Endodontics: Pulp and Periradicular Tissues

• Endodontics is the branch of dentistry concerned with the morphology, physiology, and pathology of the dental pulp and periradicular tissues.
• It includes the etiology, prevention, diagnosis, and treatment of diseases and injuries of these tissues.

Pulp

• The dental pulp is the soft tissue inside the tooth that contains blood vessels, nerves, and connective tissue.
• The main function of the pulp is to form dentin (the hard tissue that makes up the bulk of the tooth).
• Other functions include nutrition, sensation, and defense.

Periradicular Tissues

• Periradicular tissues are the tissues surrounding the root of the tooth.
• These include the periodontal ligament, cementum, and alveolar bone.
• These tissues support the tooth and attach it to the jawbone.

Etiology of Endodontic Diseases

• The most common cause of pulpal and periradicular diseases is microbial infection.
• This usually occurs as a result of dental caries (tooth decay).
• Other causes include trauma, periodontal disease, and developmental anomalies.

Diagnosis in Endodontics

• A thorough medical and dental history is essential.
• Clinical examination includes visual inspection, palpation, percussion, and mobility testing.
• Radiographic examination is crucial for assessing the condition of the pulp and periradicular tissues.
• Pulp sensibility testing (e.g., cold and electric pulp tests) helps determine the vitality of the pulp.

Radiographic Examination

• Periapical radiographs are used to visualize the entire tooth and surrounding bone.
• Bitewing radiographs help detect interproximal caries.
• Cone-beam computed tomography (CBCT) provides a three-dimensional view of the teeth and surrounding structures.
• CBCT is useful for complex cases, such as those involving root fractures, resorption, or anatomical variations.

Pulp Sensibility Testing

• Cold test involves applying a cold stimulus (e.g., ice or refrigerant spray) to the tooth.
• An exaggerated or prolonged response may indicate reversible pulpitis.
• No response may indicate pulp necrosis.
• Electric pulp test (EPT) uses an electrical stimulus to stimulate the nerve fibers in the pulp.
• A positive response indicates that the pulp is vital, but does not indicate the health of the pulp.
• Both tests can yield false positive or negative especially in young patients, heavily calcified teeth, or traumatized teeth.

Endodontic Treatment

• The goal of endodontic treatment is to eliminate infection from the root canal system and to prevent reinfection.
• Root canal treatment involves removing the infected or necrotic pulp, cleaning and shaping the root canals, and filling the canals with a biocompatible material.
• Apicoectomy involves surgical removal of the root tip and surrounding infected tissue.

Root Canal Treatment Procedure

• Access cavity preparation involves creating an opening in the tooth to access the root canals.
• Cleaning and shaping involves using files and irrigants to remove debris and bacteria from the canals.
• Obturation involves filling the root canals with a biocompatible material, usually gutta-percha and sealer.

Instruments Used in Endodontics

• Endodontic files are used to clean and shape the root canals.
• Irrigating solutions are used to disinfect the canals and remove debris.
• Obturation materials are used to fill the canals.

Irrigating Solutions

• Sodium hypochlorite (NaOCl) is a commonly used irrigant due to its antibacterial properties and ability to dissolve organic tissue.
• EDTA (ethylenediaminetetraacetic acid) is used to remove the smear layer (a layer of debris that forms on the canal walls during instrumentation).
• Chlorhexidine is an alternative irrigant with antibacterial properties.

Obturation Materials

• Gutta-percha is a natural rubber material that is commonly used to fill root canals.
• Endodontic sealers are used to fill the space between the gutta-percha and the canal walls.
• Common sealers include resin-based sealers, calcium silicate-based sealers, and zinc oxide-eugenol sealers.

Success of Endodontic Treatment

• Success depends on factors such as the preoperative condition of the tooth, the quality of the root canal treatment, and the presence of any complications.
• A successful outcome is typically defined as the absence of clinical signs and symptoms and radiographic evidence of periradicular healing.

Complications

• Procedural errors, such as perforation or instrument separation, can occur during root canal treatment.
• Flare-ups (postoperative pain and swelling) can occur after root canal treatment.
• Root canal failure can occur due to persistent infection, missed canals, or inadequate obturation.
• Treatment options for root canal failure include retreatment or apicoectomy.

Endodontic Retreatment

• Retreatment involves removing the existing root canal filling material, cleaning and shaping the canals, and obturating the canals again.
• Retreatment is often more complex than the initial root canal treatment due to the presence of the existing filling material and potential anatomical complexities.

Apicoectomy

• Apicoectomy is a surgical procedure that involves removing the root tip and surrounding infected tissue.
• It is indicated when root canal treatment or retreatment is not possible or has failed.
• A root-end filling is typically placed to seal the resected root surface.

Vital Pulp Therapy

• Vital pulp therapy aims to preserve the vitality of the dental pulp.
• Procedures include indirect pulp capping, direct pulp capping, and pulpotomy.
• Indirect pulp capping involves placing a medicament over a thin layer of remaining caries to stimulate pulp healing.
• Direct pulp capping involves placing a medicament directly on a small pulp exposure to promote healing.
• Pulpotomy involves removing the coronal portion of the pulp while leaving the radicular pulp intact.

Pulp Regeneration

• Pulp regeneration aims to regenerate the pulp tissue in a tooth with a necrotic pulp.
• It involves disinfecting the root canal system and inducing bleeding into the canal space to promote tissue regeneration.
• Growth factors and scaffolds may be used to enhance the regenerative process.

Traumatic Dental Injuries

• Endodontic treatment may be required for teeth that have been traumatized.
• Common injuries include crown fractures, root fractures, and avulsions.
• Treatment may involve root canal treatment, apexification, or replantation.

Apexification

• Apexification is a procedure performed on immature teeth with necrotic pulps to induce root-end closure.
• It involves placing a calcium hydroxide or MTA (mineral trioxide aggregate) apical plug to create a barrier against which to obturate.

Resorption

• Resorption is the physiological or pathological removal of tooth structure.
• Internal resorption occurs within the root canal system.
• External resorption occurs on the external surface of the root.
• Treatment depends on the type and extent of resorption and may involve root canal treatment or surgery.