How to convert a byte array to an int array?

I have a game with large meshes and I want to save some RAM memory with a byte array of triangles instead the int array. But when I have to pass the array to mesh.triangles I have to convert it to an int array, I tried some methods like putting (int)(Triangles) but I doesn’t work. Here’s the code:

public class Test
{
    byte[] Triangles;

    void SetTriangles()
    {
        Mesh mesh = new Mesh();
        
        mesh.triangles = (int[])(Triangles); //It doesn't work!
    }
}

Thanks for all!