Only an estimated 5.3 million adults are expected to gain oral health coverage as a result of PPACA, but that's due almost entirely because of Medicaid expansion in the few states that provide extensive dental benefits.

This will reduce the number of adults without dental benefits by about 5 percent—"a negligible impact," the ADA said. It also said that Medicaid-eligible adults may see few improvements in their ability to receive dental care.

Experts have warned the law could significantly disrupt the dental benefits market if employers drop coverage for their workers or workers opt out of duplicative plans for themselves to pay for their children's benefits. The law mandates dental insurance for children. Its definition of "essential health benefits" encompasses pediatric services, including oral and vision care.

The National Association of Dental Plans has estimated that up to 11 million Americans may drop dental coverage when their children are removed from their dental policies.

The ADA also warned there is likely to be significant pressure on Medicaid providers under PPACA changes, because the law fails to address critical factors such as administrative inefficiencies and low provider reimbursement rates.

As a result, low-income adults will likely resort to other options, including visiting emergency rooms for dental care.

Emergency room visits for dental visits have already been increasing in recent years, because of a lack of dental insurance and significant reductions in adult dental Medicaid programs. Health care professionals have warned that the increase in ER visits for dental-related problems will only increase, which in effect will strain the health care system and increase overall health costs.

The new warning from the dental industry follows red flags raised by physician groups that have repeatedly said the influx of new patients under reform—on top of the already growing physician shortage—will have profoundly negative implications for patient access to medical care.

The ADA—which represents some 157,000 dentists—urged state governments to pick up where PPACA leaves off.

"The ACA does little to break down financial and other critical barriers to dental care, and states will need to pick up the slack if we're going to address the oral health challenges facing America," Vujicic wrote.

Most state Medicaid programs currently provide no or very limited dental benefits for adults, giving states the ability to expand coverage in conjunction with reforms that would help shore up their Medicaid systems, the ADA said.

They also pointed to accountable care organizations as an opportunity to help bridge the gap between oral and body health. ACOs are meant to improve the coordination of various types of care, improve the patient experience and help reduce overall health care costs.