Rationale for Orthodontic Treatment PDF

# The Rationale for Orthodontic Treatment ## S. K. Barber ## Chapter contents - 1.1 Orthodontics - 1.2 Malocclusion - 1.3 Rationale for orthodontic treatment - 1.3.1 Need for orthodontic treatment - 1.3.2 Demand for orthodontic treatment - 1.4 Potential benefits to dental health - 1.4...

# The Rationale for Orthodontic Treatment ## S. K. Barber ## Chapter contents - 1.1 Orthodontics - 1.2 Malocclusion - 1.3 Rationale for orthodontic treatment - 1.3.1 Need for orthodontic treatment - 1.3.2 Demand for orthodontic treatment - 1.4 Potential benefits to dental health - 1.4.1 Localized periodontal problems - 1.4.2 Dental trauma - 1.4.3 Tooth impaction - 1.4.4 Caries - 1.4.5 Plaque-induced periodontal disease - 1.4.6 Temporomandibular joint dysfunction syndrome - 1.5 Potential benefits for oral health-related quality of life - 1.5.1 Appearance - 1.5.2 Masticatory function - 1.5.3 Speech - 1.5.4 Psychosocial well-being - 1.6 Potential risks of orthodontic treatment - 1.6.1 Root resorption - 1.6.2 Loss of periodontal support - 1.6.3 Demineralization - 1.6.4 Enamel damage - 1.6.5 Intra-oral soft tissue damage - 1.6.6 Pulpal injury - 1.6.7 Extra-oral damage - 1.6.8 Relapse - 1.6.9 Failure to achieve treatment objectives - 1.7 Discussing orthodontic treatment need ## Learning objectives for this chapter - Gain an understanding of the differences between need and demand for treatment. - Gain an appreciation of the benefits and risks of orthodontic treatment. - Gain an appreciation of the importance of discussing the risks and benefits of treatment with patients and their families. ## 1.1 Orthodontics Orthodontics is the branch of dentistry concerned with facial growth, development of the dentition and occlusion, and the diagnosis, interception, and treatment of occlusal anomalies. ## 1.2 Malocclusion 'Ideal occlusion' is the term given to a dentition where the teeth are in the optimum anatomical position, both within the mandibular and maxillary arches (intramaxillary) and between the arches when the teeth are in occlusion (intermaxillary). Malocclusion is the term used to describe dental anomalies and occlusal traits that represent a deviation from the ideal occlusion. In reality, it is rare to have a truly perfect occlusion and malocclusion is a spectrum, reflecting variation around the norm. | Age band | 12 years | 15 years | |-------------|---------|----------| | Children undergoing orthodontic treatment at the time of the survey | 9% | 18% | | Children not undergoing treatment, but in need of treatment | 37% | 20% | *Source data from Child Dental Health Survey 2013, England, Wales and Northern Ireland, 2015, Health and Social Care Information Centre.* ## 1.3 Rationale for orthodontic treatment Malocclusion may cause concerns related to dental health and/or oral-health-related quality of life issues arising from appearance, function, and the psychosocial impact of the teeth. The need for treatment depends on the impact of the malocclusion and whether treatment is likely to provide a demonstrable benefit to the patient. To judge treatment need, potential benefits of treatment are balanced against the risk of possible complications and side-effects in a risk-benefit analysis. ## 1.3.1 Need for orthodontic treatment Health and well-being benefits are the most appropriate determinant of treatment need. Orthodontic indices have been developed to help objective and systematic evaluation of the potential risk to dental health posed by the malocclusion and the possible benefits of orthodontic treatment (see Section 2.3). While indices were largely developed to measure treatment need, due to high treatment demand in many countries, indices are also used to manage demand and support prioritization through some form of rationing. For example, in the UK acceptance for NHS orthodontic treatment is predominantly based on need for treatment determined by the Index of Orthodontic Treatment Need (IOTN) (see Section 2.3.3). Similarly, in Sweden treatment priority is estimated using a Priority Index developed by the Swedish Orthodontic Board and the Medical Board, which aims to identify and treat the malocclusions judged to be most severe. ## 1.3.2 Demand for orthodontic treatment It can readily be appreciated that demand for treatment does not necessarily reflect objective treatment need. Some patients are very aware of minor deviations, such as mild rotations of the upper incisors, whilst others refuse treatment for malocclusions that are considered to be severe. ## 1.4 Potential benefits to dental health To determine whether orthodontic treatment is likely to carry a dental health benefit, it is necessary to consider first whether the malocclusion is likely to cause problems to dental health and secondly, whether orthodontic treatment is likely to address the problem. ## 1.4.1 Localized periodontal problems Certain occlusal anomalies may predispose individuals to periodontal problems, particularly where the gingival biotype is thin, and in these cases orthodontic intervention may have a long-term health benefit. These include: - Crowding where one or more teeth are pushed buccally or lingually out of the alveolar bony trough, resulting in reduced periodontal support and localized gingival recession. - Class III malocclusion where lower incisors in crossbite are pushed labially. - Traumatic overbites, which occur when teeth bite onto the gingiva, can lead to gingival inflammation and loss of periodontal support over time and this is accelerated by suboptimal plaque control. ## 1.4.2 Dental trauma There is evidence that increased overjet is associated with trauma to the upper incisors. Two systematic reviews have found that the risk of injury is more than doubled in individuals with an overjet greater than 3 mm and the risk of injury appears to increase with overjet size and lip incompetence. Surprisingly, overjet is a greater contributory factor in girls than boys despite traumatic injuries being more common in boys. Orthodontic intervention may be indicated where assessment and history indicate the young person is at increased risk of dental trauma (see Section 9.2.2). Mouthguards are also important in reducing the risk of dental trauma, particularly for those participating in contact sports (see Section 8.9). ## 1.4.3 Tooth impaction Tooth impaction occurs when normal tooth eruption is impeded by another tooth, bone, soft tissues, or other pathology. Supernumerary teeth can cause impaction and if judged to be impeding normal dental development, orthodontic input may be required (see Section 3.3.6). Ectopic teeth are teeth that have formed, or subsequently moved, into the wrong position; often ectopic teeth become impacted. Unerupted impacted teeth may cause localized pathology, most commonly resorption of adjacent roots or cystic change. This is most frequently seen in relation to ectopic maxillary canine teeth, which can resorb roots of the incisors and premolars. Orthodontic management of impacted teeth may be indicated to reduce the risk of pathology (see Section 14.8). ## 1.4.4 Caries Caries experience is directly influenced by oral hygiene, fluoride exposure, and diet; however, research has failed to demonstrate a significant association between malocclusion and caries. Caries reduction is therefore rarely an appropriate justification for orthodontic treatment and placement of orthodontic appliances in an individual with uncontrolled caries risk factors is likely to cause significant harm. In caries-susceptible children, for example those with special needs, malalignment may reduce the capacity for natural tooth cleansing and potentially increase the risk of caries. In these cases, an orthodontic opinion may be sought regarding methods for reducing food stagnation, such as extraction or simple alignment to alleviate localized crowding. ## 1.4.5 Plaque-induced periodontal disease The association between malocclusion and plaque-induced periodontal disease is weak, with research indicating that individual motivation has more impact than tooth alignment on effective tooth brushing. In people with consistently poor plaque control, inadequate oral hygiene is more critical than tooth malalignment in the propagation of periodontal disease. Although patients report increased dental awareness and positive habits around diet and oral hygiene patients following orthodontic treatment, poor plaque control is a contraindication for orthodontic treatment. It is essential that oral hygiene is satisfactory and any periodontal disease is controlled prior to considering orthodontic treatment to prevent worsening of dental health. ## 1.4.6 Temporomandibular joint dysfunction syndrome The aetiology and management of TMD has caused considerable controversy in all branches of dentistry. TMD comprises a group of related disorders with multifactorial aetiology including psychological, hormonal, genetic, traumatic, and occlusal factors. Research suggests that depression, stress, and sleep disorders are major factors in the aetiology of TMD and that parafunctional activity, for example bruxism, can contribute to muscle pain and spasm. Some authors maintain that minor occlusal imperfections can lead to abnormal paths of closure and/or bruxism, which then result in the development of TMD; however if this were the case, a much higher prevalence of TMD would be expected to reflect the level of malocclusion in the population. ## 1.5 Potential benefits for oral health-related quality of life The other key area where orthodontics may be beneficial is in improving oral health-related quality of life (OHRQOL). Research focussing on the effect of malocclusion suggests OHRQoL can be negatively affected by issues relating to dental appearance, masticatory function, speech, and psychosocial well-being. ## 1.5.1 Appearance Dissatisfaction with dental appearance is often the principal reason people seek orthodontic treatment and, in most cases, treatment is able to deliver a positive change. Although improved dental appearance may be cited as the main goal of treatment by patients, it is likely that the perceived benefit is not a change in appearance per se, but the anticipated psychosocial benefit associated with improved appearance. ## 1.5.2 Masticatory function Patients with significant inter-arch discrepancy including anterior open bites (AOB) and markedly increased or reverse overjet often report difficulty with eating, particularly when incising food (Fig. 1.3). This may manifest as avoidance of certain foods, such as sandwiches or apples, or embarrassment when eating in public. Patients with severe hypodontia may also experience problems with eating due to fewer teeth to bite on and concerns about dislodging mobile primary teeth and prosthetic teeth (see Chapter 21). Limited masticatory function rarely results in a complete inability to eat, but it can contribute to significant quality of life issues and this may be a driver for orthodontic treatment. ## 1.5.3 Speech Speech is a complex neuromuscular process involving respiration, phonation, articulation, and resonance. Articulation is the formation of different sounds through variable contact of the tongue with surrounding structures, including the palate, lips, alveolar ridge, and dentition. It is unlikely that orthodontic treatment will significantly change speech in most cases, as speech patterns are formed early in life before the permanent dentition is present and the teeth are only one component in the complex system. However, where patients cannot attain contact between the incisors anteriorly, this may contribute to the production of a lisp (interdental sigmatism). In these cases correcting the incisor relationship and reducing interdental spacing may reduce lisping and improve confidence to talk in public. ## 1.5.4 Psychosocial well-being Extensive research has been undertaken to examine the effect of malocclusion on psychosocial well-being in terms of self-perception, quality of life, and social interactions. Malocclusion has been linked to reduced self-confidence and self-esteem, with more severe malocclusion and dentofacial deformities causing higher levels of oral impacts. However, other research suggests visible malocclusion has no discernible negative effect on long-term social and psychological well-being. A possible explanation for this is that self-esteem is a mediator in the response to malocclusion, rather than a consequence of malocclusion. Furthermore, self-reported impact of malocclusion may not always reflect objective measurement of the severity of occlusal deviations; this has been attributed to an individual's resilience, ability to cope, as well as social and cultural factors. Dental appearance can evoke social judgements that affect peer relations and childhood emotional and social development. People with an attractive dentofacial appearance have been judged to be friendlier, more interesting and intelligent, more successful, and more socially competent. On the other hand, deviation from the norm can cause stigmatization and a high correlation has been found between victimization, malocclusion, and quality of life. The incidence of peer victimization in adolescent orthodontic patients with untreated malocclusion has been estimated to be around 12% in the UK. The extent of malocclusion may not be proportionate to the psychosocial impact, for example, more severe forms of facial deformity can elicit stronger reactions such as pity or revulsion, while milder malocclusions can lead to ridicule and teasing. ## 1.6 Potential risks of orthodontic treatment Like any other branch of medicine or dentistry, orthodontic treatment is not without potential risks. These risks need to be explained to patients during the decision-making process and where possible, steps taken to manage the risk. Patients should be made aware of their role in treatment and any self-care or behaviour required to achieve success, such as modifications to diet, oral hygiene practice, or use of a sports guard for participation in contact sports. | Problem | Avoidance/Management of risk | |-----------------------------|--------------------------------| | Intra-oral damage | | | Root resorption | - Avoid treatment in patients with resorbed, blunted, or pipette-shaped roots. - In teeth jugded to be at risk, roots should be monitored radiographically and treatment terminated if root resorption is evident. | | Loss of periodontal support | - Maintain high level of oral hygiene. - Avoid moving teeth out of alveolar bone. | | Demineralization | - Diet control, high level of oral hygiene, regular fluoride exposure. - Abandon treatment. | | Enamel damage | - Avoid potentially abrasive components e.g. ceramic brackets where there is a risk of occlusal contact. - Use of appropriate instruments and burs to remove appliances and adhesives.| | Soft tissue damage | - Avoid traumatic components. - Orthodontic wax or silicone to protect against ulceration. - Manage allergic reaction promptly. | | Loss of vitality | - If history of previous trauma to incisors, counsel patient. | | Extra-oral damage | | | Worsening facial profile | - Careful treatment planning and appropriate mechanics.| | Soft tissue damage | - Use of appropriate safety measures with headgear. - Manage allergy promptly. | | Ineffective treatment | | | Relapse | - Avoidance of unstable tooth positions at end of treatment. - Thorough assessment and accurate diagnosis. - Effective treatment planning. - Appropriate use of appliances and mechanics. | | Failure to achieve treatment objectives| | ## 1.6.1 Root resorption It is now accepted that some root resorption is inevitable as a consequence of tooth movement, but there are factors that increase the risk of more severe root resorption. # 1.6.2 Loss of periodontal support An increase in gingival inflammation is commonly seen following the placement of fixed appliances as a result of reduced access for cleaning and if oral hygiene is consistently poor, gingival hyperplasia may develop. ## 1.6.3 Demineralization Demineralized white lesions are an early, reversible stage in the development of dental caries, which occur when a cariogenic plaque accumulates in association with a high-sugar diet. If white spot lesions are not managed early and effectively they can cause permanent damage and even progress to frank caries. The presence of a fixed appliance predisposes to plaque accumulation, as tooth cleaning around the components of the appliance is more difficult. Demineralization during treatment with fixed appliances is a real risk, with a reported prevalence of between 2% and 96%. Although there is evidence to show that the lesions regress following removal of the appliance, patients may still be left with permanent 'scarring' of the enamel. ## 1.6.4 Enamel damage Enamel damage can occur as a result of trauma or wear from the orthodontic appliances. Band seaters, band removers, and bracket removal can cause fracture of enamel, or even whole cusps in heavily restored teeth. During removal of adhesives , the debonding burs can cause enamel damage, particularly if used in a high-speed handpiece. Certain components of orthodontic appliances can cause wear to opposing tooth enamel if there is heavily occlusal contact during function. This is a particular concern if ceramic brackets are used in the lower arch in cases with a deep overbite or where buccal crossbites are present. ## 1.6.5 Intra-oral soft tissue damage Ulceration can occur during treatment as a result of direct trauma from both fixed and removable appliances although it is more commonly seen in association with fixed components as an uncomfortable removable appliance is usually removed. Lesions generally heal within a few days without lasting effect. Intra-oral allergic reactions to orthodontic components are rare but have been reported in relation to nickel, latex, and acrylate. ## 1.6.6 Pulpal injury Excessive apical root movement can lead to a reduction in blood supply to the pulp and even pulpal death. Teeth which have undergone a previous episode of trauma appear to be particularly susceptible, probably because the pulpal tissues are already compromised. Any teeth that have previously suffered trauma or that are judged to be at risk of pulpal injury require thorough examination prior to orthodontic treatment, and any orthodontic treatment should be delivered with light force and careful monitoring. ## 1.6.7 Extra-oral damage Some authors have expressed concern over detrimental effects to the facial profile as a result of orthodontics, particularly retraction of anterior teeth in conjunction with extractions. While a number of studies have shown little difference in profile between extraction and non-extraction treatment, it is important that when treatment planning to correct malocclusion, the impact on overall facial appearance is considered. Contact dermatitis is reported in approximately 1% of the population and allergic reactions may be seen on facial skin in response to components of appliances, usually nickel. This may be managed by covering metal components with tape to prevent contact, or alternative treatment methods may be sought depending in the severity of the reaction. Recoil injury from the elastic components of headgear poses a rare but potentially severe risk of damage to the eyes. This is discussed in more detail in Chapter 15. Latrogenic skin damage, such as burns from acid etch or hot instruments, are avoidable using the usual precautions employed in other fields of dentistry. ## 1.6.8 Relapse Relapse is defined as the return of features of the original malocclusion following correction. Retention is a method to retain the teeth in their corrected position, and it is now accepted that without retention there is a significant risk the teeth will move. The extent of relapse is highly variable and difficult to predict but any undesirable tooth movement following orthodontic treatment will reduce the net benefit of orthodontic treatment. Relapse and retention are covered in detail in Chapter 16. ## 1.6.9 Failure to achieve treatment objectives When deciding whether orthodontic treatment is likely to be beneficial it is important to consider the effectiveness of appliance therapy in correcting the malocclusion. There are a number of operator- and patient-related factors that may prevent treatment achieving a worthwhile improvement. Errors in diagnosis, treatment planning, and delivery can lead to poor selection of appliances and ineffective treatment. It is essential to determine whether planned tooth movements are attainable within the constraints of the skeletal and growth patterns of the individual patient, as excessive tooth movement or failure to anticipate adverse growth changes will reduce the chances of success (Chapter 7). There is evidence that orthodontic treatment is more likely to achieve a pleasing and successful result if the operator has had some postgraduate training in orthodontics, as this supports appropriate appliance selection and use. - Patient co-operation is essential to achieve a successful outcome. Patients must attend appointments, look after their teeth and appliances, and comply with wear and care instructions. Patients are more likely to co-operate if they, and their family, fully understand the process and their role from the outset. This should be explicitly stated during the consent process. It is important to establish that the patient and family feel willing and able to adhere to the agreed treatment plan before commencing treatment. Long-term effectiveness of treatment depends on patients' commitment to life-long retainer wear and this must be stressed at the beginning of discussions about orthodontic treatment (see Chapter 16). ## 1.7 Discussing orthodontic treatment need It is important that patients and families are involved in the discussion about whether orthodontic treatment is needed and justified. Patients and their families have a *key role* in providing information about the impact of malocclusion, expectations from treatment, and their desired outcome. The clinician's role is to provide unbiased information about the potential risks and benefits of treatment based on best available evidence and their own clinical experience. General information should be tailored to the individual's clinical presentation and personal circumstances. Patients and families should be supported to participate in the decision about whether treatment is likely to provide sufficient benefit to outweigh any risks. Patients also have a vital role in determining whether they are likely to be able to comply with treatment adequately to achieve a satisfactory outcome. Treatment planning and consent are covered in more detail in Chapter 7. #### Key points - The decision whether to embark on orthodontic treatment is essentially a risk-benefit analysis. - The perceived benefits of orthodontic intervention should outweigh any potential risks associated with treatment. - Patients and families have an important role in determining whether treatment is likely to address issues caused by the malocclusion. ## Principal sources and further reading - American Journal of Orthodontics and Dentofacial Orthopedics, 1992, 101(1). - Davies, S. J., Gray, R. M. J., Sandler, P. J., and O'Brien, K. D. (2001). Orthodontics and occlusion. British Dental Journal, 191, 539-49.