Surgical Endodontics, Retreatment & Dental Trauma MCQ

Not every endodontic problem is a routine first canal. Some root canals fail and need retreatment, either nonsurgically (re-entering and re-disinfecting the canal) or with apical surgery. Some teeth are injured and need trauma management, where the survival of the periodontal ligament cells and pulp drives the prognosis. Immature teeth with open apices need regenerative or apexification protocols rather than a conventional fill, and resorption (from inside or outside the tooth) must be recognized. This module covers these non-routine problems. The boundary with oral surgery is practical: oral surgery owns extraction technique and facial trauma, while endodontics owns the pulp and periodontal-ligament response, replantation, and root-end procedures.

Nonsurgical Retreatment

• Nonsurgical retreatment is generally the first choice for a failing root canal when the canal can be re-accessed: the gutta-percha is removed, the canal is re-disinfected, and it is re-obturated.
• It is the chance to correct the usual reasons for failure, a missed canal (such as an MB2), persistent infection, or coronal leakage that recontaminated the canal.
• The removability of gutta-percha is exactly what makes nonsurgical retreatment possible.
• Surgery is reserved for when orthograde re-access is not feasible (for example a well-fitting post or canal obstruction) or when retreatment has not resolved the disease.

Surgical Endodontics

• Apical surgery (apicoectomy) is the surgical management of persistent periapical disease: the root apex is surgically exposed and resected (root-end resection).
• After the apex is resected, a retrograde root-end filling is placed to seal the canal from the apical side, and mineral trioxide aggregate (MTA) is a preferred root-end material because it is biocompatible and seals in the presence of moisture.
• It is indicated when nonsurgical retreatment is not feasible or has failed, and it also allows curettage of the lesion and biopsy of periapical tissue when needed.
• Surgical endodontics manages the apex and the lesion; the extraction of a tooth and broader dentoalveolar or facial surgery belong to oral surgery.

Traumatic Dental Injuries

• An avulsed permanent tooth should be replanted as soon as possible; if it cannot be replanted at the scene, it is stored in a physiologic medium (milk, Hank's balanced salt solution, or saliva), never water, which is hypotonic and lyses the periodontal ligament cells.
• The viability of the periodontal ligament cells (which depends on extra-oral time and the storage medium) largely determines whether the tooth heals or undergoes ankylosis and replacement resorption.
• After replantation or a luxation, the tooth is stabilized with a flexible (physiologic) splint for a short period; a flexible splint allows normal micromovement and lowers the risk of ankylosis compared with a rigid splint.
• A crown fracture exposing the pulp in a young tooth is managed by vital pulp therapy (pulp cap or pulpotomy) to preserve vitality, and a horizontal root fracture is repositioned and splinted, with a better prognosis when the fracture is in the apical third.

Regenerative Endodontics

• An immature permanent tooth with a necrotic pulp has an open apex and thin dentinal walls, so a conventional fill is difficult and the tooth remains weak.
• Regenerative endodontics (revascularization) disinfects the canal and induces a blood clot or scaffold to encourage continued root development, thickening the walls and closing the apex over time.
• Apexification is the alternative: inducing or placing an apical barrier (an MTA plug) to allow obturation when continued root development is not pursued.
• The goal in the immature tooth is continued root development and a stronger root when possible, which is why these teeth are not simply treated like mature ones.

Resorption

• Internal resorption originates within the pulp (clastic cells resorbing dentin from inside) and can show as a pink discoloration of the crown (the pink tooth); removing the pulp by root canal therapy arrests it.
• External resorption originates from the root surface or periodontal ligament, often after trauma, replantation, or other insult.
• Replacement resorption (ankylosis) follows death of the periodontal ligament (for example a dried-out avulsed tooth): the tooth fuses to bone and is gradually replaced by it.
• Recognizing the type of resorption (internal versus external) on the radiograph guides management, from root canal therapy for internal resorption to monitoring or intervention for external forms.