Does crown, root, and bone visualization in a clear aligner virtual setup impact treatment decisions?

Introduction

Clear aligner technology based on a machine learning algorithm is currently available for orthodontic treatment. Treatment planning on the basis of 3-dimensional crown, root, and bone imaging is claimed to provide accurate diagnosis and better treatment outcomes for adult patients with complex needs. This study aimed to answer the following questions: (1) would practitioners modify their original treatment plan once provided with the crown, root, and bone view? and (2) does practitioner satisfaction regarding treatment outcomes change once the crown, root, and bone view is provided?

Methods

An online questionnaire was emailed to members of the American Association of Orthodontists (n = 2300) and the Virginia Orthodontic Education and Research Foundation (n = 211). The survey consisted of videos of 4 patients shown in 2 presentations: crown-only and crown, root, and bone views, generated by artificial intelligence-driven treatment planning software (3D Predict aligner system; 3D Predict, New York, NY). Respondents were asked to answer treatment-related questions and rate the treatment outcomes using a visual analog scale. Statistical analyses were completed to determine the significance of crown, root, and bone view on treatment planning with clear aligners.

Results

A total of 70 orthodontists participated in the survey. There were significant differences in responses when viewing patients in crown-only and crown, root, and bone presentations. Across the 4 patients, 33%-43% of practitioners changed their sentiment toward the treatment plan ( P <0.001). When rating satisfaction on the 100-point scale, average ratings changed by 10.6 to 21.0 points; both increases and decreases in satisfaction were seen across the patients ( P <0.001).

Conclusions

When given 3-dimensional information on the position of a patient’s crowns, root, and bone coverage, orthodontists are likely to change their clear aligner treatment plan. This study showed that a confirmation of dehiscence and fenestrations using the root and bone view resulted in practitioner dissatisfaction despite an initial satisfaction with the crown-only view.

Highlights

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Clinicians make better treatment decisions with the 3D information on tooth structures.
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Algorithm-based simulation helps better visualize clear aligner treatment outcomes.
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The confirmation of the bone defects with a 3D view results in practitioner dissatisfaction.
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A treatment plan based on a crown-only view may result in compromised periodontium.

In the last decade, there has been a significant increase in the number of adult patients seeking orthodontic treatment. Clear aligners are an alternative to conventional fixed appliances for correcting malocclusions and are now the preferred treatment option, especially for adult patients. ^, A direct correlation between patients’ age and periodontal defects has been previously reported. Although tooth proclination, arch expansion, and interproximal reduction (IPR) are common methods to resolve crowding for tooth alignment, periodontal health plays a significant role in virtual treatment planning with aligners. Identifying the alveolar defects before orthodontic treatment is crucial to developing a customized treatment plan for a desirable and stable occlusion with healthy periodontal structures.

Numerous studies on the prevalence and location of fenestrations and dehiscences indicate they are common in all malocclusions. ^, These alveolar defects are more frequently present in the maxilla than in the mandible, on the buccal than lingual root surfaces, and in anterior teeth than in posterior teeth. In addition, the thickness and position of the alveolar bone are reported to be affected by occlusal forces and the tooth location, angulation, and inclination. A recent study by Nalbantoğlu and Yanik reported ≤1 mm bone thickness in 80% of maxillary anterior teeth. The reduced bone height of the periodontium of at least 1 tooth at the end of 1 year of orthodontic treatment, even in young patients aged <30 years, was also reported previously.

In orthodontics, periodontal health is traditionally assessed by probing gingival tissues and evaluating teeth’ periodontal and bony support on panoramic, periapical, or bitewing radiographs. However, conventional 2-dimensional imaging does not allow direct visualization of bony fenestrations and dehiscence. Cone-beam computed tomography (CBCT) imaging provides information on the location of defects, root positioning, and alveolar bone coverage much more accurately than 2-dimensional imaging. ^,

Grünheid et al evaluated the effect of root and bone views on practitioners’ perceptions of overall patient quality. Clinicians who initially rated the treatment outcomes favorably lowered their score once the root and bone view were revealed to them. No previous study has evaluated how much visualization would influence treatment planning decisions for clear aligners.

Today, it is possible to use machine learning algorithms and initial CBCT imaging in treatment planning for clear aligners. Choi and Lee reported that personalized 3-dimensional (3D) visual treatment goals might be prepared more accurately and objectively with deep learning and algorithms. With algorithms, the entire tooth, including the roots and their position within the alveolar housing, may provide a virtual view that allows clinicians to visualize better the progress of their proposed treatment. The treatment simulation, at the root and bone level, may offer an advantage compared with a typical clinical crown-based simulation.

The purpose of this study was to assess the effect of root and bone visualization on virtual treatment planning with clear aligners. The null hypotheses of the study were (1) practitioners would not modify their original treatment plan (ie, on the basis of viewing the crown-only presentation of the teeth) after reviewing the same patient in the crown, root, and bone view and (2) there would be no difference in treatment outcome assessment scores between the crown-only view and the crown, root, and bone view.

Material and methods

Before beginning the study, approval was obtained from the Institutional Review Board of the Virginia Commonwealth University Office of Research. Members of the American Association of Orthodontists (n = 2300) and the Virginia Association of Orthodontic Education and Research Foundation (n = 211) were contacted through email with a link to the online survey by a third party on the basis of a list that was randomly generated by the corresponding database. Study data were collected and managed using Research Electronic Data Capture (REDCap, Vanderbilt University, Nashville, Tenn) tools hosted at Virginia Commonwealth University. REDCap is a secure, Web-based software platform that supports data capture for research studies.

Initially, a brief introduction to the study and consent information were provided to the respondents. The first section of the survey requested demographic information: year of graduation, location, and experience with clear aligners. The survey consisted of 4 patient simulations (1 control and 3 experimental) generated by the 3D Predict aligner system (3D Predict, New York, NY) presented in a video format. The control patient was chosen so that treatment would differ on the basis of the information obtained from the crown-only view and crown, root, and bone view. The patients in the experimental groups had alveolar defects and exhibited either moderate anterior crowding or moderate anterior and posterior crowding, requiring molar expansion and buccal tipping of teeth.

The patients were first presented in a crown-only view from the frontal, right, left, and occlusal aspects ( Fig 1 ). The crown, root, and bone view was only available to present from the frontal aspect ( Fig 2 ). The order of patients was randomly generated by the REDCap software, and the same order was used for each participant. Each video, 5 seconds in duration, exhibited the clear aligner treatment progress from the first to the last prescribed aligner in the frontal, right, left, and occlusal views. The software generated the treatment progress and predictions.

Each respondent was asked to review the patient in the crown-only view with the ability to pause, rewind, and replay the videos to evaluate the occlusion from the frontal, right, left, and occlusal perspectives. The participant was then asked to answer multiple-choice questions. The first question was a yes-or-no question asking if the respondent agreed with the proposed treatment plan. In case of disagreement, a new question appeared with the opportunity to modify the suggested treatment plan by choosing options such as “incorporating extractions, increasing the amount of IPR, controlling torque on specific teeth, and treating the case with traditional fixed appliances or surgery.” There was also a section in which the respondent could write their thoughts or suggestions.

Once the questions related to the crown-only view were answered, the respondent could proceed with the crown, root, and bone view; however, they could not go back to the previous crown-only view section to change their answers. In the crown, root, and bone view, the respondent could view the video in the same manner and answer the same set of multiple-choice questions. The participant could proceed to the next patient presentation after reviewing and answering the questions in crown-only and crown, root, and bone views. When examining the patients in both presentation modes (crown-only and crown, root, and bone views), the respondent was also asked to rate the treatment outcome using a slider on a 100-mm visual analog scale (0, poor; 100, excellent).

Statistical analyses

Respondents indicated with a yes or no whether they agreed with the treatment plans of the 4 patients in the crown-only vs the crown, root, and bone view presentations. McNemar’s chi-square tests were used to analyze the agreement between 2 treatment plans. The overall satisfaction scores with the treatment outcomes for each of the 4 patients were compared using a paired t test to determine if satisfaction differed with the additional information from the CBCT (root and bone view).

Results

A total of 103 respondents initiated the survey, and only 70 answered the questions for both the crown-only and crown, root, and bone views for the first patient. The demographic characteristics of these respondents are provided in Table I . There was an even distribution among participants regarding years of practice and experience with clear aligners, with about 20% in each category. More than 70% of the subjects who took the survey indicated treating 11%-50% of their patients with clear aligners, and approximately 80% of the respondents reported treating >50 patients with clear aligners within the past 12 months.

Table I

Characteristics of responding providers (n = 70)

Characteristics	n (%)
Approximately how many years have you been in orthodontic practice?
<5 y	14 (20)
5-10 y	16 (23)
11-20 y	21 (30)
21-30 y	8 (11)
>31 y	11 (16)
How long have you been a clear aligner provider?
<5 y	16 (23)
5-9 y	19 (27)
10-15 y	17 (24)
>15 y	18 (26)
What percentage of your orthodontic patients do you treat with clear aligners?
0%-10%	10 (14)
11%-25%	28 (40)
26%-50%	22 (31)
51%-74%	3 (4)
75%-100%	7 (10)
How many active patients have you treated with clear aligners in the past 12 mo?
0-10	2 (3)
11-50	13 (19)
51-100	23 (33)
101-200	12 (17)
201-399	12 (17)
>400	7 (10)