External Cervical Invasive Resorption (ECIR) (alternatively described as “Invasive Cervical Resorption”) is a relatively uncommon form of resorptive process, which can be difficult to diagnose and manage. ECIR usually occurs immediately below the epithelial attachment of the tooth at the cervical region. This form of resorption has been described at length by Prof. Geoff Heithersay (1999), who had classified the resorption into its various stages based on the degree of invasion into the crown and root of the tooth.
ECIR defects can be difﬁcult to diagnose early and to manage. The pulp tissue plays no role in the etiology of ECIR and is limited from the resorptive process by the thin predentine layer surrounding the pulpal space. Pulpal symptoms often only develop during later stages of the resorption when the resorptive defect has undermined the tooth internally and communicates with gingival margin coronally, leading to a secondary bacterial challenge. As a result, such resorptions may progress undiagnosed until very late stages of the process, which may render the tooth unsalvageable or difficult to manage (see clinical case below):
- 26 year-old patient was referred for endodontic assessment of tooth 26 which was found to have extensive ECIR undermining the tooth and extending into the root upto about mid-root level. The resorption was picked up as an incidental finding during radiographic examination with the pulp noted to be vital at this time. Tooth 26 was found to have a poor prognosis due to the undermining and apical progression of the resorption which had extended into the furcal region. A CBCT of the tooth was taken which revealed the presence of an early resorptive defect on adjacent tooth 24 (25 missing; past history of orthodontic treatment) which was otherwise not visible clinically, but may be amenable to conservative treatment. These findings are significant and influence future restorative/prosthetic treatment planning. The CBCT was particularly useful in diagnosing and assessing the extent of the resorption involving both 24 and 26.
The following case describes a case of ECIR involving tooth 23 which was managed with endodontic treatment and resorption repair:
A 36 year-old patient presented with irreversible pulpitis symptoms from tooth 23 which was found to be resulting from a large palatal cervical invasive root resorption defect which was encroaching on the pulp chamber. I took a CBCT of the region which showed the true extent of the resorption, which was found to be at crestal level but was unilocular and had not extended subcrestally at this stage (Grade II-III)
Considering the palatal position of the resorption and the strategic importance of tooth 23, the patient was keen to try to retain tooth 23 for as long as possible with endodontic treatment and management of the resorption defect, understanding the associated long-term prognosis of the tooth.
I subsequently carried out treatment with the deep palatal resorption accessed and treated with tricholoroacetic acid (TCA). The resorption was found to have involved the pulp space which was found to still be vital. Endodontic treatment was carried out considering the patient’s symptoms of pulpitis and the pulpal exposure. The canal system was accessed, instrumented, disinfected and obturated with GP/AHPlus. The access was restored with a polycarboxylate base and GIC initially and I subsequently saw the patient two weeks later for a definitive composite resin restoration once the marginal tissues had healed sufficiently.
- Clinical images of palatal aspect of tooth 23 during management: (a) following removal of resorption and treatment with TCA – pulp exposure noted; (b) following obturation and sealing orifice with polycarboxylate base; (c) following restoration with GIC; (d) 2 week review following restoration with composite resin.
The patient was reviewed six months following his initial management with excellent healing noted of the marginal gingival tissues with normal periapical contours noted radiographically.
While this is a favourable outcome to date, the prognosis for the tooth is still guarded but I am hopeful that the tooth may be retained for some years. In clinical practice, I have noticed that the unilocular resorptions which appear to have a single entry point have less of a likelihood of recurrence as opposed to the ECIR defects with multiple cervical entry points, which can be difficult to remove entirely and seal adequately and therefore have a greater chance of recurrence. 3-D CBCT scans are particularly useful in assessing the true extent of the resorption and entry points prior to considering management. The occlusion in this case was reviewed and the canine is labially positioned and is not in canine guidance, which will facilitate retention, especially considering the weak cervical tooth structure. It is important in such cases that the patient is made aware of the long-term prognosis and possible future treatment, the need to maintain good oral hygiene around the deep restorative margins and the need for regular clinical and radiographic reviews.
Dr. Vijay John