Delta Dental is one of the larger providers of Dental Insurance, and it is offered in California.
http://www.deltadentalins.com/indiv/index.html
It is my understanding that this is a PPO, in other words, a network based plan, so your have better benefits for using in-network dentist, vs. out-of-network dentist, so you will be encourage to use in-network, so you get your best benefits.
There may be a Pre-Existing Condition Exclusion, which you can expect with any medical insurance, a Pre-Existing Condition is any condition or treatment, of an injury or illness that you have sought medical attention or advise with X amount of months prior to the policies effective date, may be excluded for X amount of months after the effective date.
Generally this is 6/6, 6/12, or 12/12
There are also discount plans, keep in mind that a discount plan is just that, it is not medical insurance, I would avoid these at all cost...
Good luck...