Is tetracycline safe for permanent teeth?

No, tetracycline is not considered safe for permanent teeth. Tetracycline is an antibiotic that can cause yellow or brown discoloration and mottling of the teeth when taken during periods of tooth development, which includes the time before birth, during infancy, and early childhood. This discoloration is permanent and cannot be removed or bleached. Therefore, it is recommended to avoid tetracycline and similar antibiotics during these periods to minimize the risk of tooth discoloration.