Root Fracture Risk Calculator

Fracture risk from remaining dentin thickness and loading.

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

Remaining dentin thickness (mm)

Final canal size (ISO)

Post present (0/1)

Occlusion type (1-3)

Tooth type (1-3)

Tab to move between fields

Results

Fracture risk score (0-100)

Risk category (1-3)2

Dentin deficit (mm)0

Cuspal coverage needed (0/1)1

Est. 5-year survival (%)72%

How to Use This Calculator

Enter Remaining Dentin Thickness (mm) at the thinnest point.
Input Final Canal Size (ISO) used for the apical preparation.
Toggle Post Present if a post will be or is cemented.
Select Occlusion Type (normal, bruxism, or parafunctional) and Tooth Type (anterior, premolar, molar).
Review Fracture Risk Score (0-100) and Risk Category — high-risk cases warrant crown coverage and occlusal adjustment.

How the result changes with Final canal size (ISO)

Final canal size (ISO)	Fracture risk score (0-100)
26	42
41	45
59	50
74	54

What each input means

Remaining dentin thickness (mm): Thinnest remaining dentin wall at the cervical third.
Final canal size (ISO): Final apical preparation size.
Post present (0/1): 0 = no post, 1 = post placed or planned.
Occlusion type (1-3): 1 = light, 2 = normal, 3 = heavy/bruxism.
Tooth type (1-3): 1 = anterior, 2 = premolar, 3 = molar.

What each result means

Fracture risk score (0-100): Combined vertical root fracture risk score.
Risk category (1-3): 1 = low, 2 = moderate, 3 = high risk.
Dentin deficit (mm): Shortfall below minimum recommended thickness (1mm).
Cuspal coverage needed (0/1): 1 = full cuspal coverage restoration recommended.
Est. 5-year survival (%): Estimated 5-year survival probability.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Remaining dentin thickness (mm) = 1.5, Final canal size (ISO) = 35, Post present (0/1) = 0, Occlusion type (1-3) = 2 = 5 input(s) provided
Calculate Fracture risk score
Fracture risk score
44 = 44
Calculate Risk category
Risk category
2 = 2
Calculate Dentin deficit
Dentin deficit
0 = 0