In cases of post-operative dental infections we have to remember that it all comes down to
the virulence of bacteria and the intricacies of the host defenses.
I mean, the human immune system is the one, the only, the sui generis thing on the planet that's more complex than the United States Tax Code.
And one of the most important things to keep in mind about the bugs is how complex is the chemical milieu (soup? swamp?) that is their world. They hit each other with toxins and attractor molecules. They share DNA and RNA with plasmids and direct contact. A key question: is your infection due to bacteria in their planktonic form, or have they sent out quorum sensing proteins and formed a biofilm? A much more defensible structure, from their standpoint.
(Quorum sensing proteins are, as far as I'm concerned, the coolest discovery in biology of the last two decades. Those little buggers talk to each other!)
As for the host, doesn't it all depend on what the person's own individual "library" of immune responses is, and how rapidly the host can activate the proper antibodies and T-cells and all those other smart bombs and laser-guided missiles that reside in the human immune system's armamentarium? Plus we need to remember that antibiotics may be a highly useful adjunct, but in the end, they're only there to slow things down and buy time; the immune system is still the bit that does all the heavy lifting.
Hence, the heartache for us dentists. We can do the same procedure, essentially, for hundreds, maybe even thousands of patients, and the one that has the terrible complication relating to infection was, to our macroscopic eyes, just the same as all the rest.
Only they weren't.
Some nasty little prokaryote went like this:
1-2-4-8-16-32-64-128-256 and as you see if you do that just a few more times, at half an hour a shot, pretty soon we're into real money, as they say in Congress when they're talking billions-with-a-b not millions-with-an-m.
Years ago I saw a patient my own age who had almost every possible dental diagnosis: caries, endodontic infections, periodontitis, fractured teeth... I never extract impacted third molars, wisely leaving that for my oral surgeon colleagues, but she was in pain from a fully erupted thirdie and I confidently removed it in one of the most predictable, atraumatic extractions I can remember from my entire career. After all, her body was rejecting the literally bloody thing, and it was already loose. And then she got such a severe post-operative infection that she became seriously trismatic. Airway closure would be next so I referred her to my splendid oral surgeon colleague who loaded her with antibiotics and did an incision and drainage in the O.R. and monitored her overnight. She fully recovered with astonishing rapidity.
It was the germs and the host, not the specifics of the procedure. If only we could predict this sort of thing.