THE marketing pitch came by e-mail: Would you like to make an appointment with your dentist to have your teeth cleaned? And while you’re at it, how about recommending him to a friend, or posting a review of your dental care?

I had given my e-mail address and mobile phone number to my dentist’s office a couple of years ago, for those rare occasions when he might need to communicate with me. Now, here I was receiving what I deemed unwanted promotional e-mail — and a text message — about the dentist’s services via Demandforce, a firm in San Francisco that handles customer communications for some 11,000 small business including dentists, spas and automotive shops. (Demandforce describes such messages as appointment reminders.)

Of course, some people may not mind receiving automated, unsolicited birthday greetings or thank-you e-mails on behalf of their health care providers. But I felt that the conditions under which I had provided my contact information had been violated. I wanted the dentist’s office and Demandforce to erase my information.

That proved easy enough — in this instance. But, as I looked into the matter, I discovered that I, as an American, did not actually have an automatic right to demand that a company erase personal information about me.