You are certainly not alone. Most of my children still took a bottle (usually of water) until they were well past one. I have had seven, and only one, my youngest, transitioned quickly to a sippy cup (he is 18 months and been using a sippy for several months). My friend's dd is close to 3 and she just FINALLY got her off a bottle.
Transitioning during daylight hours is much easier than at bedtime. If you slowly make her drink from a sippy cup during the day, using the bottle less and less, she will naturally transition to using it all the time.
Getting her used to going to bed without milk is a separate matter. She may wish to continue having milk to go to sleep with. You could try watering it down, every night making it a little more water than milk. This will take at least two weeks or more, so be patient.
If your primary concern is tooth rot, I have opinions on that topic. I realize you are a dental hygienist, and I am painfully aware of the mantra we are all taught about babies and teeth rot. However, many times, tooth rot is hereditary; parents with numberous fillings usually have children with numerous fillings. Parents who have infants with tooth rot often blame the bottle, but in fact, they provide a constant stream of junk food and candy to the child, which is far more caustic to their teeth than their nighttime bottles.
5 out of my first 6 children have excellent teeth (and most went to bed with bottles). You are going to cringe, and no I don't recommend this, but here's the truth: they brushed when they remembered. I have never brushed an infant's teeth. They usually begin brushing their own teeth around age 3 or 4. We don't buy a lot of junk food, but I do let them have dessert several times a week. I did not take them for regular cleanings because I simply did not have the money to do so. You would expect my kids would have had terrible teeth, yes? My 23 yr old got her first cavity at age 21. My 18 yr old had one filling when she was about 8; she didn't have to have any more until this year. My 17 yr old had a baby tooth pulled due to a cavity. My 15 yr old and 7 yr old haven't had a cavity yet. So, 5 kids, 17 years, 1 filling.
Then there's my 11 yr old and his rotten molars. He had two root canals at age 4 to preserve his 13 year molar spaces. When his adult teeth came in, the molars again rotted quickly. The dentists I took him to all sang the same song: "He obviously eats too much sugar and doesn't brush often enough." When I told them his brushing and sugar consumption was the same as his siblings, they basically called me a liar. Politely. Praise the Lord I finally found a dentist who knew a different tune!
He now has about 8 fillings, 7 of which are molars. Our current dentist said some children are simply more prone to cavities. Some children have more acidic saliva, some less acidic. My orthodontist told me when I was 15 the reason I didn't have cavities was because my saliva content protected my teeth. (I got my only cavity several years ago at age 33.) Because the bulk of my son's are molar, it is likely his crevices are deeper than normal, making it almost impossible to clean and preventing even saliva from properly rinsing away sugar deposits. Had he eaten no sugar and brushed every 6 hours, he probably would still have had as many molar cavities.
All that to say this: Sometimes it is more traumatic than it is worth to take a child off a bottle. Yes, I think sippy cups are a great idea. Yes, I think children should brush their teeth. But typically, parents allow their children entirely too much junk food and sugar. If you are one who has no problem with a constant stream of cookies, donuts, Little Debbies, candy, etc. then your child may develop cavities, but I wouldn't blame her bottle. If you make sure her snacks are things like veggies, and keep cookies and candy for a one-time treat every other day or so, then the bottle dependency shouldn't be a cause for alarm. That said, I would still start transitioning. Slowly is the best way to handle it - don't panic. It will be less traumatic for you and for your dd.