People have used that approach on me, saying it's unfair a member of my family is a faculty member at one of the dental schools I have applied, but how is that so? You can get an edge for obtaining an interview, but not for acceptance. I didn't do anything different than any other dental applicant. I did however indirectly nudge some adcoms by stating the names of some of the important people I have worked with that attended certain schools in my personal statement. Anyone else can do that too. There is also a place on your application to put any relatives that you know. But that is strictly for relatives.
Acceptance is a decision made by more than one member of the adcoms, so unless your pops is the dean of admissions, there is no advantage. I think one can only be the least bit, if at all, concerned is if and only if the one and only school a kid with connections got accepted to, among the 20 or so he/she applied, is the school his family member worked at.
Regarding legacy kids, those are always going to exist. Ivy leagues consist of a substantial amount. Get used to it, it's going to happen in dental school too. Many students you will meet will have the same last name as someone who made a generous donation to the dental school. Think about it this way, tuition itself, as expensive as it is, could not provide adequate financing for the facilities you will be using. Dental schools thrive on these generous donations.