Dental management of a patient with multiple idiopathic cervical root resorption

Clinical report

A 12-year-old patient started fixed orthodontic treatment in 2002 (Figure 1). Two years later she was referred to the Leeds Dental Institute (by her orthodontist) just before her maxillary and mandibular fixed appliances were due to be removed. A dental panoramic tomogram (DPT) revealed that LL3, LL4, LL5, LL6, UL6, UR3, UR4, UR5 and UR6 had evidence of cervical resorption (Figure 2).

Clinically, in 2004, the patient's plaque control was very good with minimal bleeding on probing. There was no periodontal pocketing associated with any tooth in the patient's dentition or any obvious pathology (Figure 3a and b). At consultation, the patient's family enquired whether the condition was related to the fixed appliance orthodontic treatment. It is possible for apical resorption to affect teeth undergoing orthodontic tooth movement (due to excessive torquing forces).¹⁵ However, it is unlikely that the multiple cervical lesions in this patient were due to orthodontic treatment as MICRR has been known also to affect unerupted permanent teeth.¹ Therefore, exposure to the oral cavity and some form of environmental insult/trauma does not appear to be a pre-requisite for the condition.

The crowns of the LL3, LL4, LL5 and LL6 spontaneously decoronated but the roots were left in situ to preserve bone. The remaining resorptive lesions were accessed surgically, granulation tissue was removed and the defects were restored with glass-ionomer cement by the paediatric dentistry team.

Over the next 2 years, resorptive defects occurred (and re-occurred) on the UR2, UR3, UR4, UR5, UR6, UL2, UL3, UL4, UL5 and LL2 teeth. On multiple occasions, buccal flaps were raised, the resorptive defects curetted and any granulation tissue/coronal tooth structure was sent for further investigation. The UL4, LL3 and UR4 were unrestorable and required extraction. The UR2, UR3, UR5, UR6, UL2, UL3, UL5 and LL2 teeth all required root canal therapy (RCT) as the resorptive defects extended into pulp. The lesions were again restored with GC Fuji IX GP® glass ionomer cement (GIC) by the paediatric dentistry team (Figure 4).

Histological examination of the granulation tissue revealed that the lesions contained multi-nucleated giant cells, which were consistent with tooth tissue resorption, as well as an associated proliferation of fibrous gingival connective tissue.

In 2006, the patient was 16 years old. It was felt that surgical curettage/repair and RCT of the affected teeth was futile as the lesions were progressive and tended to re-occur. All of the root-treated and surgically repaired teeth shown in Figure 4 started to show clinical and radiographic signs of cervical root resorption. Any further treatment provided in a similar vein would only serve as a short term measure. After joint discussion between consultants in oral/maxillofacial surgery, paediatric and restorative dentistry, it was decided to plan for an implant-based reconstruction.

The heavily restored, root treated UR6, UR5, UR3, UR2, UL2, UL3, UL5 and LL2 teeth, in addition to the LL4, LL5 and LL6 roots, were planned for extraction. A diagnostic wax-up suggested that a functional and aesthetic result could be achieved if the patient was provided with a 4-unit implant-supported bridge in the maxillary left, maxillary right and mandibular left quadrants.

The aforementioned UR6, UR5, UR3, UR2, UL2, UL3, UL5, LL2, LL4, LL5 and LL6 were removed. Radiographs suggested that insufficient bone volume was present in the maxillary left and mandibular left quadrants to allow implant placement. In 2007, the UL2, UL3 and LR2, LR3 regions were augmented with autogenous bone harvested from the patient's chin.

Three 3.3 mm diameter x 13 mm length Brånemark (Nobel Biocare UK Ltd, Uxbridge) implant fixtures were placed in the maxillary left quadrant and three more were placed in the maxillary right quadrant. Three 3.5 mm diameter x 13 mm length Astra implant fixtures (Dentsply, Weybridge, UK) were placed in the lower left mandibular quadrant. The implant system changed as a different clinician took over the patient's restorative care.

The implants were exposed and subsequently restored with 3 sets of 4 unit cement-retained metal ceramic bridges (Figure 5). The patient was satisfied with the treatment she had received at one year review.

Discussion

Given that the MICRR has been known to cluster in families,⁶ the patient's parents were made aware of this and advised that their other children should attend regular dental appointments for appropriate radiographic examination. Although there are no specific guidelines on which radiographs should be taken, the authors recommend that, as a minimum, patients should have bitewing radiographs taken (in line with their caries risk). This will allow clinicians to evaluate the CEJs of the posterior teeth clearly. However, the bitewing radiographs may have to be supplemented with periapical radiographs of the anterior teeth (if they too are to be evaluated). In this patient, the lesions were identified with tomographic radiographs. Cone Beam Computerized Tomography (CBCT) scanning may have been a better imaging modality to use. Yu et al¹ identified early lesions on CBCT scans that were not visible on the plain film images. Furthermore, the resorptive defects were often more extensive than the radiographs would suggest. They also reported that an interesting feature of the condition was that alveolar bone would grow into the root defects, and increase the height of the alveolus. Given that this would promote retention of bone, provision of implant-retained restorations (without grafting) may be possible for some of these patients. It is unknown whether sites of active resorption will have an adverse effect on long-term osseointegration¹⁶ and therefore implant retention and success.

Case reports have suggested that the resorptive process can be arrested with bisphosphonate medication.¹³ However, this may complicate the provision of implants in the future. Yu et al¹ suggested a more practical protocol to manage these patients. Lesions that have been detected early can be surgically exposed and restored with glass ionomer cement. This can maintain teeth for many years. However, the condition is progressive. Providing root treatments, surgical curettage and restoration of resorptive defects only appears to play a palliative (but important) role in the management of these patients. If the defects are sub-crestal, consideration should be given to restoring the lesions with a bioactive material, such as mineral trioxide aggregate (MTA) (Dentsply, York, PA, USA) or Biodentine (Septodent, Maidstone, Kent, UK). If a lesion is supra-crestal and in the aesthetic region, composite resin should be used to restore the defect (if moisture control permits). If affected teeth can be retained with these local measures until the patient's growth is complete, alveolar bone levels will be maintained.

As resorption continues to affect larger numbers of teeth, extraction and subsequent prosthodontic rehabilitation should be planned for. In the interim phase, this may take the form of a partial denture. In the long term, the patient may need to be rehabilitated with fixed bridge work. If conventional or resin-bonded bridges are prescribed, the abutment teeth need to be carefully examined to ensure that they are free of resorptive defects. However, the patient must be warned that the abutment teeth may also develop lesions in the future and that the bridges will need regular review. Alternatively, implant-retained crowns and bridges can be provided. Such restorations appear to have a survival rate of 95% over a 5-year period.¹⁷ Although implant-retained restorations have a high survival rate, it must still be remembered that a relatively high proportion can develop complications after a period of 5 years, including fracture of the veneering porcelain (14%) and loosening or even fracture of the retaining screws (7%).¹⁷ Even if the definitive dental rehabilitation is to be implant-based, the clinician must remember that further teeth may still be lost in the future. Therefore, one must ensure that design features are incorporated to allow for the addition of further teeth. Perhaps if implant-retained bridges are provided for such patients, screw-retained frameworks should be used. This would certainly allow for easy removal, modification and even replacement should further teeth require removal. If, however, all of the teeth are extensively affected by the resorptive process, a clearance and provision of complete dentures/implant-retained overdentures may be necessary.

MICRR is not an endodontic problem. Therefore, patients should not be provided with unnecessary root fillings. They require referral to a secondary care unit for appropriate treatment planning. Furthermore, their family members should be advised to have their own dentitions assessed and monitored as the condition can cluster in families.⁶ MICRR is also not caused by orthodontic treatment. It is possible for apical resorption to affect teeth undergoing orthodontic tooth movement.¹⁵ However, MICRR is not caused or propagated by orthodontic treatment as the condition can be seen in unerupted permanent teeth,¹ as well as in patients with no history of orthodontic treatment.⁴ Therefore, exposure to the oral cavity and some form of environmental stimulus does not appear to be a pre-requisite for the condition.

The restorative, paediatric and surgical dentist have very important roles to play in this multidisciplinary management with regard to treatment planning. They need to be involved early in the decision-making process. Issues regarding the prognosis of compromised teeth and methods of replacement (in both the short and long term) need to be discussed at the outset. These patients will clearly require multiple dental visits and interventions to manage their resorptive defects. Given the progressive nature of the condition, patients should be made aware of this at the beginning of their management. They should also be advised that any teeth which have not been removed will require life-long review, to ensure that they have not developed any new lesions. Although the dental management of MICRR is technically challenging and time consuming, these patients can be managed successfully using a carefully planned multidisciplinary approach.