A benefit that does not get a lot of attention is dental insurance. While it is a voluntary benefit, it is still important to get regular dental check-ups. According to the CDC, 37% of adults have gone over a year without seeing a dentist. Brushing, flossing and getting an annual checkup aren't the only things that impact dental health. Where you live can have an effect, too. According to a study from WalletHub, these are the states with the best and worst dental health. Related:  Voluntary benefit offerings expand to address health care costs in tight labor market Why combining core and voluntary benefits is a differentiator