What significant updates were made regarding expanded function rules in 2019?

The correct answer highlights the significant updates made in 2019 concerning the expanded function rules for dental hygienists, specifically the updates to the lists of Level 1 and Level 2 functions. This is important because these levels categorize the various tasks that dental hygienists can perform, ensuring that they are operating within their scope of practice as determined by regulations. By updating these lists, the Iowa dental board aimed to reflect current practices in the field and address the evolving needs of dental hygiene services. This revision plays a crucial role in facilitating safe and effective patient care while supporting the professional development of hygienists.

The other options do not accurately reflect the changes made in 2019, as there were no eliminations of expanded functions or changes limited solely to training requirements. Additionally, while new procedures may have been added over time, the core update focused on the existing classification of functions, which is central to practice management for hygienists.