Page name dynamic

Hello ppl, I am developing a plugin for wordpress, but as the plugin has several pages and these are called dynamically like to change the title of it, but I am not able to

I tried this way:

apply_filters ('wp_title' teste_titulo);

teste_titulo function ($ title) (
$ Title = "";

$ Title = "test just to see if";

return $ title;

)

but nothing happens …

Someone help