CDA Expert a learning tool for Dental Assistants to prepare for Certification. Dental assistants can become certified by passing an examination that evaluates their knowledge. Most dental assistants who choose to become nationally certified take the Dental Assisting National Board's (DANB) Certified Dental Assistant (CDA) examination. Becoming a Certified Dental Assistant (CDA) assures the public that the dental assistant is prepared to assist competently in the provision of dental care.