A convention of dentists, the size of a small city, began infusing Hawai'i's economy this week with an influx of cash yesterday as the American Dental Association convention kicked off.

The convention is providing a much-needed boost for Waikiki businesses that have been withering in the worst recession in decades.

Stores at the Hilton Hawaiian Village, the Sheraton and at the 40 other hotels where an estimated 24,000 dentists and their families are staying, are bustling. The convention runs through Sunday.

"It's been wonderful," said Serenity Spa owner Sheryl Bell. "It almost seems like it's back to where it was before the economy went down."

The Waikiki spa's two locations have been inundated with phone calls, walk-ins and appointments, Bell said.

"I wish it wasn't just because of one convention," she said.

Restaurants are reporting that their reservations are filled. Stores are reporting a steady flow of foot traffic. And dentists and their families are filling their off time with a slate of activities from visiting Hanauma Bay to the USS Arizona Memorial and an evening at the Polynesian Cultural Center.

The last time the American Dental Association came to town was in 1999, when the convention drew 30,000 people to the Islands.

Tourism experts estimate that this year's convention, with an international attendance roll, should pump more than $113 million in spending and $11 million in tax revenue to the local economy.

Inside the exhibition hall at the Hawai'i Convention Center, companies offered everything from toothbrushes to false teeth, dental chairs and tools to X-ray equipment.

Crest toothpaste even operated a tooth-brushing station for the convenience of the post-lunch crowd.

Outside the main exhibition hall, mother-and-daughter dentists Rhonda and Andrea Company were excited about being in Hawai'i.

This was their first trip, and they planned to pull out all the stops. Shop, sightsee, eat and take in a spa or two.

"The hotel is sold out and it's not easy to get into a restaurant without a reservation," Rhonda Company said. "People are being turned away at the door."

Before arriving, they were apprehensive about what to expect.

Did people walk around in casual attire with slippers and shorts, or did they get dressed up? she wondered.

"I didn't know if tourists would be welcome here," she said. "In some places they're not. The people here are very friendly."

After the afternoon sessions were over, workers at the Hard Rock Cafe, which is across Kalakaua Avenue from the Hawai'i Convention Center, were gearing up for their second wave of business.

Lunch was a roaring success, said Hard Rock manager Mark Whiteley.

Business was up 60 to 100 percent above a normal Thursday.

"We've been planning in advance and had planning to bring in more staff and food," Whiteley said. "We're really enjoying the business, but we still have plenty of room for our local customers."