We are sorry to hear you have had a road traffic accident.
If your vehicle was travelling faster than 5mph and the accident was enough to cause a dent in the car panelling whilst your car seat was in the car, this would suggest your car seat and isofix base would need to be replaced.
Even if there is no visible damage, a child car seat that was in a collision may have been weakened to the point where it won’t provide the same level of protection in another accident.
This is not something that would be covered under your manufacture's warranty however it may be covered by your car insurance. This would be specific to your policy and insurance company.