A review of the literature on research in expanded functions for dental auxiliaries is presented. Summaries of each of the training and evaluation studies sponsored by both private and government agencies are given. Wide variation in research methods of these studies and the failure to report important details make it difficult to interpret and use the research findings. Results from all studies indicate that dental auxiliaries can, with the proper training, perform selected reversible and irreversible dental procedures at an acceptable level of quality. Future research should be conducted in private practice settings and in new oral health care delivery systems with various configurations of expanded function dental auxiliaries.