Cosmetic dentistry also known as smile enhancement from my personal understanding is the dental process which involves making a positive change to a person's teeth and smile. This process is mainly carried out not only for correctional purposes, but also for enhancing a person's smile and looks in general. It involves cosmetic procedures which ranges from a basic color correction, gaps closing to missing teeth replacement.
Regular dentitistry is the usual oral care check ups everyone is familiar with. It's the process which involves treatment and maintenance of dental health to balance the relationship between the teeth and oral health to the entire body.
If you draw a parallel between both dentistry procedures stated above, you'd realize that the earlier is a more sophisticated process which involves more complicated procedures. And just like every other cosmetic procedures, this one is also carried out by specialist. It's only normal for procedures like this to cost more money as it involves operations which are not as simple as the usual dental health checks.