Diagnosis of Periodontal Disease
Periodontal disease is diagnosed by your dentist or dental hygienist during a periodontal examination. This type of exam should always be part of your regular dental check-up.
A periodontal probe (small dental instrument) is gently used to measure the sulcus (pocket or space) between the tooth and the gums. The depth of a healthy sulcus measures three millimeters or less and does not bleed. The periodontal probe helps indicate if pockets are deeper than three millimeters. As periodontal disease progresses, the pockets usually get deeper.
Your dentist or hygienist will use pocket depths, amount of bleeding, inflammation, tooth mobility, etc., to make a diagnosis that will fall into a category below:
Gingivitis
Gingivitis is the first stage of periodontal disease. Plaque and its toxin by-products irritate the gums, making them tender, inflamed, and likely to bleed.
Periodontitis
Plaque hardens into calculus (tartar). As calculus and plaque continue to build up, the gums begin to recede from the teeth. Deeper pockets form between the gums and teeth and become filled with bacteria and pus. The gums become very irritated, inflamed, and bleed easily. Slight to moderate bone loss may be present.
Advanced Periodontitis
The teeth lose more support as the gums, bone, and periodontal ligament continue to be destroyed. Unless treated, the affected teeth will become very loose and may be lost. Generalized moderate to severe bone loss may be present.
How Periodontal Disease Is Diagnosed
Diagnosing periodontal disease is part of every regular dental exam, not a separate appointment. Your hygienist or dentist uses several specific checks to determine whether your gums are healthy or whether disease has started. The combination of probing depths, x-rays, and visual examination tells a much more complete story than any single one of these on its own.
Periodontal probing is the central tool. A small calibrated instrument is gently inserted at six points around each tooth to measure how deep the pocket goes between the tooth and the gum. Healthy pockets are one to three millimetres deep. Pockets of four millimetres or more suggest early to moderate periodontal disease, with deeper readings indicating more advanced stages. Bleeding on probing is recorded at each site because it indicates active inflammation. The pattern of bleeding and pocket depths across the mouth tells your dentist whether problems are localized or widespread.
X-rays show what probing cannot — the bone level supporting each tooth. Healthy bone sits close to where the tooth crown meets the root. Bone loss from periodontal disease shows as the bone level having receded down the root. Comparing today's x-ray to one taken two or five years ago tracks whether disease is stable, getting better with treatment, or progressing.
Specific Findings That Indicate Periodontal Disease
The diagnosis combines multiple findings. Your dentist looks for:
- Pocket depths of four millimetres or more at one or more teeth
- Bleeding on probing — gentle pressure causes the gum to bleed
- Visible gum recession exposing tooth root surfaces
- Mobility of teeth that should be firmly anchored
- Pus discharge from gum pockets
- Bone loss visible on x-rays compared to earlier images
- Furcation involvement (bone loss between the roots of molars)
- Tooth migration — teeth that have shifted position from their original alignment
- Persistent bad breath that does not respond to better home care
- Tenderness, swelling, or discoloration of gum tissue
A single isolated finding (one pocket of four millimetres) may not warrant active treatment but is worth monitoring. A pattern of findings across multiple teeth confirms periodontal disease and triggers a treatment conversation.
Staging and What Diagnosis Means for Treatment
Periodontal disease is staged from gingivitis (mild and reversible inflammation of the gums without bone loss) through Stage I, II, III, and IV periodontitis based on severity and pattern of bone loss. The stage determines treatment intensity. Gingivitis responds to a thorough cleaning plus improved home care; Stage I and II periodontitis usually responds to scaling and root planing (deep cleaning under local anaesthetic); Stage III and IV may require surgical treatment, bone grafting, or other regenerative procedures.
Your dentist explains your specific findings in plain terms after the exam. You see your pocket-depth chart and x-rays, hear what they indicate, and discuss the treatment plan together. The plan is staged in phases — non-surgical treatment first, re-evaluation six to eight weeks later, surgical treatment if needed. Maintenance visits every three to four months replace standard six-month cleanings while disease is being managed, then continue at the right interval for your situation.
Early diagnosis dramatically affects outcomes. Gingivitis caught at a routine cleaning visit can be reversed entirely with cleaning and consistent home care. Stage IV periodontitis that has progressed for years without treatment may leave some teeth that cannot be saved. The visits that take five minutes to measure probing depths are the visits that prevent the much more involved treatments later.
What This Means for Your Care at Trillium
Trillium includes periodontal probing and gum-health assessment as part of every regular cleaning and exam visit. There is no separate charge for diagnosis itself; the cost is part of the exam. If active treatment is needed, we discuss what is recommended and what each phase costs before scheduling anything. We follow the current Ontario Dental Association Suggested Fee Guide for all periodontal services.
Most private dental insurance plans cover periodontal evaluation as part of routine exam visits and cover scaling and root planing or other treatment when documented as medically necessary. CDCP includes periodontal services within its annual benefits framework. We submit insurance claims directly where the plan allows it.
Frequently Asked Questions
Why does the hygienist measure my gum pockets?
Pocket depths are the most reliable indicator of gum health. Healthy pockets are one to three millimetres deep; deeper pockets indicate disease. Measuring at every visit shows whether things are stable or changing, which directly affects what treatment you need.
Will gingivitis turn into periodontal disease?
Not always, but it can if left untreated. Gingivitis is reversible with good cleaning and home care; periodontitis (with bone loss) is not reversible, only manageable. Treating gingivitis early prevents the progression.
Are bleeding gums normal?
No. Bleeding gums almost always indicate inflammation from plaque that needs to be removed. It is not damage from flossing too hard. The fix is more consistent flossing and a cleaning visit, not less flossing.
How accurate are x-rays for gum disease?
Very accurate for tracking bone level changes over time, which is the most reliable marker of periodontal disease progression. Comparing today's x-ray to one taken two or five years ago shows whether you are stable or losing bone.
Can periodontal disease come back after treatment?
Yes, without consistent maintenance. The bacteria that cause periodontal disease are always in the mouth. Regular three- to four-month maintenance visits and good home care keep them under control. Patients who stop maintenance often see disease activity return within a year or two.
Will I lose teeth from periodontal disease?
Possibly, if disease is advanced and untreated. Periodontal disease is the most common cause of tooth loss in adults. Early diagnosis and treatment dramatically reduce this risk. Some teeth in advanced cases cannot be saved, but most patients keep most of their teeth with appropriate care.