105 STAT. 194 PUBLIC LAW 102-40—MAY 7, 1991 "(C) For service by a dentist who serves only a portion of a year in an executive position listed in subparagraph (A) or (B) or who serves a portion of a year in such a position and also serves a portion of that year in another position or grade for which special pay is provided under this section, the annual rate shall be calculated on the basis of the proportion of time served in the position or positions for which special pay is provided. "(5) For specialty or first board certification, $2,000 and for subspecialty or secondary board certification, an additional $500. "(6) For service in a specific geographic location with respect to which there are extraordinary difficulties in the recruitment or retention of qualified dentists in a specific category of den- ' tists, an annual rate not more than $5,000. "(7)(A) For service by a dentist with exceptional qualifications within a specialty, an annual rate of not more than $5,000. "(B) Special pay under this paragraph may be paid to a dentist only if the payment of such pay to that dentist is approved by the Chief Medical Director personally and on a • ' case-by-case basis and only to the extent that the rate paid under this paragraph, when added to the total of the rates paid to that dentist under paragraphs (1) through (6), does not exceed the total rate that may be paid under those paragraphs to a dentist with the same length of service, specialty, and position as the dentist concerned. "§ 7436. Special pay: part-time dentists "(a) Subject to section 7431(e) of this title and subsection (b) of this section, special pay under this subchapter for dentists employed on a part-time basis shall be based on the special-pay factors and annual rates specified in section 7435 of this title. "(b) The annual rate of special pay paid to a dentist employed on a part-time basis shall bear the same ratio to the annual rate that the dentist would be paid under section 7435 of this title (other than for full-time status) if the dentist were employed on a full-time basis as the amount of part-time employment by the dentist bears to fulltime employment, except that such ratio may not exceed 3/4. '*§ 7437. Special pay: general provisions "(a) A physician who is provided special pay for service in an executive position under paragraph (4)(B) of section 7433(b) of this title may not also be provided scarce specialty special pay under paragraph (3) of that section. A dentist who is provided special pay for service in an executive position under paragraph (4) of section 7435(b) of this title for service as a Service Director, Deputy Service Director, Deputy Assistant Chief Medical Director, or Assistant Chief Medical Director may not also be provided scarce specialty special pay under paragraph (3) of that section. R^ruiations. "(b) The following determinations under this subchapter shall be made under regulations prescribed under section 7431 of this title: "(1) A determination that there are extraordinary difficulties (on a nation-wide basis or on the basis of the needs of a specific medical facility) in the recruitment or retention of qualified physicians in a medical specialty or in the recruitment or retention of qualified dentists in a dental specialty.