Some dark spotting on dog's gums after dental cleaning – is it normal?

Question

My dog (male chocolate labrador, 6 years old) had dental cleaning under full anesthesia a few hours ago. The ventilation tube the veterinarian tried to insert at first probably didn't enter well so he removed it and tried with a different one, after which he said that "now I'm 1,000% sure it's placed correctly" to assert he's only working with certainty.

So my dog is still a bit restless and whined a bit earlier, and I thought it might sound like he's wheezing very slightly, so I looked at his gums and inside of lips and I'm not sure if this color might be indicative of hypoxia or that it might be related to the cleaning process. I don't remember how his gums usually look to compare.

Thank you in advance.

EDIT: I will just update that I also sent the pictures to the vet just to be sure, and after an hour when he'd yet to reply I called him just so he would confirm if it's OK. After I said that online resources say dark spotty gums could be indicative of hypoxia, his reply was simply "ah? What? Stop bothering your dog, bye". What an unassuring way to treat a patient/customer (who's just paid $350 for the procedure).

Answer 1

Please keep in mind that I'm not a vet.

I was skeptical of the "dark gums" as a sign of hypoxia, because I've seen dark pigmented gums in dogs with dark skin. And to be fair, the information available on many sites is confusing, especially if several sites contradict each other.

A sign of acute lack of oxygen is called "cyanosis", which can best be translated as "turning blue". In humans you can best see it in their lips. The gums of a dog take on a dark purple or blueish color. Read more on Pet Health Network. The gums of your dog are a nice pink (where they aren't pigmented, especially in the second picture), so he doesn't have cyanosis.

On the other hand, an overall darkening of the gums can be a sign of chronic lack of oxygen, possibly due to a malformation of the lungs, infection, parasites or fungi. It's not clear to me if this darkening is always black or can be brown as well. It seems to occur in young dogs most often. Read more on PetDT.

Brown spots on the gums can be a sign of gum infection or cancer, but those spots often have a raised texture compared to the rest of the gums. Labradors are also prone to developing a "cobbled" gum texture as they age, which is not a sign of any disease (source: PetMD). I don't see any sign of those in your pictures.

A general pigmentation of the gums is normal for several breeds, including Labrador. It's very confusing when your dog has pigmented gums and you read statements like "Normal gums should be a bubble gum pink color." (source). Some breeds get naturally blue tongues, some get black gums (if they have black fur as well) or black spots (if their fur is only partially black), others get brown gums (if they have brown fur).