Orthodontic Treatment of Impacted Teeth. Adrian Becker

tooth is adequate to bring about the desired eruption. However, the surgeon may not give consideration to the orthodontic aspect and will probably insist on removing most forms of pathology as soon as a tentative diagnosis is reached, in order to obtain examinable biopsy material for the establishment of a definitive diagnosis. Nevertheless, the entirely benign nature of odontomes and supernumerary teeth causes these obstructions to be considered exceptions to this rule and the timing of their removal may be considered in a more leisurely fashion.

Whose problem?

      Patients do not go to their dentist complaining of an impacted tooth. Indeed, they are frequently totally unaware that this abnormality exists. There is no pain, no discomfort and no swelling. The layperson would not see that there is a missing tooth, since the deciduous predecessor may not have shed naturally and no gap would be visible to the untrained eye. The vast majority of impacted teeth are discovered quite by chance, often in routine dental examination, and are not the result of a patient’s direct complaint. As a general rule, it is the paediatric dentist or the general dental practitioner who, during a routine dental examination, may discover and record the existence of an over‐retained deciduous tooth. A periapical radiograph will then confirm the diagnosis.

      In the present context, there are two situations where abnormality in appearance can motivate a patient to seek professional advice.

The first typically occurs when the patient is 8–10 years old. A single maxillary central incisor has erupted a year or so previously and the discerning parent notices that the erupting lateral incisor on the opposite side has not left enough space for the anticipated eruption of the second central incisor (Figure 1.8). The deciduous central incisor may be present over‐retained or it may have exfoliated. Although the parent has recognized the abnormality, he or she will not generally have the technical understanding to think of the possibility of impaction of the unerupted central incisor.

      The second situation will occur with a 14–15‐year‐old patient who has become worried by an unsightly carious lesion in an over‐retained maxillary deciduous canine. The patient will usually be unaware that this is not a permanent tooth. Appropriate professional advice will need to be given, explaining that the appropriate line of treatment is probably not restoration, but rather extraction and resolution of the impaction of the permanent canine.

      In either of these two situations, because of symptoms related to relatively rare complications of impacted teeth, some patients in this category will have initially been seen by their general dental practitioner. The symptoms that may lead to this path are, inter alia, mobility or migration of adjacent teeth (due to extensive root resorption), painless bony expansion (dentigerous or radicular cyst) or perhaps pain and/or discharge caused by a non‐vital over‐retained deciduous tooth or an infected cyst, with communication to the oral cavity [14].

Fig. 1.8 Space loss in a 10‐year‐old child, due to an impacted maxillary right central incisor.

Initially, it will be necessary to ascertain whether there is a good chance that resolution will be spontaneous once the aetiological factor has been removed or whether active appliance therapy may be indicated. In order to do this, it is important to accurately and visually assess the exact position, long‐axis angulation and rotational status of the tooth and make an assessment of space in the arch. Having done so, the paediatric dentist or general dental practitioner will now have to decide who should treat the problem.

      Many dentists, believing that surgery will be required, will prefer not to accept responsibility for this type of situation and will refer the patient to an oral and maxillofacial surgeon. The surgeon may opine that the problem is essentially surgical in nature and will proceed to remove the over‐retained deciduous teeth, clear away other possible aetiological factors, such as supernumerary teeth, odontomes, cysts and tumours, and also expose the impacted permanent tooth. If the impacted tooth is buccally located, the surgical flap may be apically repositioned to prevent primary closure and to maintain subsequent visual contact with the impacted tooth after healing has taken place. In many cases, this will have the effect of encouraging eruption. For the few weeks following, until healing (by ‘secondary intention’) has occurred, the wound will usually be packed with a proprietary zinc oxide/eugenol‐based periodontal pack (e.g. CoePack®) or a gauze strip impregnated with Whitehead’s varnish. The surgeon uses careful placement and wedging of the pack between an impacted tooth and its neighbour in order to help free the tooth and allow it to erupt naturally when the pack is removed.

      In the more difficult impactions, wider surgical exposure may be undertaken, which would involve fairly radical bone resection, both around the crown and down to the cemento‐enamel junction, with complete removal of the dental follicle. The principal aims of this procedure are to clear away all possible impediments to eruption and to ensure that subsequent healing of the soft tissues does not cover the tooth again.

      Thereafter, for a period of several months or even years (for some of the more awkwardly positioned teeth), the surgeon, family dentist or children’s dentist will usually follow up the spontaneous eruption of the impacted tooth until it reaches the occlusal level. Only then, if alignment is poor or the tooth still has not erupted, will the patient probably be referred to the orthodontist.

      What is quite clear is that the patient should have been referred to the orthodontist directly in the first place. Although the orthodontist cannot directly influence the position of the impacted tooth until after the appropriate access has been provided surgically and until an attachment has been placed on the tooth, nevertheless, with proper planning and management, including referral for surgical exposure at the appropriate stage in the treatment, a much higher qualitative level of care would be provided and in a very much shorter time‐frame.

      This will be discussed in the ensuing chapters of this book.

The timing of the surgical intervention

      From this discussion, it is clear that the timing and nature of the surgical procedure are determined at the time of the initial diagnosis, by the degree of development of the teeth concerned.

      The first scenario occurs at an early stage, when a radiographic survey of a very young child may reveal pathology, such as a supernumerary tooth, an odontome, a cyst or a benign tumour, which appears likely to prevent the normal and spontaneous eruption of a neighbouring tooth. In such a case, it would be inappropriate to expose the crown of an immature tooth. One would not want to encourage the tooth to erupt before an adequate (half to two‐thirds) root length has been produced. Secondly, at that early stage of its development, the tooth cannot yet be considered to be impacted. Given time and freedom to manoeuvre, the tooth will probably erupt by itself.

Early exposure risks the possibility of damage to the crown and to the subsequent root development of the tooth. On the other hand, however, it would not be wise to ignore the situation after the discovery of the pathological condition (Figure 1.9). The potential for impaction has been revealed and leaving the condition untreated may worsen the prognosis. Accordingly, the appropriate treatment at this stage might be the removal of the pathological entity, without disturbing the adjacent permanent teeth or their follicular crypts. It may then reasonably be expected that normal development and eruption will occur in due course. However, while this is clearly the desirable course of action, access to the targeted area may be impeded by the proximity of adjacent developing structures, so that delay may still be advisable. A competent oral and maxillofacial surgeon should be consulted.

The second scenario occurs when the discovery of the pathological condition is only made when the patient is much older. In this case (Figure