Pediatric Dentistry · patient case question
A maxillary midline diastema is most likely to close spontaneously when it measures:
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. Less than 2 mm
- A. At 3 mm closure is doubtful; the threshold is 2 mm, and this patient's 3 mm gap sits on the wrong side of it.
- B. Correct. A diastema under 2 mm in the mixed dentition usually closes on its own as the permanent laterals and canines erupt and push the centrals together, the so-called ugly duckling stage resolving. Beyond 2 mm spontaneous closure becomes progressively less likely and orthodontic or frenal assessment is warranted.
- C. Larger than 2 mm predicts poorer spontaneous closure, not better.
- D. Above 4 mm spontaneous closure is unlikely and intervention should be planned, after ruling out a mesiodens or a thick fibrous frenum with a notched interdental crest.
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