Trial design and any changes after trial commencement
This study was a single-center; prospective 2-arm parallel randomized controlled trial with 1:1 allocation ratio. Ethical approval was granted from Ethics Committee of Islamic Azad University, Kazerun branch (IR.IAU.KAU.REC.1399.008) registered in the Iranian Registry of Clinical Trials (IRCT20180923041092N2). There were no changes to the trial after its commencement.
Participants, eligibility criteria, and settings
50 children with age range of 8 to 12 years referred to Department of Orthodontic, School of Dentistry, Shiraz Branch, Azad University (2018-2019) for removable orthodontic treatment were requested to participate in this study if they were willing to do so and did have access to WhatsApp application by smartphone. For the purpose of standardization, children whose treatment plan included the use of a removable orthodontic appliance made of auto-polymerizing acrylic resin with a midline screw and had a minimum treatment time of six months, and treated by the same orthodontist (N.N) were enrolled. The time of sending message reminder for each patients was determined with accordance to the time that parents were present at home. The patients who did not have daily access to Internet by their own smartphone or their parents, and patients who suffered from specific nutritional regimens, systemic diseases, syndromic anomalies such as cleft lip or palate and physical or mental disability were excluded from the study.
Intervention
The participants were divided randomly into two groups of message reminder and control. Both groups received adequate oral hygiene instructions at the beginning of the study. The patients in message reminder group received message reminders in Persian and videos as oral hygiene reminder while the control group did not receive any of these. Participants were not aware of the reason behind sending message reminders or the parameters evaluated in this study.
Experimental group
In the first phase (T1), the message reminders group received video and text messages containing information about the significance of oral hygiene twice a week for 4 weeks (table 1). The message reminders were sent when both parents and patients were at home. The time interval between lunch and dinner was often chosen for most patients. For the rest of the patients, a convenient time was arranged following discussion with the parents. In the second phase (T2), patients received text message and educational videos for oral hygiene once a week for 2 months. In the third phase (T3), message reminders were sent to the message reminder group once a week for 3 months. Thereafter , PI, GI, and dental caries index were recorded at baseline (T0) and one (T1), three (T2) and six (T3) months after the first day of treatment by the same blinded examiner who did not have any information about participant’s division in the two groups.
Table 1. Text messages sent to the text messaging group
This text message is from the orthodontic clinic. We have to brush our teeth for a minimum of 3 minutes after each meal. Tooth brushing helps maintain sound beautiful teeth.
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Hygienic alert! How long does your tooth brush take? 1-2 minutes? Each toothbrush has around 2500 bristles. Allow all of them to do their job and clean your teeth.
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Your next appointment is soon. If you have forgotten to regularly brush your teeth, start now!
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Did you know that after eyes, teeth have the greatest impact on facial beauty? Pay more attention to the health and appearance of your teeth!
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Just wanted to remind tooth brushing after each meal! Do it and see the extraordinary result. See you soon!
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You are approaching your next appointment fast! Keep up the good work! See you soon!
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Please make time for tooth brushing. It significantly affects the outcome of orthodontic treatment.
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A friendly reminder! Please do not forget to brush your teeth and clean the orthodontic appliance after each meal.
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Your smile is the first thing noticed by others. It is your responsibility to keep your teeth clean and it is our responsibility to level and align them by orthodontic treatment.
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Control group
The control group did not receive any text message or video during this period. The indices were measured at T0 (onset of study) and at the end of each phase (T1, T2 and T3) similar to message reminder group by the same blinded examiner .
Outcomes (primary and secondary) and any changes after trial commencement
The PI was measured using the Silness-Loe PI.25 For this purpose, presence of dental plaque was evaluated at four areas namely mesiobuccal, buccal, distobuccal and lingual of teeth #44, 24, 32, 12, 36 and 16, and each surface was given a score of 0 to 3 (Table 2). The GI was determined by assessing the degree of gingival inflammation around teeth #44, 24, 32, 12, 36 and 16. As shown in Table 3 each surface was allocated a score of 0 to 3. This index is used for assessment of the severity of gingival inflammation and its quantification. Bleeding on probing is an important criterion in this index.26 All teeth were examined for caries as shown in Table 4 and were allocated a score of 0 to 6. Presence of caries was determined by clinical examination.27
Table 2. Plaque Index (PI)
Score
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Presentation
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0
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No plaque
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1
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A film of plaque adhering to the free gingival margin and adjacent area of the tooth. The plaque may be seen in situ only after application of disclosing solution or by using the probe on the tooth surface.
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2
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Moderate accumulation of soft deposit s within the gingival pocket, or the tooth and gingival margin which can be seen with the naked eye.
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3
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Abundance of soft matter within the gingival pocket and/or on the tooth and gingival margin.
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Table 3. Gingival Index (GI)
Score
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Presentation
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0
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Normal gingiva, absence of inflammation, bleeding, or swelling
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1
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Mild inflammation, slight edema and color change, but no bleeding
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2
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Moderate inflammation, redness, swelling, and bleeding on probing
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3
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Severe inflammation, marked redness, and edema, spontaneous bleeding
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Table 4. The International Caries Detection and Assessment System (ICDAS)
Presentation
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Score
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Sound
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0
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First Visual Change in Enamel (seen only after prolonged air drying or restricted to within the confines of a pit or fissure
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1
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Distinct Visual Change in Enamel
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2
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Localized Enamel Breakdown (without clinical visual signs of dentinal involvement)
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3
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Underlying Dark Shadow from Dentin
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4
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Distinct Cavity with Visible Dentin
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5
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Extensive Distinct Cavity with Visible Dentin
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6
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On the day of delivery of removable orthodontic appliance (T0), patients received a hygienic package including an Oral-B fluoridated toothpaste (with 1100 ppm fluoride) and a soft Trisa toothbrush (6+ years). Both groups received instructions on tooth brushing during the course of orthodontic treatment and recommendations regarding maintenance of orthodontic appliance. The modified Bass tooth brushing technique was taught to all patients. They were requested to brush each of the upper and lower dental arches for 2-3 minutes, three times a day. Also, patients received comprehensive information regarding dental plaque, dental calculus, and their effects on oral health.
No changes to the study design were made after commencement.
Interim analyses and stopping guidelines
Not applicable.
Sample size selection
Randomization
Participants were randomized according to the minimization method proposed by Pandis.28 Randomization ensured patients' allocation to both groups with 1:1 ratio. The first participant was allocated to one of group at random. For each subsequent participant, we determined that allocation to which group would lead to better balance between the groups in the variables of interest. Allocation concealment, and implementation were performed before randomization process by a researcher who was not involved in the study.
Sample size calculation:
A total of 40 participants were required to achieve 85% power (instituted by G power, version 3.0.1; Franz Faul universitat, Kiel, Germany) and detect significant differences considering the effect size of 0.47 (P < 0.05). Considering the possible dropouts, the sample size was increased to 50.
Blinding
Examiner clinician, the person performing the data entry and the statistician were blinded to the intervention. It was not possible to blind the participants because the patients knew whether they had received the message reminder.
Statistical analysis
Data were analyzed using SPSS version 24. After descriptive analysis of the data, their normal distribution was evaluated using the Shapiro-Wilk test and Levene’s test. The effects of sociodemographic such as gender, father’s education level (primary school graduate or below, secondary school, post-secondary or above), mother’s education level (same grades as father‘s), father’s job (self-employed, employee, unemployed), and mother’s job (same levels as father’s ) on the patients behavior modification in plaque controls were analyzed using Bivariate analysis. For comparison between two groups employed the Mann-Whitney U test, and for others we used the Kruskal-Wallis H test.
Friedman test was used for intra-group comparisons of the mean PI and GI in each group of the message reminder g and control groups among T0, T1, T2, and T3. The Wilcoxon Mann Whitney test was used to compare the mean PI and GI between the message reminder and control groups at each phase (T0, T1, T2 and T3).
The McNemar and Cochrane’s tests were used for intra- group comparison of dental caries. The Pearson chi square test was applied to compare the two groups in terms of dental caries at each time point. Level of significance was set at 0.05. The intraclass correlation coefficient (ICC) for measurement of PI, GI and caries index was determined by assessing 10 randomly chosen participants within one hour at T0. ICC values <0.20 indicated poor agreement, values between 0.21-0.30 indicated partial agreement, 0.31-0.40 indicated fair agreement, 0.41-0.60 indicated moderate agreement, 0.61-0.70 indicated considerable agreement, 0.71-0.80 indicated strong agreement, 0.81-0.90 indicated almost complete agreement and 1 indicated complete agreement.