I have been teaching dental assisting at a local college for over a year. I have my Associates in Health Sciences. I have completed the RDA Exam and am preparing to take my National Danb CDA. I have been dental assisting for 10 years. There are several incorrect answers/questions on this application. But, in contrary, there are several great questions! Overall, you can not just use this application to study from, in my professional opinion . I also have not yet taken my exam though! I have although, purchased several study exams from the Dale Foundation which is the affiliate and only affiliate of the National Danb exam. Several of the questions did not match what I had already studied. That forces one to question the credibility. I think the questions need to be reviewed. Thank you!