Children lose teeth in a broadly consistent order, and the pattern is not coincidence. Each permanent tooth develops on its own schedule and actively removes the baby tooth in its path.
Shedding is driven from below
A permanent tooth forms in the bone beneath or behind its predecessor. As it develops and moves toward the surface, it presses on the root of the baby tooth above.
Cells recruited to that area resorb the baby tooth's root, dissolving it progressively from the tip upward. The crown is left with steadily less anchorage.
A tooth becomes loose when enough root has been removed to leave the crown poorly supported. Wiggling accelerates the final separation but does not cause the process.
Developmental timing sets the sequence
Permanent teeth begin forming at different points, with front teeth generally starting earlier than teeth further back in the arch.
Because eruption follows development, the order of shedding largely mirrors the order of formation. Lower front teeth are typically first.
Teeth also tend to erupt in matching pairs on the left and right, since the two sides develop in parallel. Marked asymmetry is worth a look.
The first permanent molars replace nothing
The permanent first molars appear behind the last baby molars rather than under them. No baby tooth is shed to make room.
Because no tooth falls out first, their arrival is frequently missed by parents. They are sometimes mistaken for baby teeth for years.
That confusion matters because these molars are permanent from the moment they arrive and have deep grooves that make them decay-prone early.
Why the timetable varies between children
Eruption timing varies considerably among healthy children, and a range of many months around any given tooth is ordinary.
Sequence tends to be more informative than exact age. A tooth that arrives late but in the expected order is usually less notable than one out of sequence.
General growth patterns, and sometimes genetics, influence the schedule, which is why siblings often follow similar timing.
What warrants a dental assessment
Early loss of a baby tooth from decay or injury removes the space holder for the tooth beneath, and the neighboring teeth may drift into that gap.
A permanent tooth erupting behind a baby tooth that has not loosened, or long delays with no successor visible, are findings a dentist evaluates with radiographs.
Routine checkups through these years exist largely to track this sequence, since deviations are easier to manage when identified early.