IADR Abstract Archives
Fracture Resistance of Adhesive Endocrowns with Different Designs and Materials
Objectives: The aim of this study was to evaluate the effect of three endocrown designs and two monolithic ceramic materials on the fracture resistance of endodontically treated upper first premolars, in comparison to a post-crown control group.
Methods: Sixty-five human extracted maxillary first premolars were endodontically treated and shortened to a level of 2 mm coronal to the cemento-enamel junction. The specimens were randomly divided into six endocrowns groups and one post-crown control group (n=8); ZrE1, ZrE2, ZrE3, LDE1, LDE2, LDE3, and PC. All endocrown groups had a pulpal inlay with 2 mm depth, 3 mm buccolingual length and 1.8 mm mesiodistal width. According to external preparation, three different designs were used: E1; flat occlusal table (without ferrule), E2; endocrowns with 1.5 mm ferrule, E3; endocrowns with flat occlusal table and 1.5 mm buccal preparation. Two monolithic ceramic materials were used: Zr; Zirconia and LD; Lithium disilicate. The control group (PC) was restored with zirconia posts and a composite build-up, and lithium disilicate crowns. Panavia V5 resin was used as luting agent. Specimens underwent a thermo-mechanical fatigue with a dynamic load of 10 kg for 1,200,000 cycles and thermocycling between 5 and 55 degree Celsius. Thereafter, the specimens were quasi-statically loaded to fracture. The results were analyzed using one way ANOVA with a post hoc test, and Sample T-Test.
Results: None of the specimens showed any signs of debonding caused by the fatigue test, The fracture resistance of PC control group showed no statistically significant difference in comparison to groups ZrE1, ZrE2 and LDE2 (P > 0.05). However, it was statistically significant different from groups LDE1, LDE3, and ZrE3 (P < 0.05).
Conclusions: The fracture resistance of endocrowns was affected by different designs and materials. The results showed superiority of the post-crowns, endocrowns with 1.5 mm ferrule and zirconia endocrowns with the flat occlusal table.
Methods: Sixty-five human extracted maxillary first premolars were endodontically treated and shortened to a level of 2 mm coronal to the cemento-enamel junction. The specimens were randomly divided into six endocrowns groups and one post-crown control group (n=8); ZrE1, ZrE2, ZrE3, LDE1, LDE2, LDE3, and PC. All endocrown groups had a pulpal inlay with 2 mm depth, 3 mm buccolingual length and 1.8 mm mesiodistal width. According to external preparation, three different designs were used: E1; flat occlusal table (without ferrule), E2; endocrowns with 1.5 mm ferrule, E3; endocrowns with flat occlusal table and 1.5 mm buccal preparation. Two monolithic ceramic materials were used: Zr; Zirconia and LD; Lithium disilicate. The control group (PC) was restored with zirconia posts and a composite build-up, and lithium disilicate crowns. Panavia V5 resin was used as luting agent. Specimens underwent a thermo-mechanical fatigue with a dynamic load of 10 kg for 1,200,000 cycles and thermocycling between 5 and 55 degree Celsius. Thereafter, the specimens were quasi-statically loaded to fracture. The results were analyzed using one way ANOVA with a post hoc test, and Sample T-Test.
Results: None of the specimens showed any signs of debonding caused by the fatigue test, The fracture resistance of PC control group showed no statistically significant difference in comparison to groups ZrE1, ZrE2 and LDE2 (P > 0.05). However, it was statistically significant different from groups LDE1, LDE3, and ZrE3 (P < 0.05).
Conclusions: The fracture resistance of endocrowns was affected by different designs and materials. The results showed superiority of the post-crowns, endocrowns with 1.5 mm ferrule and zirconia endocrowns with the flat occlusal table.
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