What are dental root caries, what age group is generally more effected by that?

Not age related. Younger people tend to have higher sugar content in the diet and are less inclined at home care so we tend to see higher degrees of decay in children then older adultsthis tends to be in the pits and fissures of the posterior teeth but we tend to see more root exposure in older adults and higher incidence of dry mouth with together increase root caries tendancies.
Root cavities. These are cavities on the root of the tooth.This part of the tooth is generally covered by the gum it can happen in any person that has exposed roots. More frequently in older populations that have diminished saliva from illness or medication.
Tooth decay. The root is usually protected from decay causing bacteria by the gum. If the gum recedes, often from brushing up and down ( not gentle wiggles with a soft brush), the root is exposed.Poor oral hygiene leaves decay causing bacteria at the gumline, on the root, people with less saliva (dry mouth) are at risk of root caries. Dry mouth is usually from medications, and is not age related.
Cavities at gum line. Root caries are more prevelant among those who have dimished salivary flow..Usually due to age or side effects of drugs.