What periodontitis is
Periodontitis is the stage of gum disease at which the inflammatory process has moved past the gum tissue itself and started to damage the deeper structures — the periodontal ligament and the alveolar bone that anchor each tooth.
The visible signs at the surface may still be similar to gingivitis, but underneath, the connective tissue that binds the gum to the tooth begins to break down. As it does, the shallow crevice around each tooth deepens into a "periodontal pocket" that traps more plaque and is harder to clean, which drives the process further.
Severity staging
The current classification (2017 consensus) describes periodontitis on two axes — stage (how much damage has occurred) and grade (how quickly it's progressing). Practically, patients hear:
- Stage I – Initial: shallow bone loss and pockets around 4 mm.
- Stage II – Moderate: pockets 5 mm, bone loss visible on X-ray but limited to the outer third of the root.
- Stage III – Severe with potential for additional tooth loss: pockets 6 mm+, bone loss reaching the middle third of the root, some tooth mobility.
- Stage IV – Severe with potential for loss of the dentition: significant bone loss, multiple missing teeth, complex rehabilitation required.
Signs
- Gums that bleed easily and consistently.
- Persistent bad breath or a metallic taste.
- Teeth that look longer as gum recedes.
- Visible spaces opening up between teeth.
- Teeth that shift or feel loose.
- A change in how upper and lower teeth fit together when you bite.
- Pus or a small abscess near the gum line.
Who's at risk
Anyone can develop periodontitis, but risk is unevenly distributed. The strongest risk factors are:
- Smoking and tobacco use — the single largest modifiable risk factor.
- Uncontrolled diabetes — bidirectional relationship.
- Genetic susceptibility — an estimated 30% of the population is more vulnerable.
- Age — cumulative exposure over decades.
- Poor oral hygiene combined with infrequent professional cleanings.
- Certain immunocompromising conditions — HIV, some autoimmune disorders.
- Stress — likely mediated through immune function and behavioral change.
Diagnosis
Periodontitis is diagnosed through a combination of periodontal probing (pocket depths of 4 mm or more with attachment loss), bleeding on probing, and radiographic evidence of bone loss. A thorough exam will also record recession, mobility, furcation involvement (bone loss where a tooth's roots divide), and any missing teeth thought to be caused by periodontal disease.
Treatment
Non-surgical: scaling and root planing
The mainstay treatment for most cases. Using specialized instruments (hand scalers and ultrasonic devices), the clinician removes plaque and tartar from the tooth surface both above and, critically, below the gum line, then smooths the root so the gum can reattach. It's usually done under local anesthesia across one or two visits.
Adjunctive therapies
- Locally delivered antibiotics placed directly into deep pockets.
- A short course of systemic antibiotics, particularly for aggressive forms.
- Sub-antimicrobial-dose doxycycline for its anti-collagenase effect.
Surgical options
Where non-surgical treatment doesn't sufficiently reduce pocket depths, surgical options include flap surgery, osseous surgery to reshape damaged bone, and various regenerative procedures using bone grafts, membranes, or growth factors.
Maintenance
The most important — and most under-discussed — part of periodontitis treatment is what happens afterwards. Treated periodontitis is not "done"; it's controlled. Most patients move to a 3-month periodontal maintenance schedule, at least initially, to catch recurrence early. Consistency at this stage is what determines long-term outcomes.
Whole-body implications
Periodontitis has documented associations with cardiovascular disease, diabetes control, adverse pregnancy outcomes, and several other conditions. The exact causal mechanisms are still being worked out, and it's important not to overstate what's known. But the trend in the evidence has been consistent: chronic oral inflammation is not confined to the mouth.