Hello, I actually figured out by myself what was confusing me. In the 「私は怖くて」 example, not only would the end of the sentence be omitted, but also a second object. (私は(歯医者が)怖くて(いけない)。) It seems like I forgot that が can be used for other adjectives than 好き. My slow thinkng is to blame.
By the way, I usually use a japanese-english dictionary, I actually used Google Translate this time because I know I wouldn't find specifically "怖くて" in the dictionary. The verified label meant that it was actually validated by a japanese, and not computer-generated, which made it trustworthy enough to me.
Unless I'm mistaken again, I don't want to make you lose more time with this thread, so this may be my last post. Farewell, and thank you for all.