Cutting Nails During the Thirty Days of Mourning for a Brother

Is it permissible for a mourner during the thirty days of mourning for a brother to cut nails?

A mourner is prohibited from cutting nails with a tool during the seven and thirty days. However, it is permissible to cut them with teeth or mouth.

In the Gemara Moed Katan 17a, it is explained that a mourner is prohibited from cutting nails, but with a change, it is permissible. Tosafot writes that from the words of the Gemara, it is implied that during the seven days, it is permissible to cut nails with a change. The early authorities disagree whether during the thirty days it is permissible only with a change or even with scissors. According to the opinion of the Rif, Riaz Gaot, Ba'al Halachot Gedolot, and Sefer HaMitzvot, during the seven days a change is required, and after seven days it is permissible even with scissors. However, Tosafot (there, s.v. "begenostri") and Ramban write that there is no difference between within seven days and after seven days, and it is always permissible only with a change. The Shulchan Aruch, Siman 390, Seif 7 rules according to Ramban: "Just as it is forbidden to shave for thirty days, so it is forbidden to cut nails with a tool; but with hands or teeth, it is permissible, even within seven days."