A STUDY OF CRACKS OCCURRING IN DENTAL MATERIALS

摘要

EVALUATION OF THE MODE OF FAILURE AND CRACK PROPAGATION IN METAL, CERAMIC AND RESIN COMPOSITE DENTAL MATERIALS EXPOSED TO CYCLIC OCCLUSAL LOADING SIMILAR TO MASTICATORY LOADS SHOW THAT IN ORDER TO INCREASE THE SUSTAINABILITY AND LONGEVITY OF DENTAL MATERIALS MUST DEMONSTRATESUFFICIENT STRENGTH TO DYNAMIC STRESSES. IN THE CASE OF MASTICATORY FORCES WITH HIGH CONTACT TENSIONS, THE CONTACT AREA OF THE SUPERFICIAL LAYERS IS UNDER A STATE OF SPECIAL-COMPLEX VOLTAGE. STRUCTURAL OR MATERIAL VARIATIONS, IMPURITIES,SCRATCHES AND VOIDS CAN DIRECTLY INFLUENCE THE STRUCTURAL INTEGRITY OF THE MATERIAL AND RESULT IN MICRO-CRACKS WHICH PROPAGATE UNDER REPEATED CYCLIC LOADING LEADING TO CATASTROPHIC FAILURE OF THE DENTAL RESTORATION.