Root canal is required when the decay has spread to the pulp chamber ..The soft core of the tooth inside. It should be performed after clinical evaluation and x ray if needed. In very young children. .It may require general anesthesia or sedation in a hospital environment. Please get her evaluated with a dentist for diagnosis and detailed treatment plan.

The objective in doing Root canal on baby teeth are to preserve them till the time they fall off. The rct differs from that for a adult as the tooth will fall away in a few months to  some years. The child's cooperation is paramount in fulfilling the objective. Depending on the age of the child and cooperation results are very predictable and it's a good idea to maintain the tooth till it's ready to fall away with the eruption of the permanent one. Alternatively a serial extraction could also be considered to make sure the permanent one erupts in its place .Timing however is what matters. Please consult with a dentist  for a clinical Evaluation and detailed discussion and attention . TC