4.1 The term “surface texture” is used to describe the local deviations of a surface from an ideal shape. Surface texture usually consists of long wavelength repetitive features that occur as results of chatter, vibration, or heat treatments during the manufacture of implants. Short wavelength features superimposed on the long wavelength features of the surface, which may arise from polishing or etching of the implant, are referred to as roughness.

4.2 This guide provides an overview of techniques that are available for measuring the surface in terms of Cartesian coordinates and the parameters used to describe surface texture. It is important to appreciate that it is not possible to measure surface texture per se, but to derive values for parameters that can be used to describe it. ISO has published a series of standards on surface texture measurements that may be consulted for more information (ISO 3274, ISO 4287, ISO 4288, ISO 5436-2, ISO 10993-19, ISO 12179, ISO 13565-1, ISO 19606, ISO 21920-1, ISO 21920-2, ISO 21920-3, ISO 25178-1, ISO 25178-2, ISO 25178-3, ISO 25178-6, ISO 25178-70, ISO 25178-71, ISO 25178-72, ISO 25178-73, ISO 25178-600, ISO 25178-601, ISO 25178-602, ISO 25178-603, ISO 25178-604, ISO 25178-605, ISO 25178-606, ISO 25178-607, ISO 25178-700, ISO 25178-701).

1.1 This guide describes some of the more common methods that are available for measuring the topographical features of a surface and provides an overview of the parameters that are used to quantify them. Being able to reliably derive a set of parameters that describe the texture of biomaterial surfaces is a key aspect in the manufacture of safe and effective implantable medical devices that have the potential to trigger an adverse biological reaction in situ.

1.2 This guide is not intended to apply to porous structures with average pore dimensions in excess of approximately 50 nm (0.05 μm).

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.