Free Cementum and Periodontium MCQs with Answers

• A. Osteoclastic activity
• B. Osteoblastic activity
• C. Myeloid activity
• D. Healing activity

Explanation: A reversal line marks the change from bone resorption to bone formation, so it indicates that osteoclastic activity has ceased and…

• A. Tome's fibres
• B. Sharpey's fibres
• C. Ray's fibres
• D. All of the above

Explanation: Sharpey’s fibres are the embedded ends of periodontal ligament fibres that extend into cementum and alveolar bone, anchoring the tooth to…

• A. Alkaline phosphatase and urease
• B. Catalase and phosphorylase
• C. Alkaline phosphatase and phosphorylase
• D. Acid phosphatase and catalase

Explanation: Alkaline phosphatase supports mineral deposition, while phosphorylase participates in carbohydrate metabolism needed during osteoblast…

• A. Haversion cone
• B. Howships cone
• C. Cutting cone
• D. Filling cone

Explanation: During osteon remodeling, osteoclasts create the cutting cone and osteoblasts follow behind to deposit new lamellae in the filling cone.

• A. Alveolar bone proper
• B. Periosteum
• C. Spongy bone
• D. Endosteum

Explanation: Haversian systems are osteons, the cylindrical structural units of compact bone, and they occur in the compact component of alveolar bone…

• A. Lamina lucida
• B. Lamina densa
• C. Lamina dura
• D. Lamina propria

Explanation: Alveolar bone proper appears as the radiopaque lamina dura lining the tooth socket on an intraoral periapical radiograph.

• A. Osteoclast
• B. Osteoblast
• C. Osteocyte
• D. Osteon

Explanation: The osteon, or Haversian system, is the basic structural and functional unit of compact bone and is organized around a central blood…

• A. Cortical
• B. Cancellous
• C. Osteophytic
• D. Exophytic

Explanation: The labial bone over the anterior teeth is generally a thin cortical plate, often with little or no cancellous bone between the cortical…

• A. 1st molar
• B. 2nd premolar
• C. 1st premolar
• D. 2nd molar

Explanation: The maxillary first molar is classically described as having roots in close relation to the floor of the maxillary sinus.

• A. Compact bone
• B. Cancellous bone covered by thin layer of compact bone
• C. Cancellous bone
• D. Compact bone covered by cancellous bone

Explanation: The mandibular condyle has a cancellous bony interior covered by a thin compact cortical layer.

• A. Ramus of the mandible
• B. Lower border of the mandible
• C. That part of the bone embracing apices of root of teeth
• D. That part of the bone containing teeth

Explanation: Basal bone is the portion of jawbone beneath and around the apices of the teeth, supporting the alveolar process.

• A. woven bone
• B. Irregular bone
• C. Resorbing bone
• D. Lamellar bone

Explanation: Mature bone is organized into concentric or parallel lamellae and is therefore called lamellar bone.

• A. Odontoblasts & megakaryocyte
• B. Osteoclasts, osteoblasts, osteoid
• C. Megakaryocytes, osteoblasts, osteoclasts
• D. None of the above

Explanation: Forming bone contains osteoblasts, which produce osteoid, and osteoclasts, which remodel the developing tissue.

• A. Same as in other parts of alveolar bone
• B. Less than the other parts of alveolar bone
• C. More than the other parts of alveolar bone
• D. Less than the cementum

Explanation: The lamina dura is a dense, highly mineralized part of the alveolar bone proper, so its calcium content is greater than that of the less…

• A. Support and retention to the complete denture
• B. Boundaries for the tongue during speech
• C. Attachment to muscles of facial expression
• D. Support the natural teeth

Explanation: The alveolar process forms the tooth sockets and provides attachment and support for the natural teeth through the periodontal ligament.

• A. Gubernacular canals
• B. Canals of Hirchfeld and Zuckerland
• C. Herversian canals
• D. Volkmann canals

Explanation: Gubernacular canals are small passages on the lingual aspect of primary teeth that guide the eruption path of their permanent successors.

• A. 0.10 mm
• B. 0.50 mm
• C. 0.25 mm
• D. 0.75 mm

Explanation: The periodontal ligament has an average width of about 0.25 mm, although it varies with age, tooth function, and location.

• A. 0.75 mm in thickness
• B. 0.5 mm in thickness
• C. 0.25 mm in thickness
• D. mm in thickness

Explanation: The periodontal ligament is approximately 0.25 mm thick on average, with normal regional variation.

• A. Cervical third
• B. Apical third
• C. It has uniform width
• D. Fulcrum of rotation

Explanation: The periodontal ligament is narrowest around the middle third of the root, which corresponds approximately to the fulcrum or center of…

• A. Periodontal ligament
• B. Gingiva
• C. Alveolar bone
• D. Cementum

Explanation: Cementicles are small calcified bodies commonly found free within, or attached to the cementum in, the periodontal ligament.