Cal. Business and Professions Code § 1633

(a) When an applicant for a license has received a grading of 85 percent or above in any given subject, the applicant shall be exempt from reexamination on that subject in subsequent examinations before the board within two years after the examination on which the applicant received the exemption. (b) Notwithstanding Section 135, an applicant who fails to pass the examination required by Section 1632 after three attempts shall not be eligible for further reexamination until the applicant has successfully completed a minimum of 50 hours of education for each subject which the applicant failed in the applicant’s last unsuccessful examination. The coursework shall be taken at a dental school approved by either the Commission on Dental Accreditation or a comparable organization approved by the board, and shall be completed within a period of one year from the date of notification of the applicant’s third failure. (c) The coursework described in subdivision (b) shall be required once for every three unsuccessful examination attempts. When the applicant applies for reexamination, the applicant shall furnish proof satisfactory to the board that the applicant has successfully completed the requirements of this section.