Is it normal for hygienist to remove decalcification?

[grinder]

My two front lower teeth #24, 25 had decalcification (white spot) on the edges. Recently during a dental cleaning the white part was scraped off along with some plaque. Is this normal? I found out because after the cleaning my tougue felt some sharp edge and I looked in the mirror.

I asked the dentist about this and he said decalcification area eventually become soft and will be removed during cleaning. Is this a valid explanation?
Or should decalcification be left alone?

 

[Busybee]

It's interesting that you should post this because I came back to this forum after a long absence as I went for a routine hygiene appointment only to have pain and sensitivity two days later because of a metal sandpaper tape being used which appears to have dislodged some cement on a crown. It is my impression that hygienists are not regulated sufficiently and can cause permanent harm to dental work and enamel. They should stick to cleaning teeth and leave any adjustments to enamel to the dentist!