Be careful with the dental treatments, for now only the UK Embassy has some approved. Anothers Embassies rejected some people for this. Better to check first with the Embassy in question.
I saw some get deny because of that yes, they require a minimum of 3 months. Maybe you can get some justification that are credible, better to consult the Embassy directly
I meet the Friday with one American that been rejected the same day that collect the passport and loose the 10k in Vientiane. The reason was because he previously overstayed in Thai.