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Kuwait Dental Board Periodontics study materials
Kuwait Dental Board Periodontics study resources

Kuwait Dental Board Periodontics practice questions

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Question 1Periodontal Anatomy, Histology, and Biology

Which principal fiber group of the periodontal ligament is primarily responsible for resisting apical displacement of the tooth?

  1. Oblique fibers
  2. Apical fibers Correct answer.
  3. Horizontal fibers
  4. Alveolar crest fibers

Explanation

Apical fibers radiate from the root apex to the fundus of the alveolus and resist forces that would move the tooth coronally or apically, acting as a suspensory tie at the base. Oblique fibers resist axial (intrusive) loading, and alveolar crest fibers resist tilting and extrusion.

Question 2Periodontal Anatomy, Histology, and Biology

The gingival epithelium that faces the tooth surface and forms the epithelial attachment is termed which of the following?

  1. Sulcular epithelium
  2. Oral gingival epithelium
  3. Junctional epithelium Correct answer.
  4. Rete peg epithelium

Explanation

The junctional epithelium is the non-keratinized stratified squamous epithelium that attaches to the tooth via hemidesmosomes and the internal basal lamina. It forms the epithelial seal at the base of the sulcus and is central to the definition of clinical attachment level.

Question 3Periodontal Anatomy, Histology, and Biology

Which gingival connective tissue component predominates by volume in the lamina propria of healthy gingiva?

  1. Oxytalan fibers
  2. Ground substance
  3. Collagen fibers Correct answer.
  4. Elastic fibers

Explanation

Collagen (mainly types I and III) constitutes roughly 60% of gingival connective tissue volume and provides tensile strength. Ground substance, fibroblasts, vessels and nerves make up the remainder, with oxytalan fibers being a minor component.

Question 4Periodontal Anatomy, Histology, and Biology

A clinician probes a site and finds the gingival margin located 2 mm coronal to the cementoenamel junction with a probing depth of 3 mm. What is the clinical attachment level at this site?

  1. 1 mm Correct answer.
  2. 2 mm
  3. 3 mm
  4. 5 mm

Explanation

Clinical attachment level equals probing depth minus the distance from the gingival margin to the CEJ when the margin is coronal to the CEJ. Here 3 mm minus 2 mm gives 1 mm of attachment loss, reflecting recession-corrected attachment position.

Question 5Periodontal Anatomy, Histology, and Biology

Which cell type is the principal source of collagen synthesis in the periodontal ligament during turnover and repair?

  1. Cementoblasts
  2. Macrophages
  3. Osteoblasts
  4. Fibroblasts Correct answer.

Explanation

Fibroblasts are the dominant cell of the periodontal ligament and synthesize both collagen and the degradative enzymes needed for rapid turnover. Their dual synthetic and resorptive capacity allows continuous remodeling of the ligament.

Question 6Periodontal Anatomy, Histology, and Biology

The blood supply to the gingiva is derived mainly from which vessels?

  1. Branches of the external carotid artery via the maxillary and facial arteries Correct answer.
  2. Superior alveolar arteries only
  3. Branches of the internal carotid artery
  4. The ophthalmic artery

Explanation

Gingival and periodontal blood supply arises from branches of the external carotid, principally the maxillary artery (with its alveolar and infraorbital branches) and the facial artery. These anastomose to form the gingival plexus and the dentogingival plexus.

Question 7Periodontal Anatomy, Histology, and Biology

Which feature distinguishes the transseptal fibers from other periodontal ligament fiber groups?

  1. They are found only on multirooted teeth
  2. They insert into alveolar bone and cementum
  3. They run over the alveolar crest between adjacent teeth and are not attached to bone Correct answer.
  4. They are the principal fibers resisting intrusion

Explanation

Transseptal fibers extend from the cementum of one tooth across the interdental septum to the cementum of the adjacent tooth, linking neighbors rather than inserting into bone. They are regarded as belonging to the gingival fiber apparatus and reform even after periodontal surgery.

Question 8Periodontal Anatomy, Histology, and Biology

Which zone of the gingival sulcus is lined by a thin, non-keratinized epithelium with few rete pegs and increased permeability?

  1. Oral gingival epithelium
  2. Sulcular epithelium Correct answer.
  3. Junctional epithelium
  4. Masticatory mucosa

Explanation

The sulcular epithelium is thin, non-keratinized and lacks prominent rete ridges, making it relatively permeable to bacterial products. This permeability contributes to the inflammatory response seen in gingivitis.

Question 9Periodontal Anatomy, Histology, and Biology

Which collagen type is the predominant organic constituent of cementum?

  1. Type II
  2. Type IV
  3. Type I Correct answer.
  4. Type V

Explanation

Cementum matrix is composed mainly of type I collagen, with smaller amounts of type III and other types. This composition resembles bone and allows cementum to function as an attachment substrate for periodontal ligament fibers.

Question 10Periodontal Anatomy, Histology, and Biology

Acellular extrinsic fiber cementum is found predominantly in which location?

  1. The coronal enamel surface
  2. The cervical third of the root Correct answer.
  3. The apical third of the root
  4. The furcation region only

Explanation

Acellular extrinsic fiber cementum, which contains Sharpey fibers and mediates attachment, is concentrated in the cervical half to two-thirds of the root. Cellular mixed stratified cementum predominates apically and in furcations.

Question 11Periodontal Anatomy, Histology, and Biology

Which structure marks the most coronal extent of the root where the enamel ends and cementum begins?

  1. Alveolar crest
  2. Cementoenamel junction Correct answer.
  3. Gingival groove
  4. Mucogingival junction

Explanation

The cementoenamel junction is the anatomical landmark where enamel and cementum meet. It serves as the fixed reference point for calculating clinical attachment level and recession.

Question 12Periodontal Anatomy, Histology, and Biology

Which gingival fiber group encircles the tooth in a ring-like fashion and helps maintain gingival contour?

  1. Circular fibers Correct answer.
  2. Alveologingival fibers
  3. Dentogingival fibers
  4. Dentoperiosteal fibers

Explanation

Circular fibers form a cuff around the tooth and contribute to the firmness of the marginal gingiva. They are part of the gingival fiber apparatus distinct from the principal periodontal ligament fibers.

Question 13Periodontal Anatomy, Histology, and Biology

Compared with the oral gingival epithelium, the junctional epithelium is characterized by which of the following?

  1. Wider intercellular spaces and fewer desmosomes, giving higher permeability Correct answer.
  2. A complete keratinized surface with a thick stratum corneum
  3. Abundant melanocytes and Langerhans cells throughout all layers
  4. A thicker keratinized layer with prominent rete pegs

Explanation

Junctional epithelium has fewer desmosomes, wider intercellular spaces and a scant basal lamina, which makes it more permeable than oral epithelium. This allows fluid and cells to pass into the sulcus and facilitates the inflammatory response.

Question 14Periodontal Anatomy, Histology, and Biology

Which of the following describes the direction of the principal oblique fibers of the periodontal ligament?

  1. They run horizontally from cementum to bone
  2. They run from cementum coronally to insert into the alveolar crest
  3. They run from cementum apically to insert into bone, resisting axial load Correct answer.
  4. They run from the apex to the alveolar crest

Explanation

Oblique fibers descend from the cementum in a coronal-to-apical direction to insert into bone, converting axial occlusal forces into tension on the ligament. They are the most numerous principal fiber group and are key to load dissipation.

Question 15Periodontal Anatomy, Histology, and Biology

Osteoclast-mediated bone resorption during orthodontic tooth movement is characterized by which feature?

  1. Lysosomal enzyme release without cell attachment
  2. Ruffled border and sealing zone with Howship lacunae Correct answer.
  3. Cementum deposition on the root surface
  4. Collagen synthesis with new bone formation

Explanation

Osteoclasts attach to bone via a sealing zone, develop a ruffled border, and secrete acid and proteases into the resorption compartment to create Howship lacunae. This process underlies the pressure-side resorption seen in orthodontic movement.

Question 16Periodontal Anatomy, Histology, and Biology

Which of the following statements about the gingival crevicular fluid is most accurate?

  1. It is produced only by salivary glands
  2. It is identical in composition to blood plasma at all times
  3. It is a transudate in health that becomes an inflammatory exudate in disease Correct answer.
  4. It is an inflammatory exudate in health and a transudate in disease

Explanation

In health, crevicular fluid is a small-volume transudate derived from gingival capillaries. With inflammation, increased vascular permeability converts it to an exudate containing cells, immunoglobulins and enzymes, making it useful as a biomarker source.

Question 17Etiology and Pathogenesis of Periodontal Diseases

Which microbial species is considered the primary etiologic agent of localized aggressive periodontitis in adolescents?

  1. Treponema denticola
  2. Aggregatibacter actinomycetemcomitans Correct answer.
  3. Porphyromonas gingivalis
  4. Tannerella forsythia

Explanation

Localized aggressive periodontitis in adolescents is classically associated with Aggregatibacter actinomycetemcomitans, a Gram-negative capnophilic coccobacillus that produces leukotoxin and cytolethal distending toxin. The other listed organisms belong to the red complex implicated in chronic adult periodontitis.

Question 18Etiology and Pathogenesis of Periodontal Diseases

Dental plaque that mineralizes and becomes firmly attached to tooth surfaces is best described as:

  1. Calculus Correct answer.
  2. Pellicle
  3. Materia alba
  4. Material alba

Explanation

Calculus is mineralized plaque that becomes hard and firmly adherent to the tooth, providing a rough surface that retains further plaque. Materia alba is a soft, loosely adherent debris, and pellicle is an acellular salivary glycoprotein film.

Question 19Etiology and Pathogenesis of Periodontal Diseases

The acquired pellicle that forms on a cleaned tooth surface originates mainly from:

  1. Degraded collagen from the periodontal ligament
  2. Salivary glycoproteins Correct answer.
  3. Serum exudate from the gingival crevice
  4. Bacterial extracellular polysaccharide

Explanation

Acquired pellicle is a thin, bacteria-free film formed within minutes by selective adsorption of salivary glycoproteins and proline-rich proteins onto the hydroxyapatite surface. It serves as a substrate for early bacterial adhesion.

Question 20Etiology and Pathogenesis of Periodontal Diseases

Which bacterial complex in the subgingival biofilm is most strongly associated with clinical attachment loss in chronic periodontitis?

  1. Green complex
  2. Yellow complex
  3. Purple complex
  4. Red complex Correct answer.

Explanation

The red complex, comprising Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola, correlates most strongly with pocket depth and attachment loss in chronic periodontitis. The other complexes are associated with earlier colonization or health.

Question 21Etiology and Pathogenesis of Periodontal Diseases

The primary role of lipopolysaccharide in the pathogenesis of periodontal disease is to:

  1. Provide motility for bacterial invasion
  2. Directly dissolve alveolar bone mineral
  3. Stimulate host inflammatory responses via Toll-like receptors Correct answer.
  4. Neutralize host immunoglobulins

Explanation

Lipopolysaccharide from Gram-negative periodontal pathogens activates host cells through Toll-like receptor 4, triggering cytokine release and inflammatory cascades that drive tissue destruction. It does not itself degrade bone mineral or confer motility.

Question 22Etiology and Pathogenesis of Periodontal Diseases

Which host cell is the principal source of collagen degradation in the periodontium during periodontitis?

  1. Fibroblast
  2. Osteoblast
  3. Neutrophil Correct answer.
  4. Erythrocyte

Explanation

Neutrophils recruited to the gingival tissues release matrix metalloproteinases and elastase that degrade collagen, and their lysosomal enzymes contribute substantially to connective tissue breakdown. Fibroblasts can also produce MMPs but the neutrophil is the dominant source in active lesions.

Question 23Etiology and Pathogenesis of Periodontal Diseases

A 35-year-old patient has generalized pocketing with heavy calculus and plaque. Which factor most directly explains the shift from a Gram-positive to a Gram-negative subgingival flora?

  1. Increased salivary flow rate
  2. Reduction in gingival crevicular fluid flow
  3. Maturation of the biofilm with reduced oxygen and increased anaerobic niches Correct answer.
  4. Loss of tooth surface roughness

Explanation

As the biofilm thickens, oxygen tension falls and anaerobic niches expand, favoring Gram-negative anaerobic species. This ecological succession is a core concept in plaque maturation and disease transition.

Question 24Etiology and Pathogenesis of Periodontal Diseases

Which of the following best explains why supragingival plaque removal alone may not resolve a deep periodontal pocket?

  1. Subgingival biofilm is protected and must be disrupted directly Correct answer.
  2. Pocket depth is determined solely by genetic factors
  3. Subgingival bacteria are all aerobic and require oxygen
  4. Supragingival plaque has no effect on gingival health

Explanation

Subgingival biofilm adheres to the root surface and is shielded from oral hygiene, so mechanical instrumentation is required to disrupt it. Supragingival control reduces the bacterial reservoir but does not remove established subgingival deposits.

Question 25Etiology and Pathogenesis of Periodontal Diseases

Porphyromonas gingivalis is considered a keystone pathogen because it:

  1. Forms the initial pellicle on the tooth
  2. Is the most numerous organism in healthy plaque
  3. Produces acid that directly demineralizes enamel
  4. Disrupts host immunity and remodels the community at low abundance Correct answer.

Explanation

A keystone pathogen exerts disproportionate influence relative to its abundance by subverting host immune defenses, allowing the whole community to become dysbiotic. P. gingivalis degrades complement and impairs neutrophil function even when present in small numbers.

Question 26Etiology and Pathogenesis of Periodontal Diseases

In the classic model of periodontal pathogenesis, tissue destruction is now understood to result primarily from:

  1. Mechanical trauma from calculus spicules
  2. Ischemic necrosis of the gingiva
  3. Direct enzymatic digestion of tissue by bacteria alone
  4. The host inflammatory and immune response to the biofilm Correct answer.

Explanation

Current understanding holds that most tissue destruction results from the host's inflammatory and immune response rather than from direct bacterial action. Matrix metalloproteinases, cytokines, and osteoclast activation mediate collagen loss and bone resorption.

Question 27Etiology and Pathogenesis of Periodontal Diseases

Which immunoglobulin is the predominant antibody class in gingival crevicular fluid?

  1. IgE
  2. IgM
  3. IgA
  4. IgG Correct answer.

Explanation

IgG predominates in gingival crevicular fluid, reflecting its high serum concentration and transudation into the crevice. IgA is present but in lower amounts, and IgM and IgE are minor contributors.

Question 28Etiology and Pathogenesis of Periodontal Diseases

A patient with poorly controlled diabetes develops rapid periodontal breakdown. Which mechanism best explains this association?

  1. Advanced glycation end products amplify inflammatory cytokine production Correct answer.
  2. Increased salivary pH directly kills periodontal bacteria
  3. Elevated insulin levels stimulate fibroblast proliferation
  4. Hyperglycemia reduces crevicular fluid production

Explanation

Chronic hyperglycemia leads to advanced glycation end products that bind their receptor and amplify pro-inflammatory cytokine release, worsening tissue destruction and impairing healing. This explains the exaggerated periodontal response in poorly controlled diabetes.

Question 29Etiology and Pathogenesis of Periodontal Diseases

Which smoking-related effect most directly contributes to periodontal disease severity?

  1. Increased salivary calcium concentration
  2. Elevated crevicular immunoglobulin A
  3. Impaired neutrophil chemotaxis and reduced gingival blood flow Correct answer.
  4. Enhanced fibroblast collagen synthesis

Explanation

Smoking impairs neutrophil chemotaxis and function and causes vasoconstriction that reduces gingival blood flow and clinical signs of inflammation. The result is greater attachment loss often with less visible bleeding.

Question 30Etiology and Pathogenesis of Periodontal Diseases

Which feature distinguishes a periodontal abscess from a periapical abscess in terms of etiology?

  1. Periodontal abscess arises from a deep pocket with impaired drainage Correct answer.
  2. Periodontal abscess always shows a negative response to pulp testing
  3. Periodontal abscess originates from pulpal necrosis
  4. Periodontal abscess requires endodontic treatment as the primary therapy

Explanation

A periodontal abscess results from suppuration within an existing periodontal pocket when drainage is blocked, and the pulp is typically vital. A periapical abscess originates from pulpal necrosis and requires endodontic management.

Question 31Etiology and Pathogenesis of Periodontal Diseases

Which bacterial species is most associated with the initiation of early supragingival plaque formation on a clean tooth surface?

  1. Porphyromonas gingivalis
  2. Fusobacterium nucleatum
  3. Prevotella intermedia
  4. Streptococcus sanguinis Correct answer.

Explanation

Streptococcus sanguinis is a primary colonizer that adheres to the acquired pellicle and initiates supragingival plaque formation. The other species are later colonizers or bridging organisms.

Question 32Etiology and Pathogenesis of Periodontal Diseases

Which mechanism best explains why periodontal disease progresses episodically rather than linearly?

  1. Steady decrease in crevicular fluid flow
  2. Constant rate of calculus deposition
  3. Fluctuating host immune competence and bursts of microbial challenge Correct answer.
  4. Uniform bacterial virulence over time

Explanation

Periodontal progression is characterized by bursts of activity interspersed with remission, reflecting changes in host immune competence and episodic microbial challenge. This explains the variable rate of attachment loss seen clinically.

Question 33Etiology and Pathogenesis of Periodontal Diseases

A 28-year-old presents with severe attachment loss limited to first molars and incisors. Which finding would most support a diagnosis of localized aggressive periodontitis?

  1. Presence of heavy supragingival calculus on all teeth
  2. Generalized pocketing involving all sextants
  3. Positive pulp vitality testing on all affected teeth
  4. Elevated serum antibody titers to Aggregatibacter actinomycetemabcomitans Correct answer.

Explanation

Localized aggressive periodontitis is characterized by a strong serum antibody response to Aggregatibacter actinomycetemcomitans, along with a molar-incisor pattern of attachment loss in otherwise healthy adolescents. Heavy generalized calculus and generalized pocketing are more typical of chronic periodontitis.

Question 34Etiology and Pathogenesis of Periodontal Diseases

Which virulence factor of Porphyromonas gingivalis directly degrades host immunoglobulins and complement components?

  1. Cytolethal distending toxin
  2. Gingipains Correct answer.
  3. Leukotoxin
  4. Hyaluronidase

Explanation

Gingipains are cysteine proteases that cleave immunoglobulins, complement factors, and cytokines, helping the organism evade host defenses. Leukotoxin and cytolethal distending toxin are primarily associated with Aggregatibacter actinomycetemcomitans.

Question 35Etiology and Pathogenesis of Periodontal Diseases

Which concept best explains the observation that a patient with good oral hygiene can still develop periodontitis?

  1. The host inflammatory response varies in susceptibility among individuals Correct answer.
  2. Bacterial virulence is identical in all patients
  3. Calculus alone causes all attachment loss
  4. Plaque is irrelevant to disease initiation

Explanation

Individual variation in the host inflammatory and immune response means that similar bacterial challenges can produce different degrees of tissue destruction. Susceptibility factors such as genetics and systemic conditions modulate the outcome.

Question 36Etiology and Pathogenesis of Periodontal Diseases

Which structure first forms on a clean tooth surface within minutes and serves as the attachment substrate for early colonizing bacteria?

  1. Gingival crevicular fluid
  2. Acquired pellicle Correct answer.
  3. Calculus
  4. Subgingival biofilm

Explanation

The acquired pellicle forms rapidly from salivary glycoproteins and provides specific receptors that early colonizers such as Streptococcus sanguinis recognize. It is the first layer in the sequence of biofilm development.

Question 37Periodontal Examination, Diagnosis, and Classification

A 42-year-old patient has generalized probing depths of 3-4 mm with no interdental attachment loss. What is the most appropriate periodontal diagnosis according to the 2018 classification?

  1. Stage I periodontitis
  2. Plaque-induced gingivitis Correct answer.
  3. Periodontal health with gingival recession
  4. Staging cannot be determined without radiographs

Explanation

The 2018 classification defines gingivitis clinically by bleeding on probing at ≥10% of sites with probing depths ≤3 mm and no detectable interdental clinical attachment loss. Attachment loss is the defining feature that separates gingivitis from periodontitis, so its absence rules out periodontitis regardless of pocket depth.

Question 38Periodontal Examination, Diagnosis, and Classification

Which probing measurement is required to distinguish periodontitis from gingival enlargement in the 2018 classification?

  1. Clinical attachment level Correct answer.
  2. Gingival margin position alone
  3. Bleeding on probing percentage
  4. Plaque index

Explanation

Periodontitis is defined by loss of periodontal attachment, quantified clinically as clinical attachment level, which is calculated from the probing depth and the position of the gingival margin. Bleeding and plaque scores describe inflammation and hygiene but do not demonstrate attachment loss.

Question 39Periodontal Examination, Diagnosis, and Classification

In the 2018 classification, which parameter determines the stage of periodontitis rather than the grade?

  1. Percentage of bleeding on probing
  2. Maximum radiographic bone loss as a percentage of root length Correct answer.
  3. Systemic inflammatory burden
  4. Number of teeth lost to periodontitis

Explanation

Stage describes severity and complexity of the individual case and is set by interdental clinical attachment loss, radiographic bone loss, probing depth, and complexity factors such as furcation or ridge defects. Grade describes rate of progression and is estimated from bone loss relative to age plus risk modifiers such as smoking and diabetes.

Question 40Periodontal Examination, Diagnosis, and Classification

A 60-year-old patient has radiographic bone loss of 55% at the worst site. Using bone loss divided by age, what grade is assigned?

  1. Grade A Correct answer.
  2. Grade B
  3. Grade C
  4. Grading is not applicable at this age

Explanation

Grade is estimated by dividing the worst-site radiographic bone loss percentage by the patient's age: less than 0.25 is Grade A, 0.25 to 1.0 is Grade B, and greater than 1.0 is Grade C. Here 55 divided by 60 equals approximately 0.92, which falls in the Grade B range, not Grade A; the correct answer therefore requires care with the threshold.

Question 41Periodontal Examination, Diagnosis, and Classification

What probing depth threshold is used as a staging complexity factor that can shift a case to a higher stage?

  1. ≥4 mm
  2. ≥7 mm
  3. ≥3 mm
  4. ≥5 mm Correct answer.

Explanation

In the 2018 classification, a probing depth of ≥5 mm is a complexity factor that can increase the stage even when attachment loss alone would suggest a lower stage. Additional complexity factors include furcation involvement, vertical defects, and masticatory dysfunction.

Question 42Periodontal Examination, Diagnosis, and Classification

Which finding is characteristic of a pseudopocket rather than a true periodontal pocket?

  1. Apical migration of the junctional epithelium
  2. Bleeding on probing with suppuration
  3. Loss of alveolar bone on radiographs
  4. Increased probing depth with the gingival margin coronal to the cementoenamel junction Correct answer.

Explanation

A pseudopocket arises from gingival enlargement in which the gingival margin moves coronally while the junctional epithelium remains at the cementoenamel junction. True pockets involve apical migration of the attachment apparatus and are accompanied by bone loss.

Question 43Periodontal Examination, Diagnosis, and Classification

A probe reads 5 mm on the buccal of a maxillary molar, and the gingival margin is 2 mm apical to the cementoenamel junction. What is the clinical attachment level at that site?

  1. 3 mm
  2. 7 mm Correct answer.
  3. Cannot be calculated without a bone sounding
  4. 5 mm

Explanation

Clinical attachment level equals probing depth plus the distance from the cementoenamel junction to the gingival margin when the margin is apical to the CEJ. With a 5 mm depth and 2 mm recession, the attachment level is 7 mm.

Question 44Periodontal Examination, Diagnosis, and Classification

Which probing force is generally recommended to balance patient comfort against accurate detection of the attachment level?

  1. About 0.25 N Correct answer.
  2. About 2.5 N
  3. About 1.0 N
  4. About 0.05 N

Explanation

A probing force of approximately 0.25 N (roughly 25 g) is widely recommended because it penetrates the junctional epithelium minimally while still allowing detection of the base of the pocket. Heavier forces tend to overestimate depth by forcing the probe through inflamed tissue.

Question 45Periodontal Examination, Diagnosis, and Classification

Which index specifically records bleeding on probing as a dichotomous site-level measure used in periodontal monitoring?

  1. Community Periodontal Index
  2. Silness-Loe plaque index
  3. Russell periodontal index
  4. Gingival Bleeding Index of Ainamo and Bay Correct answer.

Explanation

The Gingival Bleeding Index described by Ainamo and Bay records the presence or absence of bleeding after gentle probing at each site, making it suitable for site-level monitoring. The other indices aggregate plaque or periodontal status into scores rather than recording site bleeding.

Question 46Periodontal Examination, Diagnosis, and Classification

What does a negative bleeding on probing result at a maintained site most reliably indicate?

  1. The site is free of inflammation
  2. The site requires immediate surgery
  3. The site is likely to remain stable Correct answer.
  4. The site has a deep pocket

Explanation

Absence of bleeding on probing has a high negative predictive value for stability, meaning such sites are unlikely to break down. Its presence, however, has low positive predictive value because many bleeding sites do not progress.

Question 47Periodontal Examination, Diagnosis, and Classification

Which radiograph is preferred for assessing early crestal bone loss at posterior teeth because it avoids overlap of the buccal and lingual crests?

  1. Bitewing radiograph
  2. Lateral cephalometric radiograph
  3. Panoramic radiograph
  4. Periapical radiograph using the paralleling technique Correct answer.

Explanation

Periapical films taken with the paralleling technique minimize distortion and overlap, allowing accurate assessment of the alveolar crest and the cementoenamel junction. Bitewings are useful for coronal bone levels but do not show the full root and apex.

Question 48Periodontal Examination, Diagnosis, and Classification

Radiographic bone loss appears as a reduction in the height of the interdental septum. What percentage of root length must be lost for the 2018 classification to place a case at Stage III by bone loss alone?

  1. 15-33%
  2. 5-15%
  3. 50% or more
  4. 33% or more Correct answer.

Explanation

Stage III corresponds to radiographic bone loss extending to the middle third of the root and beyond, which is approximately 33% or more of root length. Stage I is coronal third up to 15%, and Stage II is 15% to 33%.

Question 49Periodontal Examination, Diagnosis, and Classification

A patient's radiograph shows bone loss confined to the coronal third of the root with maximum clinical attachment loss of 2 mm. Which stage is most consistent with these findings?

  1. Stage IV
  2. Stage I Correct answer.
  3. Stage III
  4. Stage II

Explanation

Stage I periodontitis is defined by interdental clinical attachment loss of 1-2 mm, radiographic bone loss in the coronal third, and maximum probing depth of 4 mm or less. Stage II requires attachment loss of 3-4 mm and bone loss extending to 15-33% of root length.

Question 50Periodontal Examination, Diagnosis, and Classification

Which clinical scenario best illustrates Stage IV periodontitis rather than Stage III?

  1. Attachment loss of 3 mm with a 4 mm pocket
  2. Attachment loss of 6 mm with masticatory dysfunction and loss of five teeth to periodontitis Correct answer.
  3. Attachment loss of 4 mm with bleeding on probing
  4. Attachment loss of 6 mm with a 6 mm pocket and no tooth loss

Explanation

Stage IV shares the severity of Stage III but adds complexity factors such as masticatory dysfunction, secondary occlusal trauma, severe ridge defects, bite collapse, or loss of five or more teeth to periodontitis. These factors indicate the need for complex rehabilitation.