Intentional Replantation: Does It Work?
A technique to consider in rare cases when conventional surgery is impossible
Conventional and surgical endodontic therapy are established as predictable clinical procedures that save teeth with pulpal disease.1,2 Such teeth would otherwise be extracted. When a tooth's pulp is irreversibly injured or infected subsequent to caries, cracks, trauma, or leaky restorations, endodontic therapy or extraction are the only viable options. While conventional endodontic therapy has been shown to have an excellent survival rate (97% over an 8-year period),3 this initial procedure can occasionally fail to address the entire source of infection, resulting in persistence of periapical symptoms.
When symptoms are not resolved after conventional root canal therapy and the cause is determined to be periapical and of microbial origin, surgical endodontic approaches through microsurgical apicoectomy and retrofilling have been shown to offer a last chance to save the tooth. Fortunately, the outcome of these microsurgical procedures has improved dramatically over the past 2 decades. This is largely due to advances in material science and surgical armamentarium, as well as improved diagnosis and triage of failed conventional therapy. As a result, higher success rates can be expected from these surgical procedures.2,3
However, in a small segment of failed root canal cases, when conventional surgical access to the apex for an apicoectomy is not possible, an alternative option called intentional replantation may still save some teeth. Intentional replantation is a procedure by which the tooth is gently extracted, the apicoectomy and retrofilling procedure are performed extraorally, and the tooth is replanted in the alveolar socket. The two most important factors for successful intentional replantation procedures are short extraoral time (less than 10 minutes) and atraumatic extraction. When strict adherence to protocol is combined with the proper case selection, a high success rate can be expected from this procedure.
Whenever surgical access for apicoectomy is not possible (anatomical challenges), the options of intentional replantation or final extraction should be presented to the patient. Intentional replantation is a viable option only when all of the following criteria are met:
1. The original root canal procedure cannot be non-surgically or surgically revised with retreatment or apicoectomy with a reasonable chance of success (eg, when adequately treated root canals with coronal obstructions are failing).
2. A high-quality coronal restoration is present and there is no coronal leakage.
3. The infection is localized to the apex and no periodontal disease or cracks/fractures are present.
4. The tooth's root(s) allow(s) easy extraction and easy replantation after extraction (no sharp curvatures or thin roots and ideally conical roots).
5. The patient is fully informed of the risk and the required postoperative care, is motivated, and has realistic expectations of the success rate.
Once these criteria have been met, where a conventional apicoectomy is not possible, an intentional replantation can be attempted to save a tooth with persistent periapical disease following root canal therapy.
A 56-year-old male patient presented to the author's clinic with the chief complaint of pain in the mandibular left quadrant and minor swelling. History and clinical examination revealed that the mandibular left first premolar (tooth No. 21) had a 3-year-old root canal and a new crown. The patient explained that the tooth never felt normal after root canal therapy and recalled a poor dental experience during the original treatment with his dentist. In clinical tests, all teeth tested normal, except tooth No. 21, which was sensitive to percussion and palpation and exhibited radiographic evidence of a root canal fill several millimeters short of the apex (Figure 1). A periapial radiolucency was also present at the apex of this tooth. A 3-year-old, well-sealed coronal restoration was also noted.
Due to the inadequate root canal fill, non-surgical endodontic retreatment–ie, revision through the crown–was the recommended treatment option for saving this tooth. Since basic endodontic principals had not been achieved during the original root canal therapy, a non-surgical revision was assessed as the most predictable way to address the remaining bacteria in this tooth. Unfortunately, due to patient's poor experience during the initial root canal treatment by his dentist, he rejected this recommended retreatment. Surgical apicoectomy was recommended next but was also rejected due to the small, but possible, risk of nerve damage in this area. The patient opted for extraction without replacement with either an implant or a bridge, as he wanted to minimize dental treatment.
Given the patient's decision to lose this savable tooth and not replace it with a restorative option, intentional replantation was finally offered as a last resort. It was explained to the patient that the tooth would be removed, and if the root did not fracture during the extraction process and the crown remained intact, there was a chance that the surgical apicoectomy procedure could be performed outside the mouth and the tooth replanted. As long as the tooth had to be removed anyway and the periodontal condition was normal, and since the tooth had a straight conical root with a well-sealing coronal restoration, the prognosis was deemed good as long as the tooth and the crown were able to survive the atraumatic extraction procedure.
The atraumatic extraction procedure required for intentional replantation involves the removal of the tooth in such way that damage to the cementum on the root surface is minimized. As a result, excessive use of root elevators is generally discouraged. The tooth should be gently loosened and removed with slow forceps movements, with emphasis on preserving the viability of cementoblasts and periodontal cells on the root surface. Intrusive and excessive bucco-lingual forces that can potentially crush the cementum should also be minimized. This extraction procedure generally takes longer than the normal extraction and is much gentler.