According to a recently-released survey, in March 2015,

28.2% of adults (ages 18 to 64) who had been insured for a full year, had an unmet need for health care during the past year because of affordability. Respondents could report multiple categories of unmet needs; the percentage by category follows:

• dental care: 20.1%
• prescription drugs: 13.3%
• medical care: 10.4%
•  doctor care: 10.3%
• specialist: 9.6%
• medical tests or follow-up care: 11.0%
• mental health or substance abuse treatments: 5.6%
• contraception or other family-planning services: 2.0%

Source: "Health Reform Monitoring Survey,", The Urban Institute, September 24, 2015, http://hrms.urban.org/quicktakes/Gaps-in-Dental-Care-for-Insured-Adults-Remain-under-ACA.html