Dentists who do not sign up with your insurance company are “non-participating dental care providers and can be used by you although your insurance company would prefer you did not know this.
In general dentists who do not sign up with your insurance company and become “participating providers” and “in network” is because if they sign up with an insurance company directly they are greatly limited with regards to the quality of dental care they can provide for you and are also limited in what procedures they are allowed to provide to you.
In our office it is also because we want all our work to last indefinitely (see our guarantee), and in addition we could not provide the level of preventative dental care which you as our patient deserve (see our guarantee with regards to our preventive dental program). We will help you get the maximum benefit your insurance allows and in many cases that may be cover a procedure well.
The reason you would go to a dentist who does not “take” your insurance is because you want to get the best dental care for yourself and know it will be the best value in the long run.