Periapical healing and continued root maturation following endodontic surgery and apexification

Abstract

Persistent periapical lesions associated with iatrogenic errors, such as overextended silver cone obturations, present a significant clinical challenge that often necessitates multidisciplinary treatment. This case report describes the successful management of a 25-year-old female presenting with a large (1.5 cm × 1.2 cm), unilocular periapical cyst-like lesion involving the maxillary anterior teeth (11, 12, and 21). The treatment followed a staged protocol: initial nonsurgical retrieval of overextended silver cones was performed, followed by mineral trioxide aggregate (MTA) apexification for the teeth with open apices (11, 21). Subsequent endodontic surgery was performed, incorporating a 3-mm root-end resection for tooth 12, ultrasonic retrograde cavity preparation, and MTA root-end filling. After the 10-month follow-up, the patient remained asymptomatic, with radiographs demonstrating significant bone regeneration and evidence of “continued root maturation” or lengthening.

INTRODUCTION

Nonsurgical root canal treatment remains the cornerstone intervention for the management of pulpal and periapical diseases and generally demonstrates highly predictable clinical outcomes when biological and mechanical principles are adequately followed. Nevertheless, persistent apical periodontitis may develop in previously treated teeth because of persistent intraradicular or extraradicular infection, procedural inadequacies, incomplete obturation, or tissue reactions to extruded filling materials.[1] When established cystic lesions fail to resolve following orthograde retreatment, or when anatomical or restorative constraints render nonsurgical access impractical, periapical surgery becomes the preferred strategy to salvage the tooth.[2] The scope and predictability of endodontic surgery have improved considerably with the advent of modern microsurgical techniques incorporating magnification, ultrasonic retropreparation, microsurgical instruments, and biocompatible root-end filling materials.[3] Although silver cones were historically favored because of their rigidity and ease of placement, long-term evidence has demonstrated considerable biological and sealing limitations associated with these metallic obturation materials. Corrosion, microleakage, inadequate adaptation to canal irregularities, and extrusion into periapical tissues may collectively contribute to persistent inflammation and delayed periapical healing.[4] Similar foreign body reactions associated with metallic restorative materials within periapical lesions have also been previously reported in endodontic literature.[5] Mineral trioxide aggregate (MTA) has emerged as one of the most widely used bioactive materials in endodontics because of its superior sealing ability, biocompatibility, and regenerative potential.[6] In teeth with open or compromised apices, MTA apexification creates a stable apical barrier that facilitates effective obturation while promoting favorable periapical tissue healing and hard tissue repair.[7] Furthermore, bioactive root-end filling materials may stimulate cementogenesis and periodontal ligament regeneration, thereby enhancing long-term healing outcomes following endodontic microsurgery.[6] This case report presents the successful multidisciplinary management of previously treated maxillary anterior teeth associated with failed silver cone obturation and a large periapical lesion using a combined orthograde and surgical endodontic approach. The treatment protocol included orthograde retreatment, MTA apexification for teeth with open apices, and periapical microsurgery with ultrasonic retropreparation and MTA root-end filling for the tooth with a closed apex. Follow-up radiographs demonstrated favorable periapical healing together with radiographic evidence suggestive of continued root maturation and apical remodeling.

CASE REPORT

Diagnosis and treatment planning

A 25-year-old female patient reported to the Department of Conservative Dentistry and Endodontics with a chief complaint of persistent pain and localized swelling in the maxillary anterior region over the past 3 weeks. Clinical examination revealed that teeth 11, 12, and 21 demonstrated exquisite tenderness to both vertical percussion and palpation, with a localized fluctuant swelling present in the labial vestibule. As teeth 11 and 21 were previously treated, sensibility testing was performed only for tooth 12, which showed no response to cold and electric pulp testing. Radiographic evaluation (Intraoral Periapical Radiograph) revealed a large, well-defined, unilocular radiolucency involving the periapical regions of teeth 11, 12, and 21, measuring approximately 1.5 cm × 1.2 cm, suggestive of a periapical cyst-like lesion [Figure 1a]. Furthermore, linear radiopacities extending significantly beyond the apices of 11 and 12 were noted, indicating overextended silver cone obturations. Based on the clinical and radiographic findings, the definitive diagnosis was established as Previously Treated 11 and 21 with chronic apical abscess, Pulpal Necrosis in 12 with chronic apical abscess [Figure 1a].

Figure 1.

(a) Preoperative radiograph showing extensive periapical radiolucency associated with 11, 12, and overextended obturating material in 11, 21. (b and c) Retrieval of silver cone obturation material (d) Working length determination. (e) Mineral trioxide aggregate (MTA) apexification in 11, 21. (f) Obturation done in 12 (g) Full-thickness mucoperiosteal flap reflection. (h) Curettage of periapical granulation tissue (i) Root-end resection in 12 (j and k) retrograde cavity preparation (l) MTA as retrograde filling material

Endodontic phase

The treatment plan followed a staged approach. The initial management involved nonsurgical retrieval of the overextended materials. Endodontic access was achieved through the existing crowns of teeth 11 and 21. Silver cones were carefully retrieved using Hedstrom files and fine forceps [Figure 1b and c]. Access was established for tooth 12, and working lengths were determined for teeth 11.12 and 21 [Figure 1d]. Given the purulent exudate at initial access, the canals were left unobturated for 24 h under a temporary coronal seal to allow passive decompression. After completion of canal preparation and drying, calcium hydroxide intracanal medicament was placed. The medicament was renewed after 7 days and maintained for an additional 7 days, resulting in a total intracanal medicament period of 14 days before obturation. After complete resolution of symptoms, apexification was performed for teeth 11 and 21 using MTA (MTA Angelus [Angelus, Londrina, PR, Brazil]) to create an apical plug of 5 mm [Figure 1e]. Tooth 12 was obturated using gutta-percha and Sealapex sealer (Kerr Dental, Orange, CA, USA) [Figure 1f].

Surgical phase

Periapical surgery was initiated after the Endodontic phase was completed. After achieving profound local anesthesia (2% Lignocaine with 1:80,000 adrenaline), a full-thickness mucoperiosteal flap was reflected following an incision with a #15 BP blade extending from 12 to 21. Upon reflection, a cortical bone defect was identified [Figure 1g]. Thorough surgical curettage was performed using sharp periapical curettes to remove the granulation tissue [Figure 1h]. For tooth 12, a root-end resection of 3 mm was performed with a minimal bevel (0°–10°) [Figure 1i]. For teeth 11 and 21, where MTA apexification had been performed, the root ends were smoothed and contoured. Retrograde cavity preparation was then carried out to a depth of 3 mm using an ultrasonic retro-tip (SybronEndo) attached to a physiodispenser [Figure 1j and k]. After drying the retrograde cavities, MTA was compacted as the root-end filling material [Figure 1l].

FOLLOW-UP AND RESULTS

The flap was repositioned and secured with 4-0 nonresorbable silk suture. Postoperative instructions were provided, and the patient was prescribed analgesics. During the 1^st week follow-up review, the sutures were removed, and soft-tissue healing was satisfactory. The patient was recalled for periodic follow-up evaluations at 1 month [Figure 2a], 3 months [Figure 2b], 6 months [Figure 2c], 10 months [Figure 2d], and 1 year postoperatively [Figure 2e and f]. At the 3-month follow-up, satisfactory healing was observed, leading to the reinforcement of the remaining coronal portions of the canals in teeth 11 and 21 with fiber posts (Hi-Rem Post; Overfibers, Italy) that were cemented using a dual-cure resin cement (Calibra Universal, Dentsply Sirona). The access cavities in teeth 11, 12, and 21 were subsequently restored using a total-etch adhesive protocol with Tetric N-Bond Universal (Ivoclar Vivadent, Schaan, Liechtenstein), followed by incremental placement of a nanohybrid resin composite (Tetric N-Ceram; Ivoclar Vivadent, Schaan, Liechtenstein) [Figure 2c]. At the 10-month and 1-year follow-up visits, the patient remained completely asymptomatic, and radiographs demonstrated complete resolution of the radiolucency and robust bone regeneration. Notably, the radiographic findings demonstrated an appearance suggestive of continued root maturation in relation to teeth 11, 12, and 21, possibly associated with favorable periradicular tissue healing and deposition of cementum-like hard tissue over the resected root apices [Figure 2d-f].

Figure 2.

(a) One-month postoperative follow-up radiograph, (b) 3-month postoperative follow-up radiograph, (c) 6-month postoperative follow-up radiograph, (d) 10-month postoperative follow-up radiograph demonstrating progressive periapical healing and continued root maturation. (e and f) 1-year postoperative follow-up radiograph demonstrating satisfactory periapical healing and continued root

DISCUSSION

Endodontic surgery has evolved significantly since its introduction in the late nineteenth century. Modern endodontic microsurgery employs magnification, enhanced illumination, ultrasonic root-end preparation, and bioceramic materials to achieve greater precision, improved sealing, and superior healing outcomes. Although nonsurgical retreatment remains the preferred approach for persistent apical periodontitis, surgical intervention is indicated when retreatment is unsuccessful or impractical because of complex canal anatomy, perforations, separated instruments, nonremovable posts, persistent lesions, or conditions such as true cysts and extraradicular infections.[8] In the present case, treatment failure was associated with overextended silver cone obturation and persistent periapical pathology. Although silver cones and silver amalgams were historically favored for their technical simplicity, long-term evidence has demonstrated poor biocompatibility. Direct contact with periapical tissues and tissue fluids may lead to electrochemical corrosion, persistent microleakage, and release of cytotoxic by-products, thereby eliciting foreign body giant cell reactions and sustaining chronic therapy-resistant periapical inflammation.[5] Removal of the failed obturation material and effective elimination of intracanal infection were therefore critical aspects of treatment. The orthograde retreatment phase included retrieval of the silver cones, drainage of purulent exudate, and placement of calcium hydroxide intracanal medicament to enhance disinfection of the root canal system. However, extensive cystic lesions and persistent periapical pathology may not resolve completely with nonsurgical treatment alone, thereby necessitating surgical intervention.[9] The surgical phase was performed according to contemporary microsurgical principles. A 3-mm perpendicular root-end resection was performed for tooth 12, as most apical ramifications and lateral canals are located within the apical 3 mm of the root, while also minimizing exposure of dentinal tubules harboring residual infection.[10] Ultrasonic retrograde preparation was used to create a centered, 3-mm deep coaxial cavity following the original canal anatomy, thereby preserving sound root structure.[3,8] MTA was selected for apexification and retrograde filling because of its superior sealing ability, biocompatibility, and bioactivity. MTA apexification has demonstrated clinical success rates of approximately 94% with predictable apical barrier formation, while long-term tooth survival rates reach 90% at 5 years. Likewise, endodontic microsurgery using MTA as the root-end filling material has reported success rates of 86%–94%.[11] The favorable healing response observed may be attributed to the bioactive properties of bioceramic materials. Hydrolytic conversion of the cement creates an alkaline environment that promotes calcium phosphate precipitation and formation of a biomineralized apatite layer. This bioactive interfacial layer promotes alkaline phosphatase activity, enhances osteoblastic and cementoblastic differentiation and supports periodontal ligament attachment together with cementum deposition over the resected root surface.[6]

At the 10-month and 1-year postoperative follow-ups, the patient remained completely asymptomatic, with radiographs demonstrating substantial bone regeneration and significant resolution of the periapical radiolucency. Interestingly, radiographic findings suggestive of continued apical remodeling or apparent root lengthening were observed in teeth 11, 12, and 21. Although true root elongation in mature teeth is uncommon, deposition of cementum-like tissue and regeneration of the periodontal attachment apparatus may produce a radiographic appearance resembling continued root maturation.[12] This distinctive healing response further emphasizes the biologic potential of periradicular tissues when managed with bioactive bioceramic materials. Since extensive periapical lesions may exhibit dynamic and unconventional healing responses over time, long-term clinical and radiographic follow-up remains essential to confirm stable periapical resolution.[13] As postoperative assessment was limited to standardized intraoral periapical radiographs, the observed changes could not be quantified precisely. Postoperative cone beam computed tomography (CBCT) was not indicated due to satisfactory healing and adherence to the ALARA principle. Future CBCT-based studies may provide a more accurate three-dimensional evaluation of these regenerative changes.[14] A limitation of the present report is its single-case design, which restricts the generalizability of the findings. Although favorable clinical and radiographic outcomes were observed, larger longitudinal studies are required to validate the predictability of this combined treatment approach. Furthermore, the radiographic appearance suggestive of continued root maturation could not be histologically confirmed and should therefore be interpreted cautiously.

CONCLUSION

Combined orthograde retreatment and endodontic microsurgery with MTA apexification and retrograde filling can successfully manage persistent periapical pathology associated with failed silver cone obturation. Favorable healing and bone regeneration support this approach as a predictable tooth-preserving treatment when nonsurgical retreatment alone is inadequate. Careful case selection and long-term follow-up remain essential for successful outcomes.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.