It began innocently enough, with a dentist's joke about a potbellied pig named Walter.

Then came a set of fake boar's tusks — placed in a patient's mouth — and things got really out of hand.

Now, six years, two lawsuits and millions of dollars later, the battle of the boar's tusks is still simmering.

On Monday, the state Court of Appeals ruled that an insurance company had no obligation to defend dentist Robert Woo, whose idea of a practical joke was to photograph the set of teeth in the mouth of the anesthetized patient. The ruling overturns a jury verdict of $750,000 — in favor of the dentist — but leaves intact a $250,000 settlement with the patient.

Confused? Let's start at the beginning. According to court documents, Woo, who practices oral surgery in Auburn, liked to joke with a longtime assistant about her pet pig Walter. The assistant adored Walter, and potbellied pigs in general, even going so far as to rescue unwanted pigs and adopt them out to new owners.

Woo, however, was not so enamored and sometimes joked with her about barbecuing Walter. Once, he had his photo taken with some pigs strung up in a shop window and made a point of showing her. Another time, after a hunting trip, he brought in a photo of himself alongside a dead boar.

Woo later said he'd never kill Walter and that the photos were just playful teasing. His lawyer said Woo ran his office more like a family than a dental practice, and that he and the staff, most of whom were longtime employees, were close.

Given that closeness, Woo said he decided to take the boar joke another step in the summer of 1999, when the assistant needed a dental procedure, according to court records. In addition to the temporary replacement teeth, which were ordered two weeks in advance, he also ordered an additional set of teeth made in the shape of tiny boar's tusks, the kind that curl up at the end.

In court documents, he said he planned to present the assistant with the tusks as a gag gift. But when she decided at the last minute to have full anesthesia, he came up with another plan.

While she was unconscious, he inserted the fake teeth. Other assistants came into the room to help Woo take photos. The photos show the patient and the teeth, with her eyes and mouth propped open by various sets of hands and dental instruments.

After the patient saw the photos, she broke down crying, left the office and never came back. Unbeknownst to Woo, she had been sexually assaulted as a teen. The boar's-teeth incident was a different sort of violation, but it brought forth memories of the sexual assault and spurred a case of post-traumatic stress disorder, according to a psychologist's report in the court file.

The Seattle Times generally does not name victims of sexual assault.

Woo apologized, but the woman said she was devastated. She suffered nightmares, panic attacks and suicidal thoughts, according to court documents, filing a lawsuit claiming battery, invasion of privacy and emotional distress in late 1999.

Woo's insurer, Fireman's Fund Insurance, refused to defend him through the suit, saying, among other things, his actions were not "dental services" and were therefore not covered. Woo later settled with the woman for $250,000.

But in 2001, he turned the tables on the insurance company, suing with the claim it had let him down after telling him his policies were "the best coverage money can buy," according to court records. His lawyer, Richard Kilpatrick, said insurance companies are obligated to defend their clients, even when they make blunders. After all, he said, "that's when you need the protection."

In addition, Kilpatrick said, insurance companies are liable for the harm they cause when a decision not to defend is more than just a mistake — in other words, when it's unreasonable or done in bad faith. And Woo claimed the insurance company's failure caused him mental distress, not to mention considerable legal fees.

In June 2003, a King County Superior Court jury decided there was bad faith and awarded Woo $750,000. His attorney's fees and costs, which amounted to more than $600,000, were also covered.

Fireman's Fund appealed, which resulted in Monday's ruling.

The Court of Appeals agreed with Fireman's that Woo wasn't practicing dentistry when he put the boar's teeth in the woman's mouth. And since the insurance was for the practice of dentistry, the company wasn't obliged to defend Woo for it.

"[N]o conceivably legitimate course of dental treatment includes boar tusks," the court said.

The court vacated Woo's jury award and his attorney's fees.

"Obviously Fireman's Fund is delighted with the results," the company's attorney, Michael Barr King, said.

Woo wasn't available for comment. His attorney, Kilpatrick, said "it's erroneous if any of this sounds like Dr. Woo is a poor physician. His reputation as a surgeon is excellent."

Furthermore, Kilpatrick said, this was a one-time mistake that arose only because the woman was a close employee. "Dr. Woo admitted it was wrong and owned up to his mistake. ... It's unfortunate the insurance company took his money but wouldn't honor their commitments."

Woo is considering an appeal.

Maureen O'Hagan: 206-464-2562 or mohagan@seattletimes.com