Guided Tissue Regeneration Calculator
Membrane size from defect anatomy.
About this calculator
Guided tissue regeneration places a barrier membrane over an intrabony defect to keep fast-growing gingival epithelium out of the healing space while slower periodontal ligament and bone cells repopulate it -- the technique periodontists Sture Nyman and Jan Gottlow first described using non-resorbable membranes in the early 1980s. This calculator sizes the membrane from the defect's mesiodistal and buccolingual dimensions, extending 3mm beyond each margin on every side to anchor the barrier over sound bone, then rounds up to the nearest standard commercial membrane size. Membrane TYPE is a separate choice from membrane SIZE: non-resorbable ePTFE holds its shape well but requires a second surgery to remove it, typically 4-6 weeks after placement, while resorbable collagen and synthetic membranes break down in place -- collagen's resorption timeline varies widely by formulation and cross-linking, commonly cited from a few weeks to several months -- sparing the patient that second procedure.
Graft volume is estimated separately from the defect's three dimensions (depth, mesiodistal width, buccolingual width) rather than from the membrane's footprint, since the graft fills the bony void underneath while the membrane only covers it. Expected clinical attachment gain and the estimated healing timeline both follow from the inputs rather than from a single fixed number, since deeper defects and the chosen membrane material both change what a favorable outcome looks like.
Medical Disclaimer
This calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about your health. Never disregard professional medical advice or delay seeking it because of results from this tool.
Inputs
Results
Membrane area (cm²)
1.1
How to Use This Calculator
- Enter defect depth (mm), mesiodistal width (mm), and buccolingual width (mm) from clinical measurements.
- Select the Membrane type — Non-resorbable (ePTFE), Resorbable collagen, or Resorbable synthetic.
- Review the calculated membrane area and the standard membrane size selected to fit the defect.
- Check the estimated graft volume, expected CAL gain, and success probability for the defect.
- Use the healing weeks and material cost estimates, along with whether a removal surgery is needed, to plan treatment.
How the result changes with Mesiodistal width (mm)
| Mesiodistal width (mm) | Membrane area (cm²) |
|---|---|
| 2.5 | 0.85 |
| 3.75 | 0.98 |
| 7.5 | 1.35 |
| 13 | 1.9 |
What each input means
- Defect depth (mm)
- Vertical depth of the intrabony defect.
- Mesiodistal width (mm)
- Mesiodistal dimension of the defect.
- Buccolingual width (mm)
- Buccolingual dimension of the defect.
- Membrane type
- Non-resorbable ePTFE requires a second surgery for removal; both resorbable options break down in place over weeks to months.
What each result means
- Membrane area (cm²)
- Minimum membrane area required.
- Graft volume (cc)
- Bone graft material volume needed.
- Expected CAL gain (mm)
- Anticipated clinical attachment level gain.
- Removal needed (0/1)
- 1 = second surgery needed for membrane removal.
- Success probability (%)
- Estimated regeneration success rate.
- Est. material cost ($)
- Estimated cost of membrane and graft material.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersDefect depth (mm) = 6, Mesiodistal width (mm) = 5, Buccolingual width (mm) = 4, Membrane type (1-3) = 2 = 4 input(s) provided
- Calculate Membrane areaMembrane area1.1 = 1.1
- Calculate Graft volumeGraft volume0.07 = 0.07
- Calculate Expected CAL gainExpected CAL gain4.2 = 4.2
Engine last updated . Checked against 3 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Does the membrane type I choose change the membrane size or graft volume?
No. Membrane area is calculated purely from the defect's mesiodistal and buccolingual width measurements -- extending 3mm beyond each margin -- and graft volume is calculated purely from the defect's depth, mesiodistal width, and buccolingual width. Membrane type changes the healing timeline, whether a removal surgery is needed, and the material cost estimate, but not the sizing calculations.
Why does a non-resorbable membrane need a second surgery?
Non-resorbable ePTFE membranes hold their shape well during healing, which is useful for maintaining space over the defect, but the material does not break down in the body. It has to be surgically removed once the underlying tissue has regenerated, typically several weeks after the original placement, which is the tradeoff against resorbable collagen or synthetic membranes that break down in place.
How is the recommended membrane size determined from my measurements?
The calculator extends your entered mesiodistal and buccolingual defect widths by 3mm on every side so the membrane overlaps sound bone rather than stopping exactly at the defect margin, then matches that footprint to the nearest standard commercial membrane size (15x20mm up to 30x40mm) that fully covers it.
Does a deeper defect always mean a larger expected attachment gain?
Only up to a point. Expected clinical attachment gain rises with defect depth, but this calculator caps it at 5mm, reflecting that guided tissue regeneration has a practical ceiling on predictable new attachment even for very deep intrabony defects -- the deepest defects don't get proportionally larger gains once that ceiling is reached.
Related Calculators
The questions that sit next to this one — chosen by subject, including calculators filed under a different category.
Bone Graft Volume (Perio) Calculator
Graft material from defect dimensions.
ImplantologyBone Graft Volume Calculator
Graft volume from defect dimensions.
PeriodonticsSoft Tissue Graft Calculator
Graft dimensions from recession and root coverage goals.
PeriodonticsCrown Lengthening Calculator
Bone removal and tissue repositioning for clinical crown.
More in Medical & Clinical.