How much Ativan before dentist?

Tomorrow I am going in to get a wisdom tooth removed, Prep work for a bridge, and a temporary bridge installed. I have terrible anxiety/panic attacks at dentist. Where I have to sometimes get up in the middle of the procedure because I get so nervous and feel like ill pass out. I usually take.5mg up to 1mg a day for anxiety / to help sleep. I'm thinking about taking 2mg an hour before my appointment, then driving myself 30 minutes to the appointment. The whole appointment should take about 3 1/2 hours they said. Does that seem like a good dose or should I take more?
How much Ativan before dentist?
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