I think aspirin is toxic to dogs. Not 100 % positive..but I would be careful. How about antlers to gnaw on?
Ok..just talked to family friend who is vet.she said you can use aspirin..but the dosage has to be monitored carefully and in a pup she would be reluctant. She suggested freezing wet towels and let her chew while supervising her. The cloths would defrost pretty quickly..but might help for short periods of time!