Obturation Calculator
Gutta percha and sealer for canal filling.
About this calculator
Obturation fills the cleaned and shaped canal system to seal it against reinfection, and the master gutta percha cone is the central piece of that fill -- it needs to reach all the way to working length, which is why this calculator sets the recommended master cone length directly equal to working length rather than deriving it from any other input. Accessory cone count and spreader size scale with the master cone's ISO size and taper: a larger master cone or a higher taper leaves less residual space for accessory cones to fill during lateral condensation, so fewer accessories are needed, while a smaller, lower-taper master cone leaves more space that accessory cones and sealer need to fill. Technique recommendation follows a similar logic -- larger, higher-taper preparations are well suited to warm vertical condensation (which flows softened gutta percha into irregularities more thoroughly), while smaller preparations are steered toward cold lateral condensation, a technique that works well with narrower canals.
Sealer volume is modeled as a thin film coating the canal walls rather than bulk filling, consistent with the small per-canal quantities used clinically. These are general planning estimates for chairside tray setup, not a substitute for verifying the master cone's actual fit and length radiographically before obturation.
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
Master cone length (mm)
21
How to Use This Calculator
- Enter Master Cone Size (ISO) matching the final apical file size.
- Set Working Length (mm) and Number of Canals to be obturated.
- Enter Canal Taper to verify master cone taper matches.
- Review Master Cone Length (mm), Total Accessory Cones, and Sealer Volume (mL).
- Use these quantities to prepare the tray before obturation, minimizing chairside delays.
How the result changes with Working length (mm)
| Working length (mm) | Master cone length (mm) |
|---|---|
| 11 | 11 |
| 16 | 16 |
| 32 | 32 |
| 35 | 35 |
What each input means
- Master cone size (ISO)
- ISO size of the master gutta percha cone.
- Working length (mm)
- Established working length.
- Number of canals
- Total canals to obturate.
- Canal taper
- Preparation taper (e.g. 0.04, 0.06, 0.08).
What each result means
- Master cone length (mm)
- Required master cone length to reach working length.
- Total accessory cones
- Total accessory gutta percha cones needed for all canals.
- Sealer volume (mL)
- Estimated total sealer volume for all canals.
- Technique (1-3)
- 1 = cold lateral, 2 = warm vertical, 3 = carrier-based.
- Spreader size (ISO)
- Recommended finger spreader ISO size.
- Est. obturation time (min)
- Estimated total obturation time.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersMaster cone size (ISO) = 30, Working length (mm) = 21, Number of canals = 3, Canal taper = 0.06 = 4 input(s) provided
- Calculate Master cone lengthMaster cone length21 = 21
- Calculate Total accessory conesTotal accessory cones12 = 12
- Calculate Sealer volumeSealer volume0.06 = 0.06
Engine last updated . Checked against 2 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
Why is the recommended master cone length always equal to working length?
The master cone has to reach all the way to the established working length to properly seal the apical portion of the canal, so this calculator sets master cone length directly from working length rather than deriving it from canal size, taper, or any other input. A cone that falls short of working length would leave the apical canal unfilled.
Does a larger master cone size mean more or fewer accessory cones are needed?
Fewer -- in this calculator, a larger master cone (or a higher taper) fills more of the canal's cross-section on its own, leaving less residual space during lateral condensation for accessory cones to occupy. A smaller, lower-taper master cone leaves more space that needs to be filled with additional accessory cones and sealer.
Why does taper affect the recommended obturation technique?
Warm vertical condensation works well with larger, higher-taper preparations because softened gutta percha can flow more thoroughly into a wider, more tapered canal's irregularities, while cold lateral condensation is generally better suited to narrower canal preparations where a compacted cold cone and accessories fill the space adequately without needing heat-softened flow.
Does the number of canals change the recommended master cone size?
No -- in this calculator, master cone size and technique recommendations are based on the individual canal's preparation (working length and taper), not on how many canals are being obturated in the same visit. The number of canals instead scales the total accessory cone count, sealer volume, and estimated obturation time across the whole case.
Related Calculators
The questions that sit next to this one — chosen by subject, including calculators filed under a different category.
Irrigation Protocol Calculator
NaOCl concentration and volume from canal anatomy.
EndodonticsFile Sequence Planner Calculator
Rotary file sequence from canal anatomy.
EndodonticsPost Space Calculator
Post length and diameter from root anatomy.
DentalRoot Canal vs Extraction Calculator
Compare the long-term cost of root canal therapy vs tooth extraction with implant or bridge replacement options.
More in Medical & Clinical.