Adult orthodontics

12 Adult orthodontics

An increasing number of adults are undergoing orthodontic treatment and this is a global trend. Adult dental health has improved significantly over the past few decades in the UK, with more teeth being retained for longer in this population. This has been accompanied by an increasing preoccupation with personal appearance and in particular, the importance of an attractive smile. As a result of the media and increasing use of the Internet, adults are more aware of the aesthetic improvements that can be achieved with orthodontic treatment and it has become more socially acceptable for them to wear fixed orthodontic appliances. Improvements in socioeconomic status and personal wealth have meant that the finances are increasingly available for them to seek out and embark on such treatment.

Why do adults undertake orthodontic treatment?

An adult may be motivated primarily by a desire to improve their dental appearance and may request orthodontic treatment. Amongst this group will be those who either refused or were not given the opportunity of treatment during their childhood, and those who may have received treatment but have been left dissatisfied with the result, often because of subsequent relapse or an inappropriate original treatment plan (Fig. 12.1). Routine orthodontics can be readily carried out in these patients, but the scope of increasingly complex treatment can be more limited in comparison to that which might be achieved in a growing child or adolescent. Moreover, adults can also present with other age-related problems that must be considered when providing orthodontic treatment (Box 12.1).

Box 12.1 Special problems associated with orthodontic treatment in adults

A number of features associated with adult patients can make orthodontic treatment more challenging and these all need to be taken into consideration when planning and embarking upon treatment (Nattrass & Sandy, 1995).

Periodontal Tissues

The prevalence of periodontal disease and loss of attachment increases with age, becoming more common in adults. An adult patient should undergo a complete clinical and radiographic assessment of their periodontal status before embarking on orthodontic treatment (Johal & Ide, 1999). Previous attachment loss does not preclude orthodontics, but active periodontal disease will require treatment and evidence of stabilization before any appliances are placed (Table 12.1). An excellent standard of plaque control should be attained and then maintained throughout treatment, if necessary with professional supra- and subgingival scaling. Teeth with previous attachment loss and reduced bony support will also respond differently to orthodontic force:

The centre of resistance moves apically (see Fig. 5.4) and tipping occurs more readily than bodily movement; and

Increasing age is associated with a reduction in vascularization and collagen turnover within the periodontium, with an overall reduction in bone volume. Initial tooth movement can be slower in adults and light forces should be used to avoid the risk of root resorption.

Alternatively, orthodontic treatment may not be sought directly by an adult, but prescribed as one component of a specific treatment plan:

Orthodontics as an adjunct to restorative treatment

Adults can often present with an incomplete dentition, permanent teeth having been lost prematurely as a result of caries, periodontal disease or trauma. This can lead to alterations in position of the remaining teeth due to drifting, tipping, rotation or overeruption (Fig. 12.2). Whilst there are obvious negative aesthetic consequences associated with tooth loss and alterations in the position of adjacent teeth, occlusal instability and functional problems can also occur and contribute to:

In the oral rehabilitation of adult patients affected by tooth loss, orthodontic treatment may be required as part of their multidisciplinary management in a variety of situations:

In many cases, adjunctive orthodontic treatment of this kind will not attempt definitive correction of a malocclusion; rather it will be restricted to moving only those teeth required for the specific treatment plan.

Orthodontics and orthognathic surgery

A malocclusion associated with any significant discrepancy in the dentofacial skeleton of an adult requires a combination of orthodontics and surgical repositioning of the jaws for definitive correction (Fig. 12.5). These skeletal problems can include:

Orthodontic camouflage may be possible in some cases, but this approach can be a compromise and limited by the extent of the skeletal discrepancy. Growth modification is not possible in an adult, but many of these malocclusions would be amenable to attempts at treatment with a functional appliance if diagnosed in a growing child or adolescent. However, it should be remembered that these more severe forms of skeletal discrepancy are the ones least likely to respond to attempts at growth modification and often end up requiring a surgical approach.

Orthognathic surgery can involve a range of surgical movements, which achieve repositioning of the maxilla or mandible within the facial skeleton (Fig. 12.6). Surgery of this kind does not affect any inherent growth capacity that may reside in the jaws and for this reason it is only carried out once skeletal growth has ceased, in the adult. This is particularly important for class III cases with mandibular excess, where continued forward growth of the mandible after backward surgical repositioning can lead to the reappearance of a reverse overjet if the surgery is carried out before growth has ceased.

Presurgical orthodontic treatment

There are two principle aims of presurgical orthodontic treatment:

These aims are achieved within a number of overlapping phases, primarily during presurgical treatment through orthodontic tooth movement, although occasionally some surgical intervention may also be required, particularly for expansion (Box 12.2) or levelling of the maxillary arch. Surgically-assisted expansion is carried out before the definitive osteotomy, whilst surgically-assisted levelling usually takes place with it (Table 12.2). Some controversy exists regarding the amount of orthodontic treatment that should be completed prior to surgery (Box. 12.3), but conventional planning requires full decompensation.

Table 12.2 Phases of orthodontic treatment for orthognathic patients

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Jan 1, 2015 | Posted by in Orthodontics | Comments Off on Adult orthodontics

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