Chapter 1 Periodontium: The Tooth Chapter 20 Radiographic Analysis of the
Supporting Structures Periodontium
Chapter 2 Microscopic Anatomy of the Chapter 21 Clinical Decision-Making for
Periodontium Periodontal Care
Chapter 3 Overview of Diseases of the Chapter 22 Shared Decision-Making for
Periodontium Periodontal Care
Chapter 4 Classification of Periodontal Chapter 23 Encouraging Patient Behavior
Diseases, Peri-Implant Diseases, and Conditions Change with Motivational Interviewing
Chapter 5 Periodontal Health, Gingival Chapter 24 Best Practices for Periodontal
Diseases, and Conditions Care
Chapter 6 Periodontitis Chapter 25 Nonsurgical Periodontal Therapy
Chapter 7 Mucogingival Deformities and Chapter 26 Patient’s Role in Nonsurgical
Conditions Around Teeth Periodontal Therapy
Chapter 8 Peri-Implant Health and Disease Chapter 27 Supragingival and Subgingival
Irrigation
Chapter 9 Acute Periodontal Diseases
Chapter 28 Chemotherapeutics in
Chapter 10 Risk Factors for Periodontal
Periodontal Care
Diseases and Peri-Implant Diseases/Conditions
Chapter 29 Host Modulation Therapy
Chapter 11 Oral Biofilms
Chapter 30 Periodontal Surgical Concepts for
Chapter 12 Basic Concepts of Immunity and
the Dental Hygienist
Inflammation
Chapter 31 Maintenance for the Periodontal
Chapter 13 Host Immunoinflammatory
Patient
Response to Dental Biofilm
Chapter 32 Documentation and Insurance
Chapter 14 Impact of Systemic Diseases on
Reporting of Periodontal Care
Periodontal Health
Chapter 33 Future Directions for
Chapter 15 Impact of Periodontal
Management of Periodontal Care
Inflammation on Periodontal Health
Chapter 34 Comprehensive Patient Cases
Chapter 16 Local Factors Contributing to
Periodontal Disease Chapter 35 Periodontal Disease in the
Pediatric Population
Chapter 17 Tobacco, Smoking, and
Periodontal Disease Chapter 36 Iatrosedation: Easing and
Managing Pediatric Patient Fears
Chapter 18 Nutrition, Inflammation, and
Periodontal Disease Chapter 37 Oral Malodor and Xerostomia
Chapter 19 Clinical Periodontal Assessment Chapter 38 Patient Cases: Radiographic
Analysis
,Chapter 1 – Periodontium: The Tooth Supporting
Structures
Theme: Anatomy, structure, and function of alveolar bone, cementum, PDL,
and gingiva; foundational knowledge for periodontal disease understanding.
1. A 45-year-old patient presents with mild gingival recession on
the mandibular anterior teeth. On probing, there is slight
attachment loss, but no inflammation. Which structure primarily
maintains tooth attachment in this scenario?
A. Alveolar bone
B. Cementum
C. Gingiva
D. Periodontal ligament
Answer: B
Rationale: Cementum covers the root and anchors PDL fibers, maintaining
tooth attachment even when gingival recession occurs. The PDL connects
cementum to alveolar bone, but the attachment point is the cementum.
Key words: Cementum, attachment, gingival recession, PDL, alveolar bone
2. A patient exhibits mobility of a maxillary premolar without
significant bone loss on radiographs. Which periodontal
structure's compromise most directly results in tooth mobility?
A. Gingiva
B. Alveolar bone
C. Periodontal ligament
D. Cementum
Answer: C
Rationale: The PDL suspends the tooth in alveolar bone, absorbing occlusal
forces. Damage or degradation of the PDL results in increased tooth mobility
even if bone support is radiographically intact.
Key words: PDL, tooth mobility, alveolar support, periodontal ligament
function
,3. During a periodontal assessment, you note that the attached
gingiva is tightly bound to the underlying alveolar bone. Which
functional property is primarily responsible for resisting
mechanical stress during mastication?
A. Width of attached gingiva
B. Gingival sulcus depth
C. Thickness of cementum
D. PDL fiber orientation
Answer: A
Rationale: The attached gingiva is keratinized and tightly bound to bone and
cementum, providing resistance to mechanical trauma. Sulcus depth and PDL
function are important for probing and attachment, but mechanical resistance
comes from attached gingiva.
Key words: Attached gingiva, keratinized gingiva, mechanical stress, alveolar
bone
4. A patient presents with localized alveolar bone loss due to
periodontitis. Which of the following structures is directly
resorbed during disease progression?
A. Periodontal ligament fibers
B. Cementum
C. Alveolar bone proper
D. Gingival epithelium
Answer: C
Rationale: In periodontitis, osteoclast-mediated resorption occurs in alveolar
bone, leading to attachment loss. PDL fibers may detach secondarily, and
gingiva may appear inflamed, but the bone is the primary resorbed structure.
Key words: Alveolar bone, resorption, periodontitis, osteoclast
5. Which of the following PDL fiber groups primarily resists
vertical displacement of a tooth during mastication?
A. Alveolar crest fibers
B. Horizontal fibers
C. Oblique fibers
D. Apical fibers
,Answer: C
Rationale: Oblique fibers are the most numerous PDL fibers and resist vertical
occlusal forces, protecting alveolar bone from compressive stress. Horizontal
fibers resist lateral forces, alveolar crest fibers resist extrusion, and apical
fibers stabilize apex.
Key words: PDL fibers, oblique fibers, vertical stress, mastication
6. A clinician is evaluating a patient’s gingival contour and notes
a knife-edge margin. Which part of the periodontium is most
involved in supporting this gingival architecture?
A. Alveolar bone
B. Free gingiva
C. Cementum
D. PDL
Answer: B
Rationale: The free gingiva forms the gingival margin and sulcus; it maintains
contour independent of alveolar bone. Its health and shape are key for
aesthetics and barrier function.
Key words: Free gingiva, gingival contour, sulcus, knife-edge margin
7. Which periodontal structure is primarily responsible for the
shock absorption that occurs when a patient bites a hard object?
A. Cementum
B. PDL
C. Alveolar bone
D. Attached gingiva
Answer: B
Rationale: The PDL contains collagen fibers and extracellular matrix, which
compress slightly under occlusal load, acting as a shock absorber to protect
alveolar bone and cementum.
Key words: PDL, shock absorption, occlusal load, periodontal ligament
8. A patient’s radiograph shows uniform radiolucency surrounding
the root apex without cortical bone involvement. Which structure
is likely intact and contributing to tooth support?
,A. PDL
B. Alveolar bone
C. Gingiva
D. Cementum
Answer: D
Rationale: Cementum covers the root and is present even when radiographic
changes occur around the apex. The PDL may show widening or inflammation,
and alveolar bone may be partially affected, but cementum persists as the root
attachment surface.
Key words: Cementum, radiograph, tooth support, periodontal attachment
9. In a patient with gingival inflammation but no attachment loss,
which structure primarily prevents microbial invasion into the
deeper periodontium?
A. Alveolar bone
B. Cementum
C. Junctional epithelium
D. PDL
Answer: C
Rationale: The junctional epithelium forms the barrier between the sulcus and
connective tissue, preventing microbial penetration. Alveolar bone and PDL are
deeper and not initial barriers.
Key words: Junctional epithelium, gingival barrier, microbial invasion, sulcus
10. Which of the following is least involved in maintaining tooth
stability under functional forces?
A. Oblique PDL fibers
B. Cementum
C. Free gingiva
D. Alveolar bone
Answer: C
Rationale: Free gingiva protects the tooth and forms the sulcus but
contributes minimally to mechanical tooth stability compared to PDL,
cementum, and alveolar bone.
Key words: Free gingiva, tooth stability, periodontium function
,11. A 30-year-old patient exhibits gingival enlargement but no
attachment loss. Which component of the periodontium is
primarily inflamed?
A. Alveolar bone
B. PDL
C. Gingiva
D. Cementum
Answer: C
Rationale: Gingival enlargement involves soft tissue inflammation; bone and
PDL are not yet affected in early or reversible gingival changes.
Key words: Gingiva, inflammation, enlargement, periodontium
12. Which structure forms the attachment for Sharpey’s fibers of
the PDL?
A. Alveolar bone and cementum
B. Free gingiva and junctional epithelium
C. Oblique fibers
D. Gingival sulcus
Answer: A
Rationale: Sharpey’s fibers are terminal ends of PDL fibers embedded into
cementum and alveolar bone, anchoring the tooth to the alveolus.
Key words: Sharpey’s fibers, PDL, cementum, alveolar bone
13. A patient has a deep periodontal pocket with horizontal bone
loss. Which fiber group is most likely compromised?
A. Horizontal fibers
B. Oblique fibers
C. Apical fibers
D. Interradicular fibers
Answer: A
Rationale: Horizontal fibers resist lateral forces and are often first affected in
horizontal bone loss. Oblique fibers resist vertical forces, and
, apical/interradicular fibers stabilize specific regions.
Key words: Horizontal PDL fibers, bone loss, periodontal pocket
14. Which of the following structures provides a nutrient supply
and sensory feedback to the periodontium?
A. Cementum
B. Alveolar bone
C. PDL
D. Free gingiva
Answer: C
Rationale: The PDL contains blood vessels and nerves, providing nutrients and
sensory information (pain, pressure) for the tooth and periodontium.
Key words: PDL, vascularization, innervation, periodontal support
15. A radiograph shows decreased alveolar bone height around a
tooth with minimal gingival inflammation. Which structure is
primary determinant of current attachment level?
A. PDL
B. Cementum
C. Gingiva
D. Alveolar bone
Answer: B
Rationale: Cementum maintains attachment for PDL fibers; bone loss reflects
the supporting structure but attachment level is measured from
cementoenamel junction to PDL insertion.
Key words: Cementum, attachment level, alveolar bone, periodontal support
16. During scaling, the clinician notes that the coronal part of
PDL fibers resists instrument penetration. Which fiber group is
being tested?
A. Alveolar crest fibers
B. Oblique fibers
C. Horizontal fibers
D. Apical fibers