I haven't done this in a business dinner setting, but I regularly train and speak in front of groups.
The first time I presented to a group of potential clients, I wanted to be sure I really knew my material, so I started writing down everything I wanted to say. But at some point, I realized I'd have to read my presentation from my paper. To avoid this, I forgot about the presentation, and instead focused on writing an article on the topic. Once finished, I was able to make a presentation based on my article. The only notes I had were bullet points to keep me on track. (As an added benefit, I put the article on my website and referred my audience to it afterwards.)
PowerPoint can help you keep on track, but don't overdo it. Each slide should only have basic information and/or an appropriate image to emphasize each point.
Hope that helps.