Not wanting to sound patronising but, are you sure they’re gone? They do tend to be very short/stumpy.
If they are missing, check the rest of the cats gums – if they are bright red, especially close to the teeth that may indicate an underlying problem such as viral disease. Are they vaccinated?
If the gums are a nice pale pink colour, I wouldn’t be too concerned.
Most likely nothing to worry about but, as ever, check with your own vet if any doubts.