Purpose: To Measure the fracture resistance of endodontically treated maxillary premolar teeth restored with lithium disilicate crowns retained with fiber posts and cores compared to lithium disilicate and PEEK endocrowns.
Materials and Methods: Thirty-three extracted maxillary premolars were collected and root canal treated. Teeth were mounted in epoxy resin then randomly assigned to 3 groups(n=11); Group A: Premolars with 2 mm ferrule restored with glass fiber post, build up and full coverage lithium disilicate (IPS e.max CAD, Ivoclar-Vivadent) crowns. Group B: 2 mm butt margin restored with lithium disilicate endocrowns. Group C: 2 mm butt margin restored with PEEK (Bre.CAM BioHPP, Bredent Medical) endocrowns. Teeth were scanned and restorations designed using CEREC then milled using inLab MCX5. PEEK endocrowns were designed and milled with cutback then veneered with composite. Restorations were cemented. Samples were subject to fracture resistance. Data was collected and statistically analyzed. Mode of failure was examined and evaluated.
Results: Numerical data were explored for normality (Kolmogorov-Smirnov and Shapiro-Wilk tests). One-way ANOVA test was used to compare between the three groups. There was no statistically significant difference between mean fracture resistance values in the three groups (P-value = 0.845, Effect size = 0.012).
Conclusions: All fracture resistance values were higher than the maximum masticatory force recorded for the premolar region. Endocrowns had fracture resistance similar to those of traditional post, core and crown restorations. PEEK endocrowns were found to have similar fracture resistance to lithium disilicate endocrowns and so are considered a good option for endocrowns.