Introduction

In the realm of skeletal discrepancies, a significant gray area exists comprising cases that fall outside the spectrum of simple, straightforward, or complex enough to necessitate orthognathic surgery. The treatments commonly referred to as “camouflage,” which is frequently conflated with “compromise” and has unfavorable connotations, can be taken to the next level by implementing a treatment that can enhance numerous cases without necessitating orthognathic surgery or needs of compromise. Orthodontic treatments can present challenges in specific circumstances that require a tailored approach. Combining clear aligners and orthodontically driven osteogenesis (ODO) can be a practical solution for achieving superior treatment outcomes. This approach has demonstrated promising results and is particularly beneficial in resolving complex cases in the gray areas. By leveraging the advantages of these two techniques, healthcare providers can achieve better results with fewer complications.

The importance of knowledge of biomechanics for the success of orthodontic treatments is now generally recognized. The purpose of this chapter is precisely to emphasize the “uniqueness of malocclusion” of each subject presenting such abnormalities in the various components within the complex craniofacial system, the three‐dimensional (3D) analysis of the altered structural components using current, state‐of‐the‐art technological means of investigation, and the simplified correction with equally simplified orthodontic means (for the patient, but complex for the orthodontist who must undergo an orthodontic system learning curve such as Invisalign).

However, the knowledge required by an orthodontist who wants to undertake treatment with any orthodontic technique in a patient with complex alterations of the craniofacial district must be far more significant than an orthodontist who wants to correct simple crowding.

Birth and Development of the Invisalign Technique

Clear aligners for orthodontic treatment can be traced back to the 1980s when 3D‐direct‐print aligners used as restraints were introduced in orthodontics. It soon became apparent (Kesling, 1945) that if the teeth were repositioned on the initial model and the thermoplastic sheet was adapted to this model, a tooth shift was achieved and not simply a retention of the position achieved by the orthodontic treatment performed. The device was called an “aligner” because its most common use was to align teeth in crowding.

Although the Invisalign system has been present in orthodontics since 1997, it can only be considered revolutionary in recent years, as special treatment protocols have been devised that now make it possible to treat a relatively high percentage of malocclusion types. The main feature is undoubtedly the aesthetic appearance and the characteristics of total comfort, being a wholly transparent and removable appliance.

Like all scientific “innovations,” such a system also requires a learning curve, having specific biomechanical characteristics that, among other things, are not superimposable on those of traditional orthodontics.

Continuous technological development and unique technological innovations unceasingly invest orthodontic specialists through the development of ClinCheck software, new materials for aligners, and, no less important, new types of aids used for ever better control of tooth movement (TM).

To date, although these devices are continually referred to as “aligners,” their use goes far beyond simple tooth alignment since, by using increasingly high‐performance materials and increasingly accurate orthodontic movement programming software, almost all types of malocclusion can be treated (Duong and Kuo, 2006; Miller et al., 2007; Boyd, 2008; Kravitz et al., 2009).

Treatment Phases and Characteristics Peculiar to the Invisalign System^®

As mentioned earlier, the increasingly frequent use of aligners in everyday orthodontic clinical practice and the increase in therapeutic possibilities obtainable with the devices have led to a debate in the literature about their use for treating even severe malocclusions.

Among the many existing techniques in orthodontics, some considerations apply to all of them. Arriving at, for example, an exact diagnosis and making a correct clinical judgment, a process resulting from a combination of experience, knowledge, and the ability to adapt to the patient’s demands, is essential.

Listening to the patient’s needs often turns out to be conditioning and propositional of new therapeutic orientations, as opposed to those that can be foreseen by simply taking note, analytically, of the malocclusion one is faced with.

With Invisalign, the diagnostic system remains, as it was taught in the Schools of Orthodontics, and from that, we arrive at a diagnosis and treatment plan. However, the treatment planning system has changed, as everything is highly planned and predicted before orthodontic treatment begins.

With traditional orthodontic techniques at each session, the patient arrives with a new occlusal and skeletal situation that needs to be reanalyzed and reconsidered as treatment continues. So‐called “orthodontic” reasoning is performed each time the patient is checked. The tremendous conceptual revolution of this technique lies precisely in the design from the beginning to the end of the treatment.

As technology advances, even in the medical field, predicting as much as possible is undoubtedly utopian but desirable for most dentofacial alterations.

The knowledge of the complex mechanisms of orthodontic coronal/radicular displacement must be acquired. It must be considered of fundamental importance to have therapeutic success, as well as must be regarded as indispensable, since the repercussions on the craniofacial district of the lower third and the final positions of the dental elements concerning the arch bone structure following orthodontic treatment are considerable, so much to cause phenomenon of bone remodeling with resorptions and dental appositions.

It turns out to be of utmost importance to acquire that knowledge, in its complexity, since the main functions reside in the human face, and its extreme variability since each individual is different from another and there is no recipe, or paradigm, or standardization of therapy valid for categories.

The stages of treatment with clear aligners involve, as with all clinical courses of orthodontic approach, the first dental examination and discussion of the case, clinical and radiographic examination, taking of the intraoral scan of the arches by the intraoral scanner (the scanner combines laser and optical scanning to create a digital model, the ClinCheck makes a series of incremental shifts on the digital model built from the scan, and the manufacturing center makes a coordinated series of stereo‐lithographic models for the fabrication of the aligners with an average thickness of 0.75 mm), treatment planning and simulation (ClinCheck), sequential fabrication and delivery of the aligners to the patient, periodic visits, finalization of treatment, and maintenance of the results obtained by restraint (a 1.00 mm thick aligner to be worn full time in the first few months, after that only at night).

Specific orthodontic movements require composite attachments, applied when the first aligner sequence is delivered or shortly after via a 0.30–0.50 mm thick “template” aligner.

Programmed orthodontic movements are achieved by constantly using the aligners 22 hours daily, with changes every 7–14 days. The forces the device applies are light and continuous by the aligner’s elastic properties.

Invisible orthodontics differs from traditional orthodontics in high aesthetics, especially because the area over which orthodontic forces are applied is larger. Body movement of the tooth element is possible if there is an optimal fit between the tooth and aligners (since the tooth is a rigid body, at least two points of contact are necessary), which is why Invisalign^® technology introduced composite attachments. Power ridges, optimized attachments, precision bite ramps, precision cuts, and more are all designed to achieve predictable TMs.

Advantages of the Invisalign System

Aesthetic factor: aligners are virtually invisible. Therefore, the Invisalign solution is suitable for adults who want to correct their smiles without using traditional, conspicuous braces. Nowadays, they are also requested directly by teenagers who care a lot about aesthetics.

Unlike traditional braces, Invisalign does not use metal bands, brackets, or wires that can irritate the cavity. The absence of metal and wires also means you will have to spend less time in the dentist’s chair for necessary adjustments.

Regarding oral health, removing aligners, brushing, and flossing teeth ensure typically better oral hygiene, thus decreasing the risk of plaque formation, gum disease in a marked way, and periodontal changes (Flores‐Mir and Lagravere, 2005).

The virtual orthodontic treatment program (ClinCheck) makes it possible to show the patient, the movements that the teeth will follow throughout the treatment up to its final result.

It also provides highly predictable, highly accurate movements with simultaneous or separate timing staging, so in most cases, treatment with Invisalign can achieve results up to 15% faster than conventional orthodontic treatment (Djeu et al., 2005).

The forces associated with the movement imparted by aligners are light and can be expressed separately on a single element and with different timing staging within the same arch. At each stage, only a few distinct teeth are moved, and these movements are determined by the orthodontic treatment planned for that specific stage. The result is an effective force distribution system.

This type of orthodontic system includes several technological innovations, such as 3D and digital visualization, which can significantly help the orthodontist and facilitate communication with colleagues in other branches of dentistry.

Communicating with the periodontist or maxillofacial surgeon about combining scheduling for more complex cases requiring regenerative periodontal or orthognathic surgery becomes simplified.

The choice to use a minimally invasive method for the patient, the extreme accuracy of virtual simulation during design, and the use of light forces allow the orthodontist to treat almost all malocclusions with Invisalign now.

Regenerative Corticotomy and Bone Engineering in Orthodontics with a Digital Approach

Surgical facilitation of orthodontic treatment with a surgical insult of the bony cortical (corticotomy) has evolved over time, both in surgical technique and rationale. Corticotomy, planned initially as an outpatient alternative to orthognathic surgery, was considered somewhat invasive, technically demanding, time‐consuming, and not well tolerated by the patient (Cunningham, 1984). Later, acceleration of motion became the sole focus, but the surgical approach was still quite, invasive as the theory of bone blockage was still held in high regard (Kole, 1959). More recently, the surgical procedure has been modified to be less intrusive and comparable to full‐mouth periodontal surgery (Wilcko et al., 2001). Regardless of the type of surgical approach, there have been significant innovations in the rationale for its use. When the Wilcko brothers added bone grafting to corticotomy and called this technique periodontally accelerated osteogenic orthodontics (PAOO), it was thought that bone could be regenerated as the teeth move and not simply a way to accelerate the orthodontic movement.

Adding a bone graft to the area of decortication can cause significant modification of the alveolar base, resulting in a wider choice of orthodontic treatment options (Wilcko et al., 2009). This was the beginning of bone engineering concerning bone modification and reinforcement of the alveolar base, expanding the limits of orthodontic treatment. Therefore, if corticotomy can be considered a method to accelerate orthodontic movement when combined with bone augmentation techniques, it becomes a much more efficient treatment option. So, the decisive advantage is that this technique helps to expand the basal bone, and this leads clinically to at least two main positive effects: more space to accommodate crowded teeth and thus less need for extraction of healthy premolars, and a stronger periodontium, which can help prevent recessions during or after orthodontic movement (Murphy et al., 2009). This concept can be extended to the point that “the alveolar envelope,” or the limits of the alveolar housing, may be more malleable than previously believed (Williams and Murphy, 2008). As mentioned earlier, this is the beginning of bone engineering in orthodontics.

Orthodontics and Its “Limitations”

Most studies of alveolar bone changes in patients undergoing orthodontic treatment have used bitewing and or periapical radiography, thus limiting assessments to proximal bone surfaces (Hollender et al., 1980; Bondemark, 1998).

High‐quality cone‐beam computed tomography (CBCT) allows for assessing bone changes in any dimension (Fuhrmann, 1996). During orthodontic TM, teeth may be repositioned beyond the bony alveolar socket, resulting in dehiscence and fenestration formation (Sarikaya et al., 2002).

Some authors (Lund et al., 2012