A systematic review of randomized controlled trials of interventions to improve adherence among orthodontic patients aged 12 to 18

Compliance, as it relates to health care, is the extent to which a person's behavior coincides with medical or health advice.1 A physician-led approach to prescribing treatment came to be described as “compliance” in the medical literature of the 1950s. This word quickly became unpopular for its judgmental overtones, and alternatives were sought. “Adherence” was then introduced and used interchangeably with compliance.2 

Adherence is defined as the extent to which a person's behavior, such as taking medication, following a diet, and/or executing lifestyle changes, corresponds with recommendations the person has agreed to with a healthcare provider.3 It also implies that people freely choose to undertake behavioral plans, have input to them, and have collaborative involvement in developing and adjusting their treatment strategy.4 One of the most difficult challenges that face a dental team is supporting patients in changing and sustaining change in their oral health behaviors.3 In orthodontics, adherence relates to keeping appointments, maintaining good oral hygiene, wearing elastics, wearing functional appliances or headgear as instructed, and avoiding foods that can debond the brackets.

Interventions aimed at enhancing health-related behaviors typically target three aspects of the behavior: capability, opportunity, and motivation.5 Capability (C) refers to the physical and psychological skills to perform the behavior (B). Opportunity (O) has physical components (eg, access to resources) and social environment aspects (eg, exposure to ideas) such that the person feels able to undertake the new behavior. Finally, motivation (M) refers to the person's conscious (eg, planning and decision making) and automatic (eg. innate drives, emotional reactions, habits) processes said to underline any behavior. Michie and West6 describe a “behavior change wheel” to demonstrate how existing behavioral change interventions map to this COM-B model.

Traditionally, many interventions in the dental field have focused on providing patients with improved knowledge of their disease. Patients who have a good knowledge of their disease or procedures have a better outcome than those who do not.7 Furthermore, Ley8 stated that providing the patient with greater information generally leads to increased compliance with treatment recommendations. Good communication is also associated with improved clinical outcome.9 In order for a communication to be effective, it must be both remembered and understood.10 Patients often do not understand or misinterpret the information given to them. Frequently, this is because the information is given in an inappropriate form. Material written by clinicians may be too technical or difficult for the patients to understand or ambiguous.8 In the same context, Thickett and Newton11 assessed how three different methods of presenting information affected recall of information in orthodontic patients in the short and long term. They found that mind mapping and acronyms convey a significant advantage in patient recall of information.

The aim of this article is to investigate the effectiveness of interventions to enhance adherence among orthodontic patients aged 12 to 18 years. Specific adherence outcomes included were recall of information given by the orthodontic team, attendance at orthodontic appointments, self-reported oral hygiene behavior, and clinical indexes of oral hygiene.

A systematic review of interventions aimed at improving adherence to advice given to orthodontic patients aged 12 to 18 years regarding key behaviors (appointment attendance, oral hygiene–related behaviors) was conducted.

The following inclusion criteria were used:

• Type of studies: Randomized controlled studies with a before and after design were included.

• Participants: Participants were 12- to 18-year-olds undergoing upper and lower fixed orthodontic appliances treatment.

• Types of interventions: These included verbal advice, written advice, interventions based on psychological theories, and educational interventions.

• Comparisons: These included intervention vs no intervention or comparisons of two or more interventions.

The following primary outcomes were examined:

• Recall of information as measured by a validated questionnaire.

• Attendance at orthodontic appointments as recorded in the dental and medical notes.

• Self-reported behavior.

• Clinical indexes, such as the Plaque Index.

The following secondary outcomes were examined:

• Motivation for orthodontic treatment, as assessed by any validated questionnaire.

• Expectation of orthodontic treatment, as assessed by any validated questionnaire.

• Apprehension and worries about orthodontic treatment, as assessed by any validated questionnaire.

All studies were identified through electronic and hand searches. All relevant studies were identified without regard for language, that is, non-English articles were considered for inclusion after an accurate translation.

An electronic search was conducted using Medline via OVID (January 1, 1966 through March 1, 2012), EMBASE, and the Cochrane central register of control trials until March 2012. The search strategy is listed in Table 1.

A hand search was also undertaken to identify relevant studies from the following journals: American Journal of Orthodontics and Dentofacial Orthopedics, The Angle Orthodontist, European Journal of Orthodontics, and The Journal of Orthodontics.

Authors of the included studies were contacted by the review authors, when needed, to obtain any further information about additional or unpublished studies that were eligible for inclusion in the review.

The titles and abstracts resulting from the searches were independently screened by two of the review authors to select potentially relevant studies (AA, JTN). The full text of each study was obtained, and inclusion was assessed independently and in duplicate. Any disagreement regarding the inclusion or exclusion of a study was resolved by discussion or referred to a third reviewer. The full data extraction and quality assessment were conducted by three reviewers using a specifically designed data extraction form. The variables for which data were sought are summarized in Table 2.

Each of the randomized controlled trials found in the search was reviewed using the CONsolidated Standards Of Reporting Trials (CONSORT, http://www.consort-statement.org/consort-2010, Accessed July 4 2014) criteria for risk of bias. Given that the reviews were based on published studies; there is a risk of publication bias in the findings.

A meta-analysis was planned combining data across studies to test the efficacy of interventions, provided that the data were sufficiently homogeneous and there was sufficient homogeneity in the types of intervention reported.

Through the electronic searches, 381 articles were identified. Of these, 376 proved to not be of direct relevance to the two systematic reviews we were conducting, typically because they were addressing a different orthodontic topic (though they mentioned the importance of compliance in orthodontic treatment) or were not trials. Four randomized controlled trials were included (See Figure 1).

Meta-analysis was not performed because of methodologic heterogeneity among the selected trials. The outcome measures chosen were different for each article. Each study will be viewed and appraised separately. Table 3 display the characteristics of the included randomized clinical trials.

In the first randomized controlled trial identified Richter et al.12 evaluated the effect of a reward system on improving compliance among orthodontic patients. Participants were 144 patients (63 boys, 81 girls) with an age range of 9.6 to 17.6 years who underwent orthodontic treatment. The patients were divided into three groups: a control group who received standard instructions; an award group who received compliance instruction and completed a written evaluation of compliance; and a reward group who received compliance instructions, a report card, and eligibility to receive rewards for adherent behavior. The patients in each group were divided into two main categories—high compliers and low compliers—using the Orthodontic Patient Cooperation Scale, which is used to evaluate patients' compliance at the initiation of investigation and after 6 months of treatment. Outcomes assessed were oral hygiene, appointment attendance, appliance wear, and appliance maintenance. The researchers compared compliance before and after 6 months of treatment. The results showed that there was no significant improvement for above-average compliers who received rewards. Below-average compliers did not improve significantly either. However, the oral hygiene scores for the low compliers in the reward group were better than scores for the low compliers in the control group.

Feil et al.13 used a single-blind, quasi-random assignment of 40 patients ranging in age from 14 to 18 years old with poor oral hygiene and who were undergoing fixed orthodontic treatment. The patients were randomly assigned to two groups of 20 patients. In the intervention group, the Hawthorne effect14 was induced by approaching the subjects during a regular appointment and telling them that they were participating in an experiment evaluating the effectiveness of a new orthodontic toothpaste (in reality, regular Crest with fluoride, Procter & Gamble) that would improve the oral health of orthodontic patients specifically. All toothpaste was provided in an unmarked tube except for patient identifier number. The 20 patients in the control group were not asked to participate in any activity not usually practiced during their orthodontic treatment. The outcome measured was the plaque index. Results showed that there was no plaque score difference between groups at baseline (P > .05). Means and standard deviations for tooth surface covered with disclosed plaque for the study and control groups, respectively, were 71% (±11.52) and 74% (±11.46) at baseline; 54% (±13.79) and 78% (±12.18) at 3 months; and 52% (±13.04) and 79% (±10.76) at 6 months. Finally, the intervention group showed better reduction in plaque scores at 3 and 6 months.

Wright et al.15 measured the influence of supplemental written information on adolescent anxiety, motivation, and compliance on 60 patients (age range 12–16 years) who did not undergo previous orthodontic treatment and required dual-arch appliance therapy. Randomization was done using computer-generated unstratified allocation sequence in two groups. The intervention group received verbal and written information while the control group received verbal instructions only. Outcomes measured were motivation, apprehension, anxiety, and compliance (ie, appointment attendance, periodontal status, and appliances breakages) at the beginning of treatment (T1), after 4 weeks of treatment (T2), and at 12 weeks of treatment (T3). Results showed that there was no median change in anxiety scores for either group between T1 and T2. There was a statistically significant difference in motivation scores between the groups after consent to orthodontic treatment, that is, the intervention group became more motivated. Although a generalized reduction in anxiety, motivation, and apprehension as treatment progressed was demonstrated by the negative differences between T1 and T3 for both groups, these differences were not significant. The intervention group's periodontal condition improved between T1 and T3, in contrast to the control group's periodontal condition. At T3 both groups showed similar levels of motivation, apprehension, and anxiety but the intervention group was better in appointment attendance, periodontal status, and appliance breakage.

Acharya et al.16 randomly allocated 62 orthodontic patients (age range 12–18 years) to three types of intervention. Randomization was performed using a systematic random sampling technique. Group 1 consisted of 21 patients who were motivated through conventional plaque-control measures (ie, plaque was disclosed with 2% mercurochrome). The composition of plaque, its effects on oral health, and the importance of its removal were stressed, and a horizontal scrubbing technique of brushing was demonstrated to the patients. Group 2 consisted of 23 patients who were motivated for dental plaque removal using chair-side motivational techniques. As in group 1, conventional plaque control measures were also demonstrated to the patients. Group 3 consisted of 18 patients who were motivated by showing them live motile bacteria in their own plaque under a phase contrast microscope. This study measured the plaque and gingival indexes at baseline, 1 month, 3 months, and 6 months. Results showed that plaque scores for group 3 were better than those for groups 1 and 2 at 3 months and 6 months.

Table 4 summarizes the risk of bias for the four randomized controlled trials as judged by the CONSORT criteria.

A number of interventions are advocated in the literature to improve patients' adherence during orthodontic treatment. Richter et al.12 used the report card and reward system in an attempt to improve adherence among 144 orthodontic patients. The results indicated that only oral hygiene improvement was found among the low compliance reward group compared with the low compliance award group. The finding of this study did not support the hypothesis that the award/reward intervention might improve compliance. A possible reason is the lack of attractiveness in the rewards that were used in the study, which might have influenced the results. The study mentioned that the patients were divided into high and low compliers using the Orthodontic Patient Cooperation Scale but did not indicate if calibration was considered by interexaminer reliability measurement. Furthermore, the study included patients with banding/bonding of the entire arch and some patients who were using headgear and other appliances. Appliance wear was measured on a nine-point scale by nine supervising faculty members; however, interexaminer reliability was not considered. Although the results indicated gender differences among the groups, a detailed description of the actual male/female participants in each group was not clearly provided.

In another study, the Hawthorne effect was evaluated in improving patients' compliance.13 The strength of the study lies in the randomization of two equal groups as well as the explicit and concise selection criteria. In the experimental group, the patients were asked to return the experimental toothpaste at the end of the study, which would indicate whether they complied with the instructions. The outcome revealed a reduction in plaque score in the experimental group. The Hawthorne effect might an asset in improving compliance in orthodontic patients.13 However, compliance in this study was measured by oral hygiene improvement using the Plaque Score Index only. The study did not investigate whether the Hawthorne effect influences compliance in terms of appointment attendance and appliance wear.

Wright et al.15 studied how written and verbal information affected anxiety, motivation, and compliance among 76 orthodontic patients. Results showed improvement in appointment attendance, appliance breakage, and periodontal condition in the intervention group, but this improvement was not statistically significant. The sample size was relatively small; a larger sample might have provided more convincing evidence. This study highlighted the importance of information retention in orthodontic treatment as they found that the initial positive effect of written information was not maintained throughout the treatment.

In the fourth study, the effect of three interventions to improve oral hygiene among 78 patients undergoing fixed orthodontic treatment was investigated.16 The researchers found that plaque and gingival scores reduced in group 3 patients, who were motivated by being shown live motile bacteria in their own plaque under a phase contrast microscope. One drawback to the study was the lack of a clear description on how the plaque and gingival scores were measured. Also, no information was provided on the number of examiners undertaking the assessment of plaque and gingival scores. Lastly, interexaminer and intraexaminer reliability were not reported.

The quality of the randomized controlled trials located for this review was moderate. Particular concerns related to determination of an appropriate sample size as none of the four trials identified the basis on which the sample size was determined. There were also issues concerning allocation concealment and blinding for the studies.

• The literature advocates the use of several methods to improve compliance/adherence among orthodontic patients. Although there is no evidence to support one particular intervention over another, the results demonstrate the value of spending time with patients to illustrate the importance of adherence.

• Future studies should develop multiple methods of assessing patient adherence, including self-report, behavioral observation and recording, and change in clinical indexes. Different types of interventions should be included and tested for effectiveness.

The work undertaken for this research was part of the first author's PhD studies, generously funded through the Saudi Cultural Bureau.