Look into DDS-PhD programs. A number of schools have them, UCSF, Buffalo, UConn come to mind. You will probably receive some sort of stipend for participating in it in addition to the program covering your tuition costs. You really have to probe the schools for info, the DDS-PhD path isn't as popular as the MD-PhD track. There are soooo many paths to explore in dental research. Also, check out the web pages for the NIDCR (www.nih.gov) and the IADR (www.iadr.org). Some other research-oriented schools are also Univ. of Texas-San Antonio and Iowa (they had tons of students attend the IADR meeting in San Diego this year).