Digital Platform Facilitates Successful Facially Driven Orthodontic–Restorative Treatment

Prerestorative orthodontic treatment offers numerous advantages, including the opportunity to optimize esthetics, enhance biological and functional outcomes, and preserve tooth structure. Executing an interdisciplinary approach, however, can be challenging if communication among restorative dentists, orthodontists, and patients is lacking. Restorative dentists may overlook the benefits of orthodontic tooth movement, patients may be unwilling to undergo orthodontic treatment because of a lack of understanding and appreciation for its value,¹ and orthodontists may be unfamiliar with the restorative concepts that need to be integrated into the treatment plan.

In recent years digital orthodontics using clear aligner systems have provided effective control over tooth movement while supporting smile design and treatment plans.^2-4 This approach can increase patient acceptance and facilitate minimally invasive dentistry.

This case report highlights the use of one such digital treatment planning platform, Invisalign^® Smile Architect^™ (Align Technology, Inc., invisalign.com). This facially driven orthodontic-restorative treatment planning platform provides a single ecosystem for combined visual treatment planning of orthodontics and restorations. The software allows for assessing the need for tooth movement, moving teeth within the prosthetic envelope in three dimensions, facilitating team communication, helping patients understand the value of prosthetic-driven digital orthodontics, and achieving minimally invasive restorative treatment.

A 28-year-old female patient presented with concerns about the esthetics of her proclined maxillary incisors and a gingival embrasure (ie, black triangle) between teeth Nos. 8 and 9 (Figure 1). She had undergone orthodontic treatment as a teenager, but relapse had occurred. Her chief complaint was an unpleasing smile. She desired a treatment plan that could be completed relatively quickly while preserving as much tooth structure as possible. She wanted any orthodontics to be short-term.

Upon intraoral examination, the clinician observed that the patient had an anterior open bite from teeth Nos. 7 through 10, a shifted and tilted dental midline to the right, and mesially tilted teeth Nos. 8 and 9 with a black triangle. Also, tooth No. 8 appeared darker than tooth No. 9 (Figure 2). Tooth No. 8 was nonvital, but no periapical pathology was found.

Patient documentation included standard photographs, a standard tessellation (STL) file generated from an intraoral scan (iTero^™ Element 5D Plus, Align Technology, Inc, itero.com), and a full panoramic and lateral cephalogram radiographs for case assessment.

The treatment plan began with a facially driven assessment,^5,6focusing on the position of the incisal edges of the maxillary incisors,^7,8 tooth proportion, smile curve, and gingival architecture (Figure 3). The treatment plan involved short-term orthodontics to correct the anterior open bite by retracting and extruding teeth Nos. 7 through 11 using clear aligners. This approach would offer esthetic and stable results but would not address the black triangle between the central incisors or the tooth proportion between the central and lateral incisors.

Veneers were planned for teeth Nos. 8 and 9 to modify tooth size and close the black triangle, thus further enhancing the
esthetic outcome.^9,10 During the aligner treatment, a bleaching gel (Opalescence^™, Ultradent, ultradent.com) would be prescribed
to be used in the aligner to whiten tooth No. 8 for 4 weeks.

A virtual treatment outcome was generated by submitting three standard photographs (frontal view, frontal view with smile, and lateral view with smile) taken using the Invisalign Practice App and the intraoral scan's STL file to the Invisalign system (ie, Invisalign Doctor Site). The clinician chose "Smile Architect" on the Invisalign site, and an orthodontic + restorative Clincheck^® simulation was generated with in-face visualization (Figure 4). The clinician was able to add or remove restorations according to the treatment plan and also modify the shape, length, and size of the restorations.

With the ideal tooth position determined, an optimal force system was designed to move the teeth precisely to their intended positions. The integration of the orthodontic and restorative interface enhanced the execution of the treatment plan.

Prosthetically driven tooth movement was achieved using 3D control of tooth movement in the Smile Architect platform. The clinician can control the tooth movement within the prosthetic envelope. The gingival margin was aligned, while the incisal edge was left with 1 mm of space, lessening the need for incisal edge reduction for veneer preparation (Figure 5). This approach also minimized the required tooth movement and number of aligners. Additionally, teeth Nos. 7 and 8 could be retracted palatally to create space for future veneers (Figure 6). Fourteen aligners, changed every 1 week, were used to correct the anterior open bite (Figure 7). Total orthodontic treatment time was 14 weeks.

Using prosthetically driven digital orthodontics, the teeth were positioned ideally for conservative prosthetic preparations, preserving as much tooth structure as possible. This allowed for minimal incisal edge reduction and labial reduction (Figure 8). The gingival margin was repositioned according to the smile design, eliminating the need for crown lengthening surgery. The clinician performed a mock-up using the STL file in the platform and prepared teeth Nos. 7 and 8 accordingly.

Tooth preparation entailed preparing veneers for teeth Nos. 8 and 9 based on the mock-up. Tooth No. 8 was lightened but still retained its internal discoloration. Theoretically, No. 8 would need to be prepared slightly deeper than usual in order to provide adequate space for the ceramist to mask the darkened dummy shade. The clinician, however, chose to prepare it the same as No. 9 to preserve more enamel and allow the ceramist to mask the darkened dummy shade with ceramic (Figure 9). Temporary veneers (Luxatemp, DMG America, dmg-america.com) were bonded to restore the patient's smile and confirm the final appearance.

Clinical photographs were taken according to guidelines from the ceramist to provide him information for shade matching (Figure 10 through Figure 12). An intraoral scan with the STL file was taken and sent to the ceramist for the fabrication of the lithium-disilicate veneers (IPS e.max^®, Ivoclar, ivoclar.com) (Figure 13 and Figure 14). The veneers were cemented with a luting composite (Variolink Esthetic, Ivoclar). The patient was followed-up at 1 week, 1 month, and 3 months post-treatment (Figure 15 through Figure 17).

This case report highlights the advantages of using a prosthetically driven digital orthodontic treatment planning platform (Smile Architect) to achieve an optimal treatment outcome. By integrating orthodontic and restorative concepts, the software allows for precise tooth movement within the prosthetic envelope, helping to preserve tooth structure and reduce the need for invasive procedures. The virtual treatment outcome and in-face visualization help facilitate effective communication among the dental team and enhance patient understanding and acceptance of the treatment plan.

The presented case demonstrated the successful correction of an anterior open bite, alignment of the gingival margin, closure of a gingival embrasure, and enhancement of tooth proportion using a combination of short-term orthodontics and veneer restorations. The digital platform allowed for the generation of a virtual treatment plan that both guided the tooth movement and expedited the restorative procedures. The result was an improved esthetic outcome, patient satisfaction, and minimal tooth structure removal.

This novel digital technique, which utilizes an innovative 3D software design, offers promising possibilities for prosthetically driven orthodontic treatment. It provides a comprehensive and interdisciplinary approach to achieving optimal esthetic and functional results. In the present case it was used to minimize incisal edge reduction and labial reduction, reposition the gingival margin according to the smile design, and lessen the need for surgical intervention. The integrated orthodontic-restorative treatment planning platform allows the clinician to plan orthodontic and restorative treatment simultaneously. Alternatively, the restorative dentist and orthodontist can plan the case together, saving treatment time and helping increase predictability.

The author thanks ceramist Naoki Hayashi, RDT, MDT, MDC, and the team at Ultimate Styles Dental Laboratory (ultimate-dl.com) for the fabrication of the veneers in this case.

The author had no disclosures to report.

Ryan Tak On Tse, BDS, MClinDent(London), MSc(ImplantDent)(HK)
Honorary Assistant Professor, Faculty of Dentistry, University of Hong Kong; Private Practice, Hong Kong; Membership, Faculty of General Dental Practitioners (UK); Membership, General Dentistry (MGD)