What causes gingivitis, and why you probably don't need surgery

What causes gingivitis: plaque triggers gum inflammation

What causes gingivitis in humans is a well-characterized immune cascade. Bacterial plaque accumulates at the gingival margin, and within 10 to 21 days the immune system mounts an inflammatory response.¹ That response is meant to contain the bacterial load, but the inflammatory mediators (cytokines, matrix metalloproteinases, prostaglandins) also damage soft tissue.

The specific mechanism: plaque-induced dysbiosis shifts the oral microbiome from a health-associated community to a pathogenic one, dominated by anaerobic gram-negative species.² These bacteria produce lipopolysaccharides that activate pattern-recognition receptors on gingival epithelial cells and immune cells. The result is visible inflammation: redness, swelling, bleeding on probing.

Remove the plaque, and the inflammatory cascade stops. The gums return to health. This is what distinguishes gingivitis from periodontitis: at the gingivitis stage, no irreversible damage has occurred. No bone loss, no attachment loss. The tissue is inflamed but structurally intact.

What does gingivitis look like: red, swollen, bleeding gums

Classic gingivitis presents with three cardinal signs:

1. Redness: Healthy gingiva is pale pink (or physiologically pigmented). Inflamed gingiva is red or deep pink because of increased blood flow and vascular permeability.

2. Swelling: The gingival margin becomes puffy and rounded instead of knife-edged. This is edema, the accumulation of fluid in the tissue as part of the inflammatory response.

3. Bleeding on probing: When you brush, floss, or when a hygienist probes the gum pocket, the tissue bleeds. Bleeding is not normal. It signals inflammation.

What you will NOT see in simple gingivitis: recession, mobility, or radiographic bone loss. If a clinician documents any of those findings, you no longer have gingivitis. You have periodontitis.

That distinction is not semantic. It determines whether you need surgery.

What causes gingivitis to progress to periodontitis: bone loss

Not all gingivitis progresses to periodontitis. In some individuals, inflammation remains superficial for years. In others, the inflammatory process extends apically, destroying the periodontal ligament and alveolar bone.

The driver of progression is sustained bacterial challenge in a susceptible host. Risk factors include smoking, diabetes, genetic polymorphisms in immune-regulatory genes, and inadequate plaque control. When the inflammatory front reaches the bone, osteoclast activity accelerates and bone resorbs. Once bone is lost, it does not regenerate spontaneously.

This is the irreversible threshold. Gingivitis is reversible. Periodontitis is not (though it can be arrested). Surgery is occasionally indicated for periodontitis when there are deep pockets, furcation involvement, or osseous defects that cannot be managed with scaling and root planing alone.

Surgery is never indicated for gingivitis, because gingivitis by definition has not reached the bone.

Non-surgical treatment reverses gingivitis in most cases

The evidence base for non-surgical treatment is large and consistent. Professional mechanical plaque removal (scaling and polishing) combined with improved home care (brushing, interdental cleaning) reverses gingivitis in the majority of patients.

A 2017 Cochrane review found that chlorhexidine mouthrinse as an adjunct to mechanical cleaning reduced gingivitis by 20 to 30% compared to placebo.³ A 2018 RCT in pregnant women (a population at high risk for gingival inflammation) showed that non-surgical periodontal therapy significantly reduced bleeding on probing and gingival index scores.⁴

For patients who progress to periodontitis, the evidence is equally clear. A 2018 systematic review concluded that professional tooth cleaning and non-surgical periodontal therapy effectively reduce inflammation and clinical signs of periodontal disease.⁵ A 2018 RCT in diabetics with chronic periodontitis (a particularly difficult-to-treat population) found that non-surgical scaling and root planing improved periodontal parameters and reduced HbA1c.⁶

Patient-reported outcomes are positive. A 2021 randomized field study found that patients treated non-surgically reported high satisfaction, low pain, and functional improvement.⁷ Adjunctive therapies enhance outcomes: a 2022 split-mouth RCT showed that adding diode or erbium lasers to scaling and root planing improved clinical parameters beyond scaling alone.⁸

The Cochrane collaboration has published multiple systematic reviews supporting non-surgical treatment for periodontal disease.⁹¹⁰ A 2024 two-year RCT found that supportive periodontal care (with or without repeated subgingival instrumentation) maintained microbial and clinical stability over the long term.¹¹ Laser-assisted protocols continue to show benefit.¹² And a 2025 meta-analysis found that adjunctive hyaluronic acid improved clinical attachment and reduced pocket depth in non-surgical therapy.¹³

Most importantly, a 2025 systematic review of RCTs concluded that minimally invasive non-surgical therapy (MINST) is effective even for Stage III and IV periodontitis, the most severe classifications.¹⁴ That means that even advanced bone loss can often be managed without flap surgery, osseous recontouring, or grafts.

What helps gingivitis? Professional cleaning, home care instruction, and in some cases adjunctive antimicrobials or anti-inflammatory agents. What to do if you have gum disease at the gingivitis stage? See a hygienist, get a cleaning, brush twice a day, clean between your teeth daily. The inflammation will resolve.

Surgery is for periodontitis with bone loss, not gingivitis

There are legitimate indications for periodontal surgery. Flap procedures allow direct access to root surfaces and osseous defects that cannot be adequately cleaned non-surgically. Guided tissue regeneration and bone grafts can promote some degree of attachment gain in infrabony defects. Soft-tissue grafts address recession and improve esthetics.

A 2016 RCT evaluated patient morbidity and outcomes after subepithelial connective tissue grafts combined with coronally advanced flaps or tunneling techniques.¹⁵ These are surgical procedures, and they carry surgical risks: pain, swelling, suture-related discomfort, and in some cases limited or unpredictable root coverage.

A 2019 meta-analysis examined lateral bone augmentation prior to implant placement, another surgical intervention indicated when there is insufficient bone width for implant stability.¹⁶ A 2023 meta-analysis looked at how periodontal surgery affects the subgingival microbiome, finding shifts toward a more health-compatible microbial profile post-surgery in cases where surgery was indicated.¹⁷

The key phrase is “where surgery was indicated.” Surgery is appropriate when:

• Non-surgical therapy has been attempted and failed to arrest disease.
• Pocket depths remain 6 mm or greater with bleeding on probing after scaling and root planing.
• There are accessible osseous defects (infrabony defects, furcations) that might benefit from regenerative surgery.
• There is significant gingival recession with root exposure requiring soft-tissue grafting for patient comfort or esthetics.

Surgery is not appropriate when:

• The diagnosis is gingivitis, with no bone loss.
• Non-surgical treatment has not been tried first.
• The patient has not demonstrated adequate home care, because surgery will fail without plaque control.

A 2023 systematic review of clinical practice guidelines in periodontology found broad consensus: the standard of care is non-surgical therapy first, surgical intervention only when non-surgical treatment is insufficient.¹⁸

When to seek a second opinion: if surgery is recommended without bone loss

If a dentist or periodontist recommends gum surgery and you have not been diagnosed with periodontitis (bone loss visible on radiographs, attachment loss measured with a periodontal probe), ask for documentation. Request copies of your periapical or bitewing radiographs and a full periodontal charting that shows pocket depths and attachment levels.

If the charting shows pocket depths of 3 mm or less, bleeding on probing in a few sites, and no bone loss on radiographs, the diagnosis is gingivitis. The standard treatment is professional cleaning, improved home care, and possibly an antimicrobial rinse. Surgery is not indicated.

If the recommendation is surgery without a documented trial of non-surgical therapy, seek a second opinion. Clinical guidelines are consistent: non-surgical treatment first. Even Stage III and IV periodontitis responds to minimally invasive non-surgical protocols in most cases.¹⁴

Red flags:

• Surgery recommended at the first appointment, without a hygiene phase.
• No radiographs or periodontal charting to document bone loss.
• High-pressure language: “You’ll lose your teeth if you don’t do this now.”
• No discussion of home care or non-surgical alternatives.

Not every recommendation for surgery is inappropriate. Some cases genuinely require surgical access. But simple gingivitis is not one of them. The evidence is unambiguous: what causes gingivitis (plaque) is removed non-surgically, and gingivitis resolves non-surgically.

If in doubt, consult a periodontist who is board-certified and willing to walk you through the evidence for the recommended treatment. A clinician who follows evidence-based protocols will not recommend surgery for a condition that responds to professional cleaning and a toothbrush.