The management of the dilacerated impacted maxillary central incisor

Success vs failure

It has been widely reported that the success of the above techniques in treating a dilacerated, unerupted maxillary incisor depends on a number of factors. These include:

A tooth with an obtuse angle dilaceration, with incomplete root formation, a lower position and sufficient space in the arch will give a better prognosis for orthodontic traction.¹²

Both of the surgical techniques discussed above are not without their risks of failure. Failure could occur following traction of the dilacerated tooth due to:

All of these possibilities must be discussed in-depth with the patient as part of the consent process before treatment is undertaken.

Is it worth it?

Although orthodontic alignment of dilacerated maxillary central incisors may be successful, the long-term prognosis for the tooth may be poor and extraction and prosthetic replacement could well be part of the long-term treatment plan.¹⁴ With this being said, the question is often asked whether there is justification for carrying out orthodontic alignment in the first place?

Every clinical case is different and therefore should be measured on its own merits. However, it is important to take into account the following points when treatment planning:¹⁴

On reflection of the points above, orthodontic repositioning of the dilacerated tooth, even with poor prognosis, will serve to preserve the architecture of the alveolar ridge. This will ensure that, in the long-term treatment plan, there are more restorative options available to help yield an acceptable result.¹⁴

Orthodontic space closure

Using orthodontic space closure to manage a missing maxillary central incisor will result in the lateral incisor taking the place of the central incisor (including both the aesthetic and functional roles). The canine will subsequently assume the role of the lateral incisor and the first premolar that of the canine.¹⁶

Once orthodontically repositioned the affected teeth will need to be restoratively modified and camouflaged in order to suit their new identity both aesthetically and functionally.

This type of management will involve a multidisciplinary approach with the input of the restorative dentist and/or paediatric dentist.¹⁷ Orthodontic considerations will include:

On the other hand, restorative considerations will include:

As with any procedure, there are advantages and disadvantages to orthodontic repositioning, which must be discussed fully with the patient before beginning treatment. The main advantage in this case is the biocompatibility and permanence of the treatment. Repositioning of the lateral incisor into the central incisor space allows maintenance of the alveolar bone height and soft tissue profile during growth of the dentofacial complex.²¹ It also eliminates the need for temporary and permanent prosthetic tooth replacements prior to implant consideration, along with their associated maintenance.¹⁶

The disadvantages associated with this treatment approach include: the need for close multidisciplinary care, increased complexity of treatment, overall aesthetics, increased functional load on the lateral incisor root and a risk of relapse involving anterior space re-opening.¹⁶

Surgical removal and space maintenance/prosthetic replacement

In cases where orthodontic repositioning is contra-indicated and tooth autotransplantation not possible, the remaining treatment option may be surgical removal of the dilacerated tooth and space maintenance until the patient is suitable for prosthetic replacement.

Prosthetic replacement may be in the form of:

A tissue-borne form of replacement, such as a removable partial denture or an orthodontic retainer, is generally not well tolerated by young patients and may pose a risk to the health of the palatal and gingival soft tissues.¹⁴ For this reason, it is not usually the treatment option of choice in cases where it may be many years until definitive treatment is provided to fill the space (ie in young children awaiting completion of growth for implant provision), however, it may be an option for cases in which only short-term space maintenance is required.³¹

In the patient whose remaining anterior adult teeth have fully erupted and are favourable as abutments, resin-bonded bridges may be a suitable space maintainer.³² As bridges are not tissue-borne and are fixed, they eliminate complications such as compliance and risk of prolonged damage to the soft tissues. Resin-bonded bridges should also be considered as a good prosthetic replacement option for patients who are not suitable for implant placement due to the contra-indication of surgical procedures (eg if medically compromised or severely dental phobic).

Although there are many good indications to using resin-bonded bridges as space maintainers or final prosthetic replacements, it must be remembered that this kind of restoration may require preparation of an adjacent, healthy tooth for retention.¹⁴ Even with minimal/no preparation, the abutment tooth will consequently have a poorer long-term prognosis³³ and the likelihood of need for further restorations in the future is higher. Bridges will also not maintain alveolar bone height and so may have implications if implant placement is to be considered in the future.

Recently, the single-crown implant has become one of the most common treatment modalities for the replacement of missing teeth.³⁴ As well as having continued evidence of high success rates (94.5% success rate over 5 years³⁵), another advantage of implants as a prosthetic replacement is the fact that the surrounding teeth do not require preparation. This is of particular benefit in young patients, many of whom have unrestored dentitions³¹ and larger pulp horns vulnerable to any tooth preparation. However, as previously mentioned, implants cannot be placed until facial growth is complete and so careful treatment planning with multidisciplinary teams is paramount to ensure future success.

Case 1: Surgical exposure and orthodontic alignment

A 10-year-old boy presented with a missing upper central incisor. There was no relevant medical or dental history or history of trauma to the dentition. The upper right central incisor had erupted uneventfully at age 7 years and the patient's parent had become concerned about the missing upper left incisor (UL1).

On examination, the patient had a Class I incisor relationship (Figure 1) on skeletal 1 bases with average vertical proportions.

An OPG radiograph revealed the presence of the unerupted and dilacerated upper left central incisor. The tooth was in a reasonable position vertically for alignment. The patient was referred to the oral surgery department for exposure and placement of a gold chain (Figure 2 a–d). The post-op OPG radiograph shows the UL1 in a reasonable position for alignment and highlights the gold chain in position (Figure 3).

A sectional fixed appliance was placed (Figure 4) and the treatment progressed well with the UL1 being aligned into the correct position. The patient and parents were happy with the outcome and on subsequent reviews the UL1 maintained this good position (held by a fixed retainer) (Figure 5 a–e).

Case 2: Surgical removal and prosthetic replacement

A 13-year-old girl was referred to the orthodontic department regarding the unerupted upper left central incisor (UL1). The primary incisor had been retained for several years but eventually exfoliated leaving an unsightly gap that the patient was very self-conscious about.

Clinical and radiographic examination reveals a Class I malocclusion with Class I molar relationship bilaterally (Figure 6 a–e). There was spacing in the UL1 region with displaced UL2 and UL3. The OPG and lateral cephalogram radiograph (Figure 7a, b) indicate a dilacerated incisor in a very high position. The tooth was not deemed suitable to attempt alignment and a treatment plan was discussed to create the correct space in the UL1 region for prosthetic replacement. The patient was seen on the joint orthodontic-restorative clinic where a discussion was undertaken regarding eventual replacement. Although space would be created to facilitate an implant, the patient was happy with a resin-bonded bridge as a first line of treatment. Should this be unsuccessful long term, an implant may be considered. The orthodontic treatment plan required extraction of upper 1st premolars (UR4, UL4) and lower 2nd pre-molars (LR5, LL5).

A fixed appliance system was fitted in the upper and lower arches and a pontic was ligated to the wire (Figure 8 a–d), providing a number of benefits for both patient and clinician:

A peri-apical radiograph (Figure 9) was taken to assess the root position of the UR1 and UL2 to ensure adequate apical space was created should an implant be required in the future. It is important to ensure that patients are aware that an implant may not be a viable option if correct space is not created and this may increase the duration of the orthodontic treatment time. Treatment duration was 20 months before debond and placement of a Hawley type retainer with a pontic to replace UL1. The retainer was worn for 6 months to allow the tissues to settle before placement of a resin-bonded bridge. The patient was very happy with the outcome (Figure 10 a–e).