The list as provided by Arvind Singh used to be the so-called stand-alone journal list of a list developed by Jeffrey Beall, which was stopped in 2017. This list: https://beallslist.net/standalone-journals/ and the update version https://beallslist.net/standalone-journals/#update are made available again by new (anonymous) people.
The journal “IOSR Journal of Dental and Medical Sciences” is not mentioned in this list since the publisher International Organization of Scientific Research (IOSR) behind it is: https://beallslist.net/ This is a warning sign that you might be dealing with a predatory journal (publisher). There are more red flags:
-Despite that they are out there for more than 10 years, not a single serious indexing (no Scopus, no ESCI or SCIE index)
So indeed a predatory publisher. What kind of issue do you have with them?
Best regards.
PS. Se-Lim Oh unfortunately RG does not exclude predatory journals. They do have a list of journal names that are included in the database based on journal information from CrossRef, via its Journal API. See also: https://explore.researchgate.net/display/support/Journals