Digital Workflows for Orthodontics and Clear Aligners

Melissa D. Shotell, DMD, MS
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INTRODUCTION

The digital evolution in dentistry has had a profound effect on orthodontics and particularly on the use and practice of clear aligners. While clear aligners were viewed for many years as a treatment only for adults with minor correction needs, clear aligners are now the treatment of choice by many clinicians for patients of all ages and treatment needs. The development of intraoral scanning and treatment planning software has led to an increase in the number of clear aligner cases and the increase of clear aligner treatment for comprehensive and complex cases.

Innovation within clear aligner treatment began with clinicians attempting to create their own aligners in-office.1-3 Initially, treatment was a laborious process where the doctor would have to make a series of plaster casts with reset teeth for each new aligner. While many patients were treated using analog approaches, it was not until the advent of modern clear aligner treatment by Invisalign (Align Technology)  as the first commercial aligner-specific laboratory that clear aligner treatment entered the mainstream dental workflow. Within a short period of time, clear aligners became a treatment modality that clinicians felt comfortable with treating  as they could send  to a commercial laboratory for reliable and expedited treatment. With an ever-increasing demand for aesthetic options in orthodontics, more than 6 million patients have been treated with Invisalign.4 As the world of digital dentistry has evolved with intraoral scanning and cone-beam imaging, the clinical workflows for clear aligner treatment have evolved into a completely digital process, and multiple clear aligner laboratories make a variety of aligners that vary based on design and materials. With new software developments, doctors are even able to take the design and manufacturing of clear aligners into the office of the clinician. With the diverse options available to clinicians and consumer education and awareness of clear aligners as treatment options, digital dentistry and aligner production is an ever-expanding area of treatment in both orthodontic and general dental practices.

CASE REPORTS

Case 1: Improving Aligner Treatment Options with Intraoral Scanning

Intraoral scanning has served as a new foundation for starting clear aligner treatment. With the adoption of intraoral scanners for restorative treatment, the application of this technology for clear aligners has greatly expanded clear aligner treatment in the general dental practice. The difficult process of taking full-arch polyvinyl impressions has been replaced with the ease of the intraoral scanning wand. Doctors are able to take intraoral scans and utilize the digital models as a communication tool with patients to discuss malocclusion and the need for both restorative and orthodontic treatment plans.

A patient presented to the author’s office seeking to replace maxillary crowns. To enhance communication between the patient and the laboratory, an intraoral optical scan (CS 3700 [Carestream Dental]) was made (Figure 1). The optical scans were imported into a module within the intraoral scanning software suite (CS ScanFlow [Carestream Dental]) to assist in generating a visual representation of the occlusal problems present (Figure 2). The virtual teeth were manipulated and oriented to improve the aesthetic and occlusal relationship (Figure 3). The patient was thrilled with the clinical presentation, agreed with the clinical treatment plan, and began orthodontic treatment immediately after.

Figure 1. An optical impression made with an intraoral scanner (CS 3700 [Carestream Dental]) for diagnostic purposes to evaluate treatment for the replacement of anterior crowns. Figure 2. A full-arch intraoral scan was taken to create a digital wax-up and complete assessment of the patient’s treatment needs (CS ScanFlow [Carestream Dental]).
Figure 3. Digital models in articulation gave a visual representation of the patient’s occlusion and demonstrated the need for clear aligner treatment to improve occlusion prior to restorative treatment (CS Model + [Carestream Dental]). Figure 4. Cone-beam CT (Green CT [Vatech America]) was utilized for the comprehensive diagnosis and treatment planning of orthodontic treatment using micro-osseous perforations.

Case 2: Utilization of CBCT Imaging to Enhance Visualization for a Micro-osseous Perforation

Cone-beam computed tomography (CBCT) technology has created a new standard of imaging for both restorative and orthodontic treatment. CBCT was first utilized in the United States at the Loma Linda University Orthodontics and now has wide acceptance in the dental community for 3D treatment planning of orthodontic, surgical, and restorative treatments. Today, utilization of this technology can lead to complex interdisciplinary treatment plans coordinating a pre-prosthetic clear aligner treatment planning setup for future restorative treatment.

A patient presented with multiple existing implants and fixed restorations and was interested in clear aligner therapy to help align teeth and improve his aesthetics. A CBCT scan (Green CT [Vatech America]) was made with a large field of view to permit rapid visualization of the anatomical structures needed for aligner treatment (Figure 4). The visualization of the images generated afterward allowed for discussion with the patient with his existing implant treatment and how it would impact the limited aligner tooth movement that could be achieved (Figure 5). Furthermore, utilization of the CBCT scan also permitted for visualization of the precise root position to plan micro-osseous perforations (Excellerator RT [Propel Orthodontics]) of the cortical bone to accelerate tooth movement5 (Figure 6). In addition to the perforations, high-frequency vibration was utilized to potentially reduce treatment duration.5 The patient was thrilled with his result as it reduced his treatment time so that he could complete treatment prior to enrolling in a postgraduate educational program.

Case 3: Invisalign in a Teenage Patient

A teenage patient presented with a concern of diastemas between her teeth. After seeing several other orthodontists, she did not pursue orthodontic treatment as she was given only treatment plans for traditional bracket and wire therapy (Figure 7). After a complete examination, we concluded that while bracket and wire therapy was indicated, she also would be a good candidate for aligner therapy. Optical impressions were made using an intraoral scanner (Mobile True Definition Scanner [Midmark]) and sent to a commercial laboratory (Invisalign [Align Technologies]) for aligner therapy.

Invisalign is considered the original clear aligner laboratory, is long held as the gold standard in clear aligner treatment, and has developed many pioneering innovations in the digital dental field. Invisalign created the first method for digitizing dental models and sectioning into individual teeth to create a digital setup and, together with the software (ClinCheck software [Align Technology]), created a digital ecosystem for designing clear aligner treatment.

The patient presented with significant Class II malocclusion that would necessitate elastic use during aligner therapy. Invisalign has unique features that can treat teenagers with Class II correction with mandibular advancement. Utilizing the ClinCheck software, a treatment plan was developed to incorporate the use of Class II elastics while resolving the spacing in the arches (Figure 8). Furthermore, Invisalign permits using optimized attachments that are computer-designed to aid optimal tooth movement and mechanically enhance the aesthetic scalloped-edge aligner. A comprehensive treatment plan was completed, giving the patient both functional and aesthetic results (Figure 9). The patient was thrilled with not having to get brackets and wires and requested that the aligners be made to begin treatment.

Figure 5. CBCT imaging (Green CT) was utilized to give a 3D representation of the teeth in relation to the supporting periodontal structures and the existing implant and crown restorations. Figure 6. Micro-osseous perforations were performed with an Excellerator RT hand driver (Propel Orthodontics).
Figure 7. Generalized spacing and Class II malocclusion created compromised smile aesthetics and excess overjet. Figure 8. ClinCheck software (Align Technology) was utilized to create an ideal treatment setup (Invisalign [Align Technology]).
Figure 9. Completed treatment with spaces closed and Class II malocclusion fully corrected. Figure 10. Complex malocclusion with an anterior crossbite and detorqued upper incisors.

Case 4: ClearCorrect in a Complex Adult Crossbite Case

An adult patient presented with concerns regarding the aesthetic appearance of her smile. An evaluation reveals that she had an anterior crossbite that can be challenging to treat with aligners (Figure 10). She was not interested in traditional bracket and wire orthodontic treatment and only wished to be treated if she could do aligner therapy.

An expansion of interest in clear aligner therapy has spurred multiple other commercial laboratories to fabricate clear aligners with unique characteristics. ClearCorrect (Straumann) offers a unique aligner design with a straight trimline extending beyond the gingival margin to create a highly retentive aligner and reduce the need for composite engagers on the teeth.6,7 Intraoral optical scans (TRIOS [3Shape]) were made, and the patient’s scans were sent to ClearCorrect for aligner case setup using software (ClearPilot [Straumann]) unique to its style of aligners (Figure 11). She was thrilled with the clinical presentation and scheduled aligner treatment to begin immediately. The unique design of the aligners aided expansion and movement of the teeth to relieve the crossbite and create a stable occlusion and enhanced the patient’s smile (Figure 12).

Case 5: In-Office Aligner Production

A patient who was currently being treated for conventional aligner treatment in another provider’s office presented with concerns regarding her treatment progress. She felt like she had posterior open-bite and did not feel confident with her concerns being addressed (Figure 13). Optical scans (CS3700) were made to help assist in the visualization of her potential treatment using the modules (CS Model + [Carestream Dental]) built into the scanner software (CS ScanFlow). The new aspect of the digital realm for clear aligner orthodontics is the demand for in-office clear aligners and same-day aligners. Multiple software options are now available that give doctors the ability to take full control of designing clear aligner treatment plans for their offices. The accessibility of in-office 3D printing has made it possible to produce same-day aligners.

The patient’s chief concern for seeking orthodontic treatment was to close the midline diastema and create a more pleasing smile. The use of the automatic set-up function within the software allowed a treatment plan to be developed within minutes (Figure 14). After reviewing the proposed treatment setup, the patient was thrilled and accepted aligner therapy within the author’s office. She felt comfortable knowing that her aligners would be produced by the author with full control of potential movement challenges throughout treatment. The models created within the software were then 3D printed using a desktop-grade 3D printer (SprintRay Pro [SprintRay]), and the aligners (Zendura FLX [Bay Materials]) were fabricated and delivered to the patient the same day (Figure 15).

Figure 11. Treatment setup from ClearCorrect (Straumann). Figure 12. Completed treatment with correction of crossbite and improvement of incisor position.
Figure 13. Patient pretreatment with midline diastema. Figure 14. Use of the CS Model + software (Carestream Dental) to create an automated setup for clear aligner treatment.
Figure 15. CS Model + software was utilized to create a sequence of clear aligners for comprehensive patient treatment.

CONCLUSION

Orthodontic treatment with clear aligners has been the ideal vehicle to utilize digital dentistry. The development of intraoral optical scanning, CBCT, and aligner design software has driven the use of clear aligners to an all-time high in dentistry. These rapidly changing areas of technology have facilitated the growth of highly sophisticated clear aligner systems produced by major aligner manufacturers and have created an emerging field of doctor-designed and -fabricated aligners.

References

  1. Nahoum HI. The vacuum-formed dental contour appliance. NY State Dent J. 1964;9:385-90.
  2. Nahoum HI. The dental contour appliance: a historical review. In: Tuncay OC, ed. The Invisalign system. New Malden, Surrey, United Kingdom: Quintessence; 2006.
  3. Kesling HD, inventor. Method of making orthodox appliances and of positioning teeth. U.S. Patent No. 2,467,432. April 19, 1949.
  4. Align Technology, Inc. 2020 Annual Report. Tempe, AZ: Align Technology, Inc.; 2021.
  5. Alikhani M, Raptis M, Zoldan B, et al. Effect of micro-osteoperforations on the rate of tooth movement. Am J Orthod Dentofacial Orthop. 2013;144(5):639–48. doi:10.1016/j.ajodo.2013.06.017
  6. Cowley DP, Mah J, O’Toole BJ. The effect of gingival-margin design on the retention of thermoformed aligners. J Clin Orthod. 2012;46(11):697-702.
  7. Jones ML, Mah J, O’Toole BJ. Retention of thermoformed aligners with attachments of various shapes and positions. J Clin Orthod. 2009;43(2):113-117.

Dr. Shotell is a board-certified orthodontist and practices in a multi-specialty practice in Sonora, Calif, focusing on the interplay of orthodontics and restorative treatment. She received her DMD degree at Nova Southeastern University and advanced hospital training a General Practice Residency Certificate from The Ohio State University. After spending years in general practice treating a broad range of patients, Dr. Shotell returned to complete a certificate and master’s degree in Orthodontics from Loma Linda University. At Loma Linda University, she focused her training on cutting-edge 3D imaging technology for diagnosis and treatment planning in interdisciplinary dentistry. Dr. Shotell considers education to be her passion and regularly consults and lectures on dental technology, clear aligner therapy, orthodontics, in-office clear aligners, office efficiency and workflow, and teamwork. She shares tips and tricks about orthodontics and clear aligners on social media as Alignerbee.

Disclosure: Dr. Shotell is a clinical consultant for ClearCorrect and Carestream Dental.

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