What is the recommended treatment for a 4-year-old who has lost a second primary molar?

A distal shoe is indeed a treatment option that is recommended for a 4-year-old who has lost a second primary molar, particularly if it's anticipated that the permanent successor (the first permanent molar) will erupt soon. The distal shoe is a type of space maintainer that is used in the posterior position; it helps to maintain space and ensures that the permanent first molar can correctly erupt into its proper position.

Loss of a primary molar can lead to space loss for the permanent teeth, which could cause malocclusion or other orthodontic issues later on if not addressed. The distal shoe serves to hold the space open until the permanent molar erupts. This proactive approach helps guide the eruption of the permanent tooth, promoting healthy development of the dentition.

Other treatments like space maintainers, crowns, or extraction might apply in different contexts, but specifically, for maintaining space for the succeeding permanent molar after premature loss of a primary molar, the distal shoe is particularly advantageous when the timing of eruption is critical.