Filling in 1/4" wide sharp joints on cured indoor concrete floor?
You could have caulked them a month after the slab was poured. You can caulk them now. Or vacuum/scrape them out and caulk them now.
Saw-Cut control joints (as opposed to &quot;tool-formed while the concrete was wet&quot; control joints) are inherently sharp. They are less expensive than formed joints. They need to be deep enough to accomplish the goal of having any cracks that form, form at/in them, not at random.
Use a caulking compound made for use on concrete. If the width precludes setting a bead in the top of the joint that will stay put, fill them with foam backer rod and then caulk on top of that.