Outcomes
SECONDARY
The predictor variables in this study were the use of different fluoride products. The primary outcome variable was the DL incidence; the proportion of participants with at least one new demineralized lesion, as assessed on digital photos taken before and after orthodontic treatment on the buccal surfaces of permanent teeth. Aesthetic impact (degree of injury from 1 to 4) was assessed as secondary outcomes. No changes were made to the trial outcomes after trial commencement. Before and after treatment, standard intraoral close-up photographs (one frontal photograph and two side photographs) were taken with a digital camera (Canon Powershot G7X; Canon, Inc., Tokyo, Japan) and stored in the patient’s digital journal (Edward). The photographs were taken before bonding, at the same visit as the bonding took place. The buccal surfaces of both of the maxillary and mandibular incisors, canines, premolars, and first molar were included in the DL registration. The photographs were taken ‘edge-to-edge’. The DL was assessed according to a Gorelick At baseline, the teeth were polished with a rubber cup and pumice paste and gently dried before photographs were taken. At the time of debonding, the composite material on the teeth surfaces was carefully removed with a slowly rotating carbide bur, followed by polishing with a rubber cup. After gently air drying, a new series of frontal and lateral digital photos were taken. The photographs were projected on a screen (Elite Display E222; Hewlett Packard, Palo Alto, CA, USA) in a dark room while one of the authors (HE) assessed DL. If in doubt when scoring, the lower score was chosen. Missing or poor photos were excluded from the analysis.In order to establish compliance regarding fluoride intake during treatment (at 1 year after installation of the fixed appliance), all the participants were asked to respond in writing to a questionnaire. The following questions were included in the questionnaire: 