"not in your mouth please" broken record!

[mom-in-alberta]

It's tough, because at a certain point, it's virtually necessary for sensory development and exploration. But for most children, that stage is outgrown well in advance of the first birthday.
If mom and dad aren't on board at home, and THEY let them put every little thing they grab into the mouth; it's tough. I had 2 little boys start at essentially the same age. Both really had a mouthing tendency. I had one of them for less than a month before all I had to say was "not the mouth" while the toy was heading there. He would stop. Within another couple weeks, the habit was gone. His mom is a nurse, so it probably helps that she's a bit of a clean freak, LoL. The second boy took MONTHS before he understood, and it was still an occasional challenge. He is a thumb sucker, which I also wouldn't let him do (I am not having you slime up your thumb and then touch all the toys, etc!). But mom just didn't care, and she thought the thumb sucking was cute. Let's see how cute it is when you are spending 6k on braces, and his one ear is all floppy an stretched out (he would "fold" it over in his hand while he sucked his thumb).
Have you asked the parents to help you reinforce it? You can do it nicely. "Hey, I have noticed an increase in toys being chewed on, so for everyone's health, I am asking all the parents to help teach the kiddos not to mouth stuff. Thanks!"
I do like Reggio's idea, for those that seem to NEED something in their mouth (ie; boy B above). And one thing that helps is physically interrupting them while they are starting to chew on/lick/ suck on something. Gently taking the hand down, and even removing the toy and putting it on the floor in front of them. "Not in the mouth. Only FOOD goes in our mouth. YUCKY." Stern, no nonsense voice.

[Momof4]

I'm a broken record with exactly those words too with a 16 month old & 17 month old in my daycare. They are getting much better the last month but they are both teething like crazy. I guess it's my own fault because I wean children off their soothers shortly after their first birthday.