I don't think you ever stop missing your mum, things, events, will always remind you of her. Ten years or more after my mother died I could still get tearful. If there is life after death (which I strongly belive) she is probably laughing and crying herself when if she looks back at how she was towards the end. She probably wants to hug you and say don't grieve, we will see each other again one day, made whole in death without the weakness of the body. But even if you cannot believe this, at least you know there is no more pain or bewilderment for her. Helping others is a wonderful tribute to her, we are learning more about this devastating disease all the time, and spreading that knowledge helps others to cope and know how to get help.
But try to also be kind to yourself, cry and laugh, don't feel guilty or resentful, talk to others who will listen, get out, go for walks in a park or by the sea, if you can, treat yourself to a massage, change your hairstyle, or whatever makes you feel good, maybe take up a hobby, learn something creative, perhaps buy an adult colouring book ( I love the ones where you can colour in clothes, or buildings), take a coach trip or some other holiday if you haven't already done so - you are probably exhausted.
You will never forget you mum, but try to think of her as she was before the dementia, rather than dwelling on the end, which was just a small part of her life. In time, you will learn to get by and live with the pain, which will gradually diminish. Two years is not long.