INTRODUCTION
Root canal treatment is one of the most frequently performed procedures in clinical dentistry and plays a critical role in preserving natural dentition. The primary objective of endodontic therapy is the elimination of microorganisms and necrotic tissue from the root canal system followed by complete sealing of the canal space to prevent reinfection. The success of treatment depends on accurate diagnosis, proper access cavity design, effective biomechanical preparation, adequate irrigation, three-dimensional obturation, and a well-sealed definitive restoration.
This article reviews the common procedural errors encountered during root canal treatment, their causes, clinical consequences, preventive measures, and methods of correction.
DIAGNOSTIC ERRORS
Accurate diagnosis forms the foundation of successful endodontic therapy. An incorrect diagnosis may lead to unnecessary treatment or failure to address the actual source of pain. One of the most common mistakes is the misinterpretation of pulpal status. Teeth exhibiting reversible pulpitis may be mistakenly diagnosed as having irreversible pulpitis, leading to unnecessary root canal treatment. Conversely, teeth requiring endodontic intervention may be managed conservatively, resulting in progression of pulpal disease.
INCORRECT DIAGNOSIS OF PULPAL STATUS
Examples:
Treating reversible pulpitis as irreversible pulpitis.
Performing RCT on teeth with non-odontogenic pain.
Misdiagnosing cracked tooth syndrome.
Another significant diagnostic error involves failure to identify the true source of pain. Orofacial pain may originate from periodontal disease, temporomandibular disorders, sinus pathology, neuralgias, or referred pain from adjacent teeth. Inadequate history taking and incomplete clinical examination often contribute to such errors. Comprehensive evaluation using thermal tests, electric pulp testing, percussion, palpation, periodontal assessment, and radiographic examination should be performed before initiating treatment.
Failure to detect additional canals is another common cause of treatment failure. Maxillary first molars frequently contain a second mesiobuccal canal (MB2), while mandibular molars may contain middle mesial canals. If these canals remain untreated, residual microorganisms may persist and compromise healing. The use of cone beam computed tomography (CBCT), dental operating microscopes, and magnification loupes can significantly improve canal detection rates.
ERRORS DURING ACCESS CAVITY PREPARATION
Access cavity preparation is often regarded as the most critical step in endodontic treatment because it determines the clinician’s ability to locate, clean, and shape the entire root canal system. Inadequate access may result in missed canals, instrument separation, ledge formation, and incomplete debridement.
One common error is improper positioning of the access cavity. An access cavity that is too conservative may restrict straight-line access to the canals, increasing procedural difficulties during instrumentation. Conversely, excessive removal of tooth structure can weaken the remaining dentin and predispose the tooth to fracture. Therefore, access preparation should balance adequate visibility and canal accessibility with preservation of structural integrity.
Perforation of the pulpal floor is a serious iatrogenic complication frequently encountered in molars. It usually results from failure to assess pulp chamber depth before access preparation or inadequate understanding of internal tooth anatomy. Furcation perforations can create direct communication between the root canal system and periodontal tissues, resulting in inflammation and attachment loss. Immediate sealing with mineral trioxide aggregate (MTA) or bioceramic repair materials significantly improves prognosis.
Another common problem is failure to identify all canal orifices. Missed canals remain one of the leading causes of persistent apical periodontitis after treatment. Careful inspection of the chamber floor under magnification, troughing developmental grooves with ultrasonic tips, and adherence to the laws of pulp chamber anatomy are effective methods of locating hidden canals.
ERRORS DURING BIOMECHANICAL PREPARATION
Biomechanical preparation aims to remove infected tissue, reduce microbial load, and create a continuously tapered canal shape suitable for obturation. Procedural errors during this phase may compromise cleaning and shaping effectiveness.
1.Ledge formation occurs when instruments create an artificial irregularity in the canal wall, preventing access to the apical portion of the canal. This commonly occurs in curved canals when rigid instruments are forced apically without establishing a glide path. The resulting inability to clean the apical region can significantly affect treatment success. Prevention involves the use of small pre-curved hand files, glide path preparation, and flexible nickel-titanium instruments.
2.Canal transportation is another frequently encountered error, particularly in curved roots. Excessive dentin removal from the outer wall of the canal causes deviation from the original canal path. Transportation can compromise apical sealing and increase the risk of perforation. Modern rotary nickel-titanium systems have reduced the incidence of transportation due to their superior flexibility.
3.Instrument separation remains one of the most stressful complications for clinicians. Fracture may occur due to cyclic fatigue, torsional stress, excessive force, or repeated instrument use. A separated instrument may prevent adequate cleaning of the canal beyond the obstruction. Retrieval should be attempted when feasible, particularly if the fragment compromises canal disinfection. Ultrasonic techniques under microscopic visualization offer the highest success rates for instrument retrieval.
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