Only last-minute defunding can prevent a health care disaster.

Imagine your family’s next trip to the dentist. You, your spouse and your children are covered by an insurance plan purchased through one of the new health exchanges opening next month. It was sold to you as a no-deductible plan, so it’s quite an unpleasant surprise when the dentist asks you to pay.

Sound unlikely? If only. That kind of scenario is not that far-fetched, given the persistent glitches that have surfaced as the Oct. 1 launch of Obamacare approaches.

Health insurance officials are worried – and rightly so. They’ve seen the errors that have cropped up on a new government website designed to show the public what plans are available for purchase.

“An official from Florida Blue, a large insurer, was concerned that a health policy it plans to sell on the state’s exchange would mislead customers,” Reuters recently reported. “The preview website showed no charge at all for some medical services, rather than no charge after a deductible is met.”

Or take Aetna. Policies that they once intended to sell in Ohio were withdrawn, but were still showing up on the government website. Or the glitch that led to the example cited above: Delta Dental of Wyoming noticed that its plan was showing zero deductible in policies that cover parents and children. Oops.

The Centers for Medicare and Medicaid Services, the government agency in charge of signing agreements with insurers this month to sell specific policies on the exchanges, insists it will iron out the problems and open the enrollment period on time.

Perhaps it will, but the president’s signature health law faces more than just technical problems.

For one thing, government officials have missed numerous deadlines to get a federal health exchange up and running. One Government Accountability Office report noted that “critical” activities to create the exchange had not been completed, and that the missed deadlines “suggest a potential for challenges going forward.”

Nice understatement there. A memo from the Congressional Research Service, which indicates that no fewer than 41 out of 82 Obamacare-related deadlines have been missed, indicates this “potential” is even greater than the GAO has stated.

Other unexpected problems have forced the administration to delay key parts of the law. Last April, for example, officials announced that workers won’t be able to choose plans next year from different health insurers in the small-business exchanges. Time magazine’s Joe Klein, a longtime administration supporter, called this “a really bad sign” of “Obamacare incompetence.”

Administration officials are also delaying by a year enforcement of the mandate that employers provide health insurance. The stated reason: Administration officials are still trying to craft workable regulations implementing the mandate. However, given that they’ve had three years to write those regulations, and that employer health costs are expected to increase under Obamacare, there is a strong suspicion that the administration is mainly trying to defer until next year the anticipated bad news that employers are dropping coverage and dumping their employees into the government exchanges.

Consider the fate of the high-risk pools for individuals with pre-existing conditions. The pools faced higher costs and lower enrollment than expected. Even though only 110,000 signed up (far short of the 700,000 originally projected), the government had to freeze enrollment and cut payments to doctors and hospitals to prevent the $5 billion program from going bankrupt.

Another pothole on the road to Obamacare: the Supreme Court’s ruling that states don’t have to expand their Medicaid programs to insure more people. Considering how unaffordable the program is now, it’s no wonder that states were resisting pressure from the administration to add still more to the rolls.

This is only a partial list of the problems that have plagued the new law so far. No wonder pressure is growing to defund it altogether. Rather than try to fix its myriad difficulties, it’s time to go back to the drawing board and implement serious, patient-friendly reforms that actually work and are affordable.

“It’s a train wreck,” Sen. Max Baucus, Montana Democrat, has admitted of Obamacare’s implementation. There’s still time to slam on the brakes, but we’re running out of track.