A filament for an oral care implement , the filament comprising: an elongated shaft terminating in a tip and having a mounting end portion of constant cross section, and an end portion being mechanically tapered via at least one of grinding, filing, or cutting of the elongated shaft ; wherein the mechanically tapered end portion has an areal surface roughness value of at least 0.20; characterised in that the mechanically tapered end portion has a taper length (T1) of 5 mm or more and in that the filament has a tip diameter (D2) of less than 10 microns measured at 0.05 mm from the tip of the mechanically tapered end portion; and in that the mechanically tapered end portion of the filament has a Nelson Ratio, quantifying target tip diameter, taper length, and surface roughness for the mechanically tapered end portion, which is between 0.8 to 1.20; wherein the Nelson Ratio of the mechanically tapered end portion is defined by the formula: Nelson Ratio Ω = 1 6.458 λ R 3 + 6 θ R + φ R 8 wherein λR = Taper Length Ratio = λ Actual λ Target = Measured Taper Length Target Taper Length , measured in millimeters; wherein θR = TipDiameterRatio = θActual θTarget = Base Diameter − Measured Tapered Tip Diameter Base Diameter − Target Tapered Tip Diameter , wherein the measured and target tapered tip diameters are measured at 0.05 millimeters from the tip; and wherein φR = Roughness Ratio = φActual φTarget = Sa tip actual − Sa base Sa tip target − Sa base , wherein Sa is areal surface roughness, wherein Sa tip actual and Sa tip target are measured at 4 millimeters from the tip and is at least 0.2, and wherein Sa base is measured at 7 mm from the tip. an elongated shaft terminating in a tip and having a mounting end portion of constant cross section, and an end portion being mechanically tapered via at least one of grinding, filing, or cutting of the elongated shaft ; wherein the mechanically tapered end portion has an areal surface roughness value of at least 0.20; characterised in that the mechanically tapered end portion has a taper length (T1) of 5 mm or more and in that the filament has a tip diameter (D2) of less than 10 microns measured at 0.05 mm from the tip of the mechanically tapered end portion; and in that the mechanically tapered end portion of the filament has a Nelson Ratio, quantifying target tip diameter, taper length, and surface roughness for the mechanically tapered end portion, which is between 0.8 to 1.20; wherein the Nelson Ratio of the mechanically tapered end portion is defined by the formula: Nelson Ratio Ω = 1 6.458 λ R 3 + 6 θ R + φ R 8 wherein λR = Taper Length Ratio = λ Actual λ Target = Measured Taper Length Target Taper Length , measured in millimeters; wherein θR = TipDiameterRatio = θActual θTarget = Base Diameter − Measured Tapered Tip Diameter Base Diameter − Target Tapered Tip Diameter , wherein the measured and target tapered tip diameters are measured at 0.05 millimeters from the tip; and wherein φR = Roughness Ratio = φActual φTarget = Sa tip actual − Sa base Sa tip target − Sa base , wherein Sa is areal surface roughness, wherein Sa tip actual and Sa tip target are measured at 4 millimeters from the tip and is at least 0.2, and wherein Sa base is measured at 7 mm from the tip. <EOS>