A 2009 study on Prevalence of Adult Tooth Wear published in the Journal of Prosthodontics revealed that:
1 in 33 20 year olds have severe tooth wear
1 in 6 70 year olds have severe tooth wear
Severe tooth wear is destruction of the hardest substance in the human body, tooth enamel. Once the enamel is gone the much softer dentin begins to wear even faster.