###### Abstract  
This study investigated the dose-dependent changes in the chemical composition of three dental ceramic materials--zirconia, lithium disilicate (LD), and VITA ENAMIC hybrid composite (VITA _En_)--following irradiation with an ultra-short femtosecond (_fs_) laser (800 nm, 30 _fs_, 1 kHz) in an ambient air environment using average laser power (76 mW) and scanning speeds (50, 100, and 200 mm/s), simulating dental treatment processes. The chemical composition of the ablated regions was analyzed using energy dispersive spectroscopy. All irradiated samples showed increased carbon content (by up to 42%) and reduced oxygen (by up to 33%). The observed increase in C content is likely attributed to a combination of surface reactions, adsorption of carbon from the ambient environment, and carbon deposition from the laser-induced plasma, all facilitated by the high-energy conditions created by _fs_-laser pulses. Scanning electron microscopy revealed ablation with progressive controlled melting and recrystallization, with an absence of pile-up features typically associated with significant thermal damage. These findings demonstrate that ultra-short _fs_-laser irradiation induces highly controlled, dose-dependent changes in the chemical composition and surface morphology of dental ceramic materials. d 2024 14 7641 11  
Emerging hybrid ceramic materials such as VITA ENAMIC(r) (VITA _En_) are also of interest for subtractive manufacturing of dental restorations. Hybrid ceramics are formed by infiltrating polymers into a porous feldspathic ceramic enriched with aluminum oxide and offer several advantages, including a high resistance to fracture and higher flexural strength [8] compared to both zirconia and LD materials. VITA _En_ has a composition of 86% ceramic and 14% polymer by weight [9]. Surface modifications of the fitting surfaces of dental ceramic restorations can enhance their capacity to adhere to teeth or abutment substrates through micromechanical interlocking or chemical bonding to the adhesive cement [10]. Feldspathic porcelains and LD-reinforced glass ceramics can be etched using hydrofluoric acid, creating surface roughness that enhances micromechanical interlocking with resin cements [11]. Acid etching is not feasible with zirconia due to its inert nature. Conventional surface modification techniques, such as grit blasting, are also not particularly effective on zirconia. Additionally, grit blasting can degrade the mechanical properties of zirconia [12]. Grit blasting using alumina and/or silica particles poses risks for crack propagation and may also leave blasting residue or surface contaminants [13]. Consequently, there is interest in using alternative methods to modify the surface of zirconia, including laser-based techniques [14]. Using lasers could be a non-contact surface processing method not only for zirconia but also for other dental ceramics and related materials, including hybrid ceramics [15]. This approach would eliminate issues such as dental tool wear and surface degradation such as cracking caused by contact between rotary cutting tools and the ceramic material [16]. Conventional dental lasers operating at wavelengths of 1064 and 10,600 nm in picosecond (_ps_-) or nanosecond (_ns_-) pulse widths have been used for marking, engraving, and cutting of ceramics and dental composites [17; 18]. However, the high surface temperatures caused by photothermal interactions can cause decomposition, microcracking, and the formation of amorphous glass-like phases from melting and rapid re-solidification [19]. One solution to these challenges is to employ shorter laser pulse durations within the ultra-short femtosecond (_f_s) pulse width range.