Doxy & White Lines Around Teeth

Hi Everyone,
I recently got white etching around the edges my 4 lower front teeth. It looks like white vertical lines around the edges. I floss and brush daily. Teeth have always been sensitive, less so since I stopped drinking coffee. Per my dentist, tooth color is dull because I was a tetracycline baby, given tetra for colic age 1-2 in 1960s. I see the dentist every 6 months for cleaning/check up. Haven't had other problems before this.

Internet says the white etching is demineralization. https://www.justanswer.com/dental/7q03u-white-around-gum-line.html Also mentions acidity in mouth. I'm on 400mg doxy per day. I've only been taking about 235mg calcium per day (over 2 hours away from taking doxycycline) for fear it would adversely effect the bactericidal powers of the doxy.

Could the doxycycline be causing this problem?
Could increasing my calcium supplement fix the etching?
Has anyone run into this problem? How did you fix it and did your teeth regain normal color?

Thanks, Aylett

Hi PeteZa. Thanks for the advice. I just don't want any dentist scraping at my teeth to try to get this white stuff off, if my teeth can simply be restored through minerals. So, I was looking to see if anybody had had the same experience. Also, it is nice to have information before you go meet a medical professional. I've already had enough bad diagnosis and missed diagnosis for a lifetime. I like to have all the information I can get, so I'm not at a disadvantage when I go into the office. Thanks again, Aylett