I'm beginning to think that it really depends on the dog.
yes I think you could be right, I have been using the petzlife gel on 2 of mine ( the others all have sparkling teeth) since mid march, whilst I think the dental health and hygiene has obviously improved certainly Heidi has
one large tooth at the back that the plaque just will not move however the gum line is not decayed/red so as I say think it definately helps with the bacteria.- the dogs did not mind having the gel applied despite imo quite a strong peppermint smell
I had almost finished the gel and recently purchased the spray (courtesy of Jenny(Jaspersmum)) to try, again no bother with the application just 3 -4 sprays in the mouth, again the peppermint smell quite strong but cant be that bad as all the others try to lick it off and makes them sneeze

tbh, i am not expecting the spray to remove heidis plaque any more than the gel, I have a feeling she is not using that part of her mouth to eat/chew so less likely to remove the plaque
Mine all enjoyed logic toothpaste being applied but I found it a bit of a nightmare as whilst brushing all the others were trying to get their turn