I like your statement, it needs fine tuning in terms of organization and grammar, I would take it to someone outside of here for that.
You put that dentistry was your true calling after attemping to justify an F. That doesn't sound good, and it makes you sound sketchy. If the F was due to the administration mishandling your exam how could you not have rectified the situation, you weren't clear on that.
After reading the rest of your statement, you seem passionate about dentistry and you've got a good angle with the art thing. You could probably reword the statement about getting excited about drilling teeth.
The F thing stands out like a sore thumb though and I forget all the other things that you say. I would get rid of that statement altogether.
By the way, after a circuitous journey? Anyone else think that conclusion sounds familiar? Did you google "dental school application essays"? lol Get rid of "circuitous journey" i think thats cheesy. Everyone's jourey is "circuitous". I would start the conclusion with a stronger sentence such as "Only dentistry, with its distinct combination of building relationships in the context of alleviating patient's pain and an extensive manual dexterity component, can fulfill me. I have learned this after blahblahblah"
I wouldn't worry too much about plagiarism, I'm pretty sure no one is going to write about rubbing ointment on the sores of homeless people unless they've done it.