The Effect of Oral Probiotics on Oral Hygiene and Halitosis in Orthodontic Patients.

Brackets, bands, ligatures and wires in patients receiving orthodontic treatment with fixed appliances are areas that trap food and impede oral hygiene. An ecological environment facilitating the growth of microorganisms (Actinobacillus, Bacteroides, Prevotella etc.) emerges in the mouth and may cause caries, enamel white spots, gingival inflammation and halitosis. Despite the use of specialized orthodontic brushes, interdental brushes, mouthwashes and topical fluorides, plaque removal remains inadequate in patients with fixed orthodontic appliances. On the other hand, patients undergoing orthodontic treatment with aligners have been found to have better oral hygiene because of less plaque accumulation in their mouth.Probiotics are defined as non-pathogenic bacteria that can benefit the host's general health when taken in sufficient amounts through nutrition. Nowadays probiotics can be used to enhance oral health as they are found to reduce dental biofilm formation, prevent and decrease halitosis in children, adolescents and adults. To date, there are few randomized controlled trials (RCTs) examining the efficacy of oral probiotics in patients with fixed orthodontic appliances and none reporting the incidence of halitosis and the effect of probiotics in orthodontic patients wearing aligners.

Inclusion Criteria:Patients eligible for the trial must comply with all of the following at randomization:Age between 12 and 18 years for the group with conventional orthodontic appliances This age group represents the majority of patients seeking orthodontic treatment and is homogeneous regarding occupational status (high-school and lyceum students in Greece). Younger patients might present with cooperation problems.Age ≥18 for the Invisalign™ group This age group represents the majority of patients seeking orthodontic with aligners (Invisalign™) regarding social status and other factors.Good general healthFixed orthodontic appliances Patients should have fixed labial appliances (brackets) on all teeth from central incisor to first molar, in both the maxillary and the mandibular arch. Fixed appliances should have been placed at least two months before the patient is accepted into the study and remaining treatment should be at least 3 months. All brackets will be the same (metallic, conventional/not self-ligating, same size). Molars should be banded (same bands on all molars) and all other teeth bonded.At least 20 natural teeth (in case of extraction orthodontic treatment patients can be enrolled two months after extractions) The outcomes will be evaluated at all teeth from first molar to first molar.Exclusion Criteria:Patients will be excluded for any of the following reasons:Active cariesPeriodontitisSyndromes, mental disabilities and craniofacial deformitiesSmoking or use of other tobacco productsDental fluorosis/tooth malformationAntibiotics during the last 2 monthschlorhexidine in the previous 3 weekSuffering from any disease within 2 months before measurementsAllergy to dairy productsParticipation in other trials Consent / assent Parents/guardians and patients will provide written informed consent and patients will provide written assent before randomization and before any procedures are applied.