Can you use garlic powder for toothache?

No: If you are having a toothache you are more likely to get some relief using clove oil. It has anesthetic and analgesic properties and is actually used as an ingredient in some of the products a dentist uses. Tooth aches usually don't get better and if they do they will flare up again at some point so you should get evaluated by a dentist. You can try otc nsaids to help with the pain also.

Never heard of this: Herbal treatments such as oil of clove and other home remedies generally are ubtundant treatments that will sooth an area only. You may feel better in the short term, but there is an underlying issue that will need to be addressed. Seeing a dentist to identify the problem and course of treatment is your best option. It may just be a simple needed filling. Dont wait too long.

Yes: Sure, but i don't know what that will accomplish. You need to figure out what is causing the pain. Is it decay? Will a filling take care of it? Do you need a root canal? Is it to far gone to even fix? Will it need to be extracted? Please see your dentist without delay.