Feature

Painless dentistry in pipeline thanks to new laser technology

Alex Heist Masters student at work on the new laser technology

Imagine going to the dentist with the knowledge that there will be no more painful drilling or even an anaesthetic injection. Does this sound too good to be true?

Thanks to new developments in laser technology, photonics expert Dr Johan Burger and his team of researchers from the Department of Physics at Stellenbosch University hope to ultimately take the pain out of dentistry.

They recently built the first locally produced ultra short pulse laser in Africa that works with modelocked laser optical fibre technology instead of the conventional crystal or gas media.

Currently the whole laser apparatus lays stretched out over 2m on a workbench in the Laser Research Institute of the Department. The Stellenbosch researchers hope to condense it all within the next five years into a commercially viable tool that is as small and compact as a lunchbox.

Because all the components of this optical fibre laser are contained within a glass fibre, it is possible to develop a handheld model that is easier to operate in a medical practise or during field work. It will also be more compact and robust than the more traditional gas or titanium doped sapphire laser equipment that break or move easily with even the slightest of bumps.

The picosecond high power laser pulse produced by this type of laser lasts an infinitesimal short part of a second. A picosecond is one millionth of one millionth of a second! This is much too quick for conventional measuring instruments to track.

Although the beam cannot be "seen" by electronic measuring equipment, Dr Burger has already established that the energy outset of their laser is up to a thousand times higher than that of conventional fibre laser equipment.

Thanks to the extremely fast pulse action the laser does not generate much heat. This makes it ideal for use in a dentist's practise because the laser beam does not heat nor vibrate the tooth. Therefore, no pain.

This is also advantageous for eye and skin treatment. Current equipment used for these purposes are very big and expensive, and not readily available to every surgery.

Other than the optical glass fibre thread that was made in France according to the specific specifications of the Stellenbosch researchers, all the other components are relatively cheap and therefore budget-friendly. Dr Burger and his team are being funded by the National Research Foundation.

Optical fibre laser technology has its roots in the early development of the Internet and optical telecommunication systems. Today multi-kilowatt continues fibre lasers are available, and are being used to cut and weld metal plates in automobile and shipping manufacturing.

"Unfortunately, it is only the really big companies that can afford laser equipment for manufacturing," Dr Burger explains.

Ultra short pulse lasers are even more specialised and costly equipment, and generally only found in the leading research laboratories. Dr Burger hopes that their newly developed short pulse versions will be cheaper, require less maintenance and be more reliable and user friendly to also benefit smaller firms.

So far relatively little research has been done worldwide on ultra short pulse optical fibre lasers. One of the reasons is that the physical principals behind the technique to generate short pulses are not yet fully understood.

Therefore the Stellenbosch physicists made a strategic decision three years ago to focus on this niche research market within the field of photonics.

Masters student Alex Heist is currently working on fine-tuning their equipment to ensure that it is as strong and multi-purpose as possible.

The researchers take extreme care to ensure that they do not damage the fibre during experiments. Because the short pulse laser concentrates light extremely effectively in the optical laser, the apparatus can burn itself out if it is not set up correctly.

"We know that it works, but now we have to find out why and how it works," Dr Burger explains the road ahead.

More information:

  Contact: Dr Johan Burger, Department of Physics, Stellenbosch University
(021) 808-3379 or 072 396 3592 or jpb@sun.ac.za

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