Original Article

Patient compliance with Hawley retainers fitted with the SMARTH sensor: A prospective clinical pilot study Paul Hyuna; Charles Brian Prestonb; Thikriat S. Al-Jewairc; Eunhae Park-Hyund; Sawsan Tabbaae ABSTRACT Objective: To evaluate the compliance of patients while wearing maxillary Hawley retainers embedded with SMART microsensors. Methods: The sample population consisted of 22 patients who were divided into an experimental (group A) and a control group (group B). Group A was informed that they would be monitored through the use of SMART microsensors, while group B was not informed that they would be monitored. After the delivery of the retainers (T0), the patients were evaluated at T1 and T2, represented by 6- and 12-week follow-up visits, respectively. At T1, group B was informed of our ability to monitor their compliance. Both groups continued wearing their retainers during T1 to T2. Results: During T0–T1, Group A wore their retainers for an average of 16.3 hours (SD 4.39), while group B wore their appliances for an average of 10.6 hours (SD 5.36, t 5 2.426, P 5 .027). Although group B increased their retainer wear by 0.5 hours/day from T1 to T2, this increase was not statistically significant. Conclusions: Despite significant differences being noted between the two groups at T1, group B did not show significant mean changes in their wear time before and after becoming aware of the use of the SMART microsensor. (Angle Orthod. 2015;85:263–269.) KEY WORDS: Hawley retainer; Wearing times; Compliance; Microsensors

INTRODUCTION

cooperation. Patient compliance while wearing orthodontic retention appliances is of particular importance since the oral soft tissues can take considerable time to adapt to the orthodontically attained positions of the teeth.1 It appears that conscientious retainer wear is particularly important during the first year following active orthodontic treatment.2 Protocols of postorthodontic treatment retention and more specifically the duration of the retention phase have been debated extensively in the orthodontic literature.3–7 Some practices require that patients wear their removable retainers ‘‘full-time’’ for the first 6 months after debonding, followed by a period during which the appliance wear is restricted to nighttime only.8 It has also been recommended that retainers be worn ‘‘part-time’’ for as long as a patient has the potential for growth.7 The ultimate success of any retention protocol relies greatly on patient cooperation, which at its best is somewhat suspect.9 Patient feedback regarding compliance with retainer wear tends to be subjective and difficult to translate into objective raw data. With the development of microsensors that make it possible to record the duration of retainer wear, it may become possible to monitor this aspect of patient compliance.

With the advent of modern orthodontics, noteworthy improvements have been made in the design of orthodontic appliances and in their application. Despite the positive evolution made in orthodontic appliance design, it remains true that success during orthodontic treatment relies to a large extent on patient a Postgraduate Orthodontic Resident, State University of New York at Buffalo, Buffalo, NY. b Professor and Chairman, Department of Orthodontics, School of Dental Medicine, State University of New York at Buffalo, Buffalo, NY. c Adjunct Research Associate, Department of Orthodontics, State University of New York at Buffalo, Buffalo, NY, and Assistant Professor, Department of Preventive Dental Sciences, University of Dammam, Dammam, Saudi Arabia. d Private practice, Buffalo, NY. e Assistant Professor, Department of Orthodontics, State University of New York at Buffalo, Buffalo, NY. Corresponding author: Dr Thikriat Al-Jewair, State University of New York at Buffalo, Department of Orthodontics, 140 Squire Hall, 3435 Main Street, Buffalo, NY 14214 USA (e-mail: [email protected])

Accepted: April 2014. Submitted: March 2014. Published Online: May 28, 2014 G 2015 by The EH Angle Education and Research Foundation, Inc. DOI: 10.2319/030814-163.1

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264 The idea of measuring compliance in appliance wear originated approximately 40 years ago.10 Due to their bulkiness as well as their complexity, the original recorders aimed at measuring the time of appliance wear did not survive for long.10–13 Accuracy and practicality presented the chief barriers that prevented recording sensors from being utilized during routine orthodontic treatment. Presently, the literature indicates that two new sensors, the SMART14 and the TheraMon15 microsensors, may be able to record aspects of compliance in orthodontic patients. The manufacturers of both microsensors state that their recorders monitor the oral environment through temperature, store the data in an encrypted form, and then allow a provider to upload the information wirelessly into a computer for further analysis. Only one clinical study focused on the SMART microsensor,9 while three studies reported on findings obtained with the TheraMon sensor.16–18 Ackerman and Thornton9 used the SMART microsensor in a short-term randomized clinical trial that compared a group that was aware of the microsensor with one that was blinded to it. They concluded that the aware group wore the retainer on average 2.3 hours per day more than the unaware group. This finding was statistically significant. Additional studies are required to determine if the SMART microsensor increases patient compliance with the wear of removable retainers. The first aim of this study was to measure patient compliance with the wear of a maxillary Hawley retainer fitted with the SMART microsensor. One group of subjects was made aware of the presence of the sensors while, for the first part of the study, the second group was blinded to the fact. The null hypothesis stated that there would be no differences between the two groups in the time of appliance wear. The second aim was to explore the change in retainer wear time in the control group by repeating the monitoring phase after they were informed of the presence of the SMART microsensor. The null hypothesis for this part of the study predicted that there would be no difference in retainer usage before and after being informed of the presence of the sensor. MATERIALS AND METHODS After receiving approval from the University at Buffalo Institutional Review Board, patients from the University at Buffalo, School of Dental Medicine, Orthodontic Clinic were recruited for this pilot study between February 2012 and February 2013, based on specific inclusion and exclusion criteria as shown in Table 1. Following the completion of their fixed orthodontic treatment, the patients who satisfied the Angle Orthodontist, Vol 85, No 2, 2015

HYUN, PRESTON, AL-JEWAIR, PARK-HYUN, TABBAA

inclusion criteria were invited to participate in the study and they were recruited continuously. Twenty-two subjects fulfilled the inclusion criteria for this study. By using a random number system, the recruited sample was split into two equal groups (A and B): group A (treatment group) was informed that they would be monitored through the usage of the SMART microsensor; group B (control group) was not informed that they had the microsensor present in their retainers. All of the maxillary Hawley retainers fitted in the two groups contained the SMART microprocessors, and they were manufactured by the same company and to the same standards (Great Lakes Orthodontics, Buffalo, NY). The retainers were delivered to the patients at the T0 time point. Patients were then evaluated at T1 and T2, 6 and 12 weeks, respectively, following the delivery of the retainers. At T0, one investigator gave both groups verbal instructions on what constituted an ideal retention protocol then delivered a written form with the appropriate retention instructions to each patient. The retention protocol required the patients to wear the maxillary Hawley retainers ‘‘full time’’ for the first 3 months after debonding. ‘‘Full time’’ compliance was defined as wearing the retainer at all times, and only removing it while eating, tooth brushing, or while taking part in contact sports. It was estimated that this constituted about 19 hours a day of appliance wear. Patient-topatient interaction was avoided to prevent communication with one another regarding the presence of the SMART microsensor. The SMART microsensor has a built-in clock circuit that resonates at a frequency of 32,768 Hz over temperatures ranging from 240uF to 185uF. It records the time of the day and corrects for 28-, 29-, 30-, and 31-day months.14 According to the manufacturer, their product has a lifespan estimated to be approximately 18 months. The software program that accompanies the microprocessor was designed to allow both the provider and the patient to visualize the usage of the retainer.15 At T1, the SMART system reader was used to scan the SMART microsensors located in the retainers of both groups A and B. The data were uploaded into the proprietary computer software provided by SMART. The data obtained at T1 was used by a single investigator to ascertain how diligently the subjects in groups A and B had worn the orthodontic retainer appliances. The subjects of both groups were then asked to complete a five-item questionnaire (Table 2) regarding their overall experience and comfort with their retainers. During the T1 appointment, the subjects in the control group (group B) were made aware of the fact that their retainers were equipped with SMART

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PATIENT COMPLIANCE WITH HAWLEY Table 1. Sample Inclusion and Exclusion Criteria Inclusion Criteria

Exclusion Criteria

(1) Subject age is between 14 and 17.6 years (2) Retention treatment plan is maxillary Hawley retainer (3) Acceptable alignment of maxillary anterior teeth with no teeth missing (4) Language of the subject is English (5) Written informed consent including a HIPAA authorization signed by the patient’s parent/legal guardian prior to the start of the study

(1) Craniofacial and/or dentofacial syndromes (2) Early orthodontic treatment (Phase 1) (3) Patients who turned 18 years old during the recording phase of the study (T2)

microsensors that made it possible to record for how long they had worn their appliances. The patients of both groups were once more instructed in the same retention protocol that was provided at T0. It was now possible to monitor the compliance of the subjects in the original control group (group B) in response to the knowledge that their retainers contained a microprocessor. In essence, the control group of patients acted as their own controls during this second part of the study. Four of the 22 subjects were lost from the study due to sensors that became faulty during the T0 to T1 phase of the study, and only the data of the 18 remaining patients were analyzed. At the T2 time points, the microprocessors in the appliances of both groups were scanned again to gain insight into the further compliance of the subjects included in this study. It was of particular interest to determine whether the Group B subjects modified their appliance wear routine in response to being made aware of the presence of the microprocessors. Informed consent was obtained from the subjects in the groups A and B and their parents/guardians at the time of the removal of the fixed orthodontic appliances (T0). Group B subjects were informed they were enrolling in a study on compliance with retainer wear, but no mention of the sensor was given. Due to the blinding involved with this group, an additional informed consent with full disclosure of the sensors was required and obtained at T1. Additional data were obtained from the patients’ treatment charts at T2. These data included the Discrepancy Index (DI) of the American Board of Orthodontics. The DI was used to determine whether a statistical relationship existed between the severity of a malocclusion and treatment time and difficulty and the level of patient compliance in wearing retention appliances.

Statistical Analysis Data were analyzed using SPSS for Windows version 20 (SPSS Inc, Chicago, Ill). Descriptive statistics were calculated for each variable. Two sample t-tests were used to compare groups A and B at T1. The paired t-test was used to compare the retainer wear times within the groups at T1–T2. Chisquare test was used to analyze categorical variables. Pearson correlation coefficient was used to assess the relation between the retainer wear times and other variables. Significance levels were set at .05. RESULTS Group A consisted of nine patients, of whom eight had usable recording data. Group B consisted of 13 patients, of whom 10 had usable recording data, (Table 3). The mean age of the subjects in group B was slightly higher than that noted for group A (t-test, P 5 .397). Although the sample size was not optimal for a chi-square test, there was no evidence that the test groups were unbalanced with respect to gender (P 5 .914). The average treatment time for group B (35.50 months, SD 13.575) was 9 months longer than for group A (26.75 months, SD 5.497), but the difference was not statistically significant (Table 4). The standard deviation of the treatment time for group B was nearly 2.5 times larger than that of group A. As a result, the modified t-test that does not require homogeneity of variances was used to evaluate the difference in duration of treatment time. The outcome was still a nonsignificant difference (P 5 .087) for this entity. Results of Phase I (Day 0 to Day 42) During the first phase of the study (T0–T1), the average daily hours of retainer wear for group A was 16.3 (SD 4.39), while for group B it was 10.6 (SD 5.36),

Table 2. Questionnaire Delivered to Participants at T1 (1) Please rate the overall experience with the retainers. (Score from 22 to +2, ranging from very negative to very positive, with 0 representing neutral.) (2) Please rate the overall comfortability of the retainers. (Score from 22 to +2, ranging from very negative to very positive, with 0 representing neutral.) (3) How much do you think you wear the retainers? (Score from 0% to 100%, in 10% increments.) (4) What was your self-perception of your teeth before the orthodontic treatment? (Score from 1 to 10, 10 being the best.) (5) What was your self-perception of your teeth after the orthodontic treatment? (Score from 1 to 10, 10 being the best.)

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Table 3. Sample Characteristics Eligible* No

Yes

Total

Group

Female

Male

Total

Mean Age, y

A B A and B A B A and B A B A and B

0 2 2 5 6 11 5 8 13

1 1 2 3 4 7 4 5 9

1 3 4 8 10 18 9 13 22

15.00 15.33 15.25 15.13 15.70 15.44 15.11 15.62 15.41

SD – 1.528 1.258 1.553 1.252 1.381 1.453 1.261 1.333

* Data could be scanned from the SMART microsensor with no malfunctions.

(86% compliance rate in group A vs 56% in group B). The difference in average wear of 5.7 hours per day was statistically significant (t 5 2.426, P 5 .027). Only one patient (12.5%) in group A averaged less than 12 hours per day of retainer wear compared to seven patients (70%) in group B. Results of Phase 2 (Day 43 to Day 84) The average daily retainer wear for group A decreased by 0.7 hours to 15.6 hours (SD 4.77), while in Group B it increased by 0.5 hours to 11.1 hours (SD 6.08). The difference between the groups of 4.48 hours was not statistically significant (t 5 1.703, P 5 .108). Figures 1 and 2 illustrate the retainer usage between T1 and T2 for each subject. In group A (Figure 1), six of 8 patients maintained their appliance usage, while two decreased their wear times. In group B, four maintained their appliance wear times, four increased these times, and two decreased their wear times. The data for most patients (Figure 2) seem to be located close to the no difference line, indicating that there was not a significant change in appliance wear between the two phases studied. The Pearson correlation was 0.972 for group A and 0.917 for group B. Post Study Results Results from the questionnaires showed that the majority of patients in each group had a positive overall

experience with the retainers (62.5% for group A and 80% for group B). Most patients found the retainers to be comfortable (87.5% of group A and 90% of group B). About 61% of the patients (Figure 3) overestimated the time (x-axis) that they wore their retainers as compared to the actual recorded time (y-axis). All of the patients rated their teeth as 6 or less on the attractiveness scale before they started wearing braces. The average for group A was 3.0 (SD 2.00) and for Group B it was 3.8 (SD 1.81), (t 5 0.889, P 5 .387). All of the patients rated their teeth to be 9 or 10 on the attractiveness scale at the completion of their orthodontic treatment. Group B was more positive about the outcomes of their orthodontic treatment than was group A. The correlation between the hours per day of retainer wear and the appointment show rate was statistically significant (Table 5). DISCUSSION At T1 the compliance in retainer wear between group A and group B was statistically significant (t 5 2.426, P 5 .027). This finding is consistent with that of Ackerman and Thornton9 who showed that the aware group wore their appliances for an average of 2.3 hours a day longer than the non-aware group. This finding is in accordance with the Hawthorne phenomenon according to which subjects perform better when they are aware that they are being monitored.19 The present study was novel in that it compared the compliance of subjects (group B) prior to, and after being made aware of our ability to monitor them. While these subjects increased their compliance by an average of 0.5 hour a day after T1, this increase was not statistically significant and therefore the null hypothesis cannot be rejected. This finding may be explained by the possibility that once this group achieved a habitual pattern of retainer wear (T0 to T1), it was difficult to change the habit even after being told that they were being monitored. Further, the relatively small sample size might have prevented a significant effect from emerging. The results indicate that patients who commence treatment with a higher DI score are more compliant in

Table 4. Descriptive Statistics of Variables Obtained From The Patients’ Treatment Charts at T2 Variable Treatment duration, mo Discrepancy Index Appointment show rate, %

Group Group Group Group Group Group Group

* Significance at .05. Angle Orthodontist, Vol 85, No 2, 2015

A B A B A B

N

Mean

SD

SE Mean

t-test

P Value*

8 10 8 10 8 10

26.75 35.50 14.38 9.30 80.88 80.60

5.497 13.575 6.948 4.900 7.882 9.131

1.943 4.293 2.456 1.550 2.787 2.888

1.706

.107

1.818

.088

0.067

.947

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Figure 1. Comparisons of mean wear times of the SMART retainer between T1 and T2.

terms of retainer wear than those who commence treatment with lower DI scores. Patients with more disfiguring malocclusions may be more conscious of the possibility of postorthodontic treatment relapse.

The average total treatment time in months for group B was 9 months longer than that for group A. This finding could be due to poor compliance with treatment instructions during the orthodontic treatment. Poor

Figure 2. Mean wear times of the SMART retainer during T1 and T2. Angle Orthodontist, Vol 85, No 2, 2015

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Figure 3. Comparisons of mean wear times of the SMART retainer between T1 and T2.

compliance during orthodontic treatment may well be carried forward into the retention phase. None of the attempted correlations within groups A and B were statistically significant (Table 5). However, when combining all of the subjects into one group, a moderately statistically significant correlation was evident between retainer wear and appointment show rate (r 5 0.555, P 5 .017). Given that this significant correlation was, in part, due to the larger sample size, it would be essential to increase the sample size for future studies to obtain more conclusive results. Eighty-nine percent of all subjects reported overall positive experience and comfort with the retainers. This is similar to the findings of a previous study.20 Despite the overall positive experience with the retainers, the dimensions of the SMART microsensor need some discussion. The microsensor was measured to have a diameter of 15 mm and a width of 4.5 mm. When the microsensor is placed in the Hawley retainer (average thickness of 2–3 mm), the

thickness of the acrylic on the palate is increased to about 7–11 mm. The TheraMon microsensor has similar dimensions of 13 mm 3 9 mm 3 4.5 mm.16 Schott and Go¨z15,21 in previous in vitro studies found that the TheraMon had greater versatility and more accurate recordings of wear time down to the minute than the SMART microsensor. They did conclude, however, that both microsensors could be used as objective wear-time sensors in orthodontic appliances.21 The reason that the SMART microsensor was used in our study is that the product is manufactured domestically and it is readily available in North America. Only 22 patients were recruited and four of them were lost due to sensor malfunction (27 subjects would produce 85% certainty at a significance of 5%). The manufacturers advise that that the removal of a microsensor from a retainer (grinding, vibration, etc.) could cause them to malfunction. Ackerman and Thornton9 reported that in their study of 23 subjects,

Table 5. Correlations Between the Retainer Wear Times Per Group and the Potential Indicators of Compliance With Retainers Wear at T2 Variable Appointment show rate, % Discrepancy Index Pre and post self-perception (Questions 4 and 5) Treatment duration, mo

Pearson correlation Sig. (2-tailed) Pearson correlation Sig. (2-tailed) Pearson correlation Sig. (2-tailed) Pearson correlation Sig. (2-tailed)

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Group A (N 5 8)

Group B (N 5 10)

All groups (N 5 18)

0.617 .103 20.261 .533 20.123 .771 0.687 .060

0.585 .075 0.174 .630 0.085 .816 0.159 .660

0.555 .017 0.140 .579 0.816 .918 0.062 .807

PATIENT COMPLIANCE WITH HAWLEY

three of the subjects lost their retainers while one SMART microsensor malfunctioned. Several factors could impact the outcomes of this study, Appliances that incorporate the SMART microsensors tend to be thicker than usual, and this fact may discourage patients from wearing the retainers with them. Malfunctions with the microprocessors are likely to become less of a problem as the science advances, but at the present time, this factor may cause some reluctance to use them in randomized clinical trials. CONCLUSIONS In this study: N The aware group wore the retainer more than the non-aware group, and the difference was statistically significant. N The non-aware group did not have any significant change in wear time before and after becoming aware of the use of the SMART microsensor. Whether it is difficult to change the level of a patient’s compliance between the periods or the results are due to the small sample size, future studies are warranted to provide conclusive results. N Although SMART microsensors embedded into removable appliances do allow orthodontists to measure the time of appliance wear, the functionality and practicality of the sensor needs several improvements. ACKNOWLEDGMENTS We thank Bob Dunford for his expert assistance with the statistical analysis of this research project.

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269 5. McCauley D. The cuspid and its function in retention. American Journal of Orthodontics and Oral Surgery. 1944; 30:196–205. 6. Tweed CH. Indications for the extraction of teeth in orthodontic procedure. American Journal of Orthodontics and Oral Surgery. 1944;42:22–45. 7. Proffit WR, Fields HW, Sarver DM. Contemporary Orthodontics. 4th ed. St Louis, Mo: Mosby; 2007. 8. McLaughlin RP, Bennett JC, Trevisi HJ. Systemized Orthodontic Treatment Mechanics. 2nd ed. St Louis, Mo: Mosby; 2001. 9. Ackerman MB, Thornton B. Posttreatment compliance with removable maxillary retention in a teenage population: a short-term randomized clinical trial. Orthodontics (Chic). 2011;12:22–27. 10. Northcutt M. The timing headgear. J Clin Orthod. 1974;8: 321–324. 11. Sahm G, Bartsch A, Witt E. Micro-electronic monitoring of functional appliance wear. Eur J Orthod. 1990;12: 297–301. 12. Kyriacou PA, Jones DP. Compliance monitor for use with removable orthodontic headgear appliances. Med Biol Eng Comput. 1997;35:57–60. 13. Schott TC, Go¨z G. Color fading of the blue compliance indicator encapsulated in removable clear Invisalign TeenH aligners. Angle Orthod. 2011;81:185–191. 14. Ackerman MB, McRae MS, Longley WH. Microsensor technology to help monitor removable appliance wear. Am J Orthod Dentofacial Orthop. 2009;135:549–551. 15. Schott T, Go¨z G. Wearing times of orthodontic devices as measured by the TheraMon microsensor. J Orofac Orthop. 2011;72:103–110. 16. Schott TC, Ludwig B, Glasl BA, Lisson JA. A microsensor for monitoring removable-appliance wear. J Clin Orthod. 2011; 45:518–520; quiz 516. 17. Pauls A, Nienkemper M, Panayotidis A, Wilmes B, Drescher D. Effects of wear time recording on the patient’s compliance. Angle Orthod. 2013;83:1002–1008. 18. Tsomos G, Ludwig B, Grossen J, Pazera P, Gkantidis N. Objective assessment of patient compliance with removable orthodontic appliances: a cross-sectional cohort study. Angle Orthod. 2014;84:56–61. 19. Feil PH, Grauer JS, Gadbury-Amyot CC, Kula K, McCunniff MD. Intentional use of the Hawthorne effect to improve oral hygiene compliance in orthodontic patients. J Dent Educ. 2002;66:1129–1135. 20. Schott T SS, Walter J, Glasl B, Ludwig B. Questionnaire study of electronic wear-time tracking as experienced by patients and parents during treatment with removable orthodontic appliances. J Orofac Orthop. 2013;74:217–225. 21. Schott TC, Go¨z G. Applicative characteristics of new microelectronic sensors Smart RetainerH and TheraMonH for measuring wear time [in English, German]. J Orofac Orthop. 2010;71:339–347.

Angle Orthodontist, Vol 85, No 2, 2015

Patient compliance with Hawley retainers fitted with the SMART(®) sensor: a prospective clinical pilot study.

To evaluate the compliance of patients while wearing maxillary Hawley retainers embedded with SMART microsensors...
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