The aim of this study is to present the results of a statistical inquiry measuring the bracket debonding rate using the WIN lingual technique. This inquiry was performed in the Odontology Unit at the Rothschild Hospital in the framework of the Lingual Orthodontics University Diploma at Paris VII university. Results were gathered by 8 orthodontic practitioners during two years of training from all their patients treated with the WIN lingual technique. The sample study comprised 33 patients treated exclusively with the WIN lingual technique. The 8 practitioners filled in a questionnaire relating to bracket bond failure in their patients in the course of treatment. In all, sixty-two questionnaires were analyzed. The data were then computed using the statistical tool of R software version 3.1.3. The results of this analysis demonstrate the reliability of the WIN system evidenced by an average of 2.1 bracket bond failures over the two-year treatment period, i.e. approximately 1 bracket per patient per year. Given the right conditions, (precise prescription, compliance with bonding protocols), the bond failure rate can be lower still, even compared with the buccal technique or relative to other lingual techniques. The benefits of lingual appliances, particularly in the WIN system, are essential to clinicians in their daily practice in order to optimize the quality and duration of their treatments with a view to ensuring patient satisfaction.