A bit of RTV around the dizzy base will seal it as well.
For the oil pressure sensor, I'll use some RTV copper smeared on the threads - not anything else. I've been about 50/50 using other sorts of RTV or PTFE paste with the sensor not "self-grounding," and the copper-bearing RTV seems to have solved that problem.
Since I don't like doing jobs twice, I'll only use RTV copper on one-wire sensors...
Although, I think the OP wasn't talking about the threads on the sensor proper, but a leak at the base of the hex adapter - the bit that remains when you've pulled the sensor. The hex shape leads me to believe that you can back it out with a wrench, but I've not yet had occasion to try...
Oh - and make sure it's not a "spurt up" from the oil filter adapter that is presenting as an oil pressure sensor adapter leak.
- Clean the area thoroughly.
- Let dry.
- Start engine.
- Idle for about ten minutes while you watch the suspect area(s). Stop when you've found the leak (which usually takes a good deal less than ten minutes.)
- Service or replace parts PRN, return vehicle to service.