Nonsurgical Retreatment of Mandibular Incisors with Periapical Lesions –A Case Report

Introduction

The main objective of endodontic treatment is achieved by reaching an adequate chemomechanical debridement and three-dimensional obturation of canal space.^1,2 The root canal system carries branches that convey with the periodontal ligament space apically, laterally, and furcally. Consequently, any exit from the root canal system to the periodontal attachment apparatus should be considered as a portal of exit through which endodontic breakdown by-products may pass. Refinement in the management of lesions of endodontic origin starts with the recognition of the interrelationships between pulpal disease and the flow of irritants along these anatomical pathways.

Failures in endodontics can be due to deficiencies in cleaning, shaping, and obturation, iatrogenic causes, or re-infection of the root canal system when coronal leakage occurs after the completion of endodontic treatment.³ For a successful root canal treatment, there should be a combined clinical and radiographic evaluation. The patient should be scheduled for follow-ups to determine the success of the treatment and whether the tooth in question is functional. Periapical radiographs might not detect periapical lesions restricted within the cancellous bone. Lesions of a certain size can be detected in regions covered by a thin cortex, lesions of the same size cannot be detected in regions covered by a thicker cortex. ⁴

Regardless of the etiology, the eventual causes of all failures are leakage and bacterial contamination.⁵ Endodontic failures must be evaluated so that a choice can be made among nonsurgical retreatment, surgical retreatment, or extraction.⁶ The goals of nonsurgical retreatment are to eliminate materials if present from the root canal space, address deficiencies, and restore defects that are pathological or iatrogenic in origin. These procedures confirm previously missed canals or mechanical failures. Nonsurgical endodontic retreatment procedures have enormous potential for fulfillment if the rules for case selection are respected and relevant technologies, best materials, and precise techniques are utilized.⁷ Retreatment cases are often complicated and require high expertise by the dentist.

The present case report shows that a combination of an appropriate diagnosis along with a nonsurgical re-root canal treatment can lead to the complete healing of periapical lesions.

Case Presentation

A 25-year-old female with no history of any systemic illness was referred to the outpatient department of Conservative Dentistry and Endodontics and presented with a history of throbbing pain and tenderness of lower anterior teeth for the past 3 days. The patient had undergone root canal treatment six months ago. Clinical evaluation revealed that the patient had a fixed partial denture with right and left mandibular central and lateral incisors. Tenderness on percussion was noted. Periodontal pocket and tooth mobility were not observed. Submucosal swelling was absent. On radiographic examination, the teeth that had been endodontically treated previously and substandard obturation was reported (Fig 1). Additionally, frank pathology was evident, which was present apical to the roots of the right and left central and lateral incisors. Based on the clinical and radiographic examinations, the diagnosis was made as previously treated teeth with symptomatic apical periodontitis. A nonsurgical root canal retreatment was decided accordingly. 

The fixed, partial denture was removed (Fig 2). Local anesthesia with 2% lignocaine and 1:1,00,000 epinephrine was given to the patient and rubber dam isolation was done. The access cavity was reentered and modifications were made using a high-speed handpiece with a round carbide bur (Dentsply Maillefer, Switzerland). The gutta-percha in the third coronal was removed with Gates Glidden drills #3. The gutta-percha in the middle and third apical was first softened with chloroform solvent and then removed with size #25 Hedstrom file (Mani, Japan). Purulent discharge was observed immediately after removal of the gutta-percha. After radiographic determination of working length (Fig 3), cleaning and shaping of the canals were performed with hand instrumentation (passive step-back technique) (Mani, Japan) up to master apical size 30 and step back up to 3 size larger file (#45). The root canal spaces were irrigated with 15 mL of 3% sodium hypochlorite intermittently (Percan, Septodont, India). A creamy paste of calcium hydroxide (Metapex, Metabiomed) was placed into the canals using lentulo spiral. The access cavity was sealed with temporary filling material Cavit (3M, ESPE). Before dismissal, the patient was prescribed analgesic medications.

The patient was recalled one week later. No signs and symptoms were present. Under rubber dam isolation, calcium hydroxide was removed from the canals by irrigation with 10 ml of 3% sodium hypochlorite and H-file #30. Final irrigation was done with 2% chlorhexidine (Asep-RC, Anabond, India). Root canal spaces were obturated with gutta-percha (Maillefer Densply, Switzerland) and AH plus sealer (Dentsply, Konstanz, German) using the lateral compaction technique (Fig 4). The access cavity was sealed with composite restoration and crowns were advised.

The patient was followed-up at 3, 6, 12, and 18 months after treatment. No sensitivity to palpation and percussion on clinical evaluation was noted and the radiographic examination at the end of 18 months showed complete osseous healing (Fig 5).

Discussion

It is known that periapical pathologic alterations originate from pulpal infections. When the toxic agents are removed, the immune system has mechanisms to encourage the repair of tissues and structures affected by the disease processes.⁸ Therefore, these toxic agents have to be removed from the root canal system to create a favorable environment for the repair of a periapical lesion. ^8,9 Proper cleaning and shaping of the root canal system is the major goal of root canal treatment followed by excellent obturation to seal it three dimensionally to prevent reinfection of the tooth. Although primary endodontic therapy is a predictable procedure with a high degree of success, failures can occur posttreatment.^10,11 Endodontically treated teeth with persistent periapical lesion(s) can be conserved with nonsurgical retreatment or endodontic surgery, presuming the tooth is periodontally sound, and restorable and the patient desires to withhold the tooth.¹²

In the current clinical case, nonsurgical retreatment was indicated because of the radiographic appearance of inadequate previous root canal therapy with evidence of periapical lesions. Generally, the success rate of retreatment is considered to be lower than the success rate of primary endodontic treatment. Yet, it is also deemed that if access to the apical foramen isn’t inhibited by canal blocks, retreatment can have an identical result to primary endodontic treatment. Negative prognostic factors are due to the pre-existence of periapical lesions, the quality of previous treatment, the quality of the coronal restoration, and the occurrence of iatrogenic errors.¹³

The major differences between primary root canal treatment (RCT) and retreatment lie in the compromised access to the site of apical infection, either due to iatrogenic errors in canal preparation such as ledge formation or the inability to negotiate canal blockages completely due to artificial or natural materials. The outcome of retreatment should be aimed at clearing the apical infection as long as access to the infection can be re-established. Therefore the clinicians should acquire the skill to diagnose properly and correct the procedural errors if present, as well as to prevent the introduction of further iatrogenic errors during the re-treatment procedure. Calcium hydroxide dressing provides excellent clinical and laboratory results and hence proves to be an excellent intracanal medicament. Calcium hydroxide primarily acts on inflamed tissues and epithelial cystic lining and finally results in periapical healing and bone repair. In the present case, since the symptoms were relieved after one week of calcium hydroxide, there was no need for the use of antibiotic paste.

Healing of periapical lesions is the consequence of adequate biomechanical preparation and three-dimensional filling of the entire root canal space.¹⁴ Decrease in the size of radiolucency was considered to represent the healing of the periapical pathology and thus commonly used as radiographic criteria to determine a successful treatment.¹³ Some of the studies stated that healing takes place within 12 months, while others found that this may take up to several years.¹⁵ However, in certain circumstances the healing of periapical lesions was associated with scarring. The incidence of scar formation in periapical healing, after nonsurgical root canal treatment is low.⁴ In the present case, a time of 18 months was required for the complete healing of the periapical lesion.

Permanent restorations after root canal therapy affect the prognosis and adequate coronal restoration should be placed as early as possible. In this case, immediately after obturation composite restoration and crowns were placed.

Primary endodontic treatment is proven to be successful in a majority of the cases, even though clinicians are challenged with post-treatment diseases. Endodontic retreatment might be an appropriate option, in case of a post-treatment disease following an endodontic failure. Giving attention to details not only enhances the finesse of the endodontic quality but also doubles success. This case report has highlighted the importance of case selection and the role of nonsurgical endodontic retreatment in preserving teeth. A properly performed, endodontic treatment is the pillar of restorative and reconstructive dentistry. Regular follow-ups aid in assessing the result and should be done yearly to watch for any changes.

Conflict of interest

None