A commentary on:

Timm L H, Farrag G, Baxmann M, Schwendicke F.

Factors Influencing Patient Compliance during Clear Aligner Therapy: A Retrospective Cohort Study. J Clin Med 2021; 10: 3103.

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GRADE rating

Commentary

Patient compliance is a crucial factor in successful orthodontic therapy. With treatments involving removable appliances like clear aligners, patients are expected to be more responsible in terms of adhering to specified wear time, changing aligners on periodic intervals and aligner maintenance. This is in addition to the routine oral hygiene measures they must follow, which needs to be more rigorous during active orthodontic treatment. All these require a high level of compliance during clear aligner therapy (CAT). This cohort study addresses compliance as the main outcome in subjects who completed CAT in 2019. The data for the current study was obtained from PlusDental, which is a health-tech company based in Berlin, Germany.

The sample for the study consisted of 2,644 patients, with all study subjects being above 18 years of age and with a sex distribution of 75% women and 25% men. Patients who had undergone and successfully completed orthodontic therapy for malocclusion in anterior and premolar region and requiring no extractions, were recruited in the study. The outcomes for compliance observed were: 36% fully compliant; 38.3% fair; and 25.7% poorly compliant. The fact that 679 patients (25.7%) were poorly compliant and yet they successfully completed orthodontic treatment are contradicting each other. To avoid this problem, a preferable way of appraising compliance would be to utilise a prospective study design.

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© Varangkana Petchson / EyeEm/Getty Images Plus

The total number of aligners prescribed for treatment ranged from 6 aligners to more than 24 aligners. Specifically, the number of aligners worn by the patients were spread out between 6, 9, 12, 15, 18, 21, 24 and >25 among 2,644 patients. With a huge non-homogeneity in the aligner numbers, which also makes the total treatment duration spread out, understanding the triggers in non-compliance becomes confounded by multiple unknown variables. Especially given that some patients are finishing treatment considerably earlier than the others, it is unclear if the longer duration in treatment has any contribution to compliance and whether the lack of compliance starts early in treatment or later.

A self-reported questionnaire for the patient was formulated in the app. It involved patients entering details about their daily aligner wear time, aligner change date and pressure felt during aligner wear. The analysis of the data largely depends on the assumption that patients always provide an honest response to the questionnaire. Adding a more objective method in the remote monitoring can add reliability to the assessment of compliance. One technique reported in the literature used sensors and indicators with CAT and removable appliances which estimates the wear time more accurately.1

Additionally, rating the pressure felt by patients as very weak, weak, strong or very strong has a subjective component to it. The responses by the patients can be influenced by personal variation, including individual pain tolerance and as a result, could be over-reported or under-reported. Furthermore, the significance of the pressure felt was not clinically correlated to the compliance. Thus, even though this study attempts to present a practical guideline in detection of compliance, the few relevant confounding factors were not considered. A more blinded form of detection will add precision to the results, rather than depending on patients' subjective reporting.

The authors have made a crucial step toward understanding patient involvement and ways to improve them. With clear aligner therapy being a popular form of treatment in orthodontics, having guidelines to improve patient cooperation is essential for successful treatment. From a clinician's perspective, it is also important to ensure that the instructions are thoroughly conveyed to the patient from the beginning of treatment. Proper patient education about the role of compliance is key to positive orthodontic outcome. Literature even reports that 'effective communication is the main requirement for an evidence-based, patient-centred and outcomes-focused practice.'2 Repeated communication and reminders in the form of apps and digital means should potentially strengthen the patients' sense of responsibility.