ABP Periodontal Anatomy 5

Question 1

The interradicular septum of a mandibular molar consists primarily of which type of bone?

Accepted Answer

Cancellous (spongy) bone surrounded by cortical bone

Answer

The interradicular septum consists of cancellous bone enclosed within cortical plates; the trabeculae support the roots and transmit occlusal forces.

Question 2

Cementicles found within the periodontal ligament are:

Accepted Answer

Mineralized nodules of uncertain etiology, occasionally fusing with root cementum

Answer

Cementicles are calcified bodies within the PDL whose origin is debated; they may form around epithelial cell rests or degenerated PDL fibers and can occasionally fuse to the root surface.

Question 3

The epithelial cell rests of Malassez (ERM) are remnants of which embryonic structure?

Accepted Answer

Hertwig's epithelial root sheath (HERS)

Answer

ERM are remnants of Hertwig's epithelial root sheath that remain within the PDL after root formation and may play a role in cementum repair or cyst formation.

Question 4

The col is an anatomic depression in the interdental gingiva that forms because:

Accepted Answer

The interdental gingiva conforms to the contact area of adjacent teeth, creating a concave saddle

Answer

The col is a valley-shaped depression beneath the contact point where the buccal and lingual papillae meet; it is lined by thin, non-keratinized epithelium and is highly susceptible to inflammation.

Question 5

Acellular extrinsic fiber cementum (AEFC) is found predominantly in which region of the root?

Accepted Answer

Cervical and middle thirds

Answer

AEFC is the primary cementum type in the cervical and middle thirds of the root, providing the main site of principal fiber attachment and formed before tooth eruption.

(ABP) American Board of Periodontology Practice Test

(ABP) American Board of Periodontology Practice Test

ABP Periodontal Anatomy 5