If it just happened, and you have the tooth, rush to a dental surgeon or Pedodontist and he can re-implant the tooth into the socket.
Assuming the tooth is gone, at age 10 I would suggest and upper orthodontic retainer with a tooth on it and when he gets to be 16-19 yrs of age consider an implant or fixed partial denture good luck Kevin Coughlin DMD, MBA, MAGD CEO Baystate Dental PC