I don't think you will be able to get an insurance plan to cover implants; insurance works with groups, to insure "in case" you get ill, where some people may need care this "year" and others don't (the ones who don't use it paying for the others who do) so buying into a plan when you need it, won't work as you don't have many who want to buy dental insurance who don't use it. Unlike health insurance at jobs, it's usually very elective (if offered) so only people who go to the dentist regularly generally buy it whereas there are lots of people who buy regular health insurance but don't need it, just might need it.
But mostly, dental implants are considered "cosmetic" and almost no one sells insurance for that.
http://www.myabsolutesmile.com/denta...ant-insurance/