In Canada now, some companies or groups have Orthodontic coverage in private health plan.
There is no coverage under the national type of health care and nothing provincial either.
When I was in a city in the mid 1960's, there were only two people in my school having dental work when I was threatened with this myself. (That is a story by itself!)
I moved to an isolated are but in the 1990's saw my first adult (women) with braces.
She had company insurance and decided on her 40th birthday to do this.
When a major mining company opened in my area, all the employees had insurance for orthodontic work through the company.
Despite the five hour drive one way to the nearest orthodontist, it looked like every family in town had several teenagers in braces.
I moved to a rural area in 2000, and saw one nurse with bottom lingual braces and upper metal.
Another woman I know locally, has ceramic brackets and colorful wires.
I have seen one man with a specialized retainer and lingual braces.
Also three teenage girls with orthodontic work ongoing.
If we had orthodontic coverage for all, I think a lot more would be in braces these days.