I like this logo. But I did not like the tooth that is within the loupe
Please try to slightly increase the "O" of the loupe and put some images as icons together
some pictures of equipment , dentists, dental instruments.
See the images on http://www.shutterstock.com/cat.mhtml?lang=pt&language=pt&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&searchterm=dentistry%20icon&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=210460504