14
Management of Failed Root Canal Treatment in an Anterior Tooth Using Calcium Silicate Cement
Viresh Chopra1,2,3 and Ajinkya Pawar4
1 Adult Restorative Dentistry, Oman Dental College, Muscat, Oman
2 Endodontology, Oman Dental College, Muscat, Oman
3 Bart’s London School of Medicine and Dentistry, Queen Mary University, London, UK
4 Conservative Dentistry and Endodontics, Nair Hospital Dental College, Mumbai, India
14.1 Introduction of the Case
Case of failed root canal treatment associated with a previous inadequate root canal treatment and suspected inadequate obturation. The patient reported with symptomatic apical periodontitis (SAP).
14.1.1 Patient Information
- Age: 28
- Gender: Female
- Medical history: Noncontributory
- Identification of the tooth: Right maxillary central incisor (Tooth 11)
- Dental history:
Chief complaint: Patient reported with a chief complaint of tenderness on biting. Occasionally, she felt swelling between teeth 11 and 12. The buccal vestibule between 11 and 12 is tender to touch.
- Clinical examination findings:
The tooth 11 is tender to percussion.
- Preoperative radiological assessment:
The periapical radiograph revealed previous root canal treatment in 11. The following are the observations after reading the preoperative radiograph: (Figure 14.1)
- Inadequate obturation with suspected poor lateral condensation.
- Periapical radiolucency around the root of 11
- Clinical examination findings:
Figure 14.1 Preoperative radiograph.
The patient was made aware of the inadequate RCT in relation to 11 and advised her to re‐treat the same tooth nonsurgically (NSRCT).
14.1.2 Diagnosis (Pulpal and Periapical)
Failed primary root canal treatment with SAP.
14.1.2.1 Advice
Nonsurgical re‐treatment of 11 was advised to the patient. The patient agreed for the treatment.
14.2 Treatment Plan
The treatment was planned in different stages:
Stage 1:
- Local anesthetic administration
- Rubber dam isolation
- Gaining entry in the canal and locating previous gutta‐percha (GP)
- Removal of previous GP
- Placement of intracanal medicament (IM)
Stage 2:
- Removal of IM
- Working length determination (electronic and radiographic)
- Cleaning and disinfection
- Placement of calcium silicate cement.
Stage 3:
- Obturation with thermoplasticized GP
- Core buildup
14.2.1 Treatment Procedure for the First Appointment
Buccal infiltration anesthesia was administered and rubber dam placed for isolation. The endodontic access was gained using Endo‐Z bur. Resin composite restoration was removed to reveal the previous GP in the canal. Once located, the previous GP was removed using endo shaper files (FKG Dentaire, Switzerland). Once the GP was completely removed periapical (PA) radiograph was taken to verify the same (Figure 14.2).
Figure 14.2 PA showing complete removal of GP.
The apex was clearly visualized under the microscope (OPMI Pico, Carl Zeiss, Germany) (Figure 14.3).
Figure 14.3 Wide open apex clearly visible under magnification.
IM (Opacal, Produits Dentaires, SA) was used between the appointments. It was injected with dispensing syringe directly inside the canal (Video 14.1). The patient was recalled for completion of root canal retreatment. 
14.2.2 Treatment Procedure for the Second Appointment
The second appointment was planned to continue the root canal retreatment with adequate disinfection followed with apical plug formation with calcium silicate cement. Mineral trioxide aggregate (MTA) (Produits Dentaires, Switzerland) was used as an apical plug material.
The estimated length of MTA placement was measured by placing a plugger that goes to 2 mm short of the established working length.
MTA was placed using micro apical plug system (MAP system) (Produits Dentaires, Switzerland). Incremental placement followed by gentle condensation was done in order to create an adequate apical plug (Video 14.2). Once the apical plug was formed, it was verified clinically as well as radiographically (Figures 14.4 and 14.5). 
Following apical plug formation with MTA, the canal was obturated with thermoplasticized GP using Fast Pack and Fast Fill (Eighteeth, China) (Video 14.3h). 
The obturation was verified clinically as well as with an immediate post‐obturation radiograph (Figures 14.6 and 14.7).
Figure 14.4 Clinical verification of MTA under DOM.
Figure 14.5 Radiographic verification of apical barrier placement.
Figure 14.6 Obturation of the root canal using thermoplasticized GP.
Figure 14.7 PA radiograph to verify the obturation.
14.2.3 Irrigation Protocol
- Hand files were used with EDTA gel, rinsing with saline.
- TruNatomy irrigation needles were used.
- 2.5% sodium hypochlorite throughout the cleaning and shaping procedure. Rinse with saline.
- 17% EDTA 1ml/canal with sonic/ultrasonic activation. Rinse with saline.
- Final rinse with 2.5% sodium hypochlorite with internal heating with any instrument, e.g. Touch’n Heat, and sonic ultrasonic activation for 20–30 seconds per canal.
Flushing with saline between irrigants is a must, as it will stop the irrigants from reacting with each other.
14.2.3.1 Materials Used for Obturation
Calcium silicate cement as apical plug barrier, thermoplasticized GP as core obturation material.
14.3 Technical Aspects
Root canal retreatment required certain specific case related considerations in order to achieve success. The first and foremost is complete removal of previous GP. Adequate instruments should be used to ensure that the canal is free of any residual filling material. The second consideration in such a case is that it requires minimal shaping but more of disinfection. However, care needs to be taken that the irrigant (sodium hypochlorite) should not go in the periapical area, else sodium hypochlorite accident can happen.
The third consideration is to calculate the exact area/length where MTA needs to be placed. MTA being a very biocompatible material is very friendly beyond the periapical area. However, it is not required in the periapical area, therefore, an attempt should be made to place it right at the apex. Cone beam computed tomography (CBCT) is of prime importance in such a case. However, patient could not afford it, therefore, we had to perform re‐treatment without CBCT.
Lastly, choosing the correct obturation technique is an important factor in deciding the success of the treatment provided.
14.3.1 Follow‐up
Patient became asymptomatic after the root canal treatment and follow‐up radiographs show periapical healing.
14.4 Learning Objectives
The reader should be able to understand the following:
- The significance of proper reading of the preoperative radiograph.
- The emphasis on achieving straight line access cannot be ignored.
- The role of irrigants for disinfecting the root canal system.
- The role of using adequate files to remove GP from the root canals.
- The importance of incorporating the whole root canal system in the disinfection process during primary root canal treatment.
- Choosing the correct material for apical plug barrier.
- Placement of apical barrier material with adequate tools such as MAP system.
- Choosing the correct obturation technique.
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