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Less stress in direct restorations
with
Quadrant Anterior Shine
This poster shows the stress distribution in fractured incisors restored with partial crown restorations and convential veneers. The restorations were made indirect with feldspatic ceramic or direct with Quadrant Anterior Shine. The composite resin showed reduction of stress especially at the level of the restoration/tooth interface.
These results were presented during the PEF congress (Pan European Federation) in Dublin, September 2006.
Stress Distribution Analysis of Fractured Incisor Restored with Different Solutions.
L. Pallotto, L. Scalise, E. Coccia, G. Rappelli.
University of Ancona, Italy.
Objectives:
The aim of this in vitro study was to investigate the stress distribution in a fractured incisor, comparing different tooth preparation design and different restorative materials to the healthy incisor.
Methods:
After the development of a three-dimensional finite element model (FEM) of an intact maxillary central incisor, dental fracture at the incisal third of the crown was simulated. Two different tooth preparation designs (partial coverage crown and conventional veneer) and two different restorative materials (Cavex Quadrant Anterior composite resin and feldspathic ceramic) were tested. Mechanical properties of these materials were supplied by producing companies. The stress distribution was calculated when a 50 N load was applied to the incisal edge of finite element models at an angle of 30 degrees to the long axis of the tooth. Von Mises stresses were calculated for each model as well as strain of the prosthesis.
Results:
Looking at the load's application's points (2 nodes, 0.5 mm distant), the prostheses built with compound showed a high resultant displacement (200% to 400% higher that intact tooth), but it is very localized. While all the prostheses showed similar equivalent stress (Von Mises) values (at most 10% different). In the intact natural incisor, the area of maximum stress concentration was the palatal concavity; while the marginal ridges were the zones of minimum stress concentration. Independently to preparation design, the Von Mises stress of feldspathic ceramic were similar to those of intact tooth. Under the same load conditions, the composite resin reduces stress concentration, especially at the level of the restoration/tooth interface, both in the buccal and palatal surfaces.
Conclusion:
The use of composite resin to restore a fractured incisor ensures a better stress distribution rather than ceramic material.
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