Apexification Using Mineral Trioxide Aggregate in a Previously Treated Tooth with Wide Periapical Lesion and Resorbed Root: A 2-Year Follow-Up Detailed Case Report ()
1. Introduction
Apexification remains an essential treatment approach for managing teeth with necrotic pulps and incomplete root formation. Appropriate case selection is crucial and typically involves traumatized or caries-infected nonvital permanent teeth with open apices, thin dentinal walls, and wide canal spaces, where conventional obturation techniques fail to provide an adequate apical seal [1].
Achieving apical closure in such cases is technically demanding. The absence of an apical constriction complicates working length determination, while the thin and fragile dentinal walls increase the risk of procedural errors and root fracture. Additionally, the removal of necrotic debris and the control of irrigant extrusion or overfilling are more difficult due to the large apical foramen [1].
Given these challenges, apexification serves as a crucial procedure to consider. It is defined as “a method of inducing a calcified barrier in a root with an open apex, or of promoting continued apical development in an incompletely formed root with necrotic pulp”. The primary objective is to create a stable apical barrier that enables effective obturation and long-term tooth retention.
This report describes the successful management of a previously treated maxillary central incisor with a wide periapical lesion and a resorbed open apex, treated by non-surgical retreatment and MTA apexification. A two-year follow-up demonstrated complete periapical healing and long-term functional preservation of the tooth.
2. Case Report
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Figure 1. (a) The preoperative image showing the sinus tract; (b) The initial radiograph; (c) The fistulography.
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Figure 2. (a) Endodontic desobturation of both teeth; (b) Orthograde retreatment of the tooth 12 and calcium hydroxide dressing was placed in tooth 11; (c) No clinical sign of infection.
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Figure 3. (a) Premeasured gutta percha plugger; (b) 4 mm MTA apical plug; (c) Gutta percha back filling; (d) 24 months follow up.
A 23-year-old young man presented for consultation due to a Sinus tract and a history of trauma to the primary incisors.
The extrusion of the primary incisors affected the underlying permanent tooth germs because of their close anatomical proximity, disturbing their root development and leading to arrested root formation and pulpal necrosis of the permanent incisors.
Clinical examination revealed that teeth and #12 were non-responsive to cold pulp testing. Both teeth were tender to percussion and palpation, while periodontal probing depths were within normal limits and physiologic mobility was noted.
Radiographs showed:
Tooth #11 (central incisor):
Leaky coronal and canal obturation
Immature root with an open apex
Irregular external root surface defects, consistent with external inflammatory root resorption associated with apical periodontitis
Periapical radiolucency
Tooth #12 (lateral incisor):
A sinus tract was observed on the buccal mucosa and traced with a gutta-percha cone, which radiographically led to the apical region of both teeth (Figure 1).
The diagnosis was:
2.1. The Treatment Strategy Consisted of Two Phases
1) Endodontic phase:
Removal of the existing coronal obturation material.
Refinement of the access cavity to ensure proper canal desobturation, disinfection and obturation.
Orthograde retreatment of tooth #12 (right lateral incisor).
Orthograde retreatment of tooth #11 (right central incisor) with placement of an MTA apical plug.
2) Restorative phase:
2.2. Endodontic Procedure
After local anesthesia and rubber dam isolation, the previous filling material was removed using rotary instruments.
Retreatment was carried out first on tooth #12, followed by tooth #11. The canals were gently instrumented manually and carefully disinfected. A creamy mix of calcium hydroxide (Prevest Denpro) intracanal dressing was placed in both canals for 2 weeks, until no clinical signs of infection were present (Figure 2).
2.3. Apexification Procedure for Tooth #11
At the second appointment, the canal of tooth #11 was dried. Mineral trioxide aggregate (Trioxident, Vladmiva) was mixed according to the manufacturer’s instructions to a wet-sand consistency and placed incrementally 1 mm short of the working length using pre-measured gutta-percha pluggers. The material was condensed with minimal pressure using inverted absorbent paper points.
This procedure was repeated until a 5-mm apical plug was obtained. The thickness and position of the plug were verified with sequential radiographs.
2.4. Canal Obturation and Coronal Restoration
At the following appointment gutta percha back filling followed by immediate coronal composite obturation.
This was followed by immediate coronal restoration with composite resin (Figure 3).
2.5. Follow-Up
Clinical and radiographic follow-up examinations were performed at 6, 12, and 24 months.
Clinical healing criteria included:
Absence of spontaneous pain
Absence of tenderness to percussion or palpation
Absence of swelling
Absence of sinus tract
Normal periodontal probing depths and tooth function
The sinus tract resolved within two weeks following intracanal disinfection and did not recur during the follow-up period (Figure 2).
Radiographic success was defined by:
Progressive reduction and eventual disappearance of the periapical radiolucency
Re-establishment of normal periapical bone architecture
Formation of a mineralized apical barrier at the apex of tooth #11 (Figure 3)
No adverse outcomes associated with Mineral Trioxide Aggregate apexification, such as discoloration, reinfection, material extrusion, or need for further intervention, were observed.
3. Discussion
The management of teeth with open apices and persistent periapical pathology remains one of the most challenging aspects of endodontic therapy. Two major treatment modalities have emerged: apexification and revascularization (RET), both of which frequently employ mineral trioxide aggregate (MTA) as a central biomaterial [1].
While RET can promote continued root development, its success is variable, particularly in previously treated or heavily infected teeth. In contrast, MTA apexification provides a predictable and immediate apical barrier, allowing obturation and definitive restoration in fewer appointments. MTA’s faster setting time, superior sealing ability, and bioactive potential have made it the gold standard for apical barrier formation [1].
3.1. Apexification versus Alternative Approaches
MTA Apexification vs. Revascularization (RET)
Systematic reviews report comparable long-term survival and clinical success rates between MTA apexification and RET. However, apexification remains the treatment of choice when revascularization is contraindicated. Successful outcomes in either approach depend primarily on case selection, adequate disinfection, and follow-up [1]-[3].
MTA vs. Long-term Calcium Hydroxide
Historically, calcium hydroxide apexification required prolonged treatment-often over six months-with multiple dressing changes. Beyond the practical limitations, extended Ca(OH)2 exposure has been shown to alter dentin’s physical properties, decreasing its fracture resistance. In contrast, MTA provides a stable apical barrier within a single or few visits, reducing treatment duration and preserving radicular integrity [4]-[6].
MTA vs. Customized Gutta-percha Cones
An in vitro comparison of obturation techniques in simulated immature anterior teeth demonstrated that MTA apical plugs achieved significantly better marginal adaptation to dentinal walls than single customized gutta-percha cones used with calcium silicate–based sealers. This highlights the material’s superior sealing capability in cases with wide and irregular apices [7].
3.2. Biological Mechanisms Supporting the Use of MTA
Sealing and Bioactivity
The chemical composition of MTA makes it bioactive, inducing cementogenesis and hard tissue barrier formation [8]. It provides a reliable seal at the apex, helping to control persistent apical inflammation and promote bone healing. A study compared White MTA (WMTA), Biodentine, and a BC-sealer (bio-ceramic sealer) in terms of their ability to release calcium (Ca) ions, uptake calcium (Ca) and silicon (Si) in the adjacent root dentine demonstrates that MTA (WMTA) has significant bioactivity: it can interact with phosphate in body-like fluid, form mineral precipitates and cause ion exchange/uptake by dentine. These features underlie its sealing ability and ability to promote hard tissue barrier formation [9] [10].
Upon hydration, MTA releases Ca2+ ions, leading to the formation of Ca(OH)2, which reacts with phosphate ions from tissue fluids to produce hydroxyapatite. This reaction accounts for its progressive increase in alkaline pH-from approximately 10.2 immediately after mixing to 12.5 within 3 hours-creating an environment that is antibacterial, bio inductive, and conducive to cell adhesion and mineralization [8] [11].
Cellular and Molecular Effects
At the biological level, MTA modulates inflammatory mediators and stimulates osteoblastic and odontoblastic activity. It downregulates pro-inflammatory cytokines (IL-1β, TNF-α) and upregulates anti-inflammatory pathways that favor healing. Moreover, it enhances the differentiation and migration of hard tissue–forming cells, contributing to osteogenesis, and periodontal reformation [8] [11].
3.3. Technical Considerations Affecting Prognosis
Irrigation and Disinfection
Effective chemomechanical disinfection is fundamental to the success of apexification. The absence of a natural apical constriction increases the risk of irrigant extrusion and periapical injury. Therefore, irrigation must balance antibacterial efficacy with tissue compatibility [12].
In the present case, a conservative protocol using 1.25% NaOCl, 17% EDTA, and 2% CHX, interspersed with saline rinses, was employed to maximize disinfection while minimizing cytotoxicity. Studies confirm that lower NaOCl concentrations, when used in sufficient volumes and for extended contact times, can achieve effective microbial reduction with lower extrusion risk [12] [13].
Irrigant Activation and Delivery
Activation improves irrigant penetration and biofilm disruption. However, in teeth with thin dentinal walls or open apices, ultrasonic or laser activation may jeopardize the fragile radicular structure. Safer alternatives include manual agitation using a fitted gutta-percha cone and apical negative pressure systems (e.g., EndoVacTM), which enable irrigants to reach the apical third without extrusion. The use of double-vented needles and frequent irrigant exchange further enhances cleaning efficacy [14].
For high-risk cases, a collagen apical barrier (CAB) can be temporarily placed beyond the apex to prevent extrusion and allow safe irrigant activation [15].
Intracanal Medication: Role of Calcium Hydroxide
Short-term placement (1 - 4 weeks) of a creamy calcium hydroxide dressing can elevate periapical pH, reduce inflammation, and improve the subsequent marginal adaptation of MTA (3, 4). Since MTA’s setting and sealing ability are negatively affected by acidic environments, this preconditioning step enhances treatment predictability [16].
3.4. MTA Plug Technique and Access Design
Micro-CT analyses reveal that access cavity design and placement technique significantly influence MTA plug density and void formation. Conservative accesses, though structurally conservative, may increase porosity within the plug. Therefore, a traditional access cavity was selected in this case to enhance apical visibility and compaction [17].
A 5-mm MTA plug, placed with a calibrated carrier and pluggers under a “reverse tamponade” technique, provided an optimal barrier. Evidence supports a minimum thickness of 4 mm to resist bacterial penetration and mechanical stresses. Delivery systems such as the MAP System or micro-carriers allow precise placement without the need for a matrix [18].
Material Selection: MTA, Biodentine, or Bioceramic Putties
Recent comparative studies indicate that MTA, Biodentine, and premixed bioceramic putties all demonstrate high clinical success and favorable biocompatibility [19] [20].
Biodentine offers advantages in handling and setting time, while MTA retains the longest clinical track record for apical barrier formation. However, MTA may cause coronal discoloration, exhibit porosity under acidic conditions, and has a longer setting time. Despite these drawbacks, the material’s apatite layer formation subsequently seals surface voids, ensuring a durable chemical bond with dentin [8].
Prognosis and Clinical Relevance
Apexification with MTA had demonstrated favorable clinical and radiographic outcomes and appears to be a good and reliable treatment option in the open apex teeth [21].
In a case series of 5 - 15 years, MTA as an apical barrier achieved a healing rate of 96%.
The apexification failure rate of an MTA apical plug with a single placement of calcium hydroxide for immature permanent teeth was 7.1% over 2 years [22].
4. Conclusions
The concept of regeneration and revascularization is overtaking traditional methods. Apexification with MTA is a reliable, conservative approach for managing teeth with open apices and persistent periapical pathology following failed endodontic treatment.
It remains a highly effective and biologically sound approach. When combined with conservative disinfection, controlled irrigant delivery, short-term Ca(OH)2 dressing, and precise apical plug placement, it offers excellent sealing, bioactivity, and long-term periapical healing.