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Purpose To evaluate the fracture resistance and fracture patterns of single implant‐supported crowns with different prosthetic designs and materials. Materials and Methods One hundred and forty‐four identical crowns were fabricated from zirconia‐reinforced lithium silicate (ZLS), leucite‐based (LGC), and lithium disilicate (LDS) glass‐ceramics, reinforced composite (RC), translucent zirconia (ZR), and ceramic‐reinforced polyetheretherketone (P). These crowns were divided into 3 subgroups according to restoration design: cementable crowns on a prefabricated titanium abutment, cement‐retained crown on a zirconia‐titanium base abutment, and screw‐cement crown (n = 8). After adhesive cementation, restorations were subjected to thermal‐cycling and loaded until fracture. The fracture patterns were evaluated under a stereomicroscope. Statistical analysis was performed by using 2‐way ANOVA/Bonferroni multiple comparison post hoc test (α = 0.05). Results For each prosthetic design, ZR presented the highest fracture resistance (p ≤ 0.005). Other than the differences with ZLS and RC for screw‐cement crowns (p > 0.05) and RC for crowns on zirconia‐titanium base abutments (p > 0.05), LGC showed the lowest fracture resistance. P endured higher loads than LDS (p < 0.001), except for the crowns on zirconia‐titanium base abutments (p > 0.05). Cementable crowns presented the highest fracture resistance (p < 0.001), other than LGC and LDS. The differences between LGC crowns (p > 0.05) or LDS crowns on prefabricated titanium and zirconia‐titanium abutments were nonsignificant (p = 0.133). Fragmented crown fracture was predominant in most of the restorations. Screw and abutment fractures were observed in ZR screw‐cement crowns, and all P crowns were separated from the abutments. Conclusions Restorative material and restoration design affect the fracture resistance and fracture pattern of implant‐supported single‐unit restorations. Clinicians may restore single‐unit implants in premolar sites with the materials and prosthetic designs tested in the present study.

Objective: To compare the color stability, translucency, and biaxial flexural strength (BFS) of differently glazed advanced lithium disilicate (ALDS) with those of lithium disilicate (LDS) and zirconia-reinforced lithium silicate (ZLS) after coffee thermocycling.Materials and methods: Forty disk-shaped specimens were prepared from three lithium silicate based materials (CEREC Tessera, ALDS; IPS e.max CAD, LDS; Vita Suprinity, ZLS). ALDS specimens were divided into two subgroups according to glazing procedures (reduced glaze duration, ALDS-S and normal glaze duration, ALDS-N), while LDS and ZLS specimens were crystallized and glazed. Color coordinate measurements were performed before and after coffee thermocycling. Color differences (ΔE 00 ) and relative translucency parameters (RTP) were calculated. Specimens were then subjected to BFS test. Statistical analysis was performed by using 1-(ΔE 00 and BFS) and 2-way (RTP) ANOVA tests (α = 0.05).Results: ΔE 00 values of tested materials were similar (df = 3, F = 0.150, p = 0.929). Two-way ANOVA showed the significant effect of material type, coffee thermocycling, and the interaction between these parameters on RTP values (p < 0.001). Both before and after thermocycling, LDS had the highest (p ≤ 0.001) and ZLS had the lowest (p < 0.001) RTP values, while ALDS-N had higher RTP than ALDS-S (p ≤ 0.001). Among tested materials, only LDS had similar RTP values before and after thermocycling (p = 0.865) as the other materials had lower RTP values after thermocycling (p < 0.001). ALDS-N had higher BFS values than ALDS-S (p = 0.005), while LDS had similar values to ALDS specimens (p ≥ 0.201). ZLS had the highest BFS (p ≤ 0.007).Conclusions: ALDS had comparable values to those of other materials. However, reduced glazing duration resulted in decreased translucency and BFS of ALDS.Clinical significance: ALDS may be an appropriate restorative material for those patients with increased coffee consumption considering its color stability and ability to maintain translucency, particularly when glazed by using a conventional porcelain furnace.

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PurposeTo investigate the color stability, translucency, biaxial flexural strength (BFS), and reliability of nano‐lithium disilicate and fully crystallized lithium disilicate after thermal cycling and to compare with those of a commonly used lithium disilicate.Materials and methodsThree lithium disilicate glass‐ceramics were used to prepare disk‐shaped specimens (ø:12 mm, thickness: 1.2 mm) from A2 shaded HT blocks (Amber Mill, AM; Initial LiSi Block, IN; IPS e.max CAD, EX). AM and EX specimens were crystallized, and all specimens were polished with a polishing paste (Diamond Polish Mint). A spectrophotometer (CM‐26d) was used to measure color coordinates before and after thermal cycling. BFS test was performed after thermal cycling. Color differences (ΔE00) and relative translucency parameter (RTP) values were calculated. One‐way analysis of variance (ANOVA) (ΔE00 and BFS), two‐way ANOVA followed by Tukey's HSD tests (RTP), and chi‐square tests (Weibull modulus and characteristic strength) were used for the statistical analyses (α = 0.05).ResultsNo significant differences were observed among the ΔE00 values of tested materials (df = 2, F = 2.933, p = 0.070). RTP values were only affected by material type (p < 0.001) as AM had the highest RTP (p < 0.001), whereas IN and EX had similar values (p ≥ 0.165). BFS values varied among tested materials (df = 2, F = 21.341, p < 0.001). AM and EX had similar BFS values (p = 0.067) that were higher than that of IN (p ≤ 0.001). Weibull moduli of the materials were similar (p = 0.305), whereas EX had the highest and IN had the lowest characteristic strength values (p < 0.001)ConclusionsAlthough nano‐lithium disilicate had the highest translucency, all materials had imperceptible color and translucency changes after thermal cycling when reported threshold values were considered. Newly introduced lithium disilicate glass–ceramics had adequate flexural strength as compared to the precursor material.

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Objective To analyze the wear rate of computer‐aided design and computer‐aided manufacturing (CAD/CAM) composites, polyetheretherketones and glass ceramics. Material and Methods Our study groups were prepared from two different resin‐based composites (Brillant Crios, Cerasmart), a glass ceramic (IPS Emax CAD) and reinforced polyetheretherketone (BioHPP) material (n = 10). Premolar teeth were used as antagonists. The specimens, which were subjected to two body wear tests (240,000 cycles, 1.2 Hz, 50N) in the chewing simulator, were scanned with a 3D laser scanner both before and after the wear test. Volume loss and wear depth were determined by means of the obtained images software program. The wear pattern was examined by scanning electron microscopy. Kruskal Wallis test served for analyzing. Results The least volume loss and wear depth were seen in the polyetheretherketone material (0.06 ± 0.04 mm3, 0.02 ± 0.01 mm), while the maximum volume loss was seen in the groups containing resin‐based composite. (p = 0.05). The volume loss value in glass ceramics is between CAD/CAM composites and polyetheretherketone. Conclusion The behavior of polyetheretherketone against enamel was different from glass ceramics and composite materials in terms of the amount of wear. Clinical Significance Polyetheretheketone can be considered as an alternative to other chairside materials in terms of wear resistance.