This　paper　reports　an　investigation　into　the　characteristics　of　femtosecond　laser　(800-nm　central　wavelength)　in　the　ablation　of　human　dental　enamel,　dentine,　and　cementum　at　various　laser　fluences　from　0.2　to　3.68　J/cm(2)　with　single　and　multiple　pulses.　The　femtosecond　laser　interaction　with　cementum　is　reported　for　the　first　time.　Ablation　thresholds　were　determined　to　be　0.58,　0.44,　and　0.51　J/cm(2)　for　enamel,　dentine,　and　cementum,　respectively.　Under　the　average　laser　fluences　of　1.13　to　3.68　J/cm(2),　clean　ablated　surfaces　without　debris　and　microcracks　were　obtained.　Laser　fluence　was　found　to　influence　the　ablated　diameter　and　depth,　whereas　under　a　certain　fluence,　pulse　number　only　affects　the　depth,　without　affecting　the　diameter.　The　ablation　mechanism　is　found　to　be　based　on　multi-photon　absorption,　not　previously　known　for　femtosecond　laser　ablation　of　dental　materials.　The　low　thermal　loads　of　0.708,　1.44,　and　0.404　J/cm(3)　required　for　ablating　enamel,　dentine,　and　cementum,　determined　for　the　first　time,　are　beneficial　for　minimizing　the　heat-affected　zones　and　micro-damage.　The　Raman　spectroscopic　analysis　of　phosphate　shows　that　the　chemical　components　of　the　tooth　remain　intact　before　and　after　the　fs-laser　ablation.　It　also　shows　that　different　dental　tissues　respond　differently　to　the　laser　irradiation.