Having a professional brand is extremely important. Look at the slogan "Just Do It" has done for Nike. Imagine the possibilities if your dental office was as well known within two miles of your office as Nike is world-wide.
Having a professional brand with a clean, simple logo and tag line enhances the professional image of your practice and creates a more recognizable business. At a glance, if your local residents immediately recognize you by just seeing your logo, you have a better chance of building your business. Simplicity and consistency is important in branding.