Lithium Disilicate Endocrowns Research Articles

Clinical performance of fiber reinforced FRC base and bonded CAD/CAM resin composite endocrowns versus conventional lithium disilicate endocrowns in posterior teeth (Randomized Clinical Trial)

Clinical performance of fiber reinforced FRC base and bonded CAD/CAM resin composite endocrowns versus conventional lithium disilicate endocrowns in posterior teeth (Randomized Clinical Trial)

The internal and marginal adaptation of lithium disilicate endocrowns fabricated using intra and extraoral scanners: An in-vitro study.

The impression technique highly influences the adaptation of ceramic restorations. Not enough information is available to compare the marginal (MF) and internal fit (IF) of endocrowns fabricated with various digitization techniques. Therefore, this in-vitro study aimed to compare the MF and IF of lithium disilicate (LDS) endocrowns fabricated through direct and indirect digital scanning methods. One extracted maxillary molar was used to fabricate endocrowns. The digitization of the model was performed with (G1) direct scanning (n = 10) utilizing an intraoral scanner (IOS), (G2) indirectly scanning the conventional impression taken from the model using the same IOS (n = 10), (G3) indirectly digitalizing the obtained impression using an extraoral scanner (EOS) (n = 10), and (G4) scanning the poured cast using the same EOS (n = 10). The MF and IF of the endocrowns were measured using the replica method and a digital stereomicroscope. The Kruskal-Wallis test was used to analyze data. The studied groups differed significantly (p<0.001). G2 (130.31±7.87 μm) and G3 (48.43±19.14 μm) showed the largest and smallest mean vertical marginal gap, respectively. G2 and G3 led to the highest and lowest internal gaps in all regions, respectively. With significant differences among the internal regions (p<0.001), the pulpal area demonstrated the most considerable misfit in all groups. Scanning the impression using an extraoral scanner showed smaller marginal and internal gaps.

Effects of Cervical Preparation Design on Fracture Strength of Lithium Disilicate Endocrowns in Endodontically Treated Molars: A Systematic Review

Introduction: We aimed to assess the effect of the type of finish line and ferrule on fracture resistance of lithium disilicate endocrowns. Methods: The literature search was done in Pubmed, Scopus, Dimensions, and Web of Science till August 2023, without language restrictions, using the following terms: ("endocrown" OR "endocrowns" OR "endo-crown" OR "endodontic crown" OR "endodontically treated crown") AND ("preparation" OR "preparation design") AND "fracture resistance" AND "lithium disilicate" AND "molars". Grey literature was similarly investigated via WorldCat, Open Grey, and Google Scholar. An artificial intelligence-powered software, SWIFT-Review, is employed for text mining at the selection stage. Risk of bias among included studies according to the QUIN was also assesed. Results: From 49 articles resulted from a systematic search of databases, four of them qualified as eligible studies to be reviewed. All included articles were reports of in vitro studies and their outcome were controversial. Koosha et al. and Naji et al. reported non-significant differences between specimens with ferrule and shoulder finish lines and butt-joint finish lines. However, Einhorn et al., indicated that restorations with ferrule exhibited significantly higher fracture resistance than butt-joints. Amin et al., concluded ferrule design would improve fracture resistance. All included studies in the review are evaluated as medium risk. Furthermore, no study had considered blinding in the methods. Conclusion: Outcomes of included studies were controversial, and concerning the methodological limitations of included studies it is not that easy to reach a clear and definitive conclusion.

Fracture Toughness of Monolithic Zirconia and Lithium Disilicate CAD/CAM Endocrown

&#x0D; Introduction: Endocrown is an indirect restoration following the endodontic treatment made of ceramic material as a substitute for post core crown. The endocrown is cemented to the inner wall of the pulp chamber and to the cavity margins to increase the macromechanical retention. Material commonly used are monolithic zirconia and lithium disilicate; both can be obtained using the CAD/CAM technique. Good endocrown restoration must be able to handle the chewing workload especially on the posterior tooth. Objective: To determine the difference in fracture toughness of monolithic zirconia and lithium disilicate CAD/CAM endocrown. Methods: This study used 6 endocrown CAD/CAM samples, attached to typodont prototype in 3D resin printing model produced by the printing machine. Samples were divided into 2 groups. Group A were monolithic zirconia endocrowns and group B were lithium disilicate endocrowns. The fracture toughness was calculated using the Universal Testing Machine (UTM). Results: Fracture toughness of the monolithic zirconia endocrown were 2.747 N and lithium disilicate were 769 N. The unpaired t test showed that there was significant difference in fracture toughness between groups (p &lt; 0,05). Conclusion: Monolithic zirconia endocrown has a higher fracture toughness compared to the lithium disilicate endocrown, but lithium disilicate is more recommended as an endocrown restoration material because its fracture toughness is closer to masticatory load of posterior teeth.

Biomechanical Behavior of Lithium-Disilicate-Modified Endocrown Restorations: A Three-Dimensional Finite Element Analysis

This study aimed to assess the biomechanical behavior of endocrown-restored mandibular molars according to “margin design” and “coverage extent” using finite element analysis (FEA). Six 3D solid models were fabricated, namely, those with complete occlusal coverage: A (butt joint), B (anatomic margin); partial coverage (two mesial cusps): C (butt joint), D (anatomic margin); and partial coverage with mesial class II cavity: E (butt joint), F (anatomic margin). All models received lithium disilicate endocrowns (2.0 mm thickness and 4.0 mm central retainer cavity depth). A 300 N vertical load was applied to the occlusal surface, while a 250 N oblique load was applied at 45° to the lingual inclined planes of the buccal cusps. The maximum von Mises stress (VMS) distribution patterns were calculated for the endocrown, tooth structure, and cement layer. The VMS on the prepared teeth and cement layer showed subtle differences between the tested models under vertical loads. The anatomic margin (partial and complete coverage) exhibited a more homogeneous stress distribution and offered a more adhesive area of the tooth structure. Under oblique loading, the anatomic margin (complete and partial), except Model D, exhibited the lowest VMS in the cement layer. An anatomically based endocrown could be a promising alternative to the butt joint design, providing better-devised endocrown restorations, which could potentially yield a more benign stress dissipation.

A comparative evaluation of fracture resistance of tooth restoration complex restored with PEEK and lithium disilicate endocrowns.

This in vitro study was conducted to compare the fracture resistance of tooth restoration complex restored with polyetheretherketone (PEEK) and lithium disilicate endocrowns. A total of 46 extracted premolars were collected and treated endodontically. The teeth were mounted in cylindrical molds using autopolymerizing resin and were prepared for endocrown restoration. Specimens were divided into two groups (n = 23) to receive endocrowns made with two different materials (polyetheretherketone and lithium disilicate). All the specimens were subjected to thermal cycling. The fracture resistance test was carried out using a Universal Testing Machine. Fractographic analysis was carried out using stereomicroscope and scanning electron microscope after load test. The values obtained were subjected to statistical analysis. Intergroup comparison (two groups) was performed using a t-test. Comparison of frequencies of categories of variables with groups was performed using chi-square test. Fracture resistance tests showed a statistically significant difference in values between the two groups (p<0.01). High fracture resistance values were seen with lithium disilicate endocrowns. Failure mode analysis showed that both groups exhibited mainly catastrophic failure. There were no significant differences in frequencies of the type of fracture between the groups. The fracture resistance of endocrowns fabricated with lithium disilicate material was found to be significantly higher than polyetheretherketone (PEEK) material. Hence, lithium disilicate material is superior for endocrowns.

In-Vitro Comparison of Fracture Strength of Endocrowns and Overlays in Endodontically Treated Teeth Manufactured with Monolithic Lithium Disilicate and Zirconia.

To evaluate the fracture strength and the failure mode of endodontically treated molars restored with monolithic lithium disilicate and zirconia endocrowns and overlays. A total of 48 extracted mandibular molars were endodontically treated, decoronated 2 mm above the cementoenamel junction and divided into four 12-specimen groups. Group ELD: lithium disilicate endocrowns. Group EZ: monolithic zirconia endocrowns. Group OLD: lithium disilicate overlays. Group OZ: monolithic zirconia overlays. Overlays did not extend in the pulp chamber and endocrowns extended in the pulp chamber 2 mm. After adhesive bonding of the restorations, the specimens were subjected to thermocycling (×5000 cycles) and then to fracture resistance testing at lateral static loading (1 mm/min) at a universal testing machine. The failure mode of the specimens was qualitatively evaluated. Differences in means were compared using with t-tests for independent samples or Mann-Whitney test (p < 0.05). Weibull distribution analysis was also performed. Group ELD showed significantly higher fracture strength than all other groups (p = 0.001), and the highest Weibull modulus. Conclusions: Lithium disilicate endocrowns exhibit higher fracture strength and are more reliable compared to the other types of restorations examined. Endocrowns had more catastrophic failures compared to overlays.

In Vitro Evaluation of Lithium Disilicate Endocrowns and Post and Core Crowns-A Systematic Review.

The aim of this systematic review was to summarize the results of the studies that have compared the physical and mechanical properties of lithium disilicate (LDS) endocrowns constructed for posterior teeth to those retained by post-and-core retention systems. The review was conducted following the PRISMA guidelines. The electronic search process was conducted on PubMed-Medline, Scopus, Embase and ISI Web of Knowledge (WoS) from the earliest available date till 31 January 2023. Additionally, the studies were assessed for their overall quality and risk of bias using the Quality Assessment Tool For In Vitro Studies (the QUIN). The initial search resulted in 291 articles, out of which, only 10 studies met the eligibility criteria. In all studies LDS endocrowns were compared with various kinds of endodontic posts and crowns made from other materials. There were no definite pattern or trends observed in the fracture strengths of tested specimens. There was no predilection observed in failure patters among the experimental specimens. No predilection was observed in the fracture strengths of LDS endocrowns when compared to post-and-core crowns. Furthermore, no differences in failure patterns could be observed when both types of restorations were compared. The authors propose standardized testing of endocrowns against post-and-core crowns in future studies. In conclusion, long-term clinical trials are advocated to compare the survival, failure and complication rates of LDS endocrowns and post-and-core restorations.

Evaluating The Effect of Varying Occlusal Thicknesses On The Fracture Resistance Of The Lithium Disilicate Endocrowns: An In-Vitro Study

Purpose: To evaluate the effect of varying occlusal thickness on the fracture resistance of lithium disilicate endocrowns Material and Methods: Endocrown preparation was done on the mandibular first molar typodont tooth and a metal die was obtained. A total of 30 specimens, were divided into three groups with varying occlusal thickness of endocrowns; Group 1 (G1) = 2mm occlusal thickness, Group 2 (G2) = 4mm occlusal thickness, and Group 3 (G3) = 5.5mm occlusal thickness were fabricated. Specimens were placed on the Universal Testing Machine (UTM) and subjected to axial load. The maximum force which led to the fracture of endocrowns was recorded. One-way analysis of variance (ANOVA) was used for intergroup comparisons and turkey’s pot hoc test for pairwise comparison was used. Results: Maximum fracture resistance was seen in group 3 (G3) with an occlusal thickness of 5.5mm (4253.5 N), followed by group 2 (G2) with an occlusal thickness of 4mm (2876.2 N) and least in group 1 (G1) with an occlusal thickness of 2mm (836.2 N). ANOVA for the intergroup comparison showed a high statistically significant difference in fracture resistance of lithium disilicate endocrowns between all the 3 groups (p&lt;0.001). A statistically high significant difference was found in the fracture resistance of lithium disilicate endocrowns via post hoc Tukey’s test among all three groups. Conclusion: The fracture resistance of endocrowns fabricated from lithium disilicate increases with the increasing occlusal thickness of the endocrowns upon the axial loading.

The Effect of Cement Space Parameters on the Marginal Adaptation of Milled Endocrowns: An In Vitro Study.

Background Cement film space plays a significant role in achieving good adaptation of indirect restorations. The objective of this study is to investigate the effect of cement space parameters on the marginal adaptation of computer-aided design (CAD)/computer-assisted manufacturing (CAM) endocrowns. Methodology The coronal part of 10 freshly extracted human mandibular molars was reduced to a level of 1.5 mm above the cementoenamel junction (CEJ); then, root canal treatment was performed. On each tooth, four lithium disilicate endocrowns with different cement space parameters (40, 80, 120, and 160 µm) were designed and fabricated using CAD/CAM. Endocrowns were seated to their prepared teeth, and the vertical marginal gap was measured in 20 equidistant points for each endocrown using a stereomicroscope on 90×magnification.The mean marginal gaps of the four groups were compared using a one-way analysis of variance (ANOVA) and the Tukey honestly significant difference (HSD) test considering p<0.05 as the cutoff for statistical significance. Results The mean marginal gap of the 40 µm, 80 µm, 120 µm, and 160 µm groups were 46.25±21.20 µm, 21.75±11.10 µm, 15.94±06.62 µm, and 13.10±07.08 µm, respectively. One-way ANOVA showed a significant difference in the marginal gaps between groups (p<0.001). The Tukey post hoc test showed a statistically significant mean difference between 40 µm and each of the other three groups (p<0.001). Conclusion The cement space parameter variation affects the marginal adaptation of endocrowns. The cement space of 40 µm resulted in a higher marginal gap than cement spaces of 80, 120, and 160 µm.

Endocrown restorations in premolars: influence of remaining axial walls of tooth structure and restorative materials on fatigue resistance.

To evaluate the effect of the remaining tooth structure and different CAD/CAM materials on the fatigue performance and failure mode of endodontically treated premolars restored with endocrowns. Ninety maxillary premolars were endodontically treated and assignedinto 6 groups (n = 15) according to the number of remaining axial walls (four, three, and two) and restorative materials (ultra-translucent zirconia 5Y-PSZ [KATANA UTML] and lithium disilicate [IPS e.max-CAD]). The specimens were subjected tocyclic fatigue loading test(initial load 200 N; 20Hz). An incremental step load of 100N per 10,000 cycles was applied until failure. The fatigue failure load (FFL) and number of failure cycles (CFFs) datawere statistically analyzed with two-way ANOVA and Kaplan-Meier test (α = 0.05). Failedspecimens were examined under a stereomicroscope 25 × and failure modes were determined. FFL and CFF were significantly influenced by restorative material (p < 0.05). 5Y-PSZ endocrowns showed significantly higher FFL when compared with lithium disilicate. The number of remaining walls did not affect the fatigue behavior or failure mode of the specimens. Of the lithium disilicate restorations, 51% had repairable failures, while 95% 5Y-PSZ restorations had non-repairable failures. Zirconia endocrowns showed better FFL than lithium disilicate endocrowns, regardless of the number of remaining axis walls. Lithium disilicate and 5Y-PSZ endocrowns showed FFL higher than the normal masticatory loads. Restoring endodontically treated premolars with endocrown could be a promising treatment, regardless of the remaining axial walls. However, precaution should be taken in material selection since it affects the fatigue resistance and failure mode.

Effect of various preparation designs on pull-out bond strength of endocrown.

The endocrown is described as monobloc ceramic component. The pull-out bond strength acts as a real-life scenario of failure that occurs in endocrown. The different preparation designs have been included to assess the type of preparation that resists the least failure. To evaluate the effect of three different types of preparation designs on the pull-out bond strength (PBS) of computer-aided design/computer-aided manufacturing (CAD/CAM) monolithic endocrowns. Thirty extracted mandibular first molars were used for this study. Root canal treatment was done. Samples were divided into three groups of 10 samples each. Group A consists of traditional endocrown preparation with a butt joint preparation. The group B consists of a modified preparation with 50-60 degree inward slope. The group C consists of preparation with a 50-60 degree outward slope. Endocrowns were fabricated using CAD/CAM lithium disilicate glass-ceramics. The endocrowns were adhesively bonded to the respective preparations. Pull-out bond strength was calculated using the universal testing machine at a crosshead speed of 1 mm/min. The results were statistically evaluated by one-way ANOVA and Tukey's post hoc analysis. Group B had higher pull-out bond strength compared to the other two types of preparation designs and showed a statistically significant value with a mean significant difference at 0.05 level (P < 0.05). The 50-60 degree inward bevel in endocrown preparation increased the pull-out bond strength in lithium disilicate endocrowns.

Failure loads of heat-pressed versus milled lithium disilicate endocrowns.

This study aimed to compare the failure load of heat-pressed versus milled lithium disilicate endocrowns. Twenty extracted mandibular molars were sectioned 1.5mm above the CEJ. Root canal treatment and endocrown preparation were done for all teeth. Samples were then divided into two groups: heat-pressed glass ceramic endocrowns (HP group) (n = 10) and milled endocrowns (CAD group) (n = 10). Cementation was done using self-adhesive resin cement, and a compressive load was applied on the occlusal surface of the specimens until failure occurred. The mean failure loads were significantly higher in the HP group (2546.5 ± 339N) compared to the CAD group (1759.9 ± 114.2) (p < 0.05), and majority of failures were due to fracture of the restoration. Failure loads of heat-pressed lithium disilicate endocrown are superior to milled endocrown. Molars restored with lithium disilicate endocrowns have higher failure loads than the maximum human bite force regardless of the fabrication method. Although heat-pressed endocrowns have superior failure loads to milled ones, both are indicated for restoring endodontically treated molar teeth.

Internal fit and marginal adaptation of CAD/CAM lithium disilicate endocrowns fabricated with conventional impression and digital scanning protocols. An in-vitro study

Internal fit and marginal adaptation of CAD/CAM lithium disilicate endocrowns fabricated with conventional impression and digital scanning protocols. An in-vitro study

Effect of intra-chamber extension of lithium disilicate endocrowns on the fracture resistance and failure modes in endodontically treated molars (In-Vitro study)

Effect of intra-chamber extension of lithium disilicate endocrowns on the fracture resistance and failure modes in endodontically treated molars (In-Vitro study)

Marginal and internal fit of lithium disilicate endocrowns fabricated using conventional, digital, and combination techniques.

To compare the marginal and internal adaptation of endocrowns produced using conventional technique, digital technique, and combination (cast digitization) techniques using microcomputed tomography (micro-CT). Ten freshly extracted human mandibular molar teeth were prepared for all-ceramic endocrowns. A total of 40 Lithium Disilicate (IPS e.max) endocrowns were fabricated and grouped according to the impression and production technique to four groups: Group (CO): Conventional impression/heat pressed endocrowns (n =10), Group (CAD): Direct scanning of teeth/CAD-CAM endocrowns (n =10), Group (COMIO): Combination; Cast digitization using Intraoral scanner/CAD-CAM endocrowns (n =10), Group (COML): Combination; Cast digitization using laboratory scanner/CAD-CAM endocrowns (n =10). Micro-computed tomography was used to measure the marginal and internal gaps in 11 predetermined sites. Mean marginal and internal gaps were compared using analysis of variance and Scheffe's post hoc test. CO, CAD, COMIO, and COML groups showed significant differences in the mean marginal gap (150 ± 35 μm, 120 ± 27 μm, 110 ± 24 μm, 120 ± 29 μm, respectively p =0.013), gap at line angle (280 ± 70 μm, 130 ± 37 μm, 140 ± 54 μm, 130 ± 33 μm, respectively, p < 0.001), gap at cavity wall (210 ± 76 μm, 140 ± 43 μm, 140 ± 52 μm, 150 ± 44 μm, respectively, p =0.010) and gap at pulpal floor (500 ± 150 μm, 240 ± 58 μm, 260 ± 59 μm, 240 ± 64 μm, respectively, p <0.001). Digitally fabricated endocrowns showed superior marginal and internal fit compared to the conventionally fabricated endocrowns. Marginal and internal adaptation are detrimental factors for the success and survival of dental restorations including endocrowns. When compared with the conventional impressions and conventional production techniques, Digital workflow is more predictable and reliable as it reduces errors and improves the accuracy of fit.

Endocrowns Clinical Performance and Patient Satisfaction: A Randomized Clinical Trial of Three Monolithic Ceramic Restorations.

The purpose of this randomized, double-blind, clinical trial was to assess the survival of endocrowns made from three different monolithic ceramic materials, and to evaluate patient satisfaction. Fifty-three patients (sixty root canal treated molar teeth) were enrolled. Teeth were prepared to a flat butt-joint margin and randomly divided between three material groups: lithium disilicate-reinforced glass-ceramic, monolithic zirconia and polymer infiltrated hybrid ceramic. Predefined cementation protocols were used. Clinical assessment using modified United States Public Health Service (USPHS) criteria was carried out after two years by two independent clinicians blinded to the material used. Radiographic examination was conducted to check for the presence of caries, excess cement, and periapical infection. Statistical analysis was performed using the Kruskal Wallis and Wilcoxon signed-rank tests as well as the Kaplan-Meier survival estimate. Forty-eight patients were available for assessment after 2 years (recall rate 90.6%). The overall Kaplan-Meier survival estimate among all groups was 90.9% with no statistically significant difference between the groups (p = 0.17). Three zirconia endocrowns debonded after 9, 10 and 13 months (82.4% survival rate), while 2 hybrid ceramic endocrowns chipped/fractured (89.5% survival rate). Lithium disilicate endocrowns had a 100% survival rate. The Kruskal Wallis test revealed no statistically significant difference between the groups in the USPHS criteria ratings and the radiographic assessment (P>0.05). Patient satisfaction ranged from 82.3% in the zirconia group to 100% in both the lithium disilicate and hybrid ceramic groups. Endocrowns provide a predictable option for the restoration of endodontically treated molar teeth in the short term. Lithium disilicate-reinforced ceramic had fewer complications and required less intervention compared with zirconia and hybrid ceramics. Long-term follow-up is required to substantiate these study results.

Marginal and Internal Adaptation of Lithium Disilicate Endocrowns Fabricated By Heat-Pressable and Subtractive Techniques.

To evaluate and to compare the marginal and the internal fit of milled (MLE) and heat-pressed lithium disilicate endocrowns (PLE). Thirty mandibular molars were prepared following the circumferential butt margin endocrown preparations; the cervical margin is parallel to the occlusal surface without ferrule design. A digital scan of molars was made using an intraoral digital scanner. The samples were separated into two groups (n = 15 per group); MLE: endocrowns were milled using LDS blocks and a 5-axis milling machine, PLE: endocrowns were heat-pressed using lost wax technique and LDS ingots. Marginal and internal adaptation were assessed using a replica technique and a stereomicroscope, selecting 32 measurements on each endocrown. Data were analyzed with one-way repeated measures ANOVA, two-way repeated measures ANOVA, student's t-test and paired student t-test (α = 0.05). Statistically significant interactions were recorded between fabrication technique and region (p < 0.05), F (1.97, 27.69) = 5.462. Group MLE displayed significantly smaller gaps than PLE in all regions (p < 0.001). The largest gap was observed at the pulpal floor in both groups. The internal gap was significantly larger than the marginal gap in MLE group (p < 0.001), while no statistically significant difference was observed in PLE group (p = 0.082). Heat-pressed and milled lithium disilicate endocrowns are clinically suitable, but the milled technique displayed a better fit than heat-pressed technique when marginal and internal adaptation were examined.

Comparative evaluation of marginal and internal fit of endocrowns using lithium disilicate and polyetheretherketone computer-aided design - computer-aided manufacturing (CAD-CAM) materials: An in vitro study.

Purpose:To evaluate the marginal and internal fit of endocrowns with different computer-aided design/computer-aided manufacturing (CAD-CAM) materials by measuring them with a stereomicroscope (μm).Materials and Methods:A mandibular first molar typodont tooth was prepared to receive an endocrown. The preparation was scanned using an extra-oral scanner. Endocrowns (n = 20) were fabricated using lithium disilicate (IPS e. max CAD LT block; CEREC Ivoclar Vivadent, Liechtenstein) and polyetheretherketone (PEEK) (breCAM. BioHPP®; Bredent, UK) using CAD-CAM technique. Marginal gap was evaluated using a stereomicroscope at the midpoint of all four surfaces (mid buccal, mid lingual, mid mesial, mid distal). This was followed by sectioning of the endocrowns in a sagittal plane along with the prepared tooth to evaluate the internal fit at four different points (A, B, C, D) using a stereomicroscope. Statistical analysis was performed using one-way analysis of variance test.Results:Mean values of marginal gap of lithium disilicate and PEEK endocrowns are 56.6 ± 6.1 μm and 81.3 ± 10.1 μm, respectively. Mean value internal gaps of lithium disilicate and PEEK endocrowns are 158.2 ± 11.1 μm and 199.1 ± 13 μm, respectively. Results in the present study have shown that the marginal and internal fits of lithium disilicate endocrowns are superior to that of PEEK endocrowns.Conclusions:Based on the outcomes of this in vitro study, the marginal and internal fit of lithium disilicate endocrowns is better than PEEK endocrowns. The marginal gap clinically acceptable is <120 μm. The marginal gap values recorded in this study are within the acceptable range for both materials.

Cyclic loading and load to failure of lithium disilicate endocrowns: Influence of the restoration extension in the pulp chamber and the enamel outline

• Restoration extension did not significantly influence the failure load of glass-ceramic endocrowns after cyclic loading. • The type of outline did not significantly influence the failure load of glass-ceramic endocrowns after cyclic loading. • There was no significant difference between the control and treatment groups concerning mode of failure.