How do I insert a dash in my URL?

[eluser]Unknown[/eluser]
How do I get a URL to display a dash?

Code:

example.com/section/newitem/1

to appear like this

Code:

example.com/section/new-item/1

I assumed I had to use the url_title() function with the URL helper,
but I don't know how and where to insert it in my newitem function

Code:

function newitem($id = '')
{
    if (!$id) {
    $this->load->view('item_view');
    } else {
    $this->load->view('item_' . $id);
    }
}