The teeth may need to be brushed. If you see brownish buildup on the teeth, that isn’t normal. While a dog’s saliva does have some antibacterial qualities, they still do need to have their teeth brushed. Dry food is not enough to prevent the accumulation of food deposits and unhealthy bacteria in the dog’s mouth. All dogs can have their teeth brushed weekly. You can also use chews designed for dental or a gel or water additive.