In the state of TX, you may do only "reversible" procedures w/o any permits. With the Registered Dental Assistant permit, you may take radiographs (must take 8 hour course in radiography, jurisprudence, and infection control---this can be done online with a course from the Texas Academy of General Dentistry). You may take radiographs for a year after obtaining employment w/o RDA permit, but absolutely no longer. And with separate permits, one will allow you to monitor conscious sedation (namely, lower the amount or turn it off), and the other will allow you to apply pit and fissure sealants or something like that---after 2 years of experience as a DA, with the permit, and only under the supervision of a Medicaid dentist or if the dentist practices in an area declared as underserved by the federal or TX government (pit and fissures sealant permit only, not conscious sedation or RDA). Not knowing where you live, this may or may not help you.
I've started the TAGD course---hope to do the conscious sedation one later at San Antonio College or UTHSCSA School of Allied Health Sciences, Department of Dental Hygiene.