Nowadays, in many dental practices drills are no longer used to remove caries – much to the patients’ delight. Such practices have replaced drills with lasers, a virtually painless method, with low noise levels and which does not require a local anaesthetic. This is all thanks to the work of Raimund Hibst, a physicist from the ILM in Ulm who has spent many years turning research findings into health market applications, in cooperation with industrial partners.
Since he became head of the ILM in 2008, the 52-year-old physicist has had to put his own work on the back burner while he concentrates on reorienting research at the institute. ILM stands for Institute of Laser Technologies in Medicine and Metrology and is based at the University of Ulm. Hibst plans to retain the established three-letter abbreviation, at the same time as better positioning the institute by orienting it more towards optical technologies.
In 1986, Hibst, who at the time had just finished his doctorate, could have chosen to habilitate at the University of Bochum and build a spallation neutron source. However, he chose to follow his inclination for the life sciences (his second major topic was biology) and he moved to the city of Ulm in Baden-Württemberg where the ILM had just been established. Hibst was one of two scientists to be given a permanent scientific post at the ILM.
A big institute, laboratories and an office looking out over the countryside - for a young researcher like Hibst, this was paradise. His team at the ILM was preparing for a bright future as, at the time, experts were very hopeful about the potential of using lasers to replace scalpels in medicine.
Raimund Hibst discovered “his” laser through trial and error. It soon became clear that an excimer laser, which was initially believed to be the best instrument for tissue ablation, had many disadvantages. Hibst decided to focus on the erbium-Yag laser, and the only one that existed in Europe “was just waiting to be used by him in the Ulm Hospital (Eselsberg)”, recalls Hibst. The laser was originally acquired by the hospital for the ablation of tissue. The solid-state laser, which uses pulsed laser irradiation, has an emission wavelength identical to the absorption maximum of water and was hence suitable for use on the water-rich human body.
Hibst tested the erbium-Yag laser on all kinds of tissue: cornea, skin and bones. It soon became clear that it was superior to the excimer laser in the field of tissue ablation. With the support of a chief physician from the Department of Oral Surgery (Prof. Ulrich Keller) at Ulm University, Hibst then went on to test the erbium-Yag laser on teeth. Experts regarded this field of research as somewhat strange, said Hibst.
Nevertheless, his presentation at the Annual Meeting of the American Society for Laser Surgery and Medicine in 1988 aroused the curiosity of many people, including a physicist at a company called Aesculap who were planning to enter the laser business. This contact would later turn out to be a huge advantage for the Ulm scientists when they were seeking an industrial partner – executives from the Tuttlingen-based company Aesculap had already heard of Hibst’s idea. Before they began the collaboration with Aesculap, the scientists experimented on Raimund Hibst himself who – by chance – had a carious tooth. The cooperation with Aesculap started in the same year and lasted until 2008.
Hibst had “found” his favourite research topic and in 1995 he habilitated on the basic biomedical principles and medical applications of pulsed medium infrared lasers. His major interest was the erbium-YAG laser.Over the years, Hibst and his industrial partners have used the laser for many newly identified application areas. All efforts to apply the laser to middle ear surgery and ophthalmology remained unsuccessful for various reasons. However, the scientists achieved great results in the fields of dermatology and dental medicine.After his habilitation, Raimund Hibst was obliged to focus entirely on dental medicine, because other application areas had become too complex, costly and time-consuming.
At the end of the 1990s, Hibst and the Biberach-based company KaVo Dental developed a caries detector - a global success story which originated in the laboratories of Ulm University where Hibst exploited the following circumstances: The detection of fluorescing caries bacteria (Porphyromonas gingivalis, Actinomyces odontilyticus and other porphyrin-producing bacteria) enabled the optical detection of tiny caries and periodontosis areas.
The caries detector, which is still marketed today, exploits the autofluorescence in the red spectral range. The detector is based on a patented laser fluorescence method that differentiates the fluorescence of healthy and diseased tooth substance. The Institute was selected as a winner in the first round of the German government's "Landmark in the Land of Ideas" competition.
Hibst recalls with a smile that the commercially successful discovery resulted from the fact that the industrial partner found the detection of caries using violet fluorescence too expensive, and that a graduate student had already been employed with the aim of developing such a detector.
The Ulm researchers were aware of this and sought to develop a less expensive solution. 80 years of research had already gone into the use of different wavelengths for the detection of caries. Now, the Ulm researchers were surprised to find that caries can be best detected with red excitation light. This wavelength clearly differentiates between carious and healthy teeth.
Raimund Hibst is now director of the institute and his job is to focus specifically on research management activities. But this does not mean that the researcher in him has been put totally to one side. Hibst is convinced that Erbium laser applications still have much to offer and he talks about "many plans in the dental area", including keyhole dental treatment, optical fibres that 'shoot around corners' and the use of lasers as heat source with potential uses in a broad range of indications.
At present, Raimund Hibst’s main interest is to give the ILM a new direction. The unique “research institute with integrated engineering office and own dental practice” will remain a translation think tank, not only with regard to application, but also with regard to academic publications. Hibst is sure that if he succeeds in his new task, his future career as a researcher within a small group of researchers will also be successful.