The advent of the European Union requires the biological evaluation of all medical devices used in dentistry prior to their general availability for clinical use. Biological evaluation is one component of the 'Essential Requirements' with which all devices need to conform. Such conformity will result in the issue of the CE mark. To facilitate this process, harmonised European standards are required. It is the policy of The European Committee for Standardisation (CEN) that, whenever possible, the relevant International standards will be adopted as European standards.