The orthodontic patient: examination and diagnosis

6 The orthodontic patient

examination and diagnosis

Successful orthodontic treatment begins with the correct diagnosis, which involves patient interview, examination and the collection of appropriate records. At the end of this process, the orthodontist should have assimilated a comprehensive database for each patient, from which the appropriate treatment plan can be formulated. Examination and record collection are discussed in this chapter, whilst treatment planning is the subject of Chapter 7.

Medical history

A number of medical conditions may impact upon the provision of orthodontic treatment:

Infective endocarditis

Infective endocarditis (IE) is a serious condition characterized by colonization or invasion of the heart valves or mural endocardium by a microbiological agent, following a transient entry into the bloodstream (bacteraemia). A number of factors can put a patient at high risk of developing an endocarditis:

A number of invasive medical procedures have been causally associated with bacteraemia and endocarditis in susceptible patients and these include dental treatment. The British Society for Antimicrobial Chemotherapy previously recommended the use of antibiotic prophylaxis for any form of dentogingival manipulation in high-risk patients. These recommendations have now changed in the UK.

The National Institute of Health and Clinical Excellence (NICE) now advise that antibiotics to prevent IE should not be given to adults and children with structural cardiac defects at risk of IE who are undergoing dental interventional procedures and this includes orthodontic treatment. According to NICE, current evidence suggests that such antibiotic prophylaxis is not cost effective and may lead to a greater number of deaths through fatal anaphylactic reactions than from not using preventive antibiotics.


A patient may present with a reported history of allergic reaction. Although many materials used in orthodontics are capable of inducing an allergic response, the most relevant are natural rubber latex and nickel.

Allergy to latex was first recognized in the 1970s and its occurrence has increased in recent years, particularly amongst healthcare workers following the universal adoption of wearing protective gloves. Latex allergy has been reported in orthodontic practice in relation to gloves and orthodontic elastics. The most common allergic response is a type IV delayed hypersensitivity reaction triggered by the chemical accelerators used in the manufacture of latex. This causes a localized contact dermatitis, typically associated with a pruritic eczematous rash. The IgE-mediated type I reaction is less common but has more serious consequences, including anaphylaxis. Amongst the general public, type I sensitivity has been estimated to occur in around 6% of the population (Ownby et al, 1996). Investigation is via skin prick testing or immunoassay. Patients with a confirmed type I allergy should be treated in a ‘latex-screened’ environment where potential exposure to any allergens is minimized. Synthetic gloves composed of vinyl or nitrile are available as an alternative to latex gloves, whilst the use of orthodontic elastomeric auxiliaries containing natural rubber latex should be avoided. Latex-free silicone elastics are available but show greater force decay and as such, require more frequent replacement.

Orthodontic wires and brackets contain nickel and nickel allergy is thought to be present in approximately 10% of Western populations and more common in females. It is usually a type IV allergic reaction related to the wearing of jewellery or watches and body piercing. Fortunately, oral reactions are rare, although prolonged exposure to nickel-containing oral appliances may increase sensitivity to nickel (Bass et al, 1993). Intraoral signs are nonspecific and have been reported to include erythema, soreness at the side of the tongue and severe gingivitis, despite good oral hygiene. Definitive diagnosis is usually achieved via patch testing. Stainless steel wires and brackets contain a relatively low proportion of nickel and are considered safe to use in a patient with diagnosed nickel allergy although titanium or cobalt chromium nickel-free brackets are available. In contrast, nickel titanium archwires have a much higher content, and should be avoided in these patients.

Extraoral examination

Assessment of the patient should begin with an examination of the facial features because orthodontic treatment can impact on the soft tissues of the face. Although a number of absolute measurements can be taken, a comprehensive facial assessment involves looking at the balance and harmony between component parts of the face and noting any areas of disharmony. Extraoral examination should start as the patient enters the room and it is important to look at the face and soft tissues both passively and in an animated state. Once in the dental chair, the patient should be asked to sit and the face examined from the front and in profile, in a position of natural head posture (Box 6.1).

Box 6.1 Natural head posture

Natural head posture (NHP) is the position that the patient naturally carries their head and is therefore the most relevant for assessing skeletal relationships and facial deformity. It is determined physiologically rather than anatomically and varies between individuals; however, it is relatively constant for each individual (Moorrees & Keane, 1958). As such, NHP should be used whenever possible to assess the orthodontic patient. The patient is asked to sit upright and look straight ahead to a point at eye level in the middle distance. This can be a point on the wall in front of them, or a mirror so that they look into their own eyes. Ideally NHP should also be used when taking a lateral skull radiograph, allowing the clinical examination to be related more accurately to the cephalometric data.

Frontal view

The frontal view of the face should be assessed vertically and transversely, with attention being paid to the presence of any asymmetry. In addition, the relationship of the lips within the face is examined in detail.

Vertical relationship

Vertically the face is split into thirds, with these dimensions being approximately equidistant. Any discrepancy in this rule of thirds will give an indication of disharmony within the facial proportions and where this lies. Of particular relevance is an increase or decrease in the lower face height. The lower third of the face can be further subdivided into thirds, with the upper lip falling into the upper third and the lower lip into the lower two-thirds (Fig. 6.2).

Incisor show at rest

In adolescents and young adults, 3 to 4-mm of the maxillary incisor should be displayed at rest (Fig. 6.4). In general, females tend to show more upper incisor than males, with the amount of incisor show reducing with age in both sexes. An increased incisor show is usually due to an increase in anterior maxillary dentoalveolar height or vertical maxillary excess. Occasionally it is due to a short upper lip. The average upper lip length is 22-mm in adult males and 20-mm in females.

Incisor show on smiling

Ideally 75 to 100% of the maxillary incisor should be shown when smiling (Fig. 6.4), but this also reduces with age. Some gingival display is acceptable, although excessive show or a ‘gummy smile’ is considered unattractive (Fig. 6.4).

Smile aesthetics is also an important component of orthodontic treatment planning and should be formally assessed (Box 6.2).

Box 6.2 Aesthetics of the smile

During examination of an orthodontic patient the soft tissues should be assessed in animation and not just at rest. A key component of this is the smile. Smiling is an important part of communication and an unattractive smile can be a considerable social handicap, often providing a reason to seek treatment. Creating a pleasing smile is therefore a fundamental aim in orthodontics. Three principle characteristics of the smile need to be assessed (Sarver, 2001):

Profile view

The facial profile should be assessed anteroposteriorly and vertically.

Intraoral examination

The intraoral examination is concerned primarily with the teeth in each dental arch, in both isolation and occlusion.

Dental arches

Each dental arch is assessed independently, with the mandible usually described first. The following features should be recorded for both arches:

Depth of the curve of Spee, which is described as normal, increased or decreased (Fig. 6.13). This will have a direct bearing on space requirements as an increased curve of Spee is a manifestation of crowding in the vertical plane and, as such, will require space to correct.

Static occlusion

When each dental arch has been assessed the patient is asked to occlude in intercuspal position (ICP) and the static occlusal relationship is recorded.

Orthodontic records

Clinical orthodontic records are used primarily for diagnosis, monitoring of growth and development, and are a medico-legal requirement. They provide an accurate representation of the patient prior to orthodontic treatment, demonstrate treatment progress and allow communication between orthodontists, other healthcare professionals and the patient. Records also play an important role in research and clinical audit. It is essential that accurate clinical records are taken before commencing orthodontic treatment.

Stay updated, free dental videos. Join our Telegram channel

Jan 1, 2015 | Posted by in Orthodontics | Comments Off on The orthodontic patient: examination and diagnosis

VIDEdental - Online dental courses

Get VIDEdental app for watching clinical videos