Only about a third of community health clinics in California have dental services onsite, causing some patients to forgo treatment, according to a report released Wednesday.

The study from the UCLA Center for Health Policy Research found that the state could significantly improve access to dental care, particularly for low-income and uninsured people, if dentists were available at more health clinics.

While a third of health clinics offer no dental services, another third are part of an organization that does offer dental care, but at another site.

“Dental care is often an afterthought compared to medical care,” said Jim Crall, a professor and chair of the public health and community dentistry division at the UCLA School of Dentistry, who is also a co-author of the study. “But oral health is vital for good overall health, and having a dental home helps avoid costly care that becomes necessary when oral health care is neglected.”

When dental services are located at health clinics, patients are more likely to get prompt care for oral problems. Left untreated, dental problems can sometimes exacerbate health conditions.

“Emerging evidence linking poor oral health to poor outcomes for chronic conditions such as diabetes and heart disease further underscores the potential value of integrating oral health care and primary care services to provide highly accessible, comprehensive, and whole-person care to populations most in need,” the report states.

California’s rural Northern and Sierra counties are more likely to offer joint dental and health services at clinics, researchers found. Among those counties, 51 percent of health clinics have onsite dental services.

Los Angeles County, by contrast, has the fewest number of health clinics with dental services: just 23 percent.

Many health clinics that offer dental care also have limited availability, because they employed only part-time dentists and hygienists, researchers found.