Nowadays, orthodontic treatment for adults has been the faster growing area in dental practice. Adult patients are seeking treatment in order to improve their facial aesthetics and to have tooth repositioning, making restoration or replacement of teeth easier. However, with this category of patients, a physiological adaptation is involved, and it is often symptom related, while with a child, we are more concerned by signs. A major reorientation of orthodontic reflection has occurred in the last decades . With the change in lifestyles and increased patient awareness, demand for adult orthodontics has increased. Furthermore, dental multidisciplinary allowed better management of the most complex and unique demands of adult patients, thus considerably improving the quality of care and treatment prognosis. Besides clarifying objectives, adult patients require treatment efficacy, convenience of appointments schedules, and good communication with other health professionals. About 80% of adult patients require multidisciplinary treatment in planning and treatment performance. In adults, the opinion of another expert is not casual. There are rare cases of adult orthodontics in which cooperation is not necessary .
The objectives of adult orthodontics correspond to the general objectives of orthodontics, i.e., optimum occlusal function, to improve the aesthetics of the face and teeth, and to contribute to the longevity of the stomatognathic system. However, a fourth objective can be added in adults: to realize a treatment of “aid” to the prosthesis.
The purpose of this chapter is to review, through clinical cases, the scope, effectiveness, and limitations of orthodontic treatment in adult patients.
2. Psychological considerations
The demand for correction of malocclusion is often psychological and sociological rather than somatic. The relationship between psychology and orthodontics has been either ignored or dealt with in mechanical ways. This is an area in which speculation and given work of irresponsible kind takes place .
Beauty is often more than skin deep because the psychological damage to a person who feels unattentive can be extreme. Orthodontic treatment provides a person a strong sense of feeling along with awareness, that he or she is not powerless, but that through proper cooperation can change and control outcomes.
Fundamental knowledge of psychology is necessary for modern orthodontics. The study of actions and reactions of individuals in social situations and the influence of such reactions on an individual is known as “dialectic psychology” .
Several authors have commented on the increase in the number of adults coming for orthodontic [5, 6]. This phenomenon has been attributed to several factors, including the improving of the aspect of brackets , greater conscience for the possibilities of orthodontic treatment, and social integration of the fixtures. Regardless of this, there is little information about this subgroup of patients. In particular, there is a lack of research on adult motivation for orthodontic treatment. As early as 1971, Edgerton and Knorr  proposed that the origin of the motivation may be the most important factor in determining and forecasting patient satisfaction. This statement was made in relation to patients seeking aesthetic surgery. However, it is likely that this assumption can be considered in many types of treatments, including adult orthodontic treatment.
3. Biological considerations
The orthodontic treatment of adult patients differs from that of children in that there is no further appreciable skeletal growth in adult patients and the treatment is often multidisciplinary. There are however slow skeletal changes taking place in the facial bones during adulthood, and the dentoalveolar compensation mechanism still occurs. The initially slower tissue response in adults compared with that in children does not significantly affect the total treatment time since adult patients are general more cooperative than children, which seems to compensate for the slower tissue response .
3.1. Age changes in bone
Cortical bone becomes denser, and the spongy bone reduces with age. Marginal bone loss is more common in adults, which leads to apical shifting of the center of resistance of the involved tooth, resulting in increased tipping moment produced by the applied force. This requires proper biomechanics utilizing adequate countermovement to achieve bodily movement of periodontally involved teeth .
3.2. Periodontal considerations
A viable periodontal ligament is important for cell proliferation on application of mechanical force. There is a reduction in the periodontal ligament vascularity with aging and insufficient source of preosteoblasts, which may explain the delayed response to orthodontic forces described in adults. It is mandatory to employ lighter force levels in adults as heavier forces result in vascular compression and necrosis of the blood vessels of the periodontal ligament. There is high risk of iatrogenic damage to the periodontium with uncontrolled forces, and it is important to keep the periodontal status under control during treatment [11, 12].
3.3. Vulnerability for root resorption
Adults are more vulnerable to root resorption on application of orthodontic force. This is most commonly seen during intrusion of anterior and posterior teeth. Light continuous force must be employed to minimize the risk of root resorption, and the patients must be informed of the potential risk before starting the treatment. It is mandatory to take periodical intraoral periapical (IOPA) radiographs to evaluate for signs of root resorption. In case resorption is detected, active forces must be withdrawn for 7–8 weeks, and further treatment can be continued after cessation of root resorption .
4. Diagnostic considerations
Careful diagnosis and treatment planning on a multidisciplinary approach is required to treat most adult patients. An adult, unlike a child, is usually a patient with high expectations from orthodontic treatment. He presents with minimal or no growth potential and meager accommodation to mechanics. In addition, an adult may exhibit a potential for pathological changes, such as knife-edge ridges, increased thickness of cortical plates, buried roots, impactions, gingival recession, periodontal breakdown, missing teeth, mesial tilting, extrusion of molars due to nonreplacement of extracted posterior teeth, TMJ problems, osteoporosis, osteomalacia, and diabetes mellitus. These conditions, which obtain as a result of hormonal, vitamin, or systemic disorders common to an adult, necessitate more careful and extensive diagnosis evaluations.
Orthodontic diagnosis involves the development of a comprehensive database of pertinent information. The standard diagnostic aids such as case history, clinical examination and study casts, radiographs, and photographs are mandatory .
Intraoral periapical (IOPA), occlusal, and TMJ films should be obtained routinely in addition to the panoramic radiograph and the cephalogram. The “problem-oriented diagnostic approach,” as described by Proffit and Ackerman, is strongly recommended to ensure that no aspect of the patient need is neglected .
The additional diagnostic procedures that we should consider in an adult patient are as follows:
A full series intraoral periapical radiographs and TMJ X-rays.
Requirement of multidisciplinary approach towards treatment
The diagnostic steps involved in treating adult patients are as follows:
Collect accurate history and thorough patient examination
Analyze the database
Develop a problem list and priority
Prepare tentative treatment plan according to the priorities
Interact with other specialists involved
Acquire patient acceptance for the proposed treatment plan
5. Therapeutic considerations
In the recent times, with the increasing expectations of the patients to an aesthetically and functionally stable treatment result, the practice of dentistry is changing from a single specialist or general dentist practice to that of a team approach.
This enables the best utilization of the skills and expertise of clinicians of different specialties for the best possible treatment outcome of the patient. Such joint care of a patient’s dental needs is defined as interdisciplinary treatment .
Interdisciplinary approach is indispensable for patients with mutilated dentition. Patients with congenital defects can be best treated with such a team work only. It is also of utmost importance in adult patients presenting with severe jaw discrepancies, abraded or worn teeth, old failing restorations, tipped teeth, multiple edentulous spaces from previous tooth extraction, periodontal breakdown, recession, and many other periodontal and restorative problems .
The role of orthodontist in such an interdisciplinary treatment approach can be primary or secondary. Primary as in a case wherein an orthodontic patient requires adjunctive other specialties treatment as prosthetic replacement of missing teeth, tooth buildup to match a Bolton discrepancy, periodontal rehabilitation, surgical exposure of an impacted tooth, etc. Secondary as in cases where the orthodontic treatment rendered is an adjunct to other treatment planned, like in the case of space creation or tooth uprighting to facilitate prosthetic replacement of a missing tooth, etc. .
The patient may have high expectations and hesitations in accepting visibility of orthodontic appliances. For aesthetic reasons, the patient may demand ceramic brackets or lingual orthodontics. The patient must be informed about the limitations of the treatment.
Closure of old extraction site may be difficult especially in molar region . It may need uprighting to open the space mesially to receive prosthesis.
While bonding, special considerations may be required due to presence of restorations such as porcelains and metallic surfaces . Excess adhesive around orthodontic attachments should be removed as surface roughness of adhesive attracts more plaque retention. Strict oral hygiene procedures must be reinforced as patients with periodontal problems may have various difficult areas to clean. All restorations must be properly polished to reduce the tendency of plaque retention. Stainless steel ligatures may be preferred to elastomeric modules due to less retentive to plaque .
Quantitative and qualitative changes in bone and compromised periodontal support and missing tooth may need special consideration to plan anchorage . Headgears may not be acceptable to an adult due to aesthetic reasons. Hence, intraoral anchorage devices such as palatal arches and controlled forces are used. Microimplants can also be used to avoid dependence on teeth for anchorage.
The choice of extraction for orthodontic treatment may be affected by periorestorative problems or already extracted tooth. Occlusion achieved in adults is stable in a healthy patient but compromised periodontal status may need permanent retention [22, 23].
5.1. Orthodontics–periodontics relationships
Patients with fine periodontal biotype that predisposes them to periodontal disease require strict supervision and control of oral hygiene against the accumulation of dental biofilm before the beginning of orthodontic treatment as our patient who consulted for mandibular crowding complicating dental hygiene measures [24–26]. In addition, orthodontic treatment allows the steady periodontal status to be maintained.
Despite no significant correlation between malocclusion and periodontal disease or between the effects of orthodontic treatment on periodontal improvement, literature describes the clear interaction between orthodontics and periodontics . The likely contribution of orthodontics in the field of periodontics is related to the following (Figs. 1, 2, 3, 4):
A better control of oral hygiene
A uniform distribution of forces over the dental
A rehabilitation of vertical dimension
Induced orthodontic extrusion, with no bone loss
Correction of bone vertical defects
Decreases or elimination of bruxism
Periodontal status is important and must be evaluated before contemplating orthodontic treatment in adult patients. If the periodontal disease is not treated and plaque control methods initiated before initiating orthodontic treatment, then the orthodontic tooth movement causes further periodontal destruction. This is particularly true if the teeth are moved in the direction of inflamed periodontal pockets that extend beyond the alveolar crest . It is highly necessary to assess the patients’ potential for bone loss and gingival recession during orthodontic tooth movement. The patient should be screened for the risk factors of periodontal disease.
Pretreatment consultation with a periodontist should be routine and orthodontic objectives be altered according to his advice. Movement of teeth in the presence of periodontal inflammation will result in an increased loss of attachment and irreversible crestal bone loss.
5.2. Orthodontic–prosthesis relationships
Adult patients usually require adjunctive and comprehensive treatment involving multidisciplinary treatment approach. Correcting the malocclusion helps in improving the quality of periodontal and restorative treatment outcomes besides providing aesthetic benefits.
Adults are now more frequently referred for orthodontic treatment to improve the positioning and alignment of teeth prior to the replacement of missing teeth (Figs. 5, 7). Such tooth movements may be undertaken to achieve parallel abutments of the teeth used to hold the prosthesis, to create space for a pontic (the false tooth in a bridge), or to make space for a dental implant (usually a titanium device that integrates with the jaw bone and can be used to support a crown or dental bridge) (Figs. 6, 8).
It is often possible by orthodontic treatment to close spaces or reposition the remaining teeth following tooth loss. A good example of the usefulness of orthodontic treatment is when canines and premolars are moved posteriorly, eliminating either the need for a removable partial prosthesis to replace missing molars, or to allow insertion of a short-span fixed bridge, rather than the use a removable, partial prosthesis .
Adult patients have many preexisting conditions that are usually not present in adolescent patients. Hence, additional treatment objectives are established at the start of the treatment. Although acceptable aesthetics is an integral part of treatment goal, function, stability, and health of dentition are given paramount importance. Additional treatment objectives are determined to facilitate and improve effectiveness of periorestorative treatment by 
improving axial inclination of teeth, thereby improving root positioning with sufficient bone between roots for good vascular supply and proper contact area;
achieving parallelism of abutment teeth to minimize tooth cutting for fabrication of prosthesis;
distributing most favorable abutment teeth to receive prosthesis for better stability;
uprighting and extrusion of posterior teeth with occlusal equilibration sometimes followed by endodontic treatment to improve vertical osseous defects and crown root ratio;
forced extrusion of teeth damaged up to one third of cervical line to provide better support at the margin of the prosthesis;
restoring functional occlusion, keeping in mind existing skeletal relationship rather than aiming for Andrew’s six keys to normal occlusion;
achieving better lip support for flaccid and long upper lip by maintaining anterior teeth in slight procumbent position with correction of overjet by proclining and maintaining lower incisors in more procumbent position than normal position to avert wrinkles around the lips and by restoring vertical dimension with bite plate before placing prosthesis in bite collapse.
5.3. Orthodontics–orthognathic surgery relationships
Skeletal malocclusion (dysgnathia) is defined as the congenital or acquired abnormal position or morphology of one or both jaws. Some skeletal malocclusion can be camouflaged by only an orthodontics treatment. However, when the gap is very important and that the orthodontics treatment alone cannot meet the objectives, orthognathic surgery is required. This treatment provides a stable long-term corrections in comparison with the camouflage conventional orthodontic treatment. Orthognathic surgery offers the possibility of obtaining better occlusal, skeletal and aesthetic results. Several psychological studies have shown that the aesthetic motif is the main motivation of patients requiring such treatment [30, 31].
Moderate to severe discrepancies and dentofacial deformities in adults usually require an orthodontic treatment combined with orthognathic surgery to obtain a stable, functional, and aesthetic result. The main goal of surgery is to satisfy the patient’s chief complaint. It must also restore optimal functional results and provide better facial aesthetic. For this reason, the orthodontist and the maxillofacial surgeon must be able to diagnose the skeletal and dental deformities and establish the ideal treatment plan and execute it to perfection.
While the role of the orthodontist after the end of growth is limited in the alignment of the teeth, the surgeon has the possibility to reposition the maxillary and mandibular skeletal bases and their associated structures [32, 33].
Given the relationship between facial skeletal deformities and masticatory dysfunction, as well as the limitations of nonsurgical therapies to correct these discrepancies, orthognathic surgery should be considered medically appropriate in the following circumstances.
Anteroposterior discrepancies: established norm = 2 mm
Maxillary/mandibular incisor relationship
Horizontal overjet of +5 mm or more
Horizontal overjet of zero to a negative value (Figs. 9)
Maxillary/mandibular anteroposterior molar relationship discrepancy of 4 mm or more (norm 0 to 1 mm)
Presence of a vertical facial skeletal deformity, which is two or more standard deviations from published norms for accepted skeletal landmarks
No vertical overlap of anterior teeth
Unilateral or bilateral posterior open bite greater than 2 mm
Deep overbite with impingement or irritation of buccal or lingual soft tissues of the opposing arch
Supraeruption of a dentoalveolar segment due to lack of occlusion
Presence of a transverse skeletal discrepancy, which is two or more standard deviations from published norms.
Total bilateral maxillary palatal cusp to mandibular fossa discrepancy of 4 mm or greater, or a unilateral discrepancy of 3 mm or greater, given normal axial inclination of the posterior teeth
Anteroposterior, transverse, or lateral asymmetries greater than 3 mm with concomitant occlusal asymmetry
5.3.2. Preoperative orthodontics (Fig. 10)
The goals of preoperative orthodontic treatment are to allow for maximum surgical correction of the abnormality, to facilitate potential sectional surgical procedures, and to provide the possibility for creating an ideal, stable occlusion . The major part of orthodontic treatment takes place before surgery and might last 1 1/2 to 2 years [30, 36, 37, 38].
22.214.171.124. Arch alignment
The first goal of preoperative orthodontics is to align the dental arches or their parts so that they might be compatible with each other. Correcting crowding and rotations, the management of impacted teeth and arch length discrepancies is mainly a concern of preoperative orthodontics because it facilitates arch intercuspation; otherwise, the surgical result would be restricted .
126.96.36.199. Arch flattening
The planning of dental arch flattening is particularly important. Dental flattening and alignment are usually a common one-step process in conventional orthodontics. This is not the case for all surgical cases. When the mandible is surgically moved forward or backward, the position of the lower incisor is what determines the lower facial height .
In serious skeletal discrepancies, the teeth try to maintain some contact, under the effect of external and internal forces, so as to compensate for the skeletal problem. Although this compensation improves occlusal relationships and the patient’s appearance, it restricts the extent of surgical correction. In skeletal class ΙΙΙ cases, the upper incisors are often labially inclined, while the lower ones are lingually inclined. On the contrary, in cases of skeletal class ΙΙ, the upper incisors are often upright and the lower labially inclined. A consequence of these compensatory changes is that the overjet is virtual in regard to the actual magnitude of the skeletal discrepancy. Preoperative orthodontics aims at exacerbating dental relationships, by removing the camouflage effect and placing the incisors in normal inclination for the skeletal bases, if this is feasible .
188.8.131.52. Intercuspation of the two arches
One of the goals of preoperative orthodontics is to achieve harmonization of dental arches at all levels during surgery. Before the end of the preoperative phase, upper and lower rigid rectangular wires need to be passively in position for 8 weeks before surgery. Some type of hooks or brackets with thick attachments should be placed on the wires Kobayashi so as to facilitate immobilization during surgery .
5.3.3. Surgical procedures 
184.108.40.206. LeFort I osteotomy (Fig. 11)
The vertical position of the maxilla is recorded by measuring the distance between the medial canthus and the orthodontic arch wire. These vertical measurements are absolutely critical. The cut should be made at least 5 mm above the apices of the teeth. If cuts are complete, the maxilla is downfractured with manual pressure. The amount the maxilla will be impacted or elongated was determined in the treatment plan.
220.127.116.11. Surgically assisted rapid palatal expansion
Correction of transverse maxillary constriction can be corrected in adolescence with nonsurgical orthodontic appliances. As the sutures begin to close during late adolescence, relapse increases. A multipiece LeFort osteotomy can be performed to provide simultaneous maxillary expansion, but the degree of relapse is high. In the young adult, the preferred procedure is the surgically assisted rapid palatal expansion (SARPE). The orthodontist places a palatal expander prior to the procedure.
18.104.22.168. Bilateral sagittal split osteotomy
The cut is made with electrocautery about 1 cm from the lateral aspect of the molars and extends from midramus to the region of the second molar. If insufficient tissue is left on the dental side of the incision, closure is more difficult. A periosteal elevator is used to expose the lateral mandible and the anterior coronoid process in a subperiosteal plane.
22.214.171.124. Two-jaw surgery
Moving the maxilla and the mandible in one procedure requires osteotomizing both jaws and precisely securing them into the position determined by the treatment plan. If proper treatment planning, model surgery, and splint fabrication are performed, each jaw should be able to be placed into its desired position with precision. The mandibular bony cuts are made first but terminated prior to osteotomy completion. The maxillary osteotomy is made, and the maxilla is placed into its new position using the intermediate splint. The splint is used to wire the teeth into intermaxillary fixation. The intermediate splint indexes the new position of the maxilla to the preoperative (uncorrected) position of the mandible.
5.3.4. Postoperative orthodontics (Fig. 12)
The aim of postoperative orthodontics is to bring the teeth to their final positions and secure balanced occlusion; finally, retention planning should be achieved. This phase of the treatment starts 2 to 4 weeks later, after a satisfactory range of mandibular movement has been achieved and there is good bone healing  (Figs. 13).
The treatment of adult gives us the opportunity to make the biggest service possible in orthodontics. There is a great need for orthodontic treatment for adult patients. Adult treatment remains all the same a rewarding clinically and personally experience . Treatment in adults remains easier because they are cleaner, careful, more punctual, and have less pain than adolescents, and the processing time remains the same as in youth. The continuation of education of the general population will result in an increasing demand for this type of treatment .
Problems that can occur are minimal compared to the huge results that the practitioner can get by rehabilitating the function, aesthetics, and psychological prospect of an adult patient. While the diagnosis in adults is easier to establish that in adolescents, treatment for its part remains difficult and complicated necessitating in the majority of cases a multidisciplinary approach.