Successful Retreatment of Failed Root Canal Treatment and Esthetic Rehabilitation of Maxillary Central Incisor

This case report describes the successful retreatment of failed endodontic treatment performed in maxillary right central incisor followed by post and core treatment.  A 27-year-old male patient reported to the private dental clinic with the chief complaint of pain in the upper front tooth region. Clinical and radiographic examination showed that the teeth was symptomatic, discolored and intruded with history of root canal treatment (RCT) done 7 years back. Ellis class II fracture was diagnosed during intraoral examination in relation to the maxillary left central incisor. Re-RCT was initiated in relation to the right central incisor with removal of crown followed by access restoration and gutta percha.  Canal was located, working length was established followed by chemo mechanical preparation and obturation. There was loss of significant tooth structure necessitating post and core treatment. Post space preparation was done in the canal followed by cast post cementation, core build up and full coverage restoration was given. Composite restoration was given in relation to the maxillary left central incisor.

Keywords: Esthetic Rehabilitation; Endodontic treatment; Post, core; Re-treatment; Root canal treatment.

Endodontic treatment is the gold standard for treating teeth with necrotic/non-vital pulp as the teeth exhibit variations in root number and root canal variations [1-5].  However, in some cases root canal treatment alone doesn’t suffice to obtain the desired results. This is specially challenging in cases of trauma in the permanent dentition of anterior teeth which mostly occur among children and adolescent. An awareness and knowledge about emergency management of traumatic injuries and tooth avulsion is highly essential among parents, guardians and school teachers [6,7]. Literature shows enormous number of awareness publications across the globe. Such cases not only render the pulp non-vital but may also lead to fracture of the coronal tooth structure. In such cases, reinforcement of the tooth mandates the use of post and is an indication for post and core treatment, before crown restoration. The use of post provides strength to the root structure and also helps in proper build-up of the coronal tooth structure. In this clinical report, successful management of maxillary right central incisor which had poor prognosis is shown. The failed root canal treatment was re-treated and later the root and crown portion were rehabilitated to provide final esthetic appearance to the patient which will in turn enhance self-esteem and psychological well-being of the patient.

A 27-year-old male patient reported to the private dental clinic with the chief complaint pain in the upper front teeth with a unesthetic appearance of face, after sustaining trauma due to accidental fall. Clinical and radiographic examination showed that the teeth was symptomatic, discolored and intruded with history of RCT performed to the maxillary right central incisor about 7 years back (Figure 1). Ellis class II fracture was diagnosed during intraoral examination in relation to the maxillary left central incisor. Re-RCT was initiated in relation to maxillary right central incisor. The access cavity was opened. Gutta-percha in the root canal was removed with H files ISO 25 size and down motion. Copius irrigation with sodium hypochlorite (2.5%) was performed between the files. A radiograph was taken to confirm the gutta percha removal.

Later, the apical diameter was prepared with K and H files up to size #30 in order to clean the root structure. Copius irrigation was performed between each file. Working length was determined. After that master apical diameter was prepared to size #30. Furthermore, a conical shape was given to the root canal with the step-back technique. Calcium hydroxide dressing was given. At the second appointment the tooth was ready for obturation. #30 size gutta percha was used as master cone. There are various techniques used in filling root canal systems like cold lateral compaction, warm lateral compaction, continuous wave compaction, thermoplasticized gutta-percha injection, carrier based gutta percha, Mcspadden thermomechanical compaction can be counted as the main ones. In this case, cold lateral condensation technique was used with sealapex as root canal sealer (Figure 2). There was loss of significant tooth structure necessitating post and core treatment. Post space preparation was done using peeso reamers size 1, 2 and 3 leaving 3-4 mm apical gutta percha intact.

An indirect technique was used for the fabrication of cast post. The separating media was applied to the prepared post space, and an impression of maxillary right central incisor was made with pattern resin with the help of a toothpick. The fabricated post was cemented using Glass Ionomer Cement type 1 (Figure 3). Later, the tooth was prepared with a circumferential chamfer, including 1.5 mm of ferrule preparation. Shade selection was done. Porcelain-fused metal crown was cemented using luting glass ionomer cement in relation to the maxillary right central incisor. Composite restoration was done in relation to the maxillary left central incisor. The final treatment outcome fulfilled the patient’s expectations (Figure 4).

Figure 1: Preoperative photograph (A) and radiograph (B) showing failed root canal treatment in relation to the maxillary right central incisor.

Figure 2: Endodontic Re-treatment performed in relation to the maxillary right central incisor. A – After removal of gutta-percha, B – Working length determination, C – Master cone selection and D – Post-obturation.

Figure 3: Post and core preparation in maxillary right central incisor

Figure 4: Postoperative photograph after final restoration in maxillary right and left central incisors

A pleasing smile with healthy teeth is an integral part of overall appearance and self-esteem. Anterior crown fractures lead to discomfort and serious psychological, esthetic, functional and phonetic problems that can affect social relationships. In the restoration of anterior teeth, many factors are to be considered depending on the patient’s expectations [8-10]. Restoring such teeth using materials with a similar elastic modulus to dentin appears advantageous due to the reduced risk of root fractures. The fracture resistance of endodontically treated teeth is dependent mainly on the amount of remaining tooth structure, the quality of adhesion and the type of post as posts increase the fracture resistance of the root. One report concluded that the greatest factor influencing the strength of endodontically treated teeth was the amount of remaining tooth structure [11]. Because of these properties, custom cast post was used in this case to restore the fractured teeth.

Freedman stated that the main function of the post is to anchor the post-and-core complex within the radicular portion of the remaining tooth. A post that can be bonded to tooth structure improves its ability to retain the entire foundation [12]. The use of post enables to reinforce the strength of the lost tooth structure. Posts placed in the canal subsequent to endodontic treatment increases the strength of the tooth and helps it to withstand the masticatory forces directed along the tooth. Failed root canal treatment or traumatized teeth undergo discoloration of the crown requiring different treatment management strategies. It also depends on the status of the tooth structure including crown and root structure [13].

For restoring teeth that had previously received endodontic treatment, custom cast posts and cores were thought to be state of the art in this case report. Cast posts and cores, on the other hand, have their own advantages, such as better flexibility to the root canal, and preservation of the greatest amount of tooth structure. An additional feature is an anti-rotational property. However, it has the downside of requiring several visits [13]. Using custom cast posts for root canal and crown preparation advantages include greater strength and minimum tooth structure loss. The strength of a tooth directly relates to the amount of residual tooth structure. Therefore, maximum tooth structure preservation is crucial for the success of post and core restoration [7,8]. On the other hand, prefabricated cylindrical posts chiefly rely on cement for retention. Reduced core retention of the post and the probability of rotation are the major disadvantages of this type of post [9].

Restoration of teeth after endodontic treatment is an important part of the restorative practice in dentistry. Preservation of coronal dental tissue, the use of posts with properties similar to dentin and effective post adhesion are the most important factors for the successful clinical performance of restored endodontically treated teeth.