Pediatric Dentistry · patient case question
Which cells resorb the roots of primary teeth to permit exfoliation?
Patient case: A young patient in the mixed dentition
demo: 5-year-old female
chief: Routine examination. Her mother is worried that her front teeth are coming through early.
history: Healthy. The family moved recently from a community with fluoridated water to one with none. Her mother reports the older sibling had a similar early pattern.
meds: None.
findings: Both mandibular permanent central incisors are fully erupted. A 3 mm midline diastema is present in the maxilla between the primary central incisors. A periapical film of a maxillary lateral incisor shows an invagination of enamel and dentin extending into the pulp chamber.
Show answer and explanation
Correct answer: B. Odontoclasts
- A. Fibroblasts produce and remodel the collagen of the periodontal ligament and gingival connective tissue.
- B. Correct. Odontoclasts are multinucleated cells of the monocyte-macrophage line, functionally and morphologically like osteoclasts but acting on dental hard tissue. They resorb dentin and cementum through a ruffled border, creating Howship's lacunae in the root surface.
- C. Cementoblasts deposit cementum; they build rather than resorb.
- D. Osteoblasts form bone. Osteoclasts resorb the bone overlying an erupting tooth, which is a separate process from root resorption.
Note: The eruption pathway is cleared by osteoclasts resorbing overlying bone, while the primary root is resorbed by odontoclasts. Both are needed, and which one is being asked about depends on the tissue.
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