The removal of a primary tooth anterior abutment root to salvage a fixed prosthesis

Case presentation

A 52-year-old woman patient was presented with a chief complaint of pain and swelling in the mandibular left anterior region. Clinical examination revealed a mandibular anterior fixed prosthesis extending from LR3 to LL3. An intra-oral apical swelling with a sinus opening and a deep periodontal pocket extending to the apical region of LR2 was noted (Figure 1). Radiographic examination showed that LR2 and LR3 served as non-endodontically treated primary and secondary abutments, respectively, on the right side of the prosthesis. However, LR2 showed severe periodontal bone loss with a periapical radiolucency (Figure 2). The sinus was traced and a radiograph confirmed its origin from LR2. Radiographic appearance in LR2 also resembled changes indicative of either an anatomical variation or vertical root fracture in the tooth. Removal of LR2 was suggested due to the poor periodontal prognosis, but it required the removal of the prosthesis. The patient did not wish the removal of the prosthesis to take place as she was averse to the risks involved in terms of damage to the abutments and the prosthesis itself during the removal. However, since LR3 as a secondary abutment and LL3 as a primary abutment were stable on the right and left sides of the prosthesis, respectively, sectioning and removal of LR2 root was suggested as an alternative solution to eliminate the source of infection, though LR2 was a primary abutment. This was suggested to avoid the removal of the prosthesis and salvage the prosthesis to continue its functioning in the existing condition. The patient was in agreement.

Root removal in LR2 was performed under local anaesthesia following the elevation of an envelope flap using only a horizontal intrasulcular incision extending from LR3 to midline across the labial crest of the ridge beneath the pontic of the prosthesis (Figure 3). Root sectioning in LR2 was initiated by making a horizontal cut across the cervical third of the exposed root from the labial side. The cut was made at the expense of the root portion which had to be removed in order to avoid damage to the crown margin. Once the complete sectioning was confirmed, the root was luxated labially using an angled elevator. Interestingly, the removed root displayed a rare anatomical variation in the form of an apical third bifurcation with two separate roots (Figure 4). The crown portion was left behind inside the prosthesis to act as a pontic and its undersurface was restored with glass ionomer cement (GC Gold Label 2; GC Corporation, Japan) to close its pulp chamber opening and obtain retrograde seal of its undersurface. Following smoothening of the restored undersurface, the flap was repositioned and sutured. One year follow-up showed satisfactory healing with the fixed prosthesis being intact and functional with LR3 as a primary abutment on the right side of the prosthesis and the patient was asymptomatic without any significant radiographic changes (Figure 5). The patient was advised to undergo a course of generalized periodontal therapy to manage pathologic migration observed in UL1, amongst other problems.

Discussion

Root removal in a failing multi-rooted molar abutment to salvage a fixed prosthesis is possible even if the abutment is a primary or a terminal abutment next to the edentulous space. However, root removal is not advisable in a failing single-rooted primary or terminal anterior abutment as it can lead to a cantilever type fixed prosthesis situation and risk of prosthesis failure by affecting the support of the prosthesis. Therefore, root removal and leaving the crown portion of an anterior abutment as a pontic to salvage a prosthesis is a possible treatment choice for a failing pier or an additional abutment in the presence of intact primary anterior abutments or sufficient number of remaining abutments.2^,3

Conclusion

Root removal can be a valuable treatment modality to address a failing primary anterior abutment under a fixed prosthesis. However, this requires the presence of a stronger additional or secondary abutment behind it. In the above circumstances, this treatment can avoid removal of the fixed prosthesis to address the failing abutment and help to salvage the prosthesis. However, the serviceability of a thus salvaged prosthesis depends on careful case selection and the patient must be advised that there are no studies indicating the success of this treatment.