Puffy gums around crowns but no bleeding

I have several dental crowns, procelin fused to metal type, that I've had for a few years now. I floss (in and under/round the crowns like I'm supposed to) and brush religiously, use mouthwash and overall take good care of my teeth. But I have some puffyness that just never will go down. I don't think it's inflamed because it doesn't hurt or bleed or appear red even. If I ever ended up needing a gingivectomy can this be done while retaining my existing crowns or without ruining them?

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