Bad Breath

I have a four year-old pug who has always had bad breath. I have noticed his teeth have a lot of plaque on them, especially the ones at the back. I don't want him to have dental problems later on in life, and I have tried brushing his teeth and using Lintbells products. He hates having his teeth touched so it's difficult for me to clean them properly, I really need something else to try! 

If anyone has any suggestions for me I would be very grateful! 

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