IMPACT RESISTANCE OF CROWNED ENDODONTICALLY TREATED CENTRAL INCISORS WITH INTERNAL COMPOSITE CORES

The impact fracture resistance of crowned endodontically treated teeth with composite cores but without posts, that had either no coronal de ntin remaining or a 1mm dentin collar was compared to that of unrestor ed, caries free teeth. The teeth were struck mid-labially to simulate a common trauma situation using a pendulum device and fracture resista nce determined by calculation of absorbed energies. No significant dif ference was found between the intact teeth and the crowned root treate d teeth with composite core and a 1mm dentin collar. Crowned root trea ted teeth with a composite core but no coronal dentin had significantl y reduced fracture resistance (p < 0.05). Teeth with the dentin collar mainly fractured obliquely from the buccal crown margin to a point co incident with the simulated alveolus, representing a clinical situatio n which would allow retention rather than extraction of the tooth.