# Fracture Resistance of Provisional Crowns: A Finite Element Analysis of a Semi-Permanent Resin—A Pilot Study

## TL;DR

This study uses computer modeling to compare how well different materials for temporary dental crowns resist breaking under various stress conditions.

## Contribution

The study introduces a finite element analysis approach to evaluate fracture resistance of semi-permanent provisional crown materials under extreme occlusal forces.

## Key findings

- Telio CAD showed the highest fracture resistance across all tested stress scenarios.
- Luxacrown and Protemp 4 performed well under moderate loads but failed under bruxism-level forces.
- Unifast Trad had the lowest resistance and is recommended only for short-term use.

## Abstract

Background/Objectives: Fracture resistance is crucial for provisional crowns, especially under high-stress conditions like bruxism. While semi-permanent materials such as Luxacrown are designed for durability, their performance under extreme occlusal forces remains uncertain. This study uses finite element analysis (FEA) to evaluate the fracture resistance of five common provisional crown materials. Methods: A standardized digital model of a maxillary first molar was developed with uniform crown thickness. Twenty models were created to assess Unifast Trad (self-curing PMMA), Luxatemp Star (bis-acryl composite), Luxacrown (semi-permanent bis-acryl), Protemp 4 (nanofilled bis-acryl), and Telio CAD (CAD/CAM PMMA). FEA simulations evaluated vertical (250 N), lateral (225 N), diagonal (400 N), and bruxism-level (800 N) forces. Stress-to-strength ratios (SSR) and Von Mises stress distributions were analyzed to evaluate material performance and failure risk. Results: Telio CAD exhibited the highest fracture resistance, maintaining SSR values below 100% across scenarios. Luxacrown and Protemp 4 performed adequately under moderate loads but showed increased stress concentrations under bruxism-level forces. Luxatemp Star followed a similar trend, whereas Unifast Trad demonstrated the lowest resistance, accumulating significant stress in all conditions. Conclusions: Material selection is key to provisional crown fracture resistance. Telio CAD showed the highest durability, while Luxacrown and Protemp 4 performed well under moderate loads but struggled under extreme forces, raising concerns about semi-permanent materials. Luxatemp Star showed similar trends, and Unifast Trad, the weakest, is best for short-term use.