Sometimes the deciduous (baby) teeth don’t fall out at the time they should. Instead, they stay in place and become cramped next to the normal adult teeth, which erupts alongside them. This can lead to problems like gum disease as there is more plaque-trapping, and abnormal positioning of the adult teeth which may cause incongruency and trauma long-term.
Sometimes the roots of these teeth are very long and delicate, making it challenging to remove without damaging the teeth next to it.