So glad that you shared your info and learning experience. That is so great and yes, it's always a learning experience.
I do, however, disagree w/ your equine dentist regarding the first appointments
now (or these days). Those are old standards and in our Shetlands, I've noticed that they need to be seen the first time around 12 months of age. For the last few years, most of our yearlings have had not only points, but wolf teeth that needed to be addressed. AND all of the wolf teeth pulled from our Shetlands have been larger than the wolf teeth pulled from our Arab and ArabX saddle horses years ago (I'd kept a couple of teeth, don't have them now & wish I did!)... This is with different paddocks/pastures and feeds but always getting the same hay bales from the same suppliers.
I have always wondered if different areas of the country had different teeth "growth rates" (would make sense based on minerals, both natural and supplemented in feeds). We always had fewer points on both riding horses and minis/ponies in many years ago in CO & MT than we have had in VA(didn't own any there- boarding stables we rode at in the mid-70s) and NC. I do not know why or if it is even something to worry about - was just a curious thing to note (and one more constant expense that we have here in the SE vs when we lived in west/NW). It was actually very rare in CO, that our stock horses (QH/Paint & ArabXs) ever had wolf teeth that needed to be pulled. On the other hand, our vet was the head vet at the race track in Denver, CO and he stated that TBs almost always had wolf teeth that needed to be removed (late 70s - late 80s) while they were in training at the track before first races.
So that you know - we always used to have any youngster checked before bitting them to work in ground driving situations while training. If I was hooking lines to a bit when they were 18 months old, I wanted them checked first. If we were just bitting them to get them used to a bit, or to give a mouthy/nippy one something to do, then I didn't worry about it (so much).
I do know that growth rates are individual. We had one Arab mare that needed the "waves" in her teeth floated, or leveled, every 6 months up until she died at 24 yrs of age. And Bit, our 1991 shetland mare, had her teeth done annually every year until she passed last December at 25-3/4 yrs of age. Her full sister, Bell - 1992 model, doesn't need to be done every year like Bit did, but she still gets checked. I have had many Shetlands that have not needed to be done every year (it sure helps on the $), but again, it's really very individual. 2 have needed it much more often as they've aged than they did when they were younger.