How to stop thumb-sucking

Anyone got any bright ideas of how to help my not-quite 4yr old DD to stop sucking her thumb? she has done it since she was 3 months old and it is obviously a great source of comfort to her, in fact I wasn't going to do anything about it for that reason (esp as she is starting school in Sept and might need it while she's settling in) but her teeth are visibly starting to get misaligned now and I'm concerned if we leave it too long it will impact on her adult teeth when they come through. I have so far just been doing constant reminders, she will stop each time, and then a minute later starts again, the habit is hugely ingrained I am worried it will be really hard for her to stop. She does it all the time when her hands aren't busy with something, obv more when tired and bored. I have explained the reason why she needs to stop, as well as showing her pictures of people with really wonky teeth - she just thought they were funny though! I don't want to do the nasty tasting nail-varnish thing.

I could write the same! but i am over a year further down the line, I have done eveything too and izzy says she wants braces so I have decided to just leave her

My friend taped her daughters thumb up with sellotape, which worked.

If you figure it out let me know, pippa is 5 and a thumb sucker. She never does it at school though and only tends to be when shes worn out or upset

Izzy has stopped doing it at school too!

Izzy has stopped doing it at school too!

pips also left her tigger teddy at home the first day of school without me even mentioning it which amazed me as she never leaves the house without him

She's done well today with a plaster on her thumb, she's had toys, clothes etc in her mouth all day though! I know the plaster will come off in bed tonight as well!

We started after my DD turned 5. First just at daytime and when she got used to that she did the bedtime part. We aimed at just stopping at daytime. We had a code word to remind here in the daytime (ours was Alex,the lion from Madagascar). We told here she would get a reward if she would have stopped for 2 weeks. It worked . We sometimes used a plaster.
Good luck.

I have always sucked my thumb and the only way I could break the habit was to micropore tape my thumb and first fi ger. Plasters came off in the night and i found myself sucking when i woke up.