Repair of a Perforation Defect With Calcium-Silicate-Based Cement Using an Internal Matrix: Case Report

Perforation is the result of a procedural accident that can occur in endodontic practice and affects the prognosis of root canal treatment. Perforations are the second highest cause of endodontic failure, with Ingle attributing about 9.6% of treatment failures to perforations.¹

Perforations may occur due to various reasons, such as caries, resorption, or iatrogenic injury caused during, for example, access cavity preparation, coronal shaping, or post space preparation.¹ They can happen during post space preparation, strip perforation, or at the time of retrieval of separated instruments.²When present, perforations may be discovered during the diagnostic phase of treatment in areas where restorative material is found to cross the radiographic interface between the dentin and periodontal ligament.^3,4

The prognosis of a perforation repair is dependent on various factors such as the location of the perforation, the amount of time delay before the perforation repair is made, the ability to seal the defect, and any previous contamination with microorganisms. The level at which the perforation has occurred is a determining factor in the difficulty of the repair. If the perforation has occurred in the apical one-third (such as from an instrumentation error), repair is highly challenging. If the perforation is located in the coronal one-third of the canal (ie, access perforation) or in the furcal floor, it is considered to be easily accessible.^4-6

Immediate repair is favored over delayed repair because the latter can lead to breakdown of the periodontium, resulting in endodontic-periodontic lesions, which can be more difficult to manage.^7,8 Many materials have been introduced for the repair of perforations, including amalgam, super ethoxy benzoic acid (EBA) cement, bonded composite materials, and, more recently, mineral trioxide aggregate (MTA).⁹

MTA was introduced more than two decades ago as a root filling material. It contains a mixture of 75% Portland cement, 20% bismuth oxide, 5% gypsum, and trace amounts of silicon dioxide, calcium oxide, magnesium oxide, potassium sulfate, and sodium sulfate. Two types of MTA are available: gray and white. The gray-colored formula contains calcium oxide, dicalcium silicate, tricalcium silicate, tricalcium aluminate, tetracalcium aluminoferrite, and calcium sulfate dehydrate, whereas the white-colored formula lacks the tetracalcium aluminoferrite. Currently, MTA is also being used in other clinical procedures such as apexification, pulp capping, retrograde obturation, and pulpotomy. MTA has good adherence to dentin walls making it well resistant to dislocation forces, thus it is indicated in furcation perforations.¹

This article reports a case of a permanent mandibular first molar with a distolingual floor perforation treated with MTA with an internal matrix.

A 35-year-old male patient reported to the Department of Conservative Dentistry and Endodontics at K.D. Dental College and Hospital, Mathura, Delhi, India, with a chief complaint of pain and swelling in the lower left posterior region of his mouth. This followed his treatment at a private clinic 2 days prior.

Clinical examination revealed the presence of gingival tissue through the access opening at the mandibular left first molar that occurred at a private clinic (Figure 1). Upon radiographic examination, the mandibular left first molar showed a perforation on the distolingual aspect of the pulpal floor. Proximal caries was also present in the adjacent premolar (Figure 2).

After administration of local anesthesia, under rubber dam isolation, the access opening was modified and canals were located. With the use of an apex locator (Root ZX, J Morita, morita.com)working length was established 1 mm short of the radiographic apex and was confirmed with the aid of a radiograph (Figure 3).

Shaping of canals was done using a nickel titanium file (HyFlex^™ CM, Coltene, coltene.com), and cleaning was done with the aid of 5.25% sodium hypochlorite and normal saline. Canals were enlarged up to 25/0.04 in the mesial canals (mesiobuccal and mesiolingual) and 30/0.04 in the single distal canal. A small piece of a synthetic collagen material (CollaTape^®, Zimmer Biomet Dental, zimmerbiometdental.com) was gently compacted to produce a barrier at the level of furcation. Gray MTA (MTA Angelus^® [Gray], Angelus, angelusdental.com) was mixed according to the manufacturer's instructions and seated on the CollaTape barrier. Gutta percha points were placed in the canals to avoid the flow of MTA into the canals (Figure 4).

A moist cotton pellet was applied over the MTA to promote the setting of the material, and the access cavity was sealed with temporary filling material (Cavit^™, 3M Oral Care, 3m.com). The placement of the MTA was confirmed radiographically (Figure 5).

The patient was recalled the next day. The Cavit material was removed and the MTA was checked for setting. A master cone radiograph was taken (Figure 6), and obturation was performed using a single-cone technique with the aid of a root canal sealer (AH Plus^®, Dentsply Sirona, dentsplysirona.com) (Figure 7).The access cavity was sealed with composite restoration and a porcelain-fused-to-metal (PFM) crown was placed (Figure 8).

This article reported the nonsurgical repair of a perforation in the distolingual aspect of the floor of a mandibular molar with MTA biomaterial using an internal matrix. Factors such as the level and location of the lesion, the size of the perforated area, and the time elapsed between the incidence and repair of the perforation all affect the prognosis of furcation perforations. The longer the time elapse before lesion repair, the poorer the prognosis will be.¹⁰

In the present case, the pulp chamber floor perforation was not extensive, and the time between the perforation and repair was only 2 days; thus, the treatment was able to be completed successfully, both clinically and radiographically.

To achieve successful treatment, a tightly sealed repair is needed in the perforation so that the path of contamination is closed and the periodontium apparatus is guarded for optimal healing.¹⁰ A barrier (matrix) technique has been suggested for treatment of a perforation in which the matrix-which should be sterile and non-irritating, comprised of a material such as hydroxyapatite or calcium sulfate, or resorbable collagen-is placed, over which a biomaterial like MTA is placed.¹⁰

MTA has demonstrated less leakage than amalgam and super EBA and is less cytotoxic and neurotoxic than other repair materials. Despite the advantages of MTA, it may be inconvenient to use because it requires that it be covered by a wet cotton pellet and left for at least 3 to 4 hours to set. Thus, the protocol for endodontic treatment requires the termination of the procedure and reappointment of the patient after the material has hardened, which is often inexpedient for both the patient and the practitioner.¹⁰

The use of an internal matrix of absorbable collagen provides good control for condensation of MTA against the matrix. If in the present case the plug had not been placed correctly, the seal would have been poor. Therefore, the use of the synthetic collagen material matrix enabled the MTA to be placed correctly, which in turn maximized the seal. Further studies are needed to develop the internal matrix placement approach into a standardized method so that the matrix may be placed correctly each time it is used.

Jaya Srivastava, MDS
Post-Graduate Student, Department of Conservative Dentistry and Endodontics, K.D. Dental College and Hospital, Mathura, Delhi, India

Manoj Kumar Hans, MDS
Professor, Department of Conservative Dentistry and Endodontics, K.D. Dental College and Hospital, Mathura, Delhi, India

Rohit Paul, MDS
Professor and Head, Department of Conservative Dentistry and Endodontics, K.D. Dental College and Hospital, Mathura, Delhi, India

Amit Kumar Garg, MDS
Professor, Department of Conservative Dentistry and Endodontics, K.D. Dental College and Hospital, Mathura, Delhi, India

Rhitu Shekhar, MDS
Reader, Department of Conservative Dentistry and Endodontics, K.D. Dental College and Hospital, Mathura, Delhi, India