Femtosecond laser microstructuring of zirconia dental implants

This study evaluated the suitability of femtosecond laser for microtexturizing cylindrical zirconia dental implants surface. Sixty-six cylindrical zirconia implants were used and divided into three groups: Control group (with no laser modification), Group A (microgropored texture), and Group B (microgrooved texture). Scanning electron microscopy observation of microgeometries revealed minimal collateral damage of the original surface surrounding the treated areas. Optical interferometric profilometry showed that ultrafast laser ablation increased surface roughness (R(a), R(q), R(z), and R(t)) significantly for both textured patterns from 1.2 x to 6 x-fold when compared with the control group (p < 0.005). With regard to chemical composition, microanalysis revealed a significant decrease of the relative content of contaminants like carbon (Control 19.7% ± 0.8% > Group B 8.4% ± 0.42% > Group A 1.6% ± 0.35%) and aluminum (Control 4.3% ± 0.9% > Group B 2.3% ± 0.3% > Group A 1.16% ± 0.2%) in the laser-treated surfaces (p < 0.005). X-ray diffraction and Raman spectra analysis were carried out to investigate any change in the crystalline structure induced by laser processing. The original predominant tetragonal phase of zirconia was preserved, whereas the traces of monoclinic phase present in the treated surfaces were reduced (Control 4.32% > Group A 1.94% > Group B 1.72%) as the surfaces were processed with ultrashort laser pulses. We concluded that femtosecond laser microstructuring offers an interesting alternative to conventional surface treatments of zirconia implants as a result of its precision and minimal damage of the surrounding areas.