As Isabella said, at this age, they won't "understand" explanations, as would an older child. Since this is what he is used to and what the routine has been... he adapted to it, and this is what is expected, in his 14 month old understanding. Any solution, has to be age appropriate. After he has his bottle and then falls asleep, take it away. Don't leave it there in his mouth. Sure, many give the bottle to a baby when they cry, because it helps them "soothe" and stop crying. And sometimes they are just hungry. Try offering him something else to "soothe"... like a "transition object". My 15 month old likes to hold his stuffed cow and we give him a pacifier at night. This works for him and us. The night time bottle is often the last thing that they will "wean" from. Also, don't offer any juice at night. I'm not sure that he will "wean" from a milk bottle as yet. It will take time, and be prepared for lots of protests and crying and not sleeping if you decide to go "cold turkey." He could have his bottle, but you don't have to leave it there in the crib, since you are concerned about rotten teeth, which granted, can happen. Weaning at night, whether from the bottle or breast is the hardest and the last to go. It is comfort for them, and helps them sleep. It is also a habit. In my case, with both children, I would always nurse or give the bottle to them BEFORE bed at night... but never left the bottle in the crib. Or maybe try DILUTING the milk....still in the bottle...and then give it to him. Sometimes, diluting it will not be too appealing to them, and may lessen their "habit" of wanting it at night. But of course, at his age, it is still beneficial to be nursing and giving them whole milk. Just at night, maybe try this. I have heard of other moms trying this. Also, if you want to prevent rotten teeth... perhaps, not giving him juice either, even if during the day... cavities occur with the frequency of exposure to "sugary" sources, from what I've learned from my dentist. They don't really "need" juice... or dilute that as well. Cavities happen whether during the day or night. If it is any comfort, try asking your Pediatrician or Pediatric dentist about it. Good luck.
~Susan
www.cafepress.com/littlegoogoo