ADC - Australian Dental Council Endodontic Principles and Procedures Questions and Answers

Question 1

A 25-year-old patient presents with a severe, spontaneous, throbbing pain in the mandibular right first molar (tooth 46) that worsens when lying down. Clinical examination reveals a deep carious lesion. The tooth is tender to percussion, and pulp vitality testing with a cold stimulus elicits a sharp, lingering pain. A periapical radiograph shows a widened periodontal ligament space around the mesial root apex. What is the most likely diagnosis for the pulp and periapical tissues?

Accepted Answer

Irreversible pulpitis with symptomatic apical periodontitis

Answer

The patient's symptoms of spontaneous, severe, and lingering pain are classic signs of irreversible pulpitis. The tenderness to percussion and radiographic evidence of a widened PDL indicate that the inflammation has extended into the periapical tissues, leading to symptomatic apical periodontitis. Reversible pulpitis would present with sharp, non-lingering pain to a stimulus. Pulp necrosis would not respond to cold testing, and an acute apical abscess would typically present with more pronounced swelling.

Question 2

During root canal treatment, which of the following is the primary function of sodium hypochlorite (NaOCl) as an irrigant?

Accepted Answer

Dissolution of organic tissue and antimicrobial action

Answer

Sodium hypochlorite's primary and most crucial roles in endodontics are its ability to dissolve necrotic and vital pulp tissue (organic components) and its potent broad-spectrum antimicrobial activity against bacteria and biofilms within the root canal system. While it has some lubricating effect, this is not its primary function. Removal of the smear layer (inorganic component) is primarily achieved by chelating agents like EDTA.

Question 3

A dentist is performing root canal treatment on a maxillary first molar. After creating the access cavity and beginning instrumentation, they notice a small, persistent hemorrhage from the pulpal floor, mesial to the main mesiobuccal canal orifice. Which of the following procedural errors is the most likely cause?

Accepted Answer

Perforation into the furcation

Answer

A perforation into the furcation area is a common procedural error during access cavity preparation in molars. It occurs when the bur is directed too deeply or at an incorrect angle, breaching the pulpal floor and entering the periodontal ligament space in the furcation. This typically results in persistent hemorrhage that is difficult to control. Missing a canal or a fractured instrument would not typically present with bleeding from the pulpal floor itself.

Question 4

A 10-year-old child presents to your clinic 45 minutes after avulsing their maxillary central incisor (tooth 11) during a sports accident. The tooth has been kept in a dry handkerchief. The child is medically fit. What is the most appropriate immediate management step?

Accepted Answer

Gently rinse the tooth with saline, replant it immediately, and splint for 2 weeks.

Answer

According to the International Association of Dental Traumatology (IADT) guidelines, for an avulsed permanent tooth with an open or closed apex and an extra-oral dry time of less than 60 minutes, the tooth should be gently rinsed with a sterile solution like saline, replanted as soon as possible, and a flexible splint placed for up to 2 weeks. Scrubbing the root surface is contraindicated as it damages the periodontal ligament cells. Delaying replantation significantly worsens the prognosis. Extra-oral RCT is only considered if the extra-oral dry time is prolonged ( > 60 mins).

Question 5

Which of the following is a significant advantage of using bioceramic sealers (e.g., MTA-based sealers) for root canal obturation compared to traditional zinc oxide-eugenol (ZOE) based sealers?

Accepted Answer

They are bioactive and promote hard tissue formation.

Answer

Bioceramic sealers are known for their biocompatibility and bioactivity. They can interact with periradicular tissues to promote the formation of cementum and bone, which is advantageous for healing. Unlike ZOE sealers, they are hydrophilic (set in the presence of moisture) and undergo slight expansion upon setting. A major disadvantage is that they are very difficult to remove, making retreatment challenging.

ADC - Australian Dental Council Practice Test

ADC - Australian Dental Council Practice Test

ADC - Australian Dental Council Endodontic Principles and Procedures Questions and Answers