MCQ Flashcards

Which cells are primarily responsible for bone resorption during orthodontic tooth movement?

Answer: Osteoclasts

Osteoclasts are multinucleated cells derived from monocyte precursors that resorb bone on the pressure side during orthodontic movement.

A patient presents with a periapical abscess. The causative bacteria most commonly involved is:

Answer: Porphyromonas gingivalis

Porphyromonas gingivalis is the key pathogen in periapical infections due to its virulence factors including proteases and fimbriae.

The mental foramen is most commonly located between which teeth?

Answer: Mandibular first and second premolars

The mental foramen is typically positioned between the apices of the mandibular first and second premolars, though location varies among individuals.

Which local anesthetic has the longest duration of action for pulpal anesthesia?

Answer: Bupivacaine 0.5%

Bupivacaine 0.5% with epinephrine provides the longest pulpal anesthesia duration (90–180 minutes) due to its high protein binding and lipid solubility.

Enamel matrix proteins that guide enamel crystal formation are primarily secreted by:

Answer: Ameloblasts

Ameloblasts secrete amelogenins, enamelins, and ameloblastins, which organize hydroxyapatite crystal growth during enamelogenesis.

A 45-year-old patient has a 6 mm probing depth with bleeding on probing and bone loss on radiograph. This is classified as:

Answer: Stage III Periodontitis

Stage III Periodontitis is characterized by probing depths ≥6 mm, bleeding on probing, and radiographic bone loss extending to the middle or apical third of the root.

Which instrument is used to detect subgingival calculus by tactile sensation?

Answer: Explorer

An explorer (particularly the ODU 11/12 or 3A) provides the best tactile feedback for detecting subgingival calculus deposits.