INTRODUCTION

Research designed to promote evidence-based practices and optimize patient care must extend beyond traditional academic clinics to private practice settings.¹ For over 20 years, medicine has been using practice-based research networks (PBRNs) to perform various types of research.² PBRNs are well suited for studying the development of white spot lesions (WSLs), which occur in 2% to 96% of patients, depending on the assessment methods used.^3–7 WSLs can create dissatisfaction at the end of treatment for patients, parents, referring dentists, and orthodontists and can possibly precipitate litigious proceedings.⁸

WSLs are preventable with proper oral hygiene, but orthodontic appliances cause plaque retention, and patients with poor compliance complicate the problem. Various methods have been proposed to prevent the development of WSLs during treatment, including oral hygiene instruction, fluoride varnish, fluoride rinses, glass ionomer cements, fluoride-releasing cements, antibacterial rinses, antibacterial cements, resin-sealants, and argon lasers.^9–18 Orthodontists might also consider shifting toward risk-based prevention of WSLs, as general dentistry and periodontics have done for dental caries and periodontal disease.¹⁹ The risk factors associated with WSLs in private practice settings have not been previously investigated. A PBRN would make it possible to more efficiently and effectively determine which patients are at greatest risk of developing WSLs.

The primary aims of the present study were to enlist multiple alumni from the Orthodontic Department of Texas A&M University Baylor College of Dentistry to prospectively evaluate the prevalence of WSLs and to determine risk factors associated with the development of WSLs among patients in private practice. Using alumni from the same alma mater is important because it fosters a sense of community and makes it easier to recognize the clinicians for their participation; the absence of these benefits is a well-recognized barrier to the implementation of a research network.²⁰ Using patient records from multiple practices is important to ensure the external validity of the results.

MATERIALS AND METHODS

This study was approved by the Texas A&M University Baylor College of Dentistry Institutional Review Board in Dallas (IRB Protocol #2012-06). Informed consent was obtained from all of the participating patients.

Data Collection

Fifty-seven alumni of Texas A&M University Baylor College of Dentistry returned surveys sent to determine whether they qualified and were willing to participate. To qualify, they had to be currently taking high-quality pre- and posttreatment intraoral photos. The orthodontists also had to have been using the same measures to prevent WSLs for at least the three previous years. In addition to participating in the present study, each orthodontist was also asked about his willingness to participate based on who was conducting the clinical research.

Forty-seven alumni qualified and indicated a willingness to participate in the study. Those willing to participate were contacted and asked to submit information pertaining to 10 consecutively finished cases, including (1) pre- and posttreatment intraoral photos, (2) a treatment survey (Table 1) completed by the orthodontist, and (3) an American Dental Association (ADA) Caries Risk Assessment²¹ completed by the patient/guardian, with help from clinical staff as needed. The treatment survey was used to identify treatment conditions that might contribute to lesion development, including the length of treatment, hygiene during treatment, and patient cooperation during treatment. The pretreatment photos made it possible to determine initial enamel condition, including preexisting lesions, as well as the pretreatment gingival health and oral hygiene status.

Table 1. Treatment Survey Questions

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Each orthodontist was provided with complete sets of forms for each patient and a ledger to record the patients included in the study. The treatment surveys, caries risk assessments, forms, and flash drive with photos were returned in prepaid envelopes.

Of the 47 who indicated a willingness to participate, 20 (42.6%) returned the records of 10 consecutive cases. The final sample size included 158 patients, with some cases excluded as a result of incomplete or poor record quality.

RESULTS

The 57 orthodontists initially surveyed indicated that they were much more willing to participate if a fellow alumnus conducted the study than if others, even orthodontic associations, conducted the study (Table 2).

Table 2. Percentage (%) of Alumni Willing to Participate in Clinical Research Based on Who Research Is Conducted By

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Twenty-eight percent of patients developed WSLs during treatment, and another 14% exhibited diffuse demineralization (modified Ogaard score of 1). The average patient developed 2.4 white spots, affecting 12.7% of the teeth examined. The patients who developed WSLs developed an average of 5.6 lesions each.

Patients with contributing and clinical condition risk factors were 2.3 and 3.2 times more likely, respectively, to develop WSLs than were those without the same risk factors (Table 3). General health condition risk factors did not have a significant effect on lesion development. Patients who exhibited moderate or high overall risks of developing caries were 3.2 times more likely to develop WSLs during treatment than were those who had a low caries risk. Contributing (R  =  .345, P  =  .001) and clinical (R  =  .387, P < .001) condition risk scores were both positively correlated with increasing lesion severity score.

Table 3. Risk Ratios Associated with Reported Risk Factor, Based on American Dental Association (ADA) Caries Risk Assessment

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Patients with extended treatment times (>30 months) were also more likely (2.1 times) to develop lesions than were those with shorter treatment times (Table 4). In addition, patients with fair and/or poor oral hygiene during treatment were 2.7 and 3.5 times more likely, respectively, to develop WSLs than were other patients. Patients who required repeated oral hygiene instruction were 2.3 times more likely to develop WSLs than were those who did not. Finally, patients with moderate or severe gingivitis were 2.3 times more likely to develop WSLs than were other patients.

Table 4. Risk Ratios Associated with Treatment Conditions Reported in Treatment Survey

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As oral hygiene worsened, lesion severity scores increased (r  =  .343, P  =  .001). Longer treatment times were also related to increased lesion severity scores (r  =  .287, P  =  .005), as were the number of times oral hygiene instruction had to be repeated (r  =  .341, P  =  .001). As gingival health decreased, lesion severity scores increased (r  =  .370, P < .001).

There were no statistically significant differences in WSLs between the patients who did and did not use preventive methods (42.6% smooth surface sealants, 30.9% varnish, 10.6% both). However, the lesions on unsealed teeth began at the interface of the bracket and enamel, whereas the lesions on sealed teeth were usually located at the gingival margin.

DISCUSSION

The initial group of orthodontists surveyed was most willing to participate in practice-based research conducted by an alumnus researcher. This is important because clinician participation in practice-based research depends in large part on the sense of community among the clinicians involved.²⁰ Initiating a research network through an alumni community utilizes an established community.

All those who initially expressed a willingness to participate did not do so. Only 42.5% of the respondents who indicated a willingness to participate did so. This is expected because orthodontic practices are busy, and the data collection phase required collecting records, obtaining informed consent, and completing surveys. Telephone interviews showed that most of the alumni who did not participate either forgot to reply or had put off their reply, indicating that a larger numbers of alumni could have participated.

In this study 28% of patients developed definitive WSLs, and another 14% exhibited diffuse demineralization. This rate is slightly (2–5%) higher than previously reported for large-scale studies,^3,27 likely because more teeth were included in the current study. Chapman et al.²⁸ reported a slightly higher prevalence rate of 36%.

Patients exhibiting contributing conditions of the ADA Caries Risk Assessment were more than twice as likely to develop lesions during treatment as were patients without risk factors. Sugar exposure was the only individual risk factor that proved to be significant, with a risk ratio of 2.14. Dietary sugar influences the Mutans Streptococci levels of dental plaque and is highly associated with early carious lesions.²⁹ A systematic review by Tanzer et al.³⁰ confirmed the central role of Mutans Streptococci in the initiation of smooth surface caries.

Patients with clinical condition risk factors were 3.2 times more likely to develop WSLs during treatment than were those without such risk factors. Individuals with recent history of lesions, missing teeth due to decay, and visible plaque were at greatest risk of developing WSLs. Multiple studies^31–34 have shown that previous caries history is one of the best predictors of dental caries in children. Visible plaque has been identified as a risk factor for caries development in multiple studies.^35–38

Treatment duration of greater than 30 months more than doubled the likelihood that patients will develop lesions during treatment. Julien et al.³ also found that longer treatment times increase the risk of WSLs. WSLs can develop quickly, in as few as 4 weeks,³⁹ and a large percentage of WSLs are developed in the first 6 months of treatment.⁴⁰ Longer treatment times allow more time for WSLs to develop and for a greater possibility of poor oral hygiene leading to increased carious attacks.

As expected, oral hygiene was a key factor in the development of lesions. Patients with fair or worse oral hygiene were nearly three times more likely to develop WSLs, and patients with poor oral hygiene were 3.5 times as likely. Orthodontic appliances increase the areas of plaque retention and make proper oral hygiene more difficult.⁴¹ Without continuous plaque removal the demineralization/remineralization process shifts toward demineralization and lesions form.⁴² Poor oral hygiene leads to poor gingival health, and an increase in gingivitis is seen in orthodontic patients.⁴³ In addition, the patients in the present study who exhibited worse than moderate gingivitis were more than twice as likely as the others to develop lesions during treatment. Oral hygiene and gingival status are important indicators of patients at risk of developing WSLs during orthodontic treatment.

CONCLUSIONS

• Orthodontists are more likely to participate in research conducted by alumni from their alma mater than in research conducted by others, including orthodontists and orthodontic organizations.

• Approximately 28% of orthodontic patients in private practice settings develop WSLs.

• The risk of developing WSLs is higher (2.1–3.5 times) for patients exhibiting ADA caries risk factors as well as for those with fair or poor oral hygiene, poor gingival health, and extended treatment times.

• An alumni-centered PBRN provides an effective and efficient method of collecting high-quality data from multiple clinicians and large numbers of patients.