Caries risk assessment in patients with orthodontic fixed appliances

It has been reported that the use of orthodontic appliances may lead to an increase caries experience. However the relationship between the orthodontic treatment and the risk factors is not well documented. Objectives: The present study was designed to assess the caries risk factors in patients who had been carrying fixed appliances for 6 months. Methods: 29 healthy young patients scheduled for orthodontic treatment were enrolled in this pilot study (CPP agreement n°2177) and received a clinical and X-Ray examination (exclusion criteria: low salivary flow rate, active caries lesions). A test based on RT-PCR - Cario-Analyse (Pierre Fabre, France) - was performed to count mutans streptococci (SM) in a saliva sample, at baseline and six months after the beginning of orthodontic treatment. A cariologic exam was performed at the 6 months visit. Results: At baseline, DMFT was 2.9 ± 3.4, DMFS 4.5 ± 5.9, 50 % of the patients had a low rate of salivary SM, 18 % a medium rate and 32 % a high rate. At 6 month, 28.6 % had low SM, 14.3 % a medium rate, 46.4 % a high rate and 10.7 % were rated as very high. Active lesions were recorded for 34.4 % of patients. 60 % of them had an increased SM rate at 6 months. We also noticed that the increase of SM was correlated for 61.2 % of the patients with an active lesion. Conclusion: The results obtained in the present study demonstrate that fixed orthodontic treatment lead to a modification of the oral microflora, increasing the concentration of cariogenic micro-organisms. This stresses the need of a careful monitoring of orthodontic patients for the risk of caries development.