Once the squirrel has reached the adult stage, their teeth do not regrow if lost.
Infant tree squirrels have three pairs of milk teeth that are replaced by adult teeth when the squirrel is four to five months old. Once the adult teeth come in, they do not re-grow if lost or removed. The baby’s lower incisors come in at between three and four weeks with the upper incisors following at five weeks.
However their teeth do grow continuously throughout their lives.
Squirrel incisors continuously grow in a highly curved trajectory throughout their lives, on average about 6 inches per year.