DHYG220 Periodontology Exam Prep – Real Practice Questions, Answers &
Detailed Rationales (Updated 2026) | Periodontal Disease & Gingivitis
Management, Oral Anatomy & Periodontal Structures, Plaque & Calculus
Formation, Periodontal Assessment & Charting, Scaling & Root Planing Techniques,
Infection Control, Dental Radiography, Patient Education & Preventive Periodontal
Care
Question 1: Which of the following structures is NOT considered part of the
periodontium?
A. Gingiva
B. Cementum
C. Dental pulp
D. Periodontal ligament
CORRECT ANSWER: C. Dental pulp
Rationale: The periodontium consists of the supporting structures of the tooth: gingiva,
cementum, periodontal ligament, and alveolar bone. Dental pulp is located within the
tooth and is part of the endodontic system, not the periodontium.
Question 2: According to the 2017 World Workshop classification, which stage of
periodontitis is characterized by interdental clinical attachment loss of ≥5 mm at
the site of greatest loss and radiographic bone loss extending to the mid-third of
the root or beyond?
A. Stage I
B. Stage II
C. Stage III
D. Stage IV
CORRECT ANSWER: C. Stage III
Rationale: Stage III periodontitis is defined by interdental CAL ≥5 mm at the site of
greatest loss, radiographic bone loss extending to the mid-third of the root or beyond,
and potential for tooth loss due to periodontitis. Stage IV includes additional complexity
such as need for complex rehabilitation.
Question 3: Which bacterial complex is most strongly associated with the
progression of chronic periodontitis?
A. Purple complex
B. Green complex
C. Red complex
D. Yellow complex
CORRECT ANSWER: C. Red complex
Rationale: The red complex, consisting of Porphyromonas gingivalis, Tannerella
forsythia, and Treponema denticola, is most strongly associated with clinical
,parameters of periodontitis including probing depth, clinical attachment loss, and
bleeding on probing.
Question 4: What is the primary function of the periodontal ligament?
A. To produce enamel
B. To anchor the tooth to alveolar bone and absorb occlusal forces
C. To secrete saliva
D. To initiate tooth eruption
CORRECT ANSWER: B. To anchor the tooth to alveolar bone and absorb occlusal
forces
Rationale: The periodontal ligament functions to attach the cementum of the tooth to
the alveolar bone, provide sensory feedback, nourish surrounding tissues, and absorb
and distribute occlusal forces during function.
Question 5: Which clinical parameter is considered the most reliable indicator of
current periodontal disease activity?
A. Probing depth
B. Gingival color
C. Bleeding on probing
D. Tooth mobility
CORRECT ANSWER: C. Bleeding on probing
Rationale: Bleeding on probing is a sensitive indicator of inflammation and is
considered the best clinical predictor of current disease activity and future attachment
loss, though it is not specific to periodontitis alone.
Question 6: Which of the following is a local risk factor that can contribute to
periodontal disease progression?
A. Diabetes mellitus
B. Smoking
C. Subgingival calculus
D. Genetic predisposition
CORRECT ANSWER: C. Subgingival calculus
Rationale: Subgingival calculus is a local risk factor that provides a rough surface for
plaque biofilm accumulation and hinders effective oral hygiene. Diabetes, smoking, and
genetics are systemic or behavioral risk factors.
Question 7: In a healthy periodontium, what is the typical depth of the gingival
sulcus?
A. 0.5–1 mm
B. 1–3 mm
,C. 3–5 mm
D. 5–7 mm
CORRECT ANSWER: B. 1–3 mm
Rationale: In a clinically healthy periodontium, the gingival sulcus depth typically
measures 1–3 mm. Depths greater than 3 mm may indicate a periodontal pocket and
potential disease.
Question 8: Which cell type plays a central role in the adaptive immune response in
periodontal disease?
A. Neutrophils
B. Macrophages
C. T lymphocytes
D. Keratinocytes
CORRECT ANSWER: C. T lymphocytes
Rationale: T lymphocytes are central to the adaptive immune response, mediating cell-
mediated immunity and regulating B cell antibody production in response to
periodontal pathogens. Neutrophils and macrophages are part of the innate immune
system.
Question 9: What is the primary purpose of scaling and root planing in non-surgical
periodontal therapy?
A. To whiten tooth surfaces
B. To remove biofilm, calculus, and endotoxins from root surfaces
C. To regenerate lost periodontal tissues
D. To extract hopeless teeth
CORRECT ANSWER: B. To remove biofilm, calculus, and endotoxins from root
surfaces
Rationale: Scaling and root planing aims to disrupt and remove subgingival biofilm,
calculus, and bacterial endotoxins from root surfaces to reduce inflammation and
promote periodontal healing.
Question 10: Which radiographic technique is most appropriate for detecting early
interproximal alveolar bone loss?
A. Panoramic radiograph
B. Bitewing radiograph
C. Occlusal radiograph
D. Cephalometric radiograph
CORRECT ANSWER: B. Bitewing radiograph
, Rationale: Bitewing radiographs provide high-resolution images of the crowns and
alveolar crest of posterior teeth and are most sensitive for detecting early interproximal
bone loss due to minimal distortion and proper horizontal angulation.
Question 11: Which of the following best describes "clinical attachment level"
(CAL)?
A. Distance from the cementoenamel junction to the base of the pocket
B. Distance from the gingival margin to the base of the pocket
C. Distance from the occlusal surface to the gingival margin
D. Distance from the mucogingival junction to the gingival margin
CORRECT ANSWER: A. Distance from the cementoenamel junction to the base of
the pocket
Rationale: Clinical attachment level measures the distance from the cementoenamel
junction to the base of the periodontal pocket, providing an accurate assessment of
historical periodontal destruction independent of gingival recession or swelling.
Question 12: Which systemic condition is most strongly associated with an
increased risk and severity of periodontitis?
A. Hypertension
B. Type 2 diabetes mellitus
C. Asthma
D. Osteoporosis
CORRECT ANSWER: B. Type 2 diabetes mellitus
Rationale: Type 2 diabetes mellitus is a well-established risk factor for periodontitis;
hyperglycemia impairs immune function, increases inflammatory cytokine production,
and delays wound healing, exacerbating periodontal destruction.
Question 13: What is the primary etiological factor in the development of gingivitis?
A. Occlusal trauma
B. Dental plaque biofilm
C. Vitamin C deficiency
D. Hormonal fluctuations
CORRECT ANSWER: B. Dental plaque biofilm
Rationale: Dental plaque biofilm is the primary etiological factor in gingivitis. While
hormonal changes, nutrition, and occlusion can modify the response, plaque
accumulation is necessary for inflammation to develop.
Question 14: Which of the following is a characteristic feature of necrotizing
periodontal diseases?
A. Painless gingival enlargement
B. Interdental papilla necrosis and pseudomembrane formation
Detailed Rationales (Updated 2026) | Periodontal Disease & Gingivitis
Management, Oral Anatomy & Periodontal Structures, Plaque & Calculus
Formation, Periodontal Assessment & Charting, Scaling & Root Planing Techniques,
Infection Control, Dental Radiography, Patient Education & Preventive Periodontal
Care
Question 1: Which of the following structures is NOT considered part of the
periodontium?
A. Gingiva
B. Cementum
C. Dental pulp
D. Periodontal ligament
CORRECT ANSWER: C. Dental pulp
Rationale: The periodontium consists of the supporting structures of the tooth: gingiva,
cementum, periodontal ligament, and alveolar bone. Dental pulp is located within the
tooth and is part of the endodontic system, not the periodontium.
Question 2: According to the 2017 World Workshop classification, which stage of
periodontitis is characterized by interdental clinical attachment loss of ≥5 mm at
the site of greatest loss and radiographic bone loss extending to the mid-third of
the root or beyond?
A. Stage I
B. Stage II
C. Stage III
D. Stage IV
CORRECT ANSWER: C. Stage III
Rationale: Stage III periodontitis is defined by interdental CAL ≥5 mm at the site of
greatest loss, radiographic bone loss extending to the mid-third of the root or beyond,
and potential for tooth loss due to periodontitis. Stage IV includes additional complexity
such as need for complex rehabilitation.
Question 3: Which bacterial complex is most strongly associated with the
progression of chronic periodontitis?
A. Purple complex
B. Green complex
C. Red complex
D. Yellow complex
CORRECT ANSWER: C. Red complex
Rationale: The red complex, consisting of Porphyromonas gingivalis, Tannerella
forsythia, and Treponema denticola, is most strongly associated with clinical
,parameters of periodontitis including probing depth, clinical attachment loss, and
bleeding on probing.
Question 4: What is the primary function of the periodontal ligament?
A. To produce enamel
B. To anchor the tooth to alveolar bone and absorb occlusal forces
C. To secrete saliva
D. To initiate tooth eruption
CORRECT ANSWER: B. To anchor the tooth to alveolar bone and absorb occlusal
forces
Rationale: The periodontal ligament functions to attach the cementum of the tooth to
the alveolar bone, provide sensory feedback, nourish surrounding tissues, and absorb
and distribute occlusal forces during function.
Question 5: Which clinical parameter is considered the most reliable indicator of
current periodontal disease activity?
A. Probing depth
B. Gingival color
C. Bleeding on probing
D. Tooth mobility
CORRECT ANSWER: C. Bleeding on probing
Rationale: Bleeding on probing is a sensitive indicator of inflammation and is
considered the best clinical predictor of current disease activity and future attachment
loss, though it is not specific to periodontitis alone.
Question 6: Which of the following is a local risk factor that can contribute to
periodontal disease progression?
A. Diabetes mellitus
B. Smoking
C. Subgingival calculus
D. Genetic predisposition
CORRECT ANSWER: C. Subgingival calculus
Rationale: Subgingival calculus is a local risk factor that provides a rough surface for
plaque biofilm accumulation and hinders effective oral hygiene. Diabetes, smoking, and
genetics are systemic or behavioral risk factors.
Question 7: In a healthy periodontium, what is the typical depth of the gingival
sulcus?
A. 0.5–1 mm
B. 1–3 mm
,C. 3–5 mm
D. 5–7 mm
CORRECT ANSWER: B. 1–3 mm
Rationale: In a clinically healthy periodontium, the gingival sulcus depth typically
measures 1–3 mm. Depths greater than 3 mm may indicate a periodontal pocket and
potential disease.
Question 8: Which cell type plays a central role in the adaptive immune response in
periodontal disease?
A. Neutrophils
B. Macrophages
C. T lymphocytes
D. Keratinocytes
CORRECT ANSWER: C. T lymphocytes
Rationale: T lymphocytes are central to the adaptive immune response, mediating cell-
mediated immunity and regulating B cell antibody production in response to
periodontal pathogens. Neutrophils and macrophages are part of the innate immune
system.
Question 9: What is the primary purpose of scaling and root planing in non-surgical
periodontal therapy?
A. To whiten tooth surfaces
B. To remove biofilm, calculus, and endotoxins from root surfaces
C. To regenerate lost periodontal tissues
D. To extract hopeless teeth
CORRECT ANSWER: B. To remove biofilm, calculus, and endotoxins from root
surfaces
Rationale: Scaling and root planing aims to disrupt and remove subgingival biofilm,
calculus, and bacterial endotoxins from root surfaces to reduce inflammation and
promote periodontal healing.
Question 10: Which radiographic technique is most appropriate for detecting early
interproximal alveolar bone loss?
A. Panoramic radiograph
B. Bitewing radiograph
C. Occlusal radiograph
D. Cephalometric radiograph
CORRECT ANSWER: B. Bitewing radiograph
, Rationale: Bitewing radiographs provide high-resolution images of the crowns and
alveolar crest of posterior teeth and are most sensitive for detecting early interproximal
bone loss due to minimal distortion and proper horizontal angulation.
Question 11: Which of the following best describes "clinical attachment level"
(CAL)?
A. Distance from the cementoenamel junction to the base of the pocket
B. Distance from the gingival margin to the base of the pocket
C. Distance from the occlusal surface to the gingival margin
D. Distance from the mucogingival junction to the gingival margin
CORRECT ANSWER: A. Distance from the cementoenamel junction to the base of
the pocket
Rationale: Clinical attachment level measures the distance from the cementoenamel
junction to the base of the periodontal pocket, providing an accurate assessment of
historical periodontal destruction independent of gingival recession or swelling.
Question 12: Which systemic condition is most strongly associated with an
increased risk and severity of periodontitis?
A. Hypertension
B. Type 2 diabetes mellitus
C. Asthma
D. Osteoporosis
CORRECT ANSWER: B. Type 2 diabetes mellitus
Rationale: Type 2 diabetes mellitus is a well-established risk factor for periodontitis;
hyperglycemia impairs immune function, increases inflammatory cytokine production,
and delays wound healing, exacerbating periodontal destruction.
Question 13: What is the primary etiological factor in the development of gingivitis?
A. Occlusal trauma
B. Dental plaque biofilm
C. Vitamin C deficiency
D. Hormonal fluctuations
CORRECT ANSWER: B. Dental plaque biofilm
Rationale: Dental plaque biofilm is the primary etiological factor in gingivitis. While
hormonal changes, nutrition, and occlusion can modify the response, plaque
accumulation is necessary for inflammation to develop.
Question 14: Which of the following is a characteristic feature of necrotizing
periodontal diseases?
A. Painless gingival enlargement
B. Interdental papilla necrosis and pseudomembrane formation
