Iran Dental Specialty Board - Endodontics key terms

A mild, transient pulpal inflammation provoked by stimuli such as cold or sweet, which subsides quickly once the stimulus is removed and leaves the pulp able to heal without endodontic treatment.

A severely inflamed pulp that cannot heal, producing spontaneous or lingering pain and requiring pulp removal or extraction; historically a clinical diagnosis, now increasingly judged by whether vital tissue can be preserved.

Death of pulp tissue, typically after irreversible inflammation or trauma, leaving a nonresponsive canal that may become infected and lead to apical periodontitis.

Inflammation of the periapical tissues caused mainly by microbial infection of the root canal system, usually visible radiographically as a widened periodontal ligament space or periapical radiolucency.

A structured community of bacteria attached to canal walls and embedded in an extracellular matrix, which resists irrigation, medicaments, and host defenses and is the main target of chemomechanical preparation.

A facultative, biofilm-forming gram-positive coccus frequently recovered from root canals with persistent or post-treatment disease, known for surviving nutrient deprivation and intracanal medication.

The distance from a coronal reference point to the intended apical limit of instrumentation and obturation, usually determined with an electronic apex locator and confirmed radiographically.

The narrowest point of the canal near the cementodentinal junction, generally considered the ideal apical termination for cleaning, shaping, and obturation.

Deliberate passive passage of a fine file 0.5 to 1 mm beyond the apical foramen to prevent debris accumulation and maintain the canal path, without widening the foramen.

A device that measures electrical impedance between the canal file and the periodontium to estimate the apical foramen position, useful when the apex is not clearly visible radiographically.

The capacity of a shaping instrument to remain centered in the original canal path and avoid transporting the curvature, assessed by comparing pre- and post-instrumentation cross-sections.

An artificial irregularity created on the canal wall by incorrect instrument use, which can block access to the apical portion and complicate further cleaning and shaping.

Loss of the original canal curvature caused by excessive or misdirected instrumentation, resulting in an altered path that may strip the inner wall or perforate the outer wall.

An engine-driven file made of a nickel-titanium alloy that offers greater flexibility and fatigue resistance than stainless steel, used with a crown-down or similar sequence to shape curved canals.

A back-and-forth rotational movement of a single-file system in which the cutting angle exceeds the release angle, reducing cyclic fatigue and screw-in forces in curved canals.

Failure of a rotating file from repeated tension and compression cycles in a curved canal, occurring without prior visible deformation and independent of torsional overload.

File separation caused by excessive torque when the tip binds while the shaft keeps rotating, often preceded by visible unwinding of the flutes.

The primary irrigant in endodontics, providing antimicrobial action and tissue dissolution; concentration, volume, temperature, and contact time all influence its effectiveness and its risk of extrusion injury.

A microcrystalline film of dentin debris and organic material created by instrumentation that occludes dentinal tubules, harbors bacteria, and impedes irrigant and sealer penetration unless removed.

A solution such as EDTA that binds calcium ions to dissolve the inorganic portion of the smear layer and soften canal walls, typically used as a final rinse before obturation.

A antimicrobial agent such as calcium hydroxide placed in the canal between visits to reduce bacterial load and neutralize endotoxin in cases where infection is not controlled in one appointment.

Selection of the final apical preparation diameter, usually by initial file size plus a defined enlargement, balancing bacterial reduction against the risk of transporting the foramen.

Three-dimensional filling of the cleaned canal space with a core material and sealer to prevent reinfection and entomb remaining microorganisms, typically using gutta-percha with a thermoplastic or single-cone technique.

A cement used with the core filling material to fill irregularities, seal the canal wall interface, and compensate for shrinkage or incomplete adaptation of gutta-percha.

The restoration and tooth structure that prevent oral fluids and bacteria from leaking past the canal filling; its integrity strongly influences endodontic success.

Persistent or emerging periapical inflammation after root canal treatment, usually caused by intraradicular infection, missed anatomy, or leakage, and the main indication for retreatment.

Removal of the existing filling, renegotiation and disinfection of the canal system, and re-obturation, undertaken when post-treatment disease is present and the tooth is restorable.

The attempt to remove a separated file or other object from the canal using ultrasonics, trephines, or specialized devices, weighing the risk of dentin loss and perforation against the benefit.

Complete displacement of a tooth out of its socket; management depends on extraoral time and storage medium, with replantation and splinting followed by monitoring for pulp necrosis and ankylosis.

Temporary stabilization of traumatically injured teeth with a flexible or rigid device, with the type and duration chosen to support healing while limiting ankylosis and root resorption.

Biologically based treatment of immature necrotic teeth that aims to restore pulp-like tissue and continue root development, typically using canal disinfection, a blood clot, and a coronal seal.

Conservative procedures such as pulp capping or partial and full pulpotomy that preserve part or all of the vital pulp, usually with a bioceramic or calcium hydroxide material.

Surgical removal of the apical portion of a root, usually with a bevel that respects the canal anatomy, to eliminate infected Cementum and allow retrograde sealing.

Placement of a root-end filling material into the prepared apical cavity during apical surgery to seal the canal from the periapical tissues.

A microsurgical procedure that removes periapical pathology and the infected root end, indicated when nonsurgical retreatment is impossible or has failed and the tooth remains restorable.

A lesion involving both the pulp and the periodontium, where the prognosis depends on identifying the primary cause and whether the defect communicates through the apical foramen or a lateral canal.

A surgical or orthodontic procedure that increases the supragingival tooth structure available for a restoration, often needed when caries or fracture extends below the gingival margin.

A restorative foundation placed in a prepared root canal to retain a coronal restoration, requiring preservation of at least 4 to 5 mm of apical gutta-percha to maintain the seal.

An injection targeting the inferior alveolar nerve before it enters the mandibular canal, providing anesthesia to mandibular teeth and soft tissues on the injected side, with failure often due to anatomical variation.

Inadequate anesthesia despite an apparently correct injection, caused by anatomical variation, inflammation-induced acidity, needle misplacement, or patient anxiety, and managed by modifying the technique or agent.

An amide local anesthetic with a thiophene ring that is highly lipid soluble and effective for infiltration anesthesia in mandibular teeth, metabolized mainly by plasma esterases.

A prospective study in which participants are randomly assigned to interventions, minimizing selection bias and providing the strongest primary evidence for treatment effectiveness in clinical endodontics.

A structured, reproducible synthesis of all relevant studies on a focused question, often with meta-analysis, used to summarize evidence and identify gaps in endodontic research.

A hierarchical ranking of study designs, from systematic reviews of randomized trials at the top to expert opinion and case reports at the bottom, guiding clinical decisions.

Radiographic and clinical resolution of periapical inflammation after treatment, usually assessed at 1 year and later, with size reduction or disappearance of the radiolucency and absence of symptoms.

The process of explaining diagnosis, treatment options, risks, benefits, and alternatives so the patient can make a voluntary decision, documented before endodontic care begins.

Loss of dentin and cementum from internal or external surfaces, often related to trauma, orthodontics, or inflammation, and requiring accurate diagnosis to determine whether endodontic treatment is indicated.