5. In regulation 6 (applications for vocational training numbers) in paragraph (3), for sub-paragraph (d) there shall be substituted–
“(d)he has practised in primary dental care in either the Community Dental Services or the armed forces of the Crown for a period amounting in aggregate to not less than four years full-time employment (or part-time employment of equivalent duration), and has so practised for not less than four months in full-time employment (or part-time employment of equivalent duration) within the period of four years ending with the date of his application under regulation 6(1).”.