I have to go but I'll come back later and read your posts. Meanwhile, I hope you get an honest answer from him so you can either move forward with the relationship and work on the communication, or move forward without him.
Did he tell you why he didn't call you the morning of your dental visit or the next morning after he fell asleep? I'm trying to understand if it was just this one incident or if it's a pattern.
I had a molar cut out first of all, and he said that when he's had to have that done, he was tired and wanted to be left alone. His exact words were. "I didn't want to bother you if you were sleeping"- He assumes that since he reacts a certain way, I do too. He says he didn't want to talk to anybody.
Communication is key. You need to tell him what you want. Men are not mind readers by any means...but....
Mine was like that once...I went to his apt. cause I just "had this feeling"...I was right. He was hiding a girl in his shower.
Do some investigating if he doesnt come clean after you are honest with him and put it all on the table. No sense beating a dead horse.