It is likely that you've done the SEO, created the social networks, added tons of video content to your site, and have articles and blogs frequently updated and submitted to the appropriate directories... now what?
How do you go about touching your prospective four or MORE times?
The process of becoming familiar, and also trusted, is the goal of high quality marketing. You introduce yourself in an official and appealing manner, and if you do well you are more than welcome to "visit" or communicate again. After a while, you are a familiar "friend" whose communications are appreciated, trusted, and respected.
If you keep dripping good information and offers for your dental services in front of prospective patients, you are going to create a relationship based on trust and value. This will result in the "conversion" from prospect to paying patient.