Influence of CAD/CAM Material and Preparation Design on the Long-term Fracture Resistance of Endocrowns Restoring Maxillary Premolars

Abstract

Objective: To evaluate the effect of different occlusal preparation designs and CAD/CAM materials on the fracture resistance of maxillary premolars endcrowns. Materials and Methods: sixty-four endodontically treated upper first premolars were randomly divided into four groups according to ceramic materials (Vita Enamic and IPS emax CAD) and occlusal preparation designs (Anatomical and horizontal butt joint). After teeth preparation, the restorations were all made by CAD/CAM system (Cerec MCXL). Half of each group had undergone cyclic fatigue testing of 105 cycles with 50N loading force at a frequency of 0.5Hz in a mechatronic chewing simulator machine, and then all samples were loaded to fracture using a universal testing machine with a cross head speed of 0.5mm/min recording the fracture resistance values in N . The specimens were measured and statistically analyzed using using three-way analyses of variance (ANOVA), followed by serial two-way and one-way ANOVAs at each level of the study. P-values were adjusted for multiple comparisons using BENFORRONI correction and the significance level was set at P ? 0.05 for all tests. Results: Vita Enamic endocrowns showed higher fracture resistance values than IPS e max specimens. Conclusions: Vita Enamic endocrowns with anatomical preparations were found to be more favourable restoring endodontically treated maxillary premolars. KEYWORDSEndocrowns; All-Ceramic; Fracture; Cyclic loading; CAD/CAM

Endocrown as a restorative strategy in endodontically treated teeth: an integrative literature review

“…Central incisors restored with conventional crowns and endocrowns survived thermomechanical loading without loss of retention or fracture [17]. The same dental element in the study by Alghalayini et al [18] demonstrated cracks in both restorations with the number of these failures being high throughout loading.…”

“…The findings of Biacchi and Basting [10] from mechanical strength data, consider Endocrown as a restorative strategy for endodontically treated molars with extensive coronal destruction capable of replacing conventional pin-supported crown. Finally, marginal adaptation research shows similarities between the performance of conventional crowns with long and short pins and Endocrowns for maxillary central incisors [17].…”

“…After loading, statistically significant differences were observed between restorations with the resin material (LPCpr, SPCpr, and EndoCpr) and the ceramic material (LPCer, SpCer, and EndoCer) (p = 0.0001). The performance of ceramic restorations at the marginal adaptation level was significantly lower, regardless of the type of retention that was used (pin or endocrown) [17].…”

“…Prior to aging, the continuity at the tooth-cement interface was greater than 90%, no significant differences between the different groups (p = 0.062). A trend of better behavior of the restorations with the resin material compared than ceramic material [17]. The Weibull analysis indicated that the failure probability was 95%, 2% and 2% for the inlay, endocrown and conventional crown respectively, under normal masticatory load;…”

“…Ramírez-Sebastià et al ( 2013) [17] None of the samples suffered from loss of retention or fracture; Dentin cracks could be observed in samples restored with ceramics, while no cracks were evident in the dentin when resin material was adopted;…”