Out of the 15 interviews I attended this cycle, I have met only 3 canadians that had graduated from canadian dental schools, and even fewer international students. As a Canadian myself, I think the hurdle is more of VISA issue than where you graduated from. If you do not hold permenant residency status or are not a citizen of US, you will not be able to apply to many OMFS programs, especially the dual-degree programs (eg. Parkland, LSU-Shreveport, UCLA, UCSF, Oregan, Case, Nebraska, NYU... the list goes on). This restriction is regardless of where you attend dental school. With that being said there are still many programs that consider canadians.