Surgery First and Aligners: A Case Report Combining In-House Surgical Guides and Pre-Adapted Titanium Plates

Abstract

Continuous advancements in technology have made it possible to integrate clear aligner therapy (CAT) with orthognathic surgery. This case report presents a novel, individually-planned workflow, combining CAT with a surgery-first orthognathic approach (SFOA) in collaborating with engineers for an in-house production of surgical guides and customized titanium plates. The patient was evaluated subjectively, using the Oral Health-Related Quality of Life-14 (OHIP-14) questionnaire and Orthognathic Quality of Life questionnaire (OQLQ), and objectively with the Peer Assessment Rating (PAR) index. The patient displayed the planned occlusal relationship with no report of discomfort in the temporomandibular joint (TMJ) or post-surgical complications. The surgical and occlusal outcomes have remained consistent and stable after debonding. A decreased score was reported in both questionnaires and the PAR after treatment, thereby indicating improvements in both subjective and objective evaluations. This case report demonstrates that with proper individual planning, satisfactory subjective and objective outcomes can be achieved when combining SFOA with CAT.

1. Introduction

Orthognathic surgery, a complex field within maxillofacial surgery, is crucial for correcting severe dentofacial deformities that cannot be resolved solely through orthodontic treatment. Traditionally, this process involved a lengthy presurgical orthodontic phase, often extending from over 12 to 18 months, followed by the surgical correction, and then a post-operative orthodontic phase. This method, known as the conventional approach, aims to decompensate the dental occlusion prior to surgery [1]. However, it has its limitations, particularly concerning patient aesthetics and comfort during the presurgical phase [2,3].

Over the years, a shift has occurred with the reintroduction of the Surgery-First Orthognathic Approach (SFOA), coupled with advancements in orthodontic technology, most notably the use of bone anchorage systems. The concept of SFOA, though not entirely new, was revitalized in 2009 by surgical innovators who sought to address some of the inherent disadvantages of the traditional orthognathic approach. This method prioritizes the surgical intervention at the onset of treatment, allowing for post-surgical orthodontics to handle any required tooth movement after skeletal corrections have been made. The availability of modern bone anchorage systems presents a novel opportunity for this approach to succeed as they offer stability and control during the post-surgical orthodontic phase, minimizing the need for the pre-operative decompensation of teeth [4]. The availability of bone anchorage introduces the prospect that achieving a decompensated, lower incisal position prior to surgery may not always be imperative. Research by Pelo et al. [5] demonstrated that patients undergoing the conventional orthognathic approach that consists of a presurgical orthodontic phase for decompensation of the teeth, prior to the orthognathic surgery followed by a post-orthodontic phase, experienced a detrimental impact on their quality of life compared to the SFOA group. This discrepancy was mainly due to the worsening of facial aesthetics during the presurgical orthodontic phase. By using the SFOA, addressing significant facial enhancements at the initiation of treatment and reduced treatment duration might lead to increased patient satisfaction [4,6,7]. One frequent approach of measuring the quality of life is through the use of the Oral Health-Related Quality of Life-14 (OHIP-14) questionnaire [8] and Orthognathic Quality of Life questionnaire (OQLQ) [9], where an increased score leads to the worsening of the quality of life, and a decreased score indicates an improvement. An objective way of evaluating the results is through the Peer Assessment Rating (PAR) index, where low scores indicate improved occlusion, with the weighted version prioritizing key features, and the unweighted version treating all features equally [10].

The surgery-first approach offers the advantage of utilizing the Regional Acceleratory Phenomenon (RAP) [11] and Systemic Acceleratory Phenomenon (SAP) [12], which induces accelerated tooth movement that can reduce the total treatment time. Enhancing the predictability of surgical procedures is crucial in orthognathic surgery, especially if an SFOA is chosen. Repositioning the maxillary and mandibular segments proves challenging due to the absence of prior dental decompensations, as outlined in the guidelines for surgery-first protocols [13]. It is therefore recommended to use an SFOA in cases with a mild curve of Spee, mild crowding, and mild deviations from the ideal inclination of the incisors.

In recent times, orthodontic appliances have been designed with a focus on meeting the patients’ preferences, as they now prioritize the aesthetics of orthodontic appliances, particularly adolescents [14] and adults [15,16] who prefer clear aligners. As patient-centered outcomes are a key factor in contemporary treatment philosophy [17], there is evidence suggesting that clear aligner therapy (CAT) offers enhanced comfort when compared to traditional fixed appliances [18,19]. Furthermore, in certain instances, the overall treatment duration can be shortened compared to using fixed orthodontic appliances [20]. As CAT continues to advance, it becomes increasingly capable of addressing complex malocclusions [21]. The combination of an SFOA and CAT has been mentioned in a few articles in the literature [22,23,24,25,26]. However, no official guidelines regarding case selection have been made. To date, only two articles have presented their protocols for surgery-first and aligners [27,28].

This case report presents a novel workflow in the treatment of a Class III patient using a combination of CAT and SFOA, based on virtual surgical planning (VSP) and the utilization of surgical guides and pre-adapted titanium plates produced in-house for a total Le Fort I osteotomy.

2. Methods

The workflow for the treatment included (1) diagnosis and individual treatment planning, (2) clinical preparations, (3) Le Fort I osteotomy, and (4) post-operative orthodontic phase.

Intraoral and extraoral records were taken together with a panoramic X-ray to evaluate if the patient was a candidate for CAT-SFOA. A patient was selected as eligible for treatment through an orthognathic surgical consultation with two orthodontists (TKP/KD) and an oral and maxillofacial surgeon (JB). The patient was informed about the surgical and post-orthodontic procedures, and the patient’s subjective need for treatment was evaluated.

2.1. Diagnosis and Individual Treatment Planning

A 21-year-old female, generally healthy, was referred for treatment due to her Class III malocclusion, open bite, and increased gingival display (Figure 1 and Figure 2). She was previously treated with a full fixed appliance nine as she presented agenesis of two lower premolars; however, the treatment had an unsuccessful long-term result. The completion of the previous orthodontic treatment was approximately nine years ago. Her main complaints were crowding, and a feeling of unstable occlusion. Objectively, her nose and chin deviates to the right. The pupillary line appears canted, and the right gonion is more inferiorly positioned than the left. The upper incisors appear steep, and an increased mandibular projection is evident from a lateral smile perspective. She has a straight profile, with an increased lower facial height, and a positive lip step. The distance of the lower lip is slightly decreased from the esthetic line. She presents with a maxillary hypoplasia, with a skeletal open bite, and a normal mandibular projection. She has dysplastic retroclination of the upper incisors, and compensatory retroclination of the lower incisors, based on her lateral cephalometric radiograph. Intraorally, she presents with an edge-to-edge occlusion anteriorly and posteriorly, with a mesial molar relationship bilaterally enhanced by two premolar agenesis, and slight crowding in both arches. Her upper arch appears narrow compared to her lower arch.

Based upon her diagnosis and chief complaints, a non-ex-surgery-first treatment plan was presented, with a Le Fort 1 osteotomy, maxillary impaction, and advancement in combination with a post-operative phase with aligners.

2.2. Clinical Preparations

A surgical date was set after the treatment plan was accepted by the patient. As described in

Table 1. Clinical Preparations.

Timeline	Objectives
1.5–2 months pre op	Consultation with the patient.
	Patient signed consent papers and answered the OHIP-14 and OQOL questionnaires.
	Intraoral scan was made.
	Clincheck created and passive aligners and attachment template ordered.
	Extraoral and intraoral records were taken.
1 month pre op	Invisalign attachments placed, any fixed orthodontic retainers removed and passive aligners were given to the patient.
	Clinical registrations were performed.
	Additional intraoral scan sent to the ClinCheck
1 week pre op	Buttons were placed on the planned teeth and fixated together with a steel ligature wire.
Surgery	Tads and corticotomies performed during the orthognathic surgical procedure.
1 week post op	Buttons removed and patient instructed in using active aligners.

, 1.5–2 months prior to surgery, the patient was called in to the department for extra- and intraoral records, including photos and an intraoral scan with the iTERO Element 5D Plus (Align Technology Inc., San Jose, CA, USA). The patient was asked to fill out the Orthognathic OQOL and OHIP-14 questionnaires. Records were uploaded to the doctor site at Invisalign (Align Technology^®, San Jose, CA, USA), and a pre-operative ClinCheck was made, with instructions to remove the lower fixed retainer virtually and create four passive aligners with cutouts for the buttons on most of the teeth, for intermaxillary fixation (IMF). Conventional aligner attachments were placed by the orthodontist, according to the desired tooth movements post-operation. Aligner attachments were chosen based on the planned movements needed to achieve ideal occlusion after surgery.

One month pre-operation, the aligner and IMF attachments were placed on the teeth, and any fixed retainers were removed. Passive aligners were checked for fitting and delivered to the patient. The patient was instructed to wear the passive aligners 12 h a day, to ensure retention of the teeth until the day of the surgery. For the VSP, a wax bite to establish the centric relation of the condyles, a Cone Beam Computed Tomography (CBCT) scan, and an intraoral scan was acquired. The VSP was performed using Dolphin Imaging software (version 11.9 Dolphin Imaging and Management Solutions, Chatsworth, CA, USA) by the orthodontist and oral and maxillofacial surgeon. A surgical wafer was designed and manufactured in-house, based on the VSP. The planned post-operative occlusion was exported from Dolphin Imaging software to Meshmixer (version 3.5 Autodesk Inc., San Francisco, CA, USA), together with the latest intraoral scans of the upper and lower arch oriented in the initial occlusion. The models were then modified and oriented in the planned occlusion, based on the VSP [28], and exported to the ClinCheck.

In addition, the planned set up of the VSP was exported from Dolphin Imaging software to 3-Matic (Materialise NV, Leuven, Belgium) as a Stereolithography (STL) file, to create cutting guides and spacers. Spacers were designed for the support of the planned position of the down-fractured maxilla, together with the occlusal splint. The models were rendered due to triangular geometries made after the VSP. The surgical guides were manufactured in a Form 3B 3D-printer (Formlabs Inc., Somerville, MA, USA), with BioMed Clear V1 Resin (Formlabs Inc., Somerville, MA, USA) with 0.100 mm layer thickness. The post-processing procedure was performed with alcohol wash and light curing, according to the recommendation of the manufacturer. The supports were removed after light-curing. Titanium plates (2.0 Biomet from Zimmer Biomet, Warsaw, IN, USA) were pre-adapted prior to surgery on a 3D-printed model, according to the VSP. Prior to the surgery, the surgeons granted approval for all of the designs, including the placement position and the geometry of the cutting guides and spacers.

Attachments were placed on the planned teeth and connected with a steel ligature wire a few days before the surgery. Ceramic buttons were placed on the incisors, and metallic buttons in the side segments.

2.3. Le Fort 1 Osteotomy

The planned surgical movements were a 7 mm advancement and 3 mm impaction of the maxilla, based on the VSP.

An incision in the labio-buccal sulcus was made from the premolar region crossing to the contralateral side. A subperiosteal dissection was performed to expose the anterior aspect of the maxilla.

An in-house protocol was followed, including designing and manufacturing two personalized cutting guides (right and left side), to facilitate a precise osteotomy and bone removal. The two spacers were CAD/CAM, manufactured to assist in the planned amount of impaction and advancement of the maxilla.

Four L-shaped titanium plates were adapted to fit the printed model, fulfilling a dual purpose as additional guides for repositioning the maxilla and as fixation units for the segments. A total of eight Temporary Anchoring Devices (TADs) were placed during the surgery for additional anchorage, for intermaxillary fixation and post-operative elastic guidance (Figure 3).

2.4. Post-Operative Orthodontic Phase

A week after the surgery, the buttons used for IMF and the surgical wafer were removed, and the occlusion was visually assessed and compared to the planned outcome exported to ClinCheck (Figure 4). The patient was instructed on using the planned aligners full-time (22 h/day), and removed only when eating or drinking other beverages than water. The aligners were changed initially every 5 days during the first 3 month-period post-operation to utilize the advantages of RAP and SAP, and thereafter every 7 days. The patient was seen 1 and 3 weeks after surgery, and thereafter every 8 weeks. The total duration of the treatment was one year, and the treatment result is presented in Figure 5 and Figure 6. The total Peer Assessment Rating (PAR) score was measured before and after the treatment.

3. Objective Assessment and Quality of Life Evaluation

The initial assessment using the Peer Assessment Rating (PAR) index yielded a total score of 14 for the unweighted version, and 22 for the weighted version, recorded before the start of treatment. Following the course of treatment, both the unweighted and weighted PAR scores were reduced to zero, demonstrating a complete reduction in the scores. This corresponds to a total percentage reduction of 100% in the PAR index, highlighting the measurable change observed in the occlusal assessment from the baseline to the end of treatment.

In addition to the PAR index, the patient scored 49 on the OQOL questionnaire. This score was reduced to 40 after treatment, reflecting a change in the recorded responses over time. Similarly, the OHIP-14 questionnaire showed an initial score of eight prior to treatment. This score was reduced to zero post-treatment.

4. Discussion

An SFOA is not recommended in more severe orthognathic surgical cases, due to the high demand of accuracy in a post-surgical occlusion that is not decompensated [13]; although, limits for planning an SFOA are under continuous expansion. As the understanding of an SFOA deepens, and new technological advancements emerge, the criteria for eligible cases are broadening, allowing more patients to benefit from this approach. Improvements in digital planning and 3D printing technology have made it possible to better predict post-surgical outcomes, even in moderately complex cases. The use of surgical guides and spacers can be used to overcome challenges in more complicated cases. The presented case fulfilled the guidelines for an SFOA, making her a good candidate for SFOA-CAT treatment. To date, there is no literature regarding case selections for SFOA-CAT, and our assessment is based upon our experience, where we look at the treatment modalities SFOA-CAT separately. In order to be a candidate, the patients’ malocclusion must be possible to treat with CAT, as well as fulfill the guidelines for an SFOA. One of the limiting factors for SFOA-CAT are cases that require extensive root movements without the use of auxiliaries to aid with the movements.

An alternative treatment approach involved bimaxillary surgery to correct the chin asymmetry through a bilateral sagittal split osteotomy. However, this option was not prioritized by the patient as it would entail additional surgical comorbidities. From an objective point of view, mandibular asymmetry was limited, and did not justify a bilateral sagittal split. Instead, the anterior open bite was successfully resolved by mandibular autorotation, as illustrated in Figure 7 and Figure 8. Because of earlier orthodontic treatment with full fixed appliance, the patient expressed a preference for a less conspicuous appliance and sought to minimize the use of traditional braces, if feasible. Consequently, the patient favored the use of CAT.

IMF in a clear aligner case differs from conventional treatment as there are no brackets when patients are treated with CAT. Clear aligner orthognathic splints [22,29], TADs, brackets [22], and buttons, in combination with a splint [27], have been described. Our protocol regarding IMF included ligation to buttons in upper and lower jaw teeth together with a CAD/CAM designed and manufactured surgical wafer. To minimize the risk of displacement into the surgical site in case of debonding during the procedure, we employed a passive ligation technique for the buttons. Ceramic buttons were chosen for the incisors due to esthetic reasons, while metallic buttons were used on the sides due to their radiopaque properties, in case they needed to be located if displaced. It is important to note that using buttons carries a heightened risk of debonding incidents. Additionally, TADs were strategically placed to serve as both post-elastic guidance and a safety measure, in case the surgeon encountered difficulties with the buttons for IMF. The idea behind incorporating the surgical wafer and surgical spacers was to validate the precision of the in-house manufactured surgical guides and ensure a predictable surgical outcome. However, recent research has shown that wafer-less surgery with surgical guides offers improved accuracy in the maxilla [30]. It is worth noting that in-house resin-produced surgical guides have become a viable option and have the potential to replace traditional surgical wafers.

The additional corticotomies performed during the surgery were conducted with the sole purpose of increasing the RAP. However, future investigation into the effect of corticotomies in orthognathic surgery are needed. To our knowledge, while there are reports on the effects of corticotomies in general [31], none specifically address their impact within the context of orthognathic surgery.

An accurate reconstruction of the VSP in ClinCheck is one of the challenges combining an SFOA with CAT [32]. One method involves explaining the challenge through written instructions within the ClinCheck, but this approach can be labor-intensive, leading to confusion, and, therefore, is particularly challenging in SFOA cases. To the best of our knowledge, there is only one article that offers a thorough and effective solution to this issue, utilizing a free third-party software in an efficient manner [28]. In this case, our VSP that was sent to the ClinCheck corresponded to the post-surgical outcome, as shown in Figure 4.

A decreased score from the initial to post-treatment in the OHIP-14 and OQOL questionnaires indicates an immediate positive impact in the patient’s quality of life, and the reduction in the PAR score after treatment suggests a successful post-treatment occlusion. Her facial appearance after treatment was not evaluated with an index; however, the treatment goals of a more harmonious profile and less gingival display when smiling was achieved (Figure 5).

An SFOA combined with CAT is a field that requires further research. The protocol presented in the case report appears to be an efficient way to combine these treatment modalities, leading to an objective PAR improvement in addition to an improvement in the patient’s quality of life.