Just ask Emmet O'Neill.

The 27-year-old entrepreneur is, quite literally, all smiles these days. He has just opened two high-street dental clinics in Dublin and announced a 3m investment in rolling out the chain to Limerick and Galway. Add in a restaurant, health and beauty clinic, and a profitable past venture as a master franchisee with women's gym chain Curves, and it's probably fair to say his fortune is smiling on him, too.

But it wasn't always that way.

Five years ago the Dubliner showed up for his first day's work at Anglo Irish Bank, his freshly-minted degree in hand, only to be told "we've no job for you". The aviation market had collapsed overnight, following the terrorist attacks in the US. "A plane that had been worth 100m was now worth 10m, if you could find anyone to buy it, " said O'Neill.

Despite the drastic appraisal of his immediate career prospects he initially received from Anglo Irish, O'Neill discovered there was work to be found in aviation finance if he was prepared to hustle for it. One of the bank's clients, Aergo Capital, was doing a roaring trade selling old planes to developing countries. O'Neill was impressed with the boutique finance firm, and they with him, and he joined the company from Anglo as finance manager. "This was a company of six to 10 people with profits of 7m to 10m. It was a real eye-opener in terms of how to get the best out of people, " he said.

It was also a useful lesson in adapting to tough market conditions. Selling planes during the post-11 September economic downturn is probably as tough as it gets. Now O'Neill is selling cosmetic dental treatments . . . such as bleaching, straightening and whitening . . . in a booming economy. He's taking nothing for granted, though.

"Obviously if there is a downturn things like the luxury treatments may suffer, but everyone needs a dentist so we're very well insured there. It wouldn't kill us, we'd adapt, " he said.

The idea for the Smiles dental clinic was born when its founder was informed by a dentist that it would cost 1,200 to have his teeth whitened.

O'Neill figured there must be a cheaper way of providing the service. A clinic with several dentists under a shared roof and with shared overheads seemed an obvious solution.

He consulted with a dentist friend, Hugh Bradley, and the two conceived the idea for Smiles.

The economies of scale that attracted the duo to the clinic concept appear to stack up. Smiles charges 600 for teeth whitening . . . "slightly below the average price in Dublin", according to O'Neill, and half the 1,200 he was quoted. "Slightly below the average price" won't exactly make a memorable advertising tagline, but O'Neill said Smiles is not being positioned as a low-cost, one-stop dental shop.

"We're not Easyjet. It's not about selling the seats, " he said. The idea is to accommodate busy workers and help them fit a dental visit, whether for a check-up or a cosmetic procedure, around their hectic schedules. Smiles will open seven days a week, with extended opening hours from 7am to 9pm from Monday to Thursday.

Already the retail dentistry approach is attracting custom at the new clinic on O'Connell Street, Dublin, according to O'Neill. "We opened the doors and there was, literally, a stampede of patients. We were booked out for a month within three days."

The business received a further boost when health insurer Vivas added Smiles to the list of approved clinics to which it will refer its customers for dental treatment.

O'Neill expects the O'Connell St clinic to turn over between .1.5m and 2m in its first year of business. It will be profitable at that level, he said.

The next step is to expand the dental clinics . . . or "dental spas", as O'Neill prefers to call them . . . outside Dublin.

Galway and Limerick are the two cities that have been earmarked first.

In the next year, meanwhile, Smiles is planning to open a centre in Manhattan, home to the Sex and The City set at which its luxury dental treatments are targeted. Ultimately, O'Neill said, he would love to see Smiles established as an international chain.

The young Dubliner assembled his bankroll for the dental venture by buying and selling, at a significant profit, a share in eight Curves fitness gyms. The US-based franchise, which now has over 100 outlets in Ireland, serves O'Neill as an example of what can be accomplished if you get into a growing market at the right time with the right pitch.

So will dentistry do for Smiles what the booming gym business did for Curves? O'Neill is betting that it will . . . and hoping that his sense of timing has improved since his aviation finance days.