2
Orthodontic Diagnosis and Treatment Planning: Collaborating with Medical and Other Dental Specialists
Om P. Kharbanda1, Neeraj Wadhawan2, and Karthik Sennimalai3
1 Pro Vice‐Chancellor‐Health Sciences, Ramaiah University of Applied Sciences (RUAS), Bengaluru, Karnataka, India
2 Private practice, New Delhi, India
3 Assistant Professor, Department of Orthodontics, All India Institute of Medical Sciences, Vijaypur, Jammu, Jammu and Kashmir, India
Success in any healthcare profession depends largely on accurate diagnosis, formulation of appropriate treatment goals, and precise implementation. Currently, patients with orthodontic needs span a wide range of age groups, personalities, social strata, and ethnic backgrounds, with varying levels of expectations (Abu Alhaija et al., 2010). Additionally, the increasing number of adult patients means that the present‐day orthodontist is faced with an array of systemic (van Venrooy and Proffit, 1985; Patel et al., 2009) as well as local conditions (Basdra et al., 2001; Altug‐Atac and Erdem, 2007) that may affect both the general as well as the oral health status of the individual. It is now accepted that “it is no longer appropriate to deny elective dental or medical care to patients with diagnoses that have historically been associated with poor outcomes” (Sonis, 2004: 277). The recent medical and dental advances have made it possible for many patients with significant medical and dental disorders to be successfully managed in the orthodontic office (Lux et al., 2005), provided that the orthodontist has a sound knowledge base and is keen to interact with other medical and dental professionals (Patel et al., 2009).
Before becoming a good orthodontist, an orthodontic graduate must be a competent diagnostician and a good physician. We, as orthodontists, often make a diagnosis after taking a short medical history, complemented by a physical examination concentrating only on facial appearance (in general) and occlusion (local) alone. This approach, which is more appropriately termed “regional diagnosis,” reveals the existing malocclusion, but lacks an overall perspective and the bigger picture of the medical, psychological, and pathological processes occurring elsewhere in the body gets ignored. This approach makes proper recognition of existing systemic conditions and their effects on orthodontic treatment difficult, if not impossible, to comprehend. In our “play safe” approach, many orthodontists refuse treatment to patients who could be treated successfully with suitable precautions and professional interaction with other medical/dental specialists. Including a module on diagnosis and management of medical conditions in orthodontic training programs is recommended, with sufficient exposure in clinical settings in multispecialty hospitals. This will allow development of an attitude that encourages a more professional approach when interacting with our medical and surgical colleagues, while recognizing and realizing our responsibilities and limitations. Up‐to‐date knowledge of medical problems should be combined with following proper communication protocols while referring patients to other medical and dental colleagues.
The other side of the story
Since oral health can have a significant impact on general health, dental health is often a significant concern for the medical fraternity (George et al., 2010; Yasny, 2010). Mutual referral systems are useful in these situations, with medical personnel – including specialists – referring patients with dental and oral health‐related problems to dental specialists with greater zeal, provided that the specialists on both sides are confident about and comfortable interacting with each other. We should recognize that none of us can treat all the diseases of the human body. Thus, “two‐way interaction” is essential for providing a better level of healthcare.
Teamwork is becoming increasingly significant and beneficial across a wide range of disciplines. The terms multidisciplinary, interdisciplinary, and transdisciplinary are often used interchangeably. They all relate to the varying degrees of involvement of multiple disciplines along the same continuum (Choi and Pak, 2006). The term multidisciplinary denotes working with several specialties but staying within their boundaries. For example, in multidisciplinary care patients are treated independently by various disciplines that share information, while the patient may be a mere recipient of care (Bernard‐Bonnin et al., 1995; Choi and Pak, 2006). The interdisciplinary team denotes working between several disciplines to advance fundamental understanding or solve problems whose solutions are beyond the scope of a single discipline or area of research practice (Bernard‐Bonnin et al., 1995; Choi and Pak, 2006). The interdisciplinary approach requires close communication between various disciplines and mutual respect and confidence. For instance, cleft lip and palate anomalies or craniofacial syndromes require interdisciplinary care by primarily involving craniofacial surgeons, orthodontists, clinical geneticists, otolaryngologists, speech‐language pathologists, and clinical psychologists (Long and Kharbanda, 1999; Kharbanda, 2022). A transdisciplinary approach means working across or beyond several disciplines and transcending their boundaries (Choi and Pak, 2006).
Orthodontic diagnosis from a broad perspective
From a mere tooth‐moving specialty, orthodontics has become a branch of dentistry with deep scientific and evidence‐based perspectives for its biomechanical principles. Often, clinicians remain preoccupied with the mechanotherapeutic features of various appliances and philosophies, ignoring that teeth are a part of larger, intricately linked biological systems of the body that influence the response of teeth to mechanical stimuli.
Every patient is unique, with metabolic traits that are individually specific to them (Sidell and Kaminskis, 1975; Morrison et al., 1992; Bartley et al., 1997), even though all humans have similar basic anatomical, physiological, and biochemical features. It must be appreciated that treatment is being delivered not to an artificial set of typodont teeth but rather to vital tissues – which respond differently to the same treatment protocol under the same physiological conditions in different individuals (Ren et al., 2003; McConkey, 2004; Williams, 2008), altered physiological conditions in the same individual (Brambilla et al., 1981), and various pathological conditions (Salerno et al., 1982; Verna et al., 2000).
The craniofacial complex can be considered an organization of many small organ systems and components, such as the dentoalveolar structures, the nervous system, the muscular system, the soft tissue matrix, and the air passages. These structures are so intricately interlinked that disturbances in the physiology, anatomy, or function of any one component structure are bound to cause an imbalance in the whole craniofacial complex. This understanding should be reflected in orthodontic diagnosis and treatment planning.
Concurrently, a thorough knowledge of subjects such as anthropology, genetics, growth and development, nutrition, psychology, endocrinology, and kinesiology can help us gather critical and essential data regarding the various aspects of general health and disease. Along with this knowledge, advanced biochemical, microbiological, and radiological investigative procedures can help optimally diagnose a malocclusion, thus reducing the chances of treatment failure. In brief, a comprehensive approach toward diagnosis and treatment planning helps categorize patients according to their general health status and biological limitations, and increases the probability of a successful treatment outcome.
The first interaction with the patient
The initial examination is the most overlooked step as far as orthodontic diagnosis is concerned. Planning for an orthodontic examination should begin even before the patient visits the orthodontic office, through careful screening via a telephone conversation with trained office personnel, or through emailing the patient’s knowledge of their medical history to the orthodontic office before the scheduled appointment. This preliminary review will often highlight critical medical conditions such as endocrine, hematological, cardiac, renal, hepatic, pulmonary, and allergic disorders, as well as dental health‐related conditions. Such information is vital for the orthodontist to prepare for the appointment and plan various investigative procedures and anticipated referrals, which can translate into increased efficiency and reduced time required for the screening and risk assessment of the patient. This strategy should ultimately lead to higher confidence levels and increased patient satisfaction, and lower chances of complications later during therapy.
Comprehensive diagnosis and treatment planning should start at the time of the first interaction with the prospective patient (Kharbanda, 2020). The short “look–see” examination is no longer considered adequate with the increasing number of patients with medical problems seeking orthodontic treatment. Therefore, at the first visit the orthodontist should enquire about the problems and what the patient and parents expect from orthodontic treatment (Figure 2.1) and concurrently perform an appraisal of the patient’s psychological profile, as treating patients with unrealistic expectations or with extreme mood fluctuations may result in an unhappy ending (Al‐Omiri and Alhaija, 2006). Following this initial scrutiny, a systematic examination procedure should be followed, starting with the craniofacial region. If the examination or the previous medical history indicates the presence of underlying pathology or abnormality, further investigations in the form of referrals and advanced diagnostic tests should be undertaken.
Figure 2.1 (a–d) A 12‐year‐old girl with severely compromised vision attended with her parents for protrusion of her upper anterior teeth and poor dental esthetics. She had a Class II malocclusion with bimaxillary protrusion and severe discoloration of the dentition due to fluorosis. The radiographic examination also revealed an inverted and unerupted mesiodens. The diagnosis and treatment plan in such a case must include evaluation of the patient’s and parents’ expectations in view of the reduced vision of the patient, who may not fully appreciate the benefits of improved esthetics following orthodontic treatment and correction of the discolored anterior teeth. It is also pertinent to elicit the intensity of concern in the patient and parents toward the discoloration and protrusion as well as the motivational factors with regard to treatment.
The importance of the medical history in orthodontic diagnosis and treatment planning
Many patients today would already be taking short‐ or long‐term medications, which may influence paradental tissue remodeling (Krishnan et al., 2021) and, consequently, tooth movement. Drugs such as steroids, when taken for long periods as in chronic asthma or immunosuppression, may predispose teeth to iatrogenic root resorption following a mechanical stimulus (McNab et al., 1999). In certain instances, for example in the presence of sexually transmitted diseases such as human immunodeficiency virus (HIV) infection or syphilis, the patient may hesitate to give a complete and realistic history. Thus, it becomes the prerogative of the treating doctor to sufficiently evaluate the patient, both prospectively and retrospectively, to obtain a detailed health history during the first or subsequent visits. In this regard, the orthodontist and office personnel should judge the patient’s mannerisms, attitude, and current health condition, and whether further investigations or precautions are warranted before or during treatment.
A detailed medical history is an extremely useful tool for evaluating the existing health status of an individual and identifying any medical disorders they may have. Diseases of chronic duration, those of severe intensity, those affecting bone metabolism, and those altering the inflammatory pathways have a particularly important bearing on the orthodontic treatment plan (Sonis, 2004; Patel et al., 2009). Besides nutritional imbalances, developmental disorders, and skeletal malformations, chronic diseases, liver dysfunctions, renal impairments, cardiac and pulmonary anomalies, and erosive joint diseases can have impacts on physiological growth and, thus, orthodontic treatment (Table 2.1).
Table 2.1 Common causes of short stature.
Source: Adapted from: Lifshitz (2007); Crocetti and Barone (2004); Fujieda and Tanaka (2007); Matfin (2009).
| Normal | |
| Constitutional growth delay | |
| Genetic/familial short stature | |
| Combined constitutional growth delay | |
| Pathological | |
| Nutritional | Micronutrient deficiency
Macronutrient deficiency: decreased intake
Macronutrient deficiency: reduced absorption
|
| Endocrine | Hypothyroidism Isolated growth hormone deficiency Classic Neurosecretory Growth hormone insensitivity (insulin‐like growth factor deficiency) Hypopituitarism Glucocorticoid excess Iatrogenic Cushing disease Precocious puberty |
| Chromosome defects | Turner syndrome Down syndrome Prader‐Willi syndrome |
| Low birth weight short stature (intrauterine growth retardation) | Sporadic Characteristic
|
| Defects in bone development | Achondroplasia/hypochondroplasia Chondrodystrophies Other skeletal disorders |
| Metabolic | Mucopolysaccharidoses Other storage disorders |
| Chronic diseases | Chronic renal disease Chronic liver disease Congenital heart disease (especially cyanotic conditions) Pulmonary (cystic fibrosis, asthma) Poorly controlled diabetes mellitus Chronic infections (including human immunodeficiency virus and tuberculosis) associated with birth defects or intellectual disability |
| Psychosocial deprivation | |
| Chronic drug intake | Glucocorticoids High‐dose estrogens or androgens Methylphenidate Dextroamphetamine |
Chromosomal aberrations and embryological defects, including deformities of the orofacial complex
The development of branchial arches relies on the contribution of endoderm, mesoderm, ectoderm, and neural crest cells that collectively interact to give rise to the skeletal, muscular, vascular, and nervous system elements of the craniofacial region (Frisdal and Trainor, 2014). In the fourth week of intrauterine life, the mandibular arch (also the hyoid and glossopharyngeal arches) forms discrete processes, which form the future maxilla and mandible. While the paired mandibular processes merge in the midline by the fourth week, the maxillary process continues to contribute to forming the secondary palate, the upper jaw, and lateral portions of the upper lip (Sperber et al., 2001). The period between the sixth and twelfth weeks of intrauterine life is critical for craniofacial development (Finkelstein, 2001), and anomalies during this period result in various craniofacial defects (these are covered in greater detail in Chapters 7–8). Most congenital disorders result from obscure etiology. However, in the light of newer research, many unknown causes have been identified, and now multifactorial etiology is considered the commonest cause of congenital defects, whereas isolated genetic defects have been described in 10–30% of cases (Kumar, 2008). Genetic inheritance can follow various patterns, from simple Mendelian inheritance to complex polygenic traits with variable penetrance and expression across generations. To accurately diagnose the etiology of the condition and the inheritance pattern, the orthodontist has to identify the role of genetics and delineate it from the environmental influences. Familial comparisons, pedigree analysis, and sometimes a simple cephalometric analysis may be valuable tools in identifying and differentiating the role of genetic aberrations in the causation of these conditions.
Orthodontists often encounter conditions resulting from embryonic developmental defects, such as cleft lip and palate, hemifacial microsomia, maxillofacial dysplasias, vertical facial clefts, and micro/macrognathia. The orthodontist, as an active member of the craniofacial team, should be trained to recognize the features of congenital growth anomalies or genetically linked syndromes (Sennimalai and Singhal, 2022). A thorough extraoral and intraoral examination can reveal vital information about an underlying syndrome/congenital deformity (Tables 2.2–2.4 and Figure 2.2). Facial features such as sparse hair on the head, frontal bossing, depression of the nasal bridge, telecanthus, low‐set ears, typical epicanthal folds, coloboma, external ear defects, and facial clefts are characteristic features seen in many craniofacial syndromes. It is important to note that many craniofacial deviations may be associated with systemic alterations, such as osteogenesis imperfecta with dentinogenesis imperfecta, or orofacial clefts, associated with velocardiofacial syndrome or Pierre Robin sequence. Early genetic testing can help plan the treatment strategy for these individuals, with the ultimate objective of improving their quality of life (Bartzela et al., 2017).
Table 2.2 Syndromes affecting the face and jaws associated with mandibular deficiency and Class II malocclusion.
| Condition | Features | Etiology |
|---|---|---|
| Hemifacial microsomia (Goldenhar syndrome) | Unilateral dysplasia of the ear, hypoplasia of mandibular ramus, cardiac and renal abnormalities | Most cases sporadic; few familial instances; pedigrees compatible with autosomal dominant and recessive transmissions |
| Pierre Robin complex | Micrognathia; cleft palate and glossoptosis. This condition may occur as an isolated malformation complex or part of a broader pattern of abnormalities | Heterogeneous |
| Treacher Collins syndrome | Dysplastic low‐set ears; down‐slanting palpebral fissures; micrognathia | Genetic/autosomal dominant |
Table 2.3 Syndromes affecting the face and jaws associated with midfacial deficiency and possible Class III malocclusion.
| Condition | Features | Etiology |
|---|---|---|
| Apert syndrome | Craniosynostosis proptosis hypertelorism; down‐slanting palpebral fissures; symmetric syndactyly of hands and feet | Genetic/autosomal dominant |
| Crouzon syndrome | Craniosynostosis; maxillary hypoplasia accompanied by relative mandibular prognathism; shallow orbits; proptosis | Genetic/autosomal dominant |
| Achondroplasia | Short‐limbed dwarfism; enlarged head; depressed nasal bridge; lordosis; high palate | Genetic/autosomal dominant |
Table 2.4 Syndromes associated with mandibular prognathism.
| Condition | Features | Etiology |
|---|---|---|
| Basal cell nevus (Gorlin syndrome) |
Macrocephaly; frontal and parietal bossing; prognathism; multiple jaw cysts; multiple basal cell carcinomas; bifid ribs | Genetic/autosomal dominant |
| Klinefelter syndrome | Mandibular prognathism; skeletal disproportion; gynecomastia; small testicles | Commonly XXY karyotype; XXXY and XXXXY also occur |
| Osteogenesis imperfecta | Fragile bones; blue sclera; deafness; mandibular prognathism | Autosomal dominant (common type) |
In sum, an orthodontist should be able to identify severe conditions and make appropriate referrals to medical specialists or craniofacial and genetic centers while managing the less severe ones themselves, without inflicting further trauma on the psychological status of the already burdened patient.
Acute and chronic infections (systemic and local)
Various systemic diseases, and those locally affecting the craniofacial complex, have the propensity to contribute to the etiology of malocclusion, directly or indirectly, in both the prenatal and postnatal stages. Chronic systemic infections such as tuberculosis, hepatitis, nephritis, and HIV may indirectly contribute to malocclusion by disrupting systemic growth during childhood. Acute perinatal infections such as the TORCH complex (toxoplasmosis, other infections, rubella, cytomegalovirus, herpes simplex) can lead to congenital deformities in the offspring, including orofacial clefts. Diseases such as congenital syphilis, apart from systemic alterations, can lead to an array of orofacial malformations such as saddle nose, depressed nasal bridge, and hypoplasia of the molars and incisors.
Late postnatal or acute childhood infections can cause temporary cessation of tooth development, which may be evident as enamel hypoplasia (Figure 2.3). Antibiotics used to treat early‐childhood infections may also contribute to the development of enamel defects (Faustino‐Silva et al., 2020). In other instances, infections from distant foci, acute or chronic, may disseminate via blood and lodge in one of the jawbones, leading to osteomyelitis (Fabe, 1950; Carek et al., 2001) and consequent destruction of the bone architecture or growth disturbance. Involvement of the temporomandibular joint (TMJ), due to similar reasons or from a local spread of infections from adjacent structures, as in mastoiditis (Hadlock et al., 2001) or otitis media (Semlali et al., 2004; Prasad et al., 2007), can lead to arthrosis, adhesions, and regressive changes within the joint, which may affect growth and function of the mandible, resulting in malocclusion. The role of tonsillitis and rhinitis in the etiology of mouth breathing and the development of adenoid facies cannot be overemphasized. The resulting craniofacial disharmony and reduced upper airway are potent risk factors for developing obstructive sleep apnea (Neelapu et al., 2017).
Figure 2.2 (a–c) Binder syndrome. This 11‐year‐old boy, who attended the orthodontic clinic for fixed appliance treatment, had a flat midface due to a retrognathic maxilla, broad flat nose, horizontal nostrils, short columella, and apparent lack of nasal bridge. The radiograph confirmed a short anterior cranial base, small cranial base angle, reduced sagittal depth of the nasopharynx, hypoplasia of the anterior nasal spine, downward inclination of the nasal bones, and extremely reduced sagittal maxillary length. The patient was diagnosed as having Binder syndrome after consulting with the oral medicine department, the differential diagnosis of which includes acrodysostosis and Stickler syndrome. Additional investigations may be required for differential diagnosis of the case from other similar conditions.
Figure 2.3 A 16‐year‐old female reported for treatment of anterior open bite. Intraoral examination revealed hypoplastic permanent maxillary and mandibular incisors, canines, and first molars, with characteristic defects only on the incisal/occlusal thirds. On detailed medical history, it was found that patient had recurrent episodes of upper respiratory tract infections during childhood and was treated with antibiotics. The hypoplastic teeth in this patient are possibly due the disturbances caused during the enamel matrix secretion phase of amelogenesis.
Deficiency states and malnutrition
The availability of essential nutrients profoundly influences craniofacial and dental development. Malnourished children tend to become disabled, incapable of resisting disease or withstanding its onset and progress. Animal studies have demonstrated that in rats fed on a low‐calcium and vitamin D–deficient diet, the increase in body weight is impaired, and the craniofacial dimensions are reduced (Engström et al., 1982a, b). There is no general agreement on whether growth retardation during early infancy in humans is reversible in later years. Research findings on children surviving protein‐calorie malnutrition (PCM) have shown that severe malnutrition early in life affects their postmalnutrition growth, with reduced height and head size (Krueger, 1969; Alvear et al., 1986). Other epidemiological studies have shown that catch‐up growth after malnutrition compensates for previous growth retardation and results in normal stature for previously malnourished children (Garrow and Pike, 1967; Graham and Adrianzen, 1972). Dreizen et al. (1967) stated that chronic undernutrition in the presence of nutritional or metabolic disease slows the rate of skeletal maturation, delays the onset of menarche, and retards the epiphyseal fusion period.
These research findings may have diagnostic implications, wherein children with Class II malocclusion with nutritional deficiency could present with smaller physical and craniofacial dimensions in general. Those with unusual smaller dimensions may need to be discussed with a pediatrician and a nutritionist for their nutritional requirements, which might have a bearing on the quality of the response to functional appliance treatment as well as on the tissue response during orthodontic tooth movement. Similarly, vitamin C (Litton, 1974) or D (Collins and Sinclair, 1988) deficiency may affect the remodeling response of the periodontal ligament and the alveolar bone to orthodontic forces. For a detailed description of how nutritional factors influence orthodontic diagnosis and treatment planning and how an orthodontist should obtain nutrition data from patients, see Chapter 6.
Endocrine and metabolic anomalies in the etiology of malocclusion
The endocrine system is an intricate network regulated by human physiological processes at various levels. This system is responsible for regulating the metabolic processes throughout the body, controlling the growth and differentiation of various parts of the skeleton. Hence, disruption of any part of this system may lead to widespread alterations of human physiology, resulting in metabolic, anatomical, or growth‐related disturbances. Although a disturbance in virtually any part of the endocrine system would be expected to have orthodontic implications, disorders of the pituitary, thyroid, parathyroid, and pancreas are of particular interest to the orthodontist (Table 2.5). In many instances, an alert dental professional may be the first to suspect a systemic anomaly (Cohen and Wilcox, 1993; Vitral et al., 2006; Gosau et al., 2009), leading to the diagnosis of an underlying endocrine disorder.
Table 2.5 Common endocrinopathies encountered in orthodontic patients.
Source: Kamal et al. (2020) / Centre for Evaluation in Education and Science.
| Condition | Significance | Comments |
|---|---|---|
| Diabetes mellitus | Periodontal disease | Monitor control of diabetes |
| Hyperthyroidism | ↑ BMR, possible osteoporosis | Inquire about control of disease |
| Adrenal insufficiency | ↓ Tolerance to stress, delayed healing | Inquire about steroid dosages |
| Osteoporosis | ONJ, delayed tooth movement | Inquire about medications |
| Osteopetrosis | ↑ Bone mass, delayed dentition | Avoid orthognathic surgery |
| Vitamin D deficiency | Delayed eruption, dental abscesses | Inquire about nutritional disturbances |
| Fibrous dysplasia | Facial disfigurement, malocclusion | Consider delaying treatment |
BMR, basal metabolic rate; ONJ, osteonecrosis of the jaw; ↑, increased; ↓, decreased.
Pituitary gland
The physical and mental development of a child is controlled to a great extent, apart from other genetic and nutritional factors, by the pituitary and the thyroid glands (Setian, 2007). Pituitary hormones control the functioning of various other endocrine glands, as well as the linear growth of the skeleton. Consequently, disturbances of the pituitary function (and that of the hypothalamus) are associated with the alteration of function of most other endocrine glands. Deficiency of growth hormone, one of the many hormones produced by the pituitary, is associated with reduced stature and reduced growth and development of the craniofacial complex and shortened cranial base length (Cantu et al., 1997; Van Erum et al., 1998). Patients also exhibited a reduced mandibular dimension, with a resulting tendency to Angle’s Class II occlusion, large overjet, and increased overbite (Torlińska‐Walkowiak et al., 2021). Interestingly, it has been reported that dental age may not be retarded in growth hormone deficiency states (Van Erum et al., 1998). However, according to a systematic review, the dental age was delayed by about 1–2 years (Torlińska‐Walkowiak et al., 2021). This discrepancy in results can be attributed to the use of different maturity indicators and nonstandardized definitions. With growth hormone administration, the daily rhythm of tooth formation or eruption remained unaltered (Davidopoulou and Chatzigianni, 2017). In conjunction with orthodontic treatment for growth modulation, hormone replacement therapy highlights the importance of interactive care (Davies and Rayner, 1995; Hwang and Cha, 2004; Zhang et al., 2020). On the other hand, growth hormone excess, which usually occurs secondary to a somatotrophic pituitary adenoma (Matfin, 2009), causes gigantism in childhood and acromegaly in adults. Any child or an adult who presents with unexplained gain in height or mandibular prominence should be suspected of gigantism (Yagi et al., 2004) and should be referred to an endocrinologist for further investigations and management. It is important to know that although gigantism/acromegaly typically occurs in isolation, it may be associated with other pathological endocrine conditions such as multiple endocrine neoplasia (MEN; Yagi et al., 2004; Accurso and Allem, 2010), McCune–Albright syndrome (MAS), neurofibromatosis, and the Carney complex (Eugster and Pescovitz, 1999). See Chapter 5 for a detailed description of these conditions.
Thyroid gland
The euthyroid state is essential for normal mental and skeletal development, maturation, and adult bone maintenance (Harvey et al., 2002; Murphy and Williams, 2004). Thyroid hormone has also been demonstrated to play a role in the maturation of teeth (Vucic et al., 2017). A hypothyroid state during pregnancy and early childhood results in various developmental disturbances and defects, including neurological deficits. Hypothyroidism (Figure 2.4) during pregnancy and early childhood causes intellectual disability, growth arrest, delayed bone maturation, and epiphyseal dysgenesis (Rivkees et al., 1988; Bassett et al., 2007). However, intellectual deficits may not be marked in older children and adolescents, although the delay in skeletal maturation is evident. Orofacial alterations include enlargement of the tongue (Wittmann, 1977), delayed tooth eruption, the tendency for mouth breathing, Class II malocclusion due to a retruded mandible, short posterior facial height, and anterior open bite (Shirazi et al., 1999), all of which contribute to the development of malocclusion.
In contrast, juvenile thyrotoxicosis leads to accelerated growth and advanced bone age, but it also induces short stature due to premature fusion of the growth plates and craniosynostosis (Bassett et al., 2007). In adults, thyrotoxicosis accelerates bone loss, causing osteoporosis (Murphy and Williams, 2004), and even minor disturbances of thyroid status increase the risk of fractures (Bassett et al., 2007).
Due to early recognition of thyroid deficiency states, the classic manifestations of thyroid disease may not be evident in all individuals with thyroid disorders. Also, subclinical thyroid disease is being diagnosed more frequently in clinical practice in young and middle‐aged people, as well as in the elderly, with a reported prevalence of 4–10% in the adult population (Canaris et al., 2000; Hollowell et al., 2002). Subclinical hyper‐ and hypothyroidism may have repercussions for the cardiovascular system, bone, and other organs and systems (Biondi and Cooper, 2008; Delitala et al., 2020). Hence, the clinician must be vigilant and informed to be able to suspect or diagnose underlying thyroid disease. For example, a lack of response to functional appliance treatment in a case of skeletal Class II malocclusion after a reasonable period and excellent patient cooperation may be because of an underlying growth hormone or a thyroid disorder. The literature supports the view that thyroid hormone replacement therapy results in rapid catch‐up growth (Rivkees et al., 1988; Teng et al., 2004). It has been suggested that orthodontic treatment should be combined with hormone replacement therapy for optimum results (Verna et al., 2000).
Figure 2.4 (a, b) Intraoral views and (b) radiograph of an 18‐year‐old girl diagnosed with hypothyroidism show delayed eruption of multiple teeth.
Pancreas
Diabetes mellitus, a disorder of carbohydrate, protein, and fat metabolism due to an absolute or relative deficiency of insulin, is one of the commonest metabolic disorders. The disorder, especially when poorly controlled, leads to widespread changes such as nephropathy, neuropathy, retinopathy, and vascular disease, as well as cardiovascular and cerebrovascular complications, among other possibilities (Vernillo, 2001). Uncontrolled diabetes predisposes to severe and rapidly progressive periodontal disease, osteoporosis, and increased propensity to infections, all of which can be factors in the etiology of malocclusion. It can also alter the timing of tooth eruption, causing accelerated development until about 10–11 years of age and delayed development after that (Adler et al., 1973; Orbak et al., 2008). In addition, diabetes is also associated with an exaggerated inflammatory response during normal tooth eruption (Orbak et al., 2008), xerostomia, burning mouth syndrome, candidiasis, delayed and abnormal wound healing, diminished salivary flow, and salivary gland enlargement. A systematic review of animal studies has shown that diabetes mellitus may adversely affect bone remodeling and tooth movement during the application of orthodontic forces (Najeeb et al., 2017). A child or adult with symptoms of dry mouth/burning sensation, ketone smell from the mouth, unusual intensity of periodontal breakdown, and inflamed gingivae with pockets should raise the suspicion of underlying diabetes mellitus (Lamster et al., 2008).
Neuromuscular disorders in the etiology of orthodontic problems
The influence of neuromuscular harmony on dental development, occlusion, and functions such as mastication, deglutition, speech, and respiration is well established. Animal studies have confirmed alteration in the craniofacial skeletal structures secondary to loss of muscle tone (Babuccu et al., 2009; Tsai et al., 2010). Consequently, any degenerative or inflammatory disorder affecting the neuromuscular system can significantly influence the growth and remodeling of the dentofacial structures. Disorders such as chronic seizures, hemiparesis, and cerebral and cranial nerve palsies can cause alterations in muscle tone, leading to an imbalance of forces and consequent adaptation of the skeletal structures (Fong et al., 2003), including the craniofacial skeleton, with subsequent development of a malocclusion (Cascino et al., 1993; Trujillo et al., 2002; Portelli et al., 2009). Among the muscular dystrophies, Duchenne muscular dystrophy (DMD), an X‐linked neuromuscular disease, is most common and characterized by progressive muscle degeneration and weakness. It has been shown to influence facial morphology, dental arch dimensions, and oral functions like mastication and speech (Egli et al., 2018). Similar characteristics have been reported in patients with spinal muscular atrophy (Pucciarelli et al., 2020). The consequences of orthodontic therapy are discussed in Chapter 14.
Seizure disorders, which are one of the most common neurological disorders with an incidence of 1–3% (depending on age; Annegers, 1997), can result in orofacial trauma (Sheller, 2004) and asphyxiation because of appliance aspiration during an episode of seizures. Patients with chronic seizures may manifest body asymmetry (Fong et al., 2003), including forehead and facial structures (Tinuper et al., 1992), altered mental status, and poor oral hygiene, while patients on long‐term drug therapy may show gingival hyperplasia (Sheller, 2004) and bone mineral loss (Sheth, 2004). Moreover, hypercementosis, root shortening, anomalous tooth development, delayed eruption, and cervical lymphadenopathy have also been documented in patients with seizure disorders (Johnstone et al., 1999). Since orthodontic appliances often consist of a variety of metal fixtures, they can alter or distort the signals produced by magnetic resonance imaging (MRI) and computed tomography (CT) machines (Sadowsky et al., 1988; Sheller, 2004). It has been shown that stainless steel brackets show maximum signal distortion during MRI, whereas ceramic and polycarbonate brackets, and fiber‐reinforced composite retainers, did not cause distortion. Ceramic self‐ligating brackets with metal slots, titanium retainers, multistranded stainless steel retainers, and combinations of fixed retainers caused minimal distortion (Neela et al., 2021). Hence, in patients with suspected organic lesions causing seizures who may require MRI or CT scanning, the presence of an orthodontic appliance may impede the imaging process, which needs to be considered while planning the treatment (Alqahtani, 2019).
Overview of systemic disturbances in relation to orthodontic treatment planning
Although the discussion of each disease or organ system is beyond the scope of this chapter, this section will briefly highlight the diseases affecting major organ systems and their implications for orthodontic diagnosis and treatment planning.
Psychiatric disorders
Most patients attending an orthodontic clinic are children and young adults at various stages of maturation, with rapid and drastic changes occurring in their minds and bodies. As a result, these patients are prone to developing psychological/psychiatric disorders. It is reported that up to 14–20% of American children and adolescents may develop psychiatric disorders (Cassidy and Jellinek, 1998). In addition, adults going through difficult phases of life may also develop psychiatric problems. Therefore, the orthodontist must be sufficiently conversant with psychology and any abnormal behavior that might point toward a psychiatric disorder or substance misuse.
The psychiatric disorders encountered most by orthodontists are either major depressive disorder (MDD) or attention deficit hyperactivity disorder (ADHD; Neeley et al., 2006a). Any history, sign, or symptom that points toward a psychiatric disorder or a sudden or unusual change in a patient’s behavior during treatment requires discussion with the parents and the family physician, who may consider a consultation with a clinical psychologist/psychiatrist. In addition, patients with ADHD may be under treatment with amphetamines such as methylphenidate, which predisposes them to xerostomia, dysphagia, sialadenitis, stomatitis, bruxism, and growth disturbances (Elia et al., 1999). These possibilities have important orthodontic implications, as noncompliance with the maintenance of oral hygiene, instructions in the placement of elastics at home, difficult behavior during orthodontic procedures, and missed appointments can lead to treatment failure.
Body dysmorphic disorder (BDD) is another spectrum of psychiatric disorder in which a person has an abnormal preoccupation with one or more perceived physical flaws that are not observable or appear slight to others. Individuals with BDD are likely to seek orthodontic or combination orthodontic and orthognathic surgery (Rosten et al., 2018; James et al., 2019). Therefore, pretreatment evaluation of the patient must include questions about prior or current illness and medication. In addition, any treatment plan should include a discussion with the treating psychiatrist, as discussed in Chapter 3.
Substance misuse is also a significant problem among adolescents, with a reported prevalence of up to 40% among tenth graders in the USA (Neeley et al., 2006b). In addition, intravenous drug users may have diseases transmitted through blood, such as HIV infection (Leukefeld et al., 1990) and hepatitis B (Gillchrist, 1999). Therefore, a suspected case may need to be referred to a medical specialist after consultation with a psychologist.
Diseases of the respiratory system
Diseases of the respiratory system can be broadly divided into those affecting the upper and lower airways. Diseases of the upper airway can be an outcome of anatomical, physiological, or pathological restrictions of airway space in the nose, pharynx, and larynx. Chronic restriction of the nasal airway due to sinusitis, tonsillitis, adenoiditis, and allergic rhinitis leads to mouth breathing and further to the classic adenoid facies, as well as a change in the craniofacial flexure. Disorders of the lower airway, such as asthma, chronic bronchitis, and other chronic pulmonary diseases, increase the breathing effort, and affected cases may display orofacial changes like those seen with mouth breathing, apart from consequences related to impaired general health due to low oxygenation of the blood. Moreover, children with severe asthma may be using oral or inhaled steroids, which may cause a reduction in the salivary flow (Laurikainen and Kuusisto, 1998), predisposing them to oral candidiasis and increased risk of root resorption (Davidovitch and Krishnan, 2009). However, a recent systematic review contradicted the increased predisposition to orthodontically induced root resorption (OIRR) in individuals with asthma or allergies. Other factors such as uniradicular teeth and longer treatment duration were attributed to increased risk of OIRR (Dos Santos et al., 2021). On the other hand, there is strong evidence of the association between asthma and periodontal destruction, especially gingivitis (Moraschini et al., 2018; Ferreira et al., 2019). A proper consultation with a pulmonologist is essential while treating these patients so that any complications that may develop during orthodontic treatment can be effectively managed.
Diseases of the cardiovascular system
Patients with congenital heart disease and valvular defects often have poor general health, retarded physical growth, and increased susceptibility to infections, such as infective endocarditis, and are at a high risk of bleeding (if on anticoagulants). In general, patients with mild valvular dysfunction can tolerate dental procedures well, but patients with mitral regurgitation are particularly susceptible to exacerbation of pulmonary oedema and acute shortness of breath (Warburton and Caccamese, 2006).
Infective endocarditis
Infective endocarditis is a serious condition with an incidence of 1.6–6.2 per 100 000 patients (Prendergast, 2006) and high annual mortality, approaching 40% (Cabell et al., 2002). Various dental and orthodontic procedures predispose the patient to systemic bacteremia, which may lead to episodes of infective endocarditis in the presence of predisposing cardiac defects. Therefore, any patient prone to infective endocarditis should be considered for treatment only after consultation with the treating physician. Although the need for routine antibiotic prophylaxis against infective endocarditis in dental procedures remains controversial (Gould et al., 2006), the use of prophylactic antibiotics in high‐risk cases (Task Force on Infective Endocarditis, 2004) is still advisable for procedures likely to cause bacteremia. However, procedures that involve manipulation of gingival tissue or the periapical region of teeth or breach of the oral mucosa may require antibiotic prophylaxis. Some high‐risk procedures are placement of separators, orthodontic bands, suture removal, biopsies, and extractions (Vandersluis and Suri, 2020). If a patient develops symptoms of infective endocarditis during treatment, immediate referral to a cardiologist is advisable.
Coronary artery disease and hypertension
Patients with angina or uncontrolled hypertension will be poor orthodontic patients because they are prone to cardiovascular accidents and stroke. In addition, many of these patients take antiplatelet and anticoagulant drugs, making them prone to bleeding. It must be kept in mind that patients with a history of hypertension are prone to episodes of hypertensive emergencies leading to cardiovascular or cerebrovascular accidents (Marik and Varon, 2007) and that certain conditions, such as adrenal tumors, Grave’s disease, chronic renal disorders, and vascular disorders, are known to trigger hypertensive crises (Lip and Beevers, 2005). Hence, a complete medical evaluation and consultation with the patient’s cardiologist are imperative during diagnosis and treatment planning.
Diseases of the gastrointestinal tract
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