Because gum disease is painless until the final stages, it often goes unnoticed. The good news is that gum disease can be stopped. Gum disease can be easily detected by your general dentist during a dental examination. That is why regular checkups are important. Your dentist or dental hygienist may do a periodontal examination. This is when a small measuring instrument is inserted between the tooth and gum to measure how deep the pockets are between your teeth and gums. X-rays may be taken to look at the bone supporting the teeth.
If you notice these warning signs, see your dentist immediately.
Gums that bleed when you brush your teeth
Red, swollen or tender gums
Gums that have pulled away from your teeth
A metallic taste or persistent bad breath
Pus or discharge between your teeth and gums
Loose or separating teeth
A change in the way your teeth fit together when you bite
A change in the fit of partial dentures
Information as per the ODA https://www.oda.ca/oral-health-basics/oral-conditions-diseases/gum-disease/