Completely UnOptimised
Put bluntly, this website hasn't been targeted at any specific keyword at all. The homepage has no meta description, and the page title simply says "home", and seeing as that is the most important ranking factor for a page, this page isn't going to rank for anything.
It should contain keywords around dentist, teeth whitening services, and the area such as Sheffield and South Yorkshire.
There is also not an optimised H1 header on the page, and it's lacking any relevant content pieces which would greatly improve its rankings.
