Pediatric Dentistry · patient case question
At what point is a space maintainer no longer required?
Patient case: Premature loss of primary molars in the mixed dentition
Patient: Female, 6 years old
Chief Complaint: Referred after two primary molars were extracted because of gross caries.
Background: Tooth T (the mandibular right second primary molar) and tooth L (the mandibular left first primary molar) have both been lost prematurely.
Current Findings: The permanent mandibular first molars have not yet erupted. The permanent lateral incisors are unerupted. No crowding is evident in the anterior segment. She is otherwise healthy.
Show answer and explanation
Correct answer: B. Once the permanent lateral incisor and the permanent first molar have erupted
- A. Waiting for the permanent canine is far too late — the canine erupts around age 11 to 12, well after space loss would have occurred.
- B. The general rule taught for this decision is that no space maintainer is needed once the permanent LATERAL INCISOR and the permanent FIRST MOLAR have erupted. Their eruption marks the point at which arch dimension has been established and the incisor liability period has passed, so the risk of significant space loss from a lost primary tooth drops sharply.
- C. Waiting for full exfoliation of the primary dentition removes the very reason for the appliance long after it mattered.
- D. Chronological age is a poor guide; dental development varies widely between children of the same age.
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