Femtosecond-pulse laser ablation of dental hydroxyapatite and single-crystalline fluoroapatite

Laser microdrilling of healthy human enamel and dentine using 300 fs pulses at a wavelength of 615 nm and 3 Hz repetition rate leads to an enhanced structuring quality in comparison with nanosecond-laser results. Microcracking and damage to neighboring tissue can be reduced. Ablation threshold fluences for 100 laser pulses of 0.3 J cm^-2 (human dentine), 0.6 J cm^-2 (human enamel) and 0.8 J cm^-2 (single crystalline fluoroapatite) could be determined. Ablation depths per pulse below 1 7m were observed.