Endo-Aesthetic Management of Teeth with Open Apex: A Case Report

  Introduction

Pulp necrosis after injury or inflammatory apical root resorption is considered as the most common causative factor for developing wide juvenile apices with weak dentinal walls and a future root fracture hazard if not treated.¹

The age group between 17 and 20 years constitutes the majority of critical cases of dental trauma resulting from falls and accidents. It occurs primarily in the maxillary anterior region.² Incomplete rhizogenesis leads to the formation of blunderbuss canal where there is absence of adequate root development giving funnel taper to the canal.

The treatment of these cases involves two approaches-surgical and non-surgical. The non-surgical intervention comprises contemporary endodontic therapy using either the roll cone technique to the full length of the canal or apexification with calcium hydroxide, MTA, or biodentine followed by obturation either with the roll cone technique or with thermoplasticized gutta-percha or revascularization.³

The surgical intervention includes performing an apicectomy, followed by filling the root canal retro-gradely with an appropriate material and obturation by routine methods. The advantages of retrograde treatment include faster treatment rate, reinforcement of the dentinal walls decreasing the risk of fracture, immediate resolution of periapical lesion, and a strong apical barrier.^3,4

Endodontic treatment in such cases places a clinician in ambiguous situation due to the issues with canal debridement owing to wide apex, lack of apical stop  posing difficulties in obturation, and risk of fracture due to thin root canal walls.^3,5 These issues can be addressed through a technique called apexification, which promotes hard tissue formation at the apex, creating a barrier and strengthening the root against fractures.  

Case Presentation

A 33-year-old male patient reported with a chief complaint of broken upper front teeth since childhood. The patient gave a history of self-fall trauma in childhood which had led to fracture of the upper front teeth. The pain was insidious in onset, mild, dull aching, and non-radiating type. He was not on any medication and did not consult a dentist for the same.

On examination, both the maxillary central incisors showed discoloration with cervical abfraction and coronal fracture. The teeth were non-tender on percussion, with no vestibular changes. Severe abfraction was noted irt 12 with mild tenderness on percussion. Patient had a Class II molar relation with proclined upper anteriors and deep bite. A provisional diagnoses of Ellis class IV fracture with pulp necrosis irt 11 and 21, and pulp necrosis with asymptomatic periapical abscess irt 12 were established.

These teeth were subjected to pulp vitality testing and no response was noted. On sinus tract tracing, the gutta-percha tip pointed to the large oval-shaped periapical rarefaction associated with 11,12 and 13.

Periapical radiographs revealed an open apex irt 11 & 21. A large, unilocular, well-defined radiolucency, with a thin radiopaque border on all its contours, involving periapical region of 11,12, and 13, measuring approximately 6 × 10 mm was noted. Similarly, a well-defined periapical radiolucency of approximately 5×5 mm size was also noted involving the root tip of 21 and partially that of 22.

A final diagnosis of chronic periapical abscess involving immature teeth irt 11, 21 and mature tooth irt 12 with a cyst-like periapical lesion (presumptive pocket cyst) was reached. A conservative approach involving non-surgical endodontic treatment for these teeth was planned, along with continuous monitoring of the lesion.

Treatment procedure

After obtaining written consent from the patient, access cavity preparation was done for 12 using high-speed diamond bur along the long axis under rubber dam isolation, without administration of LA. Apical patency was established with 10 k file (Dentsply Maillefer, Swit-zerland). Root canal treatment was carried out using standardized protocol and calcium hydroxide was placed as an intracanal medicament for two weeks. Later, obturation was done with lateral compaction technique using AH plus sealer. Similarly, endodontic treatment was also initiated irt 11 and 21 in the subsequent visits. After gaining access, no. 80 K file was used to determine the working length. Minimal instrumentation technique was used for the cleaning and shaping procedure.

The canals were irrigated alternating between sodium hypochlorite (NaOCl) and normal saline. Calcium hydroxide was placed as intracanal medicament and was replaced every two weeks for two months, during which follow-up radiographs were also taken. During the course of this treatment, the patient expressed a desire to restore 11 and 21 with a temporary prosthesis for personal reasons.

Indirect composite veneers (Vario link N intro pack, Ivoclar Vivodent) were placed as temporary restorations. After nine months, the patient revisited for continuation of his treatment.

Follow-up RVG revealed intact composite veneers and calcium hydroxide in both the canals. The patient remained asymptomatic during this period. Subsequently, Ca(OH)₂ was removed using mechanical instrumentation and irrigated out of the canals with 17% EDTA, NaOCl, and saline. Paper points were then used to absorb any remaining moisture in the canals.

MTA apexification was planned for 11, and roll cone technique was planned for 21. MTA was manipulated according to the set guidelines and carried into the canal using a MTA carrier. Pluggers were used to condense the MTA. Application of excess apical pressure was avoided to prevent extrusion through the apex. Radiograph was taken to confirm 5 mm of apical plug.

A sterile cotton pellet dipped in saline was placed in the canal and the access cavity was temporized. After 24 hours, the hard set of MTA was confirmed with a plugger, and the thermoplasticized gutta-percha technique was used to obturate the remaining root canal using AH plus sealer. Access was filled with composite resin (Tetric N Ceram, Ivoclar).

For the treatment of 21, a custom cone technique was planned. 80-size gutta-percha points were softened with heat and rolled together between glass slabs. Tips of gutta-percha points were elasticized using a heated instrument and then introduced into the canal to record the internal morphology of canal. This process was repeated till proper tugback was achieved. The canal was sealed up to the level of CEJ. The composite veneers were removed by sectioning using crown-cutting burs. Crown preparation was carried out for the PFM (porcelain fused metal) prosthesis and crowns were cemented using glass ionomer cement (GC Fuji). During follow-up visits, teeth remained asymptomatic and RVG (Radiovisiography) revealed significant improvement in the bone trabecular formation.

Discussion

Successful treatment of immature permanent teeth critically depends on thorough cleaning of the entire canal space which can be quite challenging, as conventional mechanical instrumentation in wide, open apex canals is always not feasible. Therefore, disinfection relies primarily on the chemical action of sodium hypochlorite and the use of root canal medicaments.⁶

At high concentrations, sodium hypochlorite is known to be toxic, especially when it extrudes apically. There-fore, a low concentration of NaOCl (3%) was used for disinfection. 17% EDTA solution was used to dissolve the smear layer and clear dentinal tubules for penetration of Ca(OH)₂ through the dentin.⁷

Literature reports usage of different materials to initiate the apical barrier formation, like calcium hydroxide, freeze-dried dentin, freeze-dried cortical bone, MTA, Bone morphogenic proteins (BMP’s), and Biodentine.^8,9

Among these, the most commonly utilized materials include calcium hydroxide, biodentine and MTA. Initially, calcium hydroxide was used for inducing the apical constriction. However, evidence has shown that the apical barrier formation with calcium hydroxide is time-consuming (few months to a year), the barrier formed is porous, and in some instances, even contains soft tissues.^3,4

The use of MTA in apexification procedure as a one-step strategy is steadily supplanting the conventional utilization of calcium hydroxide. Calcium hydroxide is known to modify the mechanical properties of root dentin, predisposing it to root fracture. MTA is a bio-compatible material that promotes the deposition of bone and periodontium around its interface. Therefore, MTA apexification was chosen as the treatment approach.

In this current case report, the custom-made roll cone technique was chosen for 21 obturation, as the canal walls were three-dimensionally more parallel compared to 11, facilitating a fluid-tight seal. A case report by Gupta et al. reported comparable healing of the apical lesions and recovery of peri-radicular tissues with the roll cone technique.¹⁰

At the two-year follow-up, the patient exhibited no clinical symptoms and showed satisfactory periapical healing.

Thus, in addition to the benefits of MTA, successful endodontic treatment relies on several critical factors such as, thorough canal disinfection, achieving a fluid-tight seal, controlling the apical barrier, and ensuring proper obturation within the canal. Each of these elements play a crucial role in the overall success of the procedure.

Conflict of Interest

None