Hi,
Even though I am a dentist this is a very difficult question to answer.I am sorry to hear that you have had bad experiences in the past which have made you less trusting of dentists.While there is the odd bad apple a vast majority of dentists are good people trying to do the best they can for their patients in a trying environment like the oral cavity.
Next Steps
As you have had bad experiences before one of the best ways is to get multiple referrals from friends and acquaintances.If many people you know have had a good experiences with a particular dentist then your chances of a positive experience is also high.Once you shortlist a dentist make an appointment and pay him/her a visit.Check out the cleanliness and staff behaviour.Does the dentist make you feel comfortable, takes time and listens and answers your doubts without using complicated jargon?Does he/she explain the treatment and costs in detail?All these factors taken together will help you make a decision .Best of luck