A new review pooled data from studies of children aged 4 to 9 who had a lower second baby molar (a primary molar) removed early. The review included four studies overall, and three of them, involving just 38 children, were combined in the main analysis. Researchers measured how much space was lost in the lower jaw over time.
The pooled results showed a small but steady loss of space. On average, space decreased by 0.80 mm at 3 months, 1.10 mm at 6 months, and 1.24 mm at 9 to 10 months after extraction. A measure of the dental arch also shrank by about 1.06 mm at 6 months. These numbers were statistically significant, but they come from a very small group of children.
The review has important limits. It covers only short-term results, and there was not enough data on the upper jaw to draw any conclusion there. It is also unknown whether this small space loss later leads to crooked teeth or the need for braces. The authors say the evidence is not strong enough to support routine use of space maintainers, the devices sometimes used to hold space open.
For parents, this suggests early loss of a baby molar may cause a modest shift in the short term, but the long-term picture is still unclear. Decisions about space maintenance should be made case by case with a dentist, based on each child's bite, crowding, and growth.
