Hi, I would usually not go digging around in the gum for the remnant of the baby tooth unless your child is showing signs of an infection (swollen gum, occasionally pus may drain out of the swelling which is called an abscess).
This is for 2 reasons:
1) The baby tooth is usually resorbed by the continued root growth of the adult tooth as it erupts through the gum.
This is something that is practiced in trauma cases where a baby tooth has fractured underneath the gum. Most of the time, the adult tooth eventually erupts normally despite leaving the baby tooth fragment inside.
This process of eruption of the adult tooth can take about 3 years to complete.
2) If the baby tooth fragment is completely embedded in the gum, your child will need a minor surgical procedure to remove the fragment and this can cause damage to the cells that are finishing up the development of the adult tooth's root.
This procedure can also be quite traumatic for the child and we may lose cooperation for future dental treatments. It sounds like your child may have ongoing severe tooth decay and it is important to not lose sight of the bigger picture (getting the tooth decay under control and improving oral hygiene and diet practices in preparation for future orthodontic treatment).
Whether it is better to leave the fragment alone of have it removed is a decision that should be made only after a proper assessment that includes X-rays, as Dr Sylvia has mentioned.
Assessment of the adult tooth's alignment can be done on a continued basis at regular hygiene appointments and this is easily corrected with braces when your child is older. Hope this helps!
