Our dog barked and a 8yo boy ran tripped over something and broke his leg across the street from my home?

From your limited fact pattern it would not appear likely but if a claim is made report it to your insurance carrier.

Consult with a local lawyer immediately to get a more detailed opinion.

Can I sue the hospital for malpractice ?

Consult with a local lawyer immediately.

I would not worry about it as I agree with the other two gentlemen.

I'd like to sue a dentist but don't have money for lawyer (no money for retainer)

You should contact lawyers in your area, immediately, for a consult.

What steps can I take to hold my dentist accountable for using false X-rays for financial gain?

Consult with a lawyer in your area to determine your options.

Should I hire an attorney for my workers compensation case?

You should at least consult with a W/C lawyer and then decide what you want to do.

Is it common for the Plaintiff to pay in advance the cost of the Medical Expert Witness's Report?

Read your retainer agreement to see who pays these expenses in advance.

Insurance claim denied, reason - medical episode

Consult with a lawyer in your area.

How do i get a second appraisal? Who do i call? Where do i find one and can i bill it to the insurance company?

Bring your car to the auto body shop you wish to use to get an appraisal and also check into a claim for the diminished value to your car.