"They're very few pediatric dentists that accept Medicaid in this area, so these children have nowhere to go even if they do have insurance.... It's a big problem."
An important problem for the specific children who are suffering, described in the article, but also a problem more generally. You can extend insurance coverage, but it doesn't cause the caregivers to come into existence. What will happen when everyone is forced to buy health insurance — it's not some government munificence, but something you paid for — and then the coverage is for something unavailable? I can't imagine the anger that will arise if/when that happens.