To the best of authors’ knowledge, this study is the first randomized controlled trial to assess the effect of message reminders on oral hygiene status of children and adolescents between 8–12 years using removable orthodontic appliances. In the present study, minimization method was used for participant randomixation; minimization is a method of randomization used to ensure the balance of important prognostic factors among the groups and does not have the disadvantages of other randomization methods. List of randomization is not prepared in this method before the onset of study; instead, it is prepared in the process of selection of participants. It is a dynamic method of randomization.29
The effect of message reminders on oral hygiene was evaluated by measuring the PI, GI and caries index. The results showed that the message reminder group had significantly lower PI and GI at T2 (3 months after the onset of treatment) and T3 (6 months after the onset of treatment). However, no significant difference was found between the message reminder and control groups in PI or GI at T1 (one month after the onset of treatment). According to psychosocial studies, the mean time required for change of behavior to a habit is approximately 66 days.29 Thus, absence of a significant difference between the two groups at T1 may be due to inadequate time for formation of a new habit.29 Moreover, it has been shown that at the beginning of treatment, the conditions are very challenging for patients since they ought to get used to the new appliance and learn how to practice oral hygiene and clean the appliance. This explains the reason why at T1, challenges encountered by patients to get used to the appliance can result in insignificant effect of message reminders on PI and GI compared to T2 in the two groups.
Previous studies revealed that orthodontic appliances complicate daily oral hygiene practice in patients ,which may lead to accumulation of dental plaque and microbial biofilm on tooth surfaces and orthodontic appliances.2–5 Nonetheless, the current results showed significant increase in GI in the control group between T0-T3 and no significant increase in PI during the course of study. This trend of change can be due to the fact that patients knew that they were participating in a study and this positively affected the behavior of patients in the control group with regard to oral hygiene. Oral hygiene instructions provided for both groups at the beginning of the study may have influenced the results accordingly.
Thus, significantly lower PI and GI in the message reminder group at T2 and T3 is strong evidence supporting the positive effect of message reminder on oral hygiene status. The current results were in agreement with those of studies that reported the positive efficacy of message reminders for oral hygiene promotion of patients during fixed orthodontic treatment.22–25
Evidence shows that dental caries following orthodontic treatment can negatively affect the patients’ perception of orthodontic treatment, which would negatively impact the future attendance of patients.22 Although initial enamel lesions may develop within 2–3 weeks following microbial plaque accumulation on tooth surfaces,31 the current study did not show any significant change in caries index in the two groups during the 6-month course of treatment and the two groups were the same in this respect. Eppright et al. 22 suggested that studies on initial enamel lesions should follow-up patients for more than 6 months.
Several studies have evaluated the positive efficacy of SMS and email reminders for acceptance of orthodontic treatment by patients.22–25 In our study, the message reminder group showed a significant reduction in oral hygiene indices over time compared to the control group; although the trend of this reduction was not the same throughout the study. During T2-T3, a significant increase in PI and GI was noted in the message reminder group. Significant increase in PI and GI in T3 can be due to the decreased impact of the “novelty effect”; the novelty effect is defined as initial improvement in performance in response to increased interest in new technology.20 Thus, after a while, the new technology, i.e. the SMS or email reminders would no longer have its initial novelty and attractiveness and gradually loses its efficacy. Although the current study was performed over a longer period of time (6 months) compared to previous studies,22–25 it appears that assessment of the long-term effects of reminders requires further studies.
Sending weekly text or multimedia messages to parents to remind their children to adhere to their oral hygiene protocol does not seem to a difficult task for a private office. At present, several communication companies provide services with regard to automatic sending of message reminders and many of such services are available free of charge in the Web. Moreover, particular applications in smartphones can be used as reminders. Providing such services would strengthen the communication between orthodontists and patients and indicate that the orthodontists are concerned about each and every one of their patients. Such behaviors can positively affect the patient satisfaction as well.
The generalizability of these results might be limited to 8 to12 years old children with removable orthodontic appliance.
This study was a single-center study; a multi-centric study would increase the sample in a shorter period and would increase validation of results. In this study, we used just clinical indices to determine oral hygiene status, further studies with microbial evaluation of acrylic base plate can be useful.