Final answer:
Permanent dentition with tetracycline staining occurs when the permanent teeth become discolored as a result of being exposed to the antibiotic tetracycline during their development.
Step-by-step explanation:
Permanent dentition with tetracycline staining occurs when the permanent teeth become discolored as a result of being exposed to the antibiotic tetracycline during their development. This typically happens during childhood when tetracycline is used to treat infections. The antibiotic binds to the developing enamel and dentin of the teeth, resulting in a yellow or grayish discoloration.