day aging process, the samples were daily rinsed with 0.05% NaF solution for 14 days. 24h after the last fluoride rinse, s.mutans (1 x 106) were placed on the surface of each sample for 1 hour at 37ºC to establish direct contact. Fresh media was added and samples were monitored for 24h by temperature controlled spectrophotometer. Similar experiments were conducted on samples 48h and 72h after the last fluoride rinse. Results: 24h after the last fluoride rinse, the resin modified glass- ionomer - Fuji Ortho LC and the glass–ionomer CX Plus, showed potent antibacterial properties, whereas the other composite-based materials showed none. The 48h experiment the resin modified glass- ionomer - Fuji Ortho LC and glass–ionomer CX Plus showed potent bacteriostatic properties, whereas the composite based material- Transbond XT and Transbond Plus encouraged bacterial growth.72h after the last fluoride rinse only the Fuji Ortho LC maintained its bacteriostatic properties while all the other tested materials showed no antibacterial activity. Conclusions: a 14 days daily fluoride rinse temporarily revives the antibacterial properties of the the resin modified glass-iIonomer material- Fuji Ortho LC and glass–ionomer CX Plus whereas the other composite-based materials showed no effect.