Purpose:
To use finite elements analysis to examine stress distribution patterns in simulated root sections
Materials/Methods:
N=6 tooth root models and 2 vertical root fractured tooth roots
simulated root sections were varied systematically with respect to canal shape and size, external root morphology, and dentin thickness to determine relative contributions to vertical root fracture
6 models:
–I: round root and canal
–II: oval root, round canal
–III: round root, oval canal
–IV, V, VI: oval root and canal with varying degrees of dentin thickness
similar models were constructed based on cross sections of human roots that had been fractured clinically or experimentally
applied various face loads to models in the finite elements program and observed stress patterns
Results:
- models showed that canal curvature seems more important than external root morphology (in terms of stress concentration)
- also, decreased dentin thickness increases the magnitude but not direction of maximum tensile stress
- models based on actual root fracture showed strong similarity between tensile-stress distribution and fracture patterns
Clinical Significance:
Vertical root fracture generally follow a B-L fracture pattern.