The clinical distinction
The 2018 AAP/EFP World Workshop, which is the current international classification framework for periodontal disease, distinguishes between periodontal health, gingivitis (gum inflammation without attachment loss), and periodontitis (inflammation with attachment loss).1 2 The distinguishing line — visible to the clinician but not to the patient at home — is whether the supporting attachment of the tooth to the bone has been lost.
| Gingivitis | Periodontitis | |
|---|---|---|
| What's affected | Only the gum tissue (gingiva) | Gum, periodontal ligament, and alveolar bone |
| Reversible? | Yes, with treatment and ongoing care | No — lost bone does not regrow on its own; the disease can be stopped but the prior damage stays |
| Symptoms you notice | Bleeding gums, puffy gums, mild bad breath | Bleeding, recession, loose teeth, gaps opening, persistent bad breath |
| What the clinician finds | Bleeding on probing; pockets typically ≤3 mm | Pockets >4 mm; clinical attachment loss; bone loss visible on x-ray |
| Typical treatment | Professional cleaning + better home care | Specialist non-surgical (and sometimes surgical) therapy + lifelong maintenance |
Why the distinction matters for patients
The clinical reason: the bone that anchors a tooth in the jaw is a finite resource. Once it has been resorbed in response to the bacterial challenge of periodontitis, it does not regenerate spontaneously. Some defects can be partially regrown with specialist surgical techniques (bone grafts, enamel matrix derivative, growth factors), but most cannot.
The pragmatic reason: catching gum disease at the gingivitis stage means a course of thorough cleaning and an updated home-care routine. Catching it at the periodontitis stage means specialist treatment and a maintenance programme for life. The cost difference, the time difference, and the prognosis difference all sit at that line.
How a clinician decides which it is
The diagnosis is not made by appearance alone. A periodontist (or a general dentist doing a careful periodontal screening) needs to:
- Probe each tooth. A calibrated periodontal probe is gently inserted into the sulcus between gum and tooth at six points around every tooth. Healthy sulcus depth is 1–3 mm. Anything deeper than 4 mm is abnormal. Anything deeper than 6 mm warrants specialist assessment.
- Measure recession. The probe also records how far the gum has migrated down the root from its original position.
- Calculate clinical attachment loss. Pocket depth plus recession equals attachment loss — the most important number in periodontal diagnosis.
- Record bleeding on probing. Sites that bleed when probed have active inflammation.
- Take radiographs. Periapical and panoramic x-rays show bone level around the root. Healthy bone sits within about 2 mm of the cemento-enamel junction; lower than that indicates loss.
A patient with bleeding gums, pocket depths ≤3 mm, and no x-ray evidence of bone loss has gingivitis. The same patient with pockets of 5 mm or more and visible bone loss has periodontitis. The conversation with the patient — and the treatment plan — moves on the basis of those two numbers.
Can gingivitis become periodontitis?
Not always, and not predictably. Most patients with gingivitis never progress to periodontitis. A subset do — and the subset is partly determined by genetic susceptibility, smoking, diabetes, immune status, and other factors discussed in What causes gum disease?. The honest summary is that gingivitis is a necessary precondition for periodontitis (you cannot have the second without going through the first), but it is not a sufficient one. Treating gingivitis when you see it is the rational response either way.
What treatment looks like for each
Gingivitis treatment: one or two professional cleanings to remove plaque and calculus above and just below the gum line, oral hygiene instruction (brushing, interdental cleaning), and a follow-up review at 4–6 weeks to confirm resolution. After that, ongoing professional cleanings at the patient's usual cadence (commonly 6-monthly).
Periodontitis treatment: specialist non-surgical periodontal therapy (sometimes called scaling and root planing) over two to four visits, performed under local anaesthetic, with instrumentation that reaches the calculus that has formed below the gum line. Re-evaluation at 6–8 weeks; if pockets remain deep, surgical access is considered for those specific sites. Then, indefinitely, three- to four-monthly maintenance with a periodontal hygienist.3
The EFP S3 clinical practice guideline summarises the evidence-based sequence of care for stages I to III of periodontitis. Treatment plans we discuss at the practice align with that guideline.
What you should do if you are unsure which you have
The simplest path is a periodontal screening. Most general dentists perform a routine periodontal screening (BPE or PSR) at every check-up — if your dentist has not mentioned periodontal screening, ask for one. If the screening flags pockets above 4 mm or bleeding above ~10% of sites, ask for a referral to a specialist for a full periodontal examination.
This article cannot diagnose your specific situation. The terms gingivitis and periodontitis sit on a clinical continuum, and the line between them is established by examination, not by reading.