"Reunion" joke

While waiting for my first appointment in the reception room of a new dentist, I noticed his certificate, which bore his full name. Suddenly, I remembered that a tall, handsome boy with the same name had been in my high school class some 45 years ago.

Upon seeing him, however, I quickly discarded any such thought. This balding, grey-haired man with the deeply lined face was too old to have been my classmate.

After he had examined my teeth, I asked him if he had attended the local high school.

"Yes," he replied.

"When did you graduate?" I asked.

"In 1952."

"Why, you were in my class!" I exclaimed.

He looked at me closely, and then asked, "What did you teach?"