INTRODUCTION

Adherence concerns the extent to which a person's behavior such as taking medication, following a diet, or engaging in lifestyle changes correspond with agreed recommendations received from a health care provider.¹ A number of studies in the field of orthodontics have investigated how patient adherence is associated with a range of outcomes such as discontinuation of treatment and patient satisfaction.^2,3 These studies consistently demonstrate that a lack of patient adherence is a major obstacle in achieving the desired goals of any medical treatment, even for the most promising treatment plans.^2,4

Accordingly, adherence is also an important concept for dental treatment, so several types of direct and indirect measures have been developed and used to estimate adherence in orthodontic settings.⁵ A number of studies have used direct measures of adherence such as timing devices attached to the appliances,^6,7 charting techniques, and clinical assessment by the orthodontist. Examples of these direct assessments involve examination of malocclusion improvement, cleanliness of headgear tubes and headgear strap, and ease of appliance placement.⁸ In contrast, indirect measures are mainly based on self-reports from the patient and other related persons. These often include feedback about wearing the appliance,⁹ appointment keeping, and changes in oral hygiene.^10–12 Although direct and indirect measures of adherence can be useful, they vary in reliability and applicability in orthodontic settings.² Due to this limitation, it is useful to understand orthodontist views regarding adherence and its measurement by directly asking them to summarize the importance and application of specific predictors.

Orthodontists' views on adherence have been researched in three questionnaire studies.^2,5,13 On the basis of these practitioner reports, a set of predictive behaviors have been proposed as indicators of poor adherence, such as level of oral hygiene and appointment keeping. While these indicators are useful, in these three studies a number of limitations have been identified. These studies have been conducted on young and adolescent orthodontic patients but have not examined adults, none of the studies looked at orthodontists in the UK, and the most recent study was conducted almost 10 years ago. These studies have also looked at either open- or closed-ended questions, rather than both types of questions, which would give more in-depth information about views on adherence. Further investigation into the appropriate predictors of adherence in this setting is therefore necessary.

This study aims to explore predictors of adherence in adult orthodontic patients, ranked in terms of importance and actual use, as reported by orthodontists. Specifically, the present study addresses the limitations of the previous studies, and examines what orthodontists who treat adult patients in the UK view as the most important and useful predictors of adherence and which of these, if any, they use in their daily practice. In particular, the following two questions are investigated: (1) What do orthodontists think patient adherence is? (2) How do orthodontists measure and record adherence?

MATERIALS AND METHODS

RESULTS

Research Questions

1. What factors do orthodontists consider as important when assessing adherence in adult patients?

Thirty-one (N  =  31) respondents were approached, and of those, 23 submitted full data, giving a response rate of 77%. Participants were presented with 14 factors that they rated on a five-point Likert scale. Higher scores indicate higher importance rating assigned to the factor. The mean ratings for each factor (and SD) are presented in Table 1.

Table 1. Mean Importance Ratings for Each Factor in Order of Highest Importance. Responses From N  =  23 Orthodontists

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Based on a cutoff score of 4.5 out of 5, it appears that the three highest-rated factors in terms of importance were “The patient keeps appointments,” “The patient cooperates with the use of removable dental appliances (such as retainers) and/or elastics,” followed by “The patient demonstrates excellent oral hygiene.” The lowest-rated factors, factors that scored on average below 3.5, were “The patient is pleasant to the clinic staff” and “The patient speaks of personal problems or demonstrates such problems,” while items such as “The patient arrives promptly at clinic”; “The patient's behavior is sullen, hostile, belligerent, or rude”; “The patient complains about having to wear braces”; and “The patient has a negative view or perception of their malocclusion” were rated moderately.

When considering the pattern of ratings, there was uniform agreement on how important each of the following items was rated (with all clinicians thinking it was either very important or extremely important): “The patient keeps appointments,” “The patient cooperates with the use of removable dental appliances (such as retainers) and/or elastics,” and “The patient demonstrates excellent oral hygiene.”

When looking at the items on which clinicians disagree about level of importance for adherence, we find that factors such as “The patient is pleasant to the clinic staff,” “The patient speaks of personal problems or demonstrates such problems,” and “The patient thinks that facial aesthetics are important” show a varied pattern of response.

2. What factors do orthodontists report to use for assessing adherence of adult patients in their daily practice?

Participants were presented with the same 14 factors as before, which they rated on a five-point Likert scale. Higher scores indicate higher frequency of use assigned to the factor. The mean ratings for each factor (and SD) are presented in Table 2.

Table 2. Mean and SD frequency of Use for Each Factor in Order of Highest Utilization. Responses From N  =  23 Orthodontists

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It appears that the highest-rated factors, with a rating of 4.4 or higher, were “The patient demonstrates excellent oral hygiene,” “The patient keeps appointments,” followed by “The patient cooperates with the use of removable dental appliances.” The lowest rated factors, receiving an average of 3.4 or lower, were “The patient speaks of personal problems or demonstrates such problems,” and “The patient's behavior is sullen, hostile, belligerent, or rude.” Items such as “The patient has a negative view or perception of their malocclusion,” “The patient is observed to be involved in treatment,” and “The patient complains about having to wear braces” were rated moderately.

There was uniform agreement on how frequently each of these items was used, with all clinicians reporting that either it was used most of the time or always utilized to assess adherence: “The patient demonstrates excellent oral hygiene” and “The patient keeps appointments.”

When looking at items on which clinicians disagree about the frequency of use in assessing adherence, we find factors such as “The patient speaks of personal problems or demonstrates such problems”; “The patient's behavior is sullen, hostile, belligerent, or rude”; and “The patient is pleasant to the clinic staff.”

It thus appears that there is uniform agreement that two of the adherence predictors appearing in the literature are the most frequently used factors when assessing adherence: “The patient demonstrates excellent oral hygiene” and “The patient keeps appointments.”

When looking at the importance (Table 1) and use (Table 2) factors and their associated ratings, we noted with interest that the same three factors (appointment keeping, use of appliances, and oral hygiene) which were rated as the top three factors in terms of importance, also appeared as the top-rated factors in terms of use. With regard to those factors rated as not particularly important (pleasantness to clinic staff, speaking of personal problems, and patient views about facial esthetics; Table 1), there is no uniform agreement among respondents as to the importance of these factors (pleasantness to staff and talk about personal problems) although they do generally feature as low-rated variables in terms of use in everyday clinical practice. Some of the middle-rated variables in terms of use (eg, patient involvement in treatment, prompt arrival at clinic, and distorted wires or bands), which are rated as moderately important (Table 1), are also moderately used as adherence predictors in practice.

3. Are there any other factors that do not appear in the literature that orthodontists believe are predictors of adherence?

In general, clinicians think that factors such as the level of awareness about different dimensions of the treatment (eg, “Treatment awareness”), the associated costs, self-image issues, general importance for patient's life, previous experiences with orthodontists, and difficulties with work schedule, are aspects that are identified as important in adherence. These factors are also used to assess it (Table 3).

Table 3. Mean and Standard Deviation of Groups of Factors That Do Not Appear in the Literature and Were Added by Clinicians

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The most important additional factor for adherence, according to orthodontists, is “Cost of treatment” (M  =  4.75; SD  =  0.55), whereas the least important factor is “Previous experiences” (M  =  3.5; SD  =  .71). The most frequently used factor to assess adherence is knowledge about the “Importance for patient's life” (M  =  4.5; SD  =  .71), whereas the least employed is “Cost of treatment” (M  =  2.42; SD  =  1.52).

In summary, from the factors given to clinicians, there were three that were rated as the most important by everyone, which describe adherence in terms of the regularity in attending appointments, use of appliances, and demonstration of adequate oral hygiene. Likewise, two of these factors were, in addition, reported as the most frequently used to assess adherence in daily practice, namely “The patient demonstrates excellent oral hygiene,” and “The patient keeps appointments.”

Similarly, the factors that did not seem to be universally endorsed as important were “The patient is pleasant to the clinic staff,” “The patient speaks of personal problems or demonstrates such problems,” and “The patient thinks that facial aesthetics are important.” Likewise, factors less frequently employed to assess adherence were “The patient speaks of personal problems or demonstrates such problems”; “The patient's behavior is sullen, hostile, belligerent, or rude”; and “The patient is pleasant to the clinic staff.” Therefore, both “The patient is pleasant to the clinic staff” and “The patient speaks of personal problems or demonstrates such problems” were signaled as the least important in adherence and the least frequently used to assess such behavior in adult patients.

DISCUSSION

This study investigated the extent to which factors of adherence found in the literature are signaled by orthodontists as important indicators of such behavior and frequently utilized when assessing adult patients in daily practice. The procedure requested a group of clinicians to rate a list of 14 factors as to their relevance to adherence and their frequency of utilization. Examples of factors indicating adherence were “The patient demonstrates excellent oral hygiene” and “The patient keeps appointments.” Apart from those extracted from the literature, an open-ended question was included to collect any other factor relevant or used by the sample.

The results of the study show a clear pattern of agreement for three factors signaled by all the clinicians as particularly important in adherence. These factors were related to the consistency of patients in keeping their appointments, behaviors that demonstrated a high standard of oral hygiene, and cooperation in using removable appliances (such as retainers) and elastics. Of these three factors, two factors were also largely employed by clinicians when assessing adherence in adult patients in clinical contexts: patient effectiveness in keeping appointments throughout the treatment span and patient concern with their own oral hygiene. Such results indicated attitude-behavior agreement in the orthodontists' responses wherein, broadly, the factors they say they use in clinical practice as indicators of adherence were the same as those they deem important. These findings were consistent with some of the items included in the scale of patient cooperation developed by Slakter et al.¹³ and partially support some of the findings reported by Mehra et al.⁵ In both cases, behaviors associated with maintaining regular appointments, good oral hygiene, and adequate use of appliances were reported to be relevant factors in the adherence of orthodontic patients.

Even though all the factors were rated as somewhat important and used, two clearly yielded a varied pattern of disagreement among clinicians. These factors referred to when patients were pleasant to the clinic staff and when they conveyed personal problems in this context. In both cases, there was an unclear pattern of importance and use for assessing adherence in adult patients, so whereas some clinicians rated these items either as important/used or not important/not used, others evaluated them as irrelevant to make a judgment in any direction.

These results appear to contrast with Slakter et al.,¹³ who found that speaking or demonstrating personal problems during appointments was an adequate measure of adherence. However, as results yielded in our study are related to behaviors in adult patients, such contrast rather indicates that this factor is specific for the case of children, which would contribute to confirming that this factor may be less applicable to older ages.

As with all studies using nonprobabilistic samples, there are obvious limitations in this study that offer opportunities for further research. For instance, it would be worthwhile to evaluate whether these findings can be replicated when a larger and randomly selected sample from a similar population of clinicians is requested to rate the same list of factors. Further, administering a similar procedure to orthodontists from a different setting would enhance the external validity of the results, as different results could be achieved in other cultural contexts. However, as this study has only an exploratory scope, much work remains to be done on identifying reliable and valid factors indicating adherence in adult orthodontic patients.

CONCLUSIONS

• Overall, there was a high level of agreement on which factors are most important and utilized for predicting adherence in orthodontic settings.

• Appointment keeping, cooperating with the use of removable appliances, and excellent oral hygiene were rated as the most important and utilized factors by orthodontists when assessing adherence in adult patients.

• In open-ended questions, orthodontists also highlighted the perceived cost of treatment as an important factor in adherence.