See, with me it is tricky because I do not have pure dental phobia, per se. I have been diagnosed with Generalized Anxiety Disorder with Panic Disorder since 2001, though thinking back - I remember having issues well before then just didn't know what they were. As it stood at that time, it was merely generalized - no real root or cause known. Doctor's even chalked it up to perhaps a purely overactive adrenaline gland. However, most of my worst anxiety is caused by health issues. For the most part, I am quite healthy and always have been. I am not a hypochondriac really, but am constantly worried about my health when things crop up.
After much self-reflection and memory conjuring
I have narrowed it down to a few issues.
1.) When I was 19 I had a swollen lymph-node in my groin area just below my waist. I was going through loads of stress and partying a bit more than I probably should have. No insurance, so I went to free clinic. I was told point blank that I had one of 3 things (and it was presented this were the only three options) since I didn't have mono. Either cat-scratch fever (which was ruled out immediately), HIV, or Lymphoma. I knew I didn't have HIV, so that pretty much left one thing. I thought I had cancer at 19 with no insurance and my first child on the way...yikes! Turns out that was not anywhere close to the problem - it was just a simply infection - however, the long-term damage, mentally, started to creep in as my earliest remembered instances of symptoms was shortly thereafter.
2.) Also, when I was 19 I was standing in a store waiting for my sub to be made. Felt fine, just a little hungry and was probably not sleeping as I should. I remember it vividly - the lady turned around to ask me what kind of chips I wanted and all of a sudden everything went black and I completely passed out and fell backwards. I was only out for about 1 second bystanders said, but I refused to go to the hospital. I have not had any issues with this type of thing since - it has been 13 years now and think it may have been just a fluke, but this was one of the biggest instances I think that started my anxiety.
3.) Just about 3-6 months before I was diagnosed with GAD w/panic disorder I was having the symptoms of sudden onset panic attacks and went to the doctor. They didn't even consider anxiety and immediately put me on a holter monitor and sent me to a cardiologist - again, no insurance.
4.) I had a massive panic attack in May 2001 - had to call the ambulance for me. The next year was a living nightmare because I was caught in a horrible whirlwind of the "circle of anxiety and panic".
So all of these things sort of add up to my anxiety problem. Like I said, it is more centered around health issues and my biggest phobia is of passing out (feeling dizzy, lightheaded, etc. - which is great right since anxiety causes all those symptoms!) - I think it was just the sudden unexpected lack of control that came with the first (coupled with not actually going to the hospital to get checked out) that causes this.
When it comes to the dentist, my biggest issue is fearing the anxiety, which I am sure you all know what I am referring to. It is not about the needles, not so much about the pain, not so much about the gagging (though I do not like that) - but just a pure realization that those situations cause me anxiety and I do not like experiencing that!
Mike