How I can find the new Federal Law that was passed concerning nursing homes being responsible for hearing aids, dentures, etc.?

The regulation says the facility must take reasonable care of items, such as labeling them and inventorying belongings. Patients will still lose items, leave them in common areas, flush them or throw them out.
It does not mean the facility will automatically pay for them.

Do a search for Federal Registers/Regulations passed recently regarding NH, maybe on the cms.gov website.

As a side note, it stated that Nursing Homes had to take reasonable precautions and that liability waivers in boilerplate form were not always permitted. You need to see what you signed in admission papers, and what they agreed to in the services that you agreed to. You may have agreed to an arbitration even if they are liable, and you may have to prove negligence on the part of staff as opposed to your person losing them or throwing them away.

"Nursing Home Residents Gain New Protections" is the name of the article and it ran on January 27 2017. You can find the article by doing an online search for it (this site won't permit url's or links).
It linked to the Center for Medicare and Medicaid CMS website and blogs with descriptions of the regulations. There is an over 700 page document that was published on the Federal Register on September 28, 2016 that you can review. I am not going to include all the links, but since you're reading this on computer, you can search with the following info:
"This document is scheduled to be published in the Federal Register on 10/04/2016 and available online at https://federalregister.gov/d/2016-23503, and on FDsys.gov
DEPARTMENT OF HEALTH AND HUMAN SERVICES
Centers for Medicare & Medicaid Services
42 CFR Parts
405, 431, 447, 482, 483, 485,488,and 489
[CMS-3260-F]
RIN 0938-AR61
Medicare and Medicaid Programs; Reform of Requirements for Long-
Term Care Facilities
AGENCY: Centers for Medicare & Medicaid Services (CMS), HHS.
ACTION: Final rule."