🩸 Tooth Mobility & Bone Loss Progression Simulator

Normal Periodontal Bone Support

Healthy bone anchors the root right up to the CEJ.

• 0 mm: Bone level (from CEJ)
• 0: Mobility grade (physiologic only)
• 0%: Attachment loss (root support intact)
• 1–3 mm: Probing depth (healthy sulcus)

Cementoenamel junction as reference

CEJ marks where enamel meets root cementum.

Alveolar crest position

Healthy crest sits 1–2 mm below the CEJ.

Periodontal ligament function

PDL fibers cushion and anchor tooth to bone.

Early Horizontal Bone Loss

Plaque biofilm triggers the first measurable crestal bone loss.

• ~2 mm: Bone level (apical to CEJ)
• 0: Mobility grade (still firm)
• ~20%: Attachment loss (of root support)
• 3–4 mm: Probing depth (shallow pockets)

Biofilm-driven inflammation

Bacterial plaque inflames gingiva, triggering bone resorption.

Radiographic sign

Crestal bone flattens instead of following a sharp peak.

Reversibility window

Early loss is largely stabilized by scaling and cleaning.

Moderate Bone Loss & Grade 1 Mobility

Root support drops 30–50%, and the tooth starts to shift.

• ~5 mm: Bone level (apical to CEJ)
• 1: Mobility grade (<1 mm lateral shift)
• ~45%: Attachment loss (of root support)
• 5–6 mm: Probing depth (true periodontal pockets)

Lever-arm effect

Less bone means a longer unsupported crown lever arm.

Grade 1 mobility defined

Grade 1 is barely perceptible horizontal movement.

Treatment response

Scaling and root planing can still slow the loss.

Advanced Bone Loss & Grade 2 Mobility

Over half the root support is gone, mobility becomes obvious.

• ~8 mm: Bone level (apical to CEJ)
• 2: Mobility grade (1–2 mm lateral shift)
• ~70%: Attachment loss (of root support)
• 7–9 mm: Probing depth (deep pockets, furcation risk)

Furcation involvement

Multi-rooted teeth may show bone loss between roots.

Grade 2 mobility defined

Grade 2 movement is over 1 mm, clearly visible.

Functional impact

Chewing forces now accelerate further bone destruction.

Severe Bone Loss & Tooth Loss Risk

Support is nearly gone, and Grade 3 mobility risks exfoliation.

• ~11 mm: Bone level (apical to CEJ)
• 3: Mobility grade (depressible, rotates)
• ~92%: Attachment loss (of root support)
• Severe: Tooth loss risk (imminent without care)

Grade 3 mobility defined

Grade 3 moves in all directions, even vertically.

Prognosis

Root support this low usually means a hopeless prognosis.

Remaining options

Extraction and implant or bridge planning become priorities.