Biomechanical behavior of endodontically treated premolars using different preparation designs and CAD/CAM materials
Objectives To evaluate the effect of restoration design (‘2.5-mm deep endocrown’, ‘5-mm deep endocrown’ or ‘5-mm deep post&crown’) and CAD/CAM material type (composite or lithium disilicate glass-ceramic) on the load-to-failure of endodontically treated premolars in absence of any ferrule. Metho...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2017 |
| País: | Brasil |
| Institución: | Universidade Estadual Paulista (UNESP) |
| Repositorio: | Repositório Institucional da UNESP |
| Idioma: | inglés |
| OAI Identifier: | oai:repositorio.unesp.br:11449/169496 |
| Acceso en línea: | http://dx.doi.org/10.1016/j.jdent.2017.02.007 http://hdl.handle.net/11449/169496 |
| Access Level: | acceso abierto |
| Palabra clave: | CAD/CAM Composite Compressive load Cyclic aging Endocrown Lithium disilicate |
| Sumario: | Objectives To evaluate the effect of restoration design (‘2.5-mm deep endocrown’, ‘5-mm deep endocrown’ or ‘5-mm deep post&crown’) and CAD/CAM material type (composite or lithium disilicate glass-ceramic) on the load-to-failure of endodontically treated premolars in absence of any ferrule. Methods The crowns of 48 single-rooted premolars were cut and the roots were endodontically treated. Teeth were randomly divided into six groups (n = 8); teeth in each group were restored using one of the two tested materials with standardized CAD/CAM fabricated endocrowns (with either 2.5-mm or 5-mm deep intra-radicular extension) or conventional crowns (5-mm deep post&crown). After cementation using luting composite, the specimens were immersed in distilled water and subjected to 1,200,000 chewing cycles with a load of 50 N applied parallel to the long axis of the tooth (0°). After cyclic loading, a compressive load was applied at 45° to the tooth's long axis using a universal testing machine until failure. Load-to-failure was recorded (N) and the specimens were examined under a stereomicroscope with 3.5x magnification to determine the mode of failure. Results All specimens survived the 1,200,000 chewing cycles. A significant interaction between restoration design and CAD/CAM material was found using two-way ANOVA. In the ‘2.5-mm deep endocrown’ groups, the composite achieved a significantly higher load-to-failure than the lithium disilicate glass-ceramic, while no differences between materials were found in the ‘5-mm deep endocrown’ and ‘5-mm deep post&crown’ groups. More unfavorable failures (root fractures) were observed for higher load-to-failure values. Conclusions Only following a ‘2.5-mm deep endocrown’ design, composite appeared more favorable than lithium disilicate glass-ceramic as crown material; this may be explained by their difference in elastic modulus. Clinical significance Shallow endocrown preparations on premolars present less surface for adhesive luting and a difference in crown material becomes apparent in terms of load-to-failure. The use of a more flexible composite crown material appeared then a better option. |
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