Hi Tony.
Let me first say, I am so sorry you are feeling this way. It is completely valid and you've been so brave to start taking the steps to start your dental journey. You did an amazing thing taking the time to e-mail those dentists and make an appointment. You can take all the time you need and proceed when you feel comfortable.
I understand what it's like to be afraid of medical professionals. I have severe white coat syndrome stemming from a period of my childhood when I was severely ill. During that time, I visited many doctors and specialists. None of them could figure out what I had. I was subjected to many procedures, medicines, and tests. Some of those things made me sicker. That meant even more doctors visits. Sometimes, I felt like you did. Like the doctors treated my condition like an experiment.
However, I was incredibly fortunate to be referred to a kindhearted doctor who recognized the fear, pain, and anxiety I felt. She took extra time to just sit and talk to me before starting her exam. She made me feel like she cared--like I was safe and comfortable. Then she made sure I knew I was fully in control of whatever happened. She did her exam slowly and took note of my every reaction. In the end, that doctor was the person who cured me.
Despite my positive experience with that amazing doctor, I still have a lot of fear and anxiety about going to the doctor nearly two decades later because of the experiences I had during my illness. I feel dread in the pit of my stomach and my hand shakes when I pick up the phone to make an appointment. My file at the doctor's office has a special tab on it warning the assistants about my white coat syndrome. My blood pressure can't even be taken in the office, I need to pre-measure and bring readings to my appointments. It's the memory of that one positive experience that gives me the courage to go back.
The biggest recommendation I can give you is this: find a kind, compassionate dentist that's skilled in handling people with dental phobia and anxiety. Those dentists know exactly how to reassure you and go the extra mile to help you feel comfortable. They'll take the time and effort to help you calm down, destress, and make your time in their office a LOT more pleasant. It's worth it.
Next, remember that you are 100% in control of what does and does not happen. You are the person in the chair, the teeth being worked on belong to you, and you know exactly what you are comfortable with. Nothing happens without your approval. Before the appointment starts, ask your dentist if he or she can let you know exactly what they're going to do, then tell them what you feel you can handle. Work out a non-verbal signal you can give them so they know that you're not comfortable--maybe raising a hand or a wave. When they see that, they'll know to stop. In my experience, most dentists are happy to accommodate.
Do not feel pressured to start treatment immediately. The dentist will likely do a cleaning, exam, and x-rays at the first appointment. After that, they'll talk to you about what needs to be done and print up a list of suggested work. You can take the treatment plan home, think about how to proceed, then keep going. You can wait a few months, gather courage, and then proceed. You can ask the dentist questions. You can choose not to proceed with any treatment. Remember, nothing happens without your consent.
Finally, remember that if you don't like the dentist you went to or want a second opinion, you can consult another dentist. You might not find the right fit immediately. That's okay. You'll find it eventually.
If you ever feel overwhelmed or anxious, remember that you can always come here and post again. Like Catie McBain said, there are so many caring and compassionate people on this forum who are great listeners. They give awesome advice.