The number of orthodontic treatment provided to Brazilian population has been increased. Unfortunately, some negative effects such as gum bleeding and bad breath are commonly observed. It partially happens because tooth brushing and flossing become more difficult in the presence of braces. Therefore, there is a need for clinical protocols able to maintain the mouth healthy during orthodontic treatment.

Considering that proper use of mouthwashes by in individuals without braces is accompanied by decrease in plaque and gum inflammation levels, it was hypothesized that, during orthodontic treatment their anti-gingivitis and anti-plaque properties would positively affect oral health. Objectives: The present study will compare the effects of two commercially available mouthwashes with a placebo mouthwash in orthodontic patients wearing fixed appliances.

Whole-mouth clinical examinations will be performed in periodontally healthy patients 15 days before, at the day of bonding and also 3 and 6 months after braces bonding. Hard and soft tissues status, presence of gingivitis and amount of dental plaque will be monitored to determine mouthwashes efficacy. At these same time-points plaque samples will be collected from dental sites and braces surfaces aiming at determining total levels of bacteria and levels of specific bacteria related to gum disease. After a full-mouth ultrasonic debridement to remove dental plaque, stains and tartar, patients will be randomly assigned to an Essential oils, Cetylpyridinium chloride or a placebo mouthwash for 6 months (40 ml/day). Further, samples of orthodontic wires will be analyzed under microscopy to check whether regular use of mouthwashes increases the risk of corrosion or not.

Inclusion Criteria:

• good general health;
• class I or class II malocclusions with a nonsurgical orthodontic treatment plan for alignment and leveling including no-extraction, extraction of two upper premolars or extraction of four premolars; no previous orthodontic treatment; overbite and overjet that allowed brackets to be placed on the lower teeth without occlusal interferences;
• periodontal health (with no clinical signals of inflammation, GI <1 e no clinical attachment loss);
• at least 26 natural teeth;

Exclusion Criteria:

• severe skeletal malocclusion in anteroposterior, vertical or transverse dimensions; surgical orthodontic plan;
• mouth breathing;
• gingivitis; periodontitis; gingival overgrowth;
• prosthetic fixed devices, removable partial dentures or overhanging restorations;
• systemic diseases or conditions that could influence the periodontal status;
• smokers and former-smokers;
• pregnancy or breast-feeding;
• history of sensitivity or suspected allergies following the use of oral hygiene products; any antibiotic prophylaxis;
• antibiotics and/or anti-inflammatory drug use in the six months prior to the beginning of the study;
• regular use of chemotherapeutic antiplaque/antigingivitis products;
• periodontal treatment performed within six months prior to study initiation;
• unwillingness to return for follow-up.

No individual participant data will be shared.