There is no magic number to this limit: Some people can't manage to care for the teeth of one IG and some have no problem caring for the daily dental needs of 7-10 IGs.
(This number The general rule of thumb is this: Brush DAILY for excellent oral health.
When the mouth is healthy I recommend using Maxi Guard daily and a solution with chlorhexidine once every week or two.
Think of a native American infant in a papoose: keeping them held snugly will give them a sense of security and keep them To get your dog down on his/her side in the first place, hold the dog firmly against your chest and lower the dog to your side (or lap) while still against your chest.Once the dog is completely down (sandwiched between your side, or lap, and chest) put your hand on his shoulder and lift your body away from the dog.The first several times you miss a 3rd day of brushing the tartar won't be visible but it darken.Brush for a few minutes each day, alternating between Maxi Guard (or another unflavoured or mint flavor canine toothpaste) and a canine oral solution containing .12% chlorhexidine (an antibacterial agent) like Enzadent.Italian Greyhounds, like many other toy breeds, are notoriously prone to gum disease.
Contributing factors are a long narrow skull with tight lips and a dry mouth.As the adult teeth become fully erupted you can start gently wiping them with a moistened gauze pad.I don't advise waiting for all of the adult teeth to be fully and completely in before starting dental care because I have seen several IGs that had to have adult incisors pulled at one year of age.This will only encourage the dog to lick a lot, making efficient brushing more difficult.Mint flavour is not tasty to the dog and makes their breath fresher.If you don't want a breed that requires this level of attention you might be better off with a breed that has a head like a Fox Terrier.