Patients with multi-bracketed fixed orthodontic treatment are at increased risk of developing white spot lesions (WSL) and gingivitis. Various preventive strategies have been examined to prevent the development of WSLs. During initial non-surgical periodontal therapy, the use of subgingival air-polishing with erythritol powder has shown promising results in reducing deep pockets and gingival inflammation. The efficacy of its use as monotherapy in preventing WSLs and gingival inflammation in patients during orthodontic treatment, has not yet been tested.

The primary objective of the present study is to compare the effectiveness of an air-polishing device used as monotherapy versus ultrasonic instrumentation (the current gold standard procedure) in preventing white spot lesions (WSL) and gingivitis among young patients undergoing multi-bracketed fixed orthodontic treatment.

This is a randomized clinical study for evaluating the performance of an air-polishing device in preventing WSLs and gingivitis among patients undergoing multi-bracketed fixed orthodontic treatment. The null hypothesis tested is that there is no difference between the air-polishing device and the conventional ultrasonic device in preventing WSLs and gingivitis during orthodontic treatment.

Clinical examination and clinical samples will be taken before, during and after orthodontic treatment. It is a single center study of 3 years duration involving samples of 60 patients attending the Division of Orthodontics for treatment. Half of the participants will be randomly assigned for treatment with the air-polishing device in every orthodontic appointment, meaning once per month, the other half will be treated with a standard ultrasonic scaler every six months. The study duration for each participant will be approximately 2 years. The investigators will then analyze the prevalence of WSLs using the Quantitative light-induced fluorescence (QLF) method. Gingivitis will be evaluated throughout the study by using standard clinical parameters; the antimicrobial efficacy against several known periodontal pathogens and the host-response (inflammatory markers in GCF) will be measured by the qPCR assay and the multiplex immunoassay, respectively. Clinical evaluation and collection of samples for microbial and host response analysis will be performed every 6 months. Incidence of bracket debonding we will be calculated and compared.

Inclusion Criteria:

• Subjects about to undergo fixed orthodontic treatment will be invited to participate.
• Age between 12 and 16 years only participants
• Informed written consent obtained by the parents

Exclusion Criteria:

• Clinically significant concomitant disease states (e.g., renal failure, hepatic dysfunction, cardiovascular disease, etc.),
• Known or suspected non-compliance, drug or alcohol abuse
• Inability to follow the procedures of the investigation, e.g. due to language problems, psychological disorders, dementia, etc. of the subject
• Participation in another investigation with an investigational drug or another MD within the 30 days preceding and during the present investigation
• Previous enrolment into the current investigation
• Enrolment of the PI, his/her family members, employees and other dependent persons
• History of fixed orthodontic treatment
• Defects on enamel on labial surfaces of the teeth
• Untreated cavitated lesions
• Plaque levels >25%
• Periodontitis
• Multiple missing teeth
• Cleft lip and/or palate or other craniofacial anomalies or syndromes
• Patients taking any regular medication
• Patients with asthmatic problems

The examiner, the biostatistician and people working in the laboratory for the analyses, will be blinded for allocation group. Only the operator and the participant will be aware of the type of treatment based on the computer-generated allocation table that will be kept at the Trial Master File (TMF) of the study.