The 15-year-old male patient had undergone auto-transplantation therapy at the University of North Carolina at Chapel Hill (UNC-CH) Adams School of Dentistry (ASOD) Graduate Periodontic Clinic. The treatment planning included a full periodontal examination, such as probing depths and plaque index. Cone beam computed tomography (Orthophos SL 3D, Dentsply Sirona, Charlotte, NC) was used to evaluate recipient sites and donor teeth for surgical planning. The periodontic resident determined the auto-transplantation procedure by selecting donor teeth #4 and #13 and transplanting the teeth at recipient sites #29 and #20, respectively (Figures 1(a), 1(b), 1(c), 1(d), and 1(e)).
All auto-transplantation procedures were performed by the periodontic resident at the UNC-CH ASOD Graduate Periodontic Clinic. While one auto-transplanted tooth (donor tooth #4, recipient site #29) was successfully integrated into recipient sites, the other auto-transplanted tooth (donor tooth #13, recipient site #20) developed severe bone loss and apical periodontitis. Therefore, after 6 weeks, the patient was referred to UNC-CH ASOD Graduate Endodontic Clinic for evaluation of #20 (Figures 2(a), 2(b), 2(c), 2(d), 2(e), 2(f), 2(g), and 2(h)).
Upon evaluation at UNC-CH ASOD Graduate Endodontic Clinic, the patient's chief complaint was minor pain when biting and the presence of a sinus tract on the mandibular left quadrant. His medical history was unremarkable. He had no drug allergies, medications, or cardiac/joint diseases requiring antibiotic prophylaxis. His dental history included routine dental care, low caries risk, and good oral hygiene. The extra oral exam and perioral soft tissue exam were within normal limits. His temporomandibular joint function was normal, without any deviation upon opening or discomfort upon palpation. The intraoral examination revealed normal soft tissues with neither pathology nor symptoms. Clinically, tooth #20 had no restorative or carious defects. Examination did not reveal any cracks or fractures, and discomfort upon percussion, palpation, and bite stick testing was minor. Teeth #19 and #21 were tested with EndoIce (Coltene Whaledent, Cuyahoga Falls, OH, USA) and responded within normal limits. Tooth #20 did not respond to EndoIce. The radiographic examination revealed normal PDL space around teeth #19 and #21 but widening of the PDL space, loss of lamina dura, and localized loss of marginal bone on the mesial and distal of tooth #20 (Figure 2(f)). The endodontic diagnosis for this patient was pulp necrosis with chronic apical abscess.
Treatment options discussed with the patient included NSRCT or extraction. After considering the risks and benefits of both procedures, an agreement was made to proceed with NSRCT due to recent auto-transplantation. The NSRCT for this tooth started the day of the evaluation to alleviate the patient's discomfort and sinus tract. Local infiltration of 3.6 ml of 4% articaine with 3.6 ml of 1 : 100,000 epinephrine (Septocaine; Septodont, New Castle, DE, USA) was administered. Dental clamp and dental dam modifications were necessary to achieve the appropriate isolation due to the present orthodontic bracket and archwire; adjunctive endodontic isolation was performed with OraSeal (Ultradent Products, South Jordan, UT, USA). Access to cavity preparation was challenging due to multiple factors, including tooth mobility and maxillary premolar anatomy in a mandibular arch. Magnification up to 20x and illumination of 125 K (Prima, Labomed, Gurgaon, India) were used for canal identification and to reduce the possibility of missed canals.
A single canal was found, and the working length was determined using an electronic apex locator (Root ZX II, Morita, Kyoto, Japan); measurement films were taken at multiple angulations to visualize canal configurations and apical termini. Debridement was accomplished using hand instrumentation with K-type and Hedstrom files (Dentsply-Sirona, Johnson City, TN, USA) to a size #80 (Figure 3(a)). Copious irrigation of 2.5% sodium hypochlorite (NaOCl) (Henry Schein, Melville, NY, USA) was used during the cleaning and shaping process, followed by a final rinse of 17% ethylenediaminetetraacetic acid (EDTA) (Henry Schein, Melville, NY, USA) to remove the smear layer. The irrigation solutions were delivered via the EndoVac Negative Pressure Irrigation system (Discus Dental, Culver City, CA, USA). The tooth was dried with medium endodontic paper points (Dentsply-Sirona, Johnson City, TN, USA) until the paper points were stiff. Calcium hydroxide (Sultan Healthcare, York, PA, USA) was mixed with 2.5% NaOCl and placed with an amalgam carrier 2 mm from the radiographic apex (Figure 3(b)). The tooth was then temporized with Teflon tape and Fuji TRIAGE (GC America, Alsip, IL, USA).
The patient presented 4 weeks later for follow-up and obturation. No symptoms were observed, the chief complaint had been resolved, and mobility had decreased to class two. Administration of local anesthesia and a rubber dam placement technique was used. A nickel-titanium plugger (SybronEndo, Kerr, Brea, CA, USA) was selected to obtain an appropriate apical fit of 2 mm from the radiographic apex and working length (Figure 4(a)). After the nickel-titanium plugger placement was confirmed, the canals were dried with medium paper points (Dentsply-Sirona, Johnson City, TN, USA). Once the canal was dried thoroughly, it was obturated using EndoSequence Bioceramic Root Repair Material Fast Set Putty (Brasseler, Savannah, GA, USA) in 2 mm incremental layers. A radiograph was exposed to ensure a proper 2-4 mm apical seal (Figure 4(b)). The aim of this technique was to achieve a three-dimensional fill and create an apical plug to prevent gutta-percha extrusion. After the apical plug, backfill was performed with a Kerr Backfill unit (SybronEndo, Kerr, Orange, CA, USA) in incremental layers of gutta-percha to the cementoenamel junction (CEJ).
When obturation was complete, excess gutta-percha was removed from the chamber using a heated posterior endodontic plugger (Kerr Dental, Orange, CA, USA). The tooth was restored by placing 37% ortho-phosphoric acid etch on the enamel for 30 seconds and rinsing with water. Once the tooth was dry, Optibond Solo Plus (Kerr Dental, Orange, CA, USA) was coated and scrubbed in the endodontic access for 20 seconds, air-dried, and cured for 30 seconds. Lastly, a packable composite (Filtek Supreme, 3M, Two Harbors, MN, USA) was placed in 2 mm incremental layers until access was filled and then cured for 1 minute. The composite was smoothed and polished with a football-shaped bur (Komet USA, Rock Hill, SC), and occlusion was checked with articulating paper until acceptable occlusal contact was determined. The final post-operative radiograph was exposed (Figure 5). The patient was referred to his orthodontist for continued care.
The patient was recalled for an 8-month follow-up to NSRCT, and the endodontic outcome was considered favorable. The radiograph showed normal PDL, and the lamina dura had no signs of periapical pathology. The patient has remained asymptomatic after the completion of NSRCT; a radiographic exam revealed complete healing of periapical pathosis (Figure 6). The permanent restoration was intact without any evidence of leakage. All probing depths were within normal limits with normal physiological mobility.