I suggest making a level 2 or 3 or a level 2a and 2b. For instance Iowa has different levels of expanded functions and different requirements. Their level 1 expanded functions can do among other place gingival retraction, make temporaries, take final impressions, preliminary c harting etc. Only their level 2 expanded functions can place fillings. 

See link here: 

https://dentalboard.iowa.gov/practitioners/expanded-functions/dental-assistants-expanded-functions

I think if you made a level that allowed dental assistants to be expanded functions to what most dentist utilize them for, like final impressions, temporaries, cord packing etc and make this a smaller course. 

Most dentist do not want their assistants placing fillings. So having this as a separaste options like Iowa means a lot more assistants would be able to get certified in what dentist wants them to do. Making the training requirements so hard because they need to know how to place fillings still keeps it too hard to get them certified and does not solve the underlying problem. You need to divive it up into basic and advanced expanded functions to make it functional.