NDEE Exam 6 Periodontology Practice Exam
100 Clinical Questions with Detailed
Rationales | 2026/2027 Edition
SECTION 1: Anatomy and Histology of the Periodontium
(Questions 1-15)
Question 1
The periodontal ligament is composed primarily of which type of
collagen fibers?
A) Type I collagen
B) Type II collagen
C) Type III collagen
D) Type IV collagen
Correct Answer: A
Rationale: The periodontal ligament (PDL) is composed
primarily of Type I collagen fibers, which provide the tensile
strength needed to withstand occlusal forces. Type III collagen is
also present in smaller amounts. Type II collagen is found in
cartilage, and Type IV collagen is found in basement membranes.
The PDL fibers are arranged in distinct groups (principal fibers)
that connect the cementum to the alveolar bone and include the
alveolar crest, horizontal, oblique, apical, and interradicular
fibers.
,Question 2
The junctional epithelium attaches to the tooth surface via which
structures?
A) Hemidesmosomes
B) Desmosomes
C) Gap junctions
D) Tight junctions
Correct Answer: A
Rationale: The junctional epithelium attaches to the tooth
surface via hemidesmosomes, which are specialized cell-to-
extracellular matrix adhesion structures. Desmosomes (B) attach
epithelial cells to each other. Gap junctions (C) allow
communication between cells. Tight junctions (D) prevent
leakage between cells. The junctional epithelium provides a seal
between the oral environment and the underlying connective
tissue, acting as a barrier to bacterial invasion.
Question 3
The gingival crevicular fluid (GCF) is an inflammatory exudate
that originates from which source?
A) Salivary glands
B) Gingival capillary bed
C) Periodontal ligament
D) Alveolar bone marrow
Correct Answer: B
,Rationale: Gingival crevicular fluid (GCF) originates from the
gingival capillary bed, specifically from the microcirculation of the
gingival connective tissue. In health, GCF is present in very small
amounts. In inflammation, the volume increases significantly as
fluid and inflammatory cells (neutrophils, monocytes) migrate
from the blood vessels into the gingival crevice. The flow rate is
directly related to the severity of inflammation. GCF composition
can be used to assess periodontal disease activity and monitor
treatment response.
Question 4
The normal depth of the gingival sulcus in a healthy periodontium
is:
A) 1-3 mm
B) 3-5 mm
C) 5-7 mm
D) Less than 1 mm
Correct Answer: A
Rationale: The normal depth of the gingival sulcus in a healthy
periodontium is 1-3 mm. This measurement is taken from the
gingival margin to the base of the sulcus (the coronal extent of the
junctional epithelium). Depths greater than 3 mm may indicate
pseudopockets (gingival enlargement without attachment loss) or
periodontal pockets (attachment loss with apical migration of the
junctional epithelium). Probing depths of 4 mm or more are
associated with periodontal disease and require clinical
evaluation.
, Question 5
The gingival epithelium that faces the tooth and forms the base of
the gingival sulcus is called the:
A) Oral epithelium
B) Sulcular epithelium
C) Junctional epithelium
D) Keratinized epithelium
Correct Answer: C
Rationale: The junctional epithelium is the gingival epithelium
that faces the tooth and forms the base of the gingival sulcus. It is
a non-keratinized stratified squamous epithelium that attaches to
the tooth surface via hemidesmosomes. The sulcular epithelium
(B) lines the gingival sulcus but does not attach to the tooth. The
oral epithelium (A) is the outer epithelial layer of the gingiva.
Keratinized epithelium (D) refers to the type of epithelium found
on the gingiva and hard palate.
Question 6
Which of the following is NOT a principal fiber group of the
periodontal ligament?
A) Alveolar crest fibers
B) Horizontal fibers
C) Circular fibers
D) Oblique fibers
Correct Answer: C
100 Clinical Questions with Detailed
Rationales | 2026/2027 Edition
SECTION 1: Anatomy and Histology of the Periodontium
(Questions 1-15)
Question 1
The periodontal ligament is composed primarily of which type of
collagen fibers?
A) Type I collagen
B) Type II collagen
C) Type III collagen
D) Type IV collagen
Correct Answer: A
Rationale: The periodontal ligament (PDL) is composed
primarily of Type I collagen fibers, which provide the tensile
strength needed to withstand occlusal forces. Type III collagen is
also present in smaller amounts. Type II collagen is found in
cartilage, and Type IV collagen is found in basement membranes.
The PDL fibers are arranged in distinct groups (principal fibers)
that connect the cementum to the alveolar bone and include the
alveolar crest, horizontal, oblique, apical, and interradicular
fibers.
,Question 2
The junctional epithelium attaches to the tooth surface via which
structures?
A) Hemidesmosomes
B) Desmosomes
C) Gap junctions
D) Tight junctions
Correct Answer: A
Rationale: The junctional epithelium attaches to the tooth
surface via hemidesmosomes, which are specialized cell-to-
extracellular matrix adhesion structures. Desmosomes (B) attach
epithelial cells to each other. Gap junctions (C) allow
communication between cells. Tight junctions (D) prevent
leakage between cells. The junctional epithelium provides a seal
between the oral environment and the underlying connective
tissue, acting as a barrier to bacterial invasion.
Question 3
The gingival crevicular fluid (GCF) is an inflammatory exudate
that originates from which source?
A) Salivary glands
B) Gingival capillary bed
C) Periodontal ligament
D) Alveolar bone marrow
Correct Answer: B
,Rationale: Gingival crevicular fluid (GCF) originates from the
gingival capillary bed, specifically from the microcirculation of the
gingival connective tissue. In health, GCF is present in very small
amounts. In inflammation, the volume increases significantly as
fluid and inflammatory cells (neutrophils, monocytes) migrate
from the blood vessels into the gingival crevice. The flow rate is
directly related to the severity of inflammation. GCF composition
can be used to assess periodontal disease activity and monitor
treatment response.
Question 4
The normal depth of the gingival sulcus in a healthy periodontium
is:
A) 1-3 mm
B) 3-5 mm
C) 5-7 mm
D) Less than 1 mm
Correct Answer: A
Rationale: The normal depth of the gingival sulcus in a healthy
periodontium is 1-3 mm. This measurement is taken from the
gingival margin to the base of the sulcus (the coronal extent of the
junctional epithelium). Depths greater than 3 mm may indicate
pseudopockets (gingival enlargement without attachment loss) or
periodontal pockets (attachment loss with apical migration of the
junctional epithelium). Probing depths of 4 mm or more are
associated with periodontal disease and require clinical
evaluation.
, Question 5
The gingival epithelium that faces the tooth and forms the base of
the gingival sulcus is called the:
A) Oral epithelium
B) Sulcular epithelium
C) Junctional epithelium
D) Keratinized epithelium
Correct Answer: C
Rationale: The junctional epithelium is the gingival epithelium
that faces the tooth and forms the base of the gingival sulcus. It is
a non-keratinized stratified squamous epithelium that attaches to
the tooth surface via hemidesmosomes. The sulcular epithelium
(B) lines the gingival sulcus but does not attach to the tooth. The
oral epithelium (A) is the outer epithelial layer of the gingiva.
Keratinized epithelium (D) refers to the type of epithelium found
on the gingiva and hard palate.
Question 6
Which of the following is NOT a principal fiber group of the
periodontal ligament?
A) Alveolar crest fibers
B) Horizontal fibers
C) Circular fibers
D) Oblique fibers
Correct Answer: C
