{Reference Type}: Journal Article {Title}: In vivo biological safety investigation of Yb-CALGO femtosecond laser dental surgery. {Author}: Pu T;Wang J;Wang W;Jing B;Han Q;Li C;Liang H; {Journal}: Opt Lett {Volume}: 49 {Issue}: 13 {Year}: 2024 Jul 1 {Factor}: 3.56 {DOI}: 10.1364/OL.525402 {Abstract}: While lasers have found their successful applications in various clinical specialties, in clinical dental practice, traditional mechanical drills are still predominantly utilized. Although erbium-doped lasers have been demonstrated for dental therapy, their clinical performance is still not satisfactory due to the long pulse width, low peak power, and small repetition rate. To attain a smaller thermal diffusion thus better biological safety and surgical precision, as well as more rapid ablation, the advancement of femtosecond laser techniques has opened another route of dental surgery; however, no biological safety investigation has been reported. Here, we present a systematic study of dental ablation by a Yb:CaAlGdO4 regenerative amplifier with a central wavelength of 1040 nm and pulse width of 160 fs. The in vivo experiment of dental surgery investigating the inflammatory response has been reported, for the first time to the best of our knowledge. It is demonstrated that dental surgery by Yb:CaAlGdO4 femtosecond laser ablation has better biological safety compared to the turbine drilling, thanks to its non-contact and ultrafast heat dissipation nature.