The aim of this article was to compare the efficacy of a messaging application compared to verbal instructions for improving oral hygiene in patients undergoing fixed orthodontic treatment with conventional ligature brackets (MBT technique) over a 3-month period. Randomized clinical trial of two parallel groups with 1:1 allocation ratio. Conducted in the orthodontic postgraduate clinic of the conventional ligation technique (MBT) at the Fundación Universitaria CIEO- UniCIEO, Bogotá, Colombia.

Sixty patients aged 18 to 30 years with periodontal health and active WhatsApp application on smartphone, who started fixed orthodontic treatment with conventional ligation brackets (MBT technique) were included.

Randomization Intervention: all participants received verbal oral hygiene instructions, were randomly assigned by software to the mobile app group (GAM) (n=30) (mean-----DE---- years) that used WhatsApp to reinforce oral hygiene, or to the control group (CG) (n=30) (mean-----DE---- years).

The primary outcome was bacterial plaque level determined with the orthodontic plaque index (OPI) and bleeding on probing (BOP) index measured at three points, after appliance cementation (T0), 1 month later (T1), 2 months later (T2) and 3 months later (T3). Blinding: By two trained operators and blinded to the assignment. The secondary outcome was the identification of microorganisms in the bacterial plaque of the bracket ligation. The data were analyzed by

In this study the researchers are going to recruit patients from the orthodontic clinics with conventional ligation brackets of the MBT technique, from the CIEO - UniCIEO University Foundation; who receive a sequence of archwires, according to the phases of the treatment such as the initial alignment and leveling phase: Nickel - titanium archwires of caliber 0.014, 0.016. Patients entering the study will be randomly assigned to each of the groups; participants in group 1 will receive the WhatsApp application, and at the same time they will receive verbal instructions in oral hygiene; they will be sent reminders, through images and videos with necessary, accurate and instructive information; messages will be sent twice a week for three months. In group 2 the participants will receive verbal instructions given by the researcher on oral hygiene and a video with instructions on the important elements to perform oral hygiene in orthodontic patients. Two indices will also be evaluated: the orthodontic plaque index and the bleeding on probing index.

Inclusion Criteria:

• Voluntarily agree to participate in the study.
• Age from 18 to 30 years
• Patients undergoing orthodontic treatment with fixed appliances using the MBT technique.
• Periodontal health on intact periodontium or diminished periodontium with no history of periodontitis, no presence of bacterial plaque score 0 No plaque deposits on tooth surfaces surrounding the bracket base; according to OPI index, no presence of periodontal pockets, calculus, gingival inflammation and bleeding verified by the periodontist.
• Have cell phone with active WhatsApp application and possibility to connect twice a week, verified by patient interview previously.
• No kinship between participants (affinity/consanguinity)

Exclusion Criteria:

• Systemic history (diabetes, hypertension, poor nutrition), verified by previous patient interview.
• Smokers (smoke 10 cigarettes per day), verified by previous patient interview.
• Pregnancy and lactation.
• Participating in another research or oral health education program.
• Difficulty in speaking or writing Spanish.
• Physical or mental limitation.
• Diagnosis of SARS COV-2.
• Use of mouthwash during the three months of the study.
• Use of additional appliances (lingual arch, transpalatal bar, among others)

It is not possible to blind the interventions to the patients, nor to the clinicians performing the orthodontic treatment, however the operators, should not know the assignment of the study participants, the processing of the microbiological samples and the statistical advisor will also be blinded, this will be done by means of codes for each group.