Femtosecond laser in dentistry

We review the use of ultrashort laser systems in dentistry with a particular focus on the potential of femtosecond laser pulses for highly precise multiphoton ablation (plasma-mediated ablation) and the nonlinear diagnosis of dental caries. Their potential dental applications are discussed in comparison with the current gold standard, namely mechanical drilling devices, as well as with pulsed dental Er:YAG lasers operating at 2.9μm with a microsecond pulse width in combination with a water-spray module to enhance tissue laser absorption. In addition, the application of femtosecond two-photon microscopes/tomographs equipped with FLIM/PLIM modules for the early detection of dental caries is addressed. Certain pathogenic oral bacteria produce red-light–sensitive porphyrins, such as protoporphyrin IX, which exhibit long autofluorescence lifetimes in the nanosecond range and can be detected using fluorescence lifetime imaging (FLIM). Furthermore, phosphorescence lifetime imaging (PLIM) enables lifetime measurements in the microsecond range.