truthsharer,
It is a machlokes as to whether shaking hands is derech chiba, and a machlokes as to whether derech chiba is objective or subjective.
According to those that hold derech chiba is subjective, it would depend on the feelings one has when touching the other person. If getting a teeth cleaning by a person of the opposite gender generates such feelings then it would be problematic.
According to those that hold derech chiba is objective, we look at the purpose of the touching as perceived by the outside observer. If the outside observer would view such touching as being motivated by chiba or (and?) tayvah than it would be ossur.
Agav, actual touching of skin derech chiba with someone who has the status of arayos to you (which includes almost every Jewish woman in the world), is yeharog v’al ya’avor. Pikuach Nefesh would not help.