EICR (External Invasive Cervical Resorption)
Jon Richards DDS MS
Tooth resorption is one of those evasive, nebulous, poorly-understood processes that can cause a lot of frustration and confusion amongst both patients and providers. This particular case is one that required a significant amount of planning to address its condition.
EICR (External Invasice Cervical Resorption) typically presents as a non-painful radiographic finding. It is most often discovered late in the process, which is unfortunate because EICR tends to be a progressive, destructive process. By our best understanding, EICR results when resorptive cells from the periodontal ligament “go rogue” and chew up the dentin, progressing towards the pulp.
It can happen on any tooth, and most often occurs within the attachment of the gingival fibers or at the level of the osseous crest. From what I understand, there is not a bacterial component, and the resorptive defect will never truly invade the pulp space (for reasons I can futher expound on if anyone really is interested). For this reason, and because the affected area is covered by the gingival tissue, the patient is most often asymptomatic but may feel occasional “it-doesn’t-feel-quite-right” sensation in the area. If the condition remains undetected, the resorption will often progress apically and pulpally, until such a significant amount of dentin is involved and the tooth will be lost. Patients that have had EICR, are more likely than others to have it in other areas. There have been studies suggesting an association of EICR with previous orthodontic therapy and trauma, but it should be emphasized that this is speculation and not a cause-and-effect accepted link.
Treatment of EICR is dependant on the processes’ progression. In very early stages, the affected dentin can be removed and restored, often requiring simple reflection of the gingival tissue for access. One big problem with EICR, however, is its tendency to reoccur. It is suspected that if not removed completely, the same cells causing the resorption will persist and continue to invade dentin. Treatment protocol should include TCA (trichloroacetic acid) after removal of the defect from either an internal or external approach. Multiple applications are most often necessary, alternating with Ca(OH)2 applications between appointments.
In this particular case, the patient was evaluated multiple times due to a complaint of vague, painful, poorly localized sensation in the palatal region of tooth #3. Examination could not reproduce her symptoms, and periapical and bitewing radiographs did not provide enough evidence to recommend any treatment. After 6 months of unsuccessfully identifying the source, a CBCT scan was taken and revealed fairly advanced EICR on the mesio-palatal aspect of tooth #3.
An internal and external approach was utilized. First, endodontic therapy was initiated and 4 canals were cleaned and medicated with Ca(OH)2. Next, the resorptive defect was removed intrenally through the occlusal access cavity, and TCA gel was applied for several minutes, followed by replacement of the Ca(OH)2. This was repeated 3 times until there was no longer an abnormal appearance or tactile feel to the dentin. Her symptoms never completely resolved up to this point. The P canal was obturated and backfilled with glass ionomer material, but the B canals remained in Ca(OH)2. Next, a gingival flap was reflected and a Class V-like cavity preparation removed the external entry point of the EICR. The GI that was place prior protected the canal/chamber space from contamination. The prepared cavity was restored with amalgam. As a side comment, RMGI is often used for the restoration here, but I do expect eventual recession and exposure of the material, so I elected to use amalgam for wear resitance and longevity. After the external repair, the soft tissue was sutured, with the sutures being removed 3 days later. Finally, the symptoms resolved, and the remaining 3 canals were obturated, and the access cavit restored with a bonded amalgam restoration.
Overall, 4 appointments and a lot of patience for it to be addressed. As with any case, success will be determined at subsequent recall examinations. In the short term, it appears to have improved the patient’s situation. Hopefully this treatment will last a very long time.