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It may depend on the pH of your mouth and saliva. Some people get more plaque and tartar than other people and it's inevitable to need more work during the bi-annual cleaning. If you are lucky and your pH and composition of saliva lead to less plaque, then it's also easier to avoid bleeding.
In any case, the dentist needs to go below the gum line and this may easily bring some limited bleeding. It doesn't mean you are not cleaning your teeth well enough.
Source for the first paragraph: common sense but also http://onlinelibrary.wiley.com/doi/10.1111/j.1600-051X.2010.01673.x/abstract "The composition of the oral microbiota is influenced by temperature, pH, and atmosphere, as well as by the host defences and host genetics. In addition, the host supplies endogenous nutrients and a variety of surfaces for biofilm formation. In health, the resident oral microbiota forms a symbiotic relationship with the host, regulated by active host–microbe cross talk."
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