Effect of repeated firings on fatigue behaviors of posterior occlusal veneers made of glass ceramic

doi:10.19439/j.sjos.2020.06.005

Abstract

Abstract: PURPOSE: To investigate the effect of firing times on the fatigue properties and failure modes of posterior occlusal veneers made of lithium disilicate glass ceramics. METHODS: According to the number of times of firing (1, 3, 5, 7 times), IPS e.max CAD(IC) and IPS e.max Press(IP) occlusal veneer restorations with a thickness of 1.2mm were prepared, and then cemented to the maxillary molar composite resin dies. Each group was subjected to thermo-mechanical fatigue(TMFT) test (5-55 ℃, 5000 cycles, 30-300 N, 10 Hz, sinusoidal wave, 500 000 cycles) and compressive loading. The maximum force at fracture was recorded. Stereomicroscope and scanning electron microscope(SEM), energy dispersive X-ray spectroscopy(EDX) and X-ray diffraction(XRD) were adopted to analyze the failure modes and microstructural features. Statistical analysis was performed with SPSS 20.0 software package. RESULTS: The highest average loads (N) at fracture for IC groups were (1546.73±192.85) N after one firing time; in IP group, the highest average loads were (1504.46±138.56) N after three firing times. There was no significant difference in the fracture load with different firing times for IC/IP(P>0.05). EDX and XRD analysis showed no significant difference in the composition of two materials. SEM showed that the size of crystal was shorter and the porosity increased after multiple firing. CONCLUSIONS: After repeated firing, the fatigue loading of lithium disilicate glass ceramics has a decreasing trend of fracture load value without any significant difference, and it meets clinical requirements.

Key words: Occlusal veneers, Lithium disilicate glass ceramic, Firing times, Fatigue properties

CLC Number:

R783.1

GU Li-ling, GUO Yong-jin, CHENG Hui, LI Xiu-rong, ZHANG Bei-jie. Effect of repeated firings on fatigue behaviors of posterior occlusal veneers made of glass ceramic[J]. Shanghai Journal of Stomatology, 2020, 29(6): 586-590.

References

[1] Muts EJ, van Pelt H, Edelhoff D, et al. Tooth wear: a systematic review of treatment options[J]. J Prosthet Dent, 2014, 112(4): 752-759.
[2] Guess PC, Selz CF, Steinhart YN, et al.Prospective clinical split-mouth study of pressed and CAD/CAM all-ceramic partial-coverage restorations: 7-year results[J]. Int J Prosthodont, 2013, 26(1): 21-25.
[3] Nejatidanesh F, Amjadi M, Akouchekian M, et al.Clinical performance of CEREC AC Bluecam conservative ceramic restorations after five years-a retrospective study[J]. J Dent, 2015, 43(9): 1076-1082.
[4] Subasi MG, Demir N, Kara Ö, et al.Mechanical properties of zirconia after different surface treatments and repeated firings[J]. J Adv Prosthodont, 2014, 6(6): 462-467.
[5] 陈文利, 骆小平. 多次烧结对二硅酸锂玻璃陶瓷颜色和透光性的影响[J]. 口腔材料器械杂志, 2015, 24(3): 118-122.
[6] Anwar M, Tripathi A, Kar SK, et al.Effect of PFM firing cycles on the mechanical properties, phase composition, and microstructure of nickel-chromium alloy[J]. J Prosthodont, 2015, 24(8): 634-641.
[7] Aurélio IL, Prochnow C, Guilardi LF, et al.The effect of extended glaze firing on the flexural fatigue strength of hard-machined ceramics[J]. J Prosthet Dent, 2018, 120(5): 755-761.
[8] Lien W, Roberts HW, Platt JA, et al.Microstructural evolution and physical behavior of a lithium disilicate glass-ceramic[J]. Dent Mater, 2015, 31(8): 928-940.
[9] 张钊, 陈树国, 李雅娟, 等. 烧结次数对金瓷冠微观结构的影响[J]. 现代口腔医学杂志, 2004, 18(4): 317-319.
[10] Polli GS, Hatanaka GR, Abi-Rached FO, et al.Fatigue behavior and surface characterization of a Y-TZP after laboratory grinding and regeneration firing[J]. J Mech Behav Biomed Mater, 2018, 88: 305-312.
[11] Özdemir H, Özdogan A.The effect of heat treatments applied to superstructure porcelain on the mechanical properties and microstructure of lithium disilicate glass ceramics[J]. Dent Mater J, 2018, 37(1): 24-32.
[12] Riquieri H, Monteiro JB, Viegas DC, et al.Impact of crystallization firing process on the microstructure and flexural strength of zirconia-reinforced lithium silicate glass-ceramics[J]. Dent Mater, 2018, 34(10): 1483-1491.
[13] Borba M, de Araujo MD, Fukushima KA, et al. Effect of the microstructure on the lifetime of dental ceramics[J]. Dent Mater, 2011, 27(7): 710-721.
[14] Belli R, Wendler M, Ligny D, et al.Chairside CAD/CAM materials. Part 1: measurement of elastic constants and microstructural characterization[J]. Dent Mater, 2017, 33(1): 84-98.
[15] Tang X, Tang C, Su H, et al.The effects of repeated heat-pressing on the mechanical properties and microstructure of IPS e.max Press[J]. J Mech Behav Biomed Mater, 2014, 40: 390-396.
[16] Gozneli R, Kazazoglu E, Ozkan Y.Flexural properties of leucite and lithium disilicate ceramic materials after repeated firings[J]. J Dent Sci, 2014, 9(2): 144-150.
[17] Kang SH, Chang J, Son HH.Flexural strength and microstructure of two lithium disilicate glass ceramics for CAD/CAM restoration in the dental clinic[J]. Restor Dent Endod, 2013, 38(3): 134-140.
[18] 袁坤, 王富, 高婧, 等. 一种新型牙科二硅酸锂玻璃陶瓷的微观结构分析[J]. 口腔医学研究, 2014, 30(12): 1121-1123.
[19] Al-Akhali M, Chaar MS, Elsayed A, et al.Fracture resistance of ceramic and polymer-based occlusal veneer restorations[J]. J Mech Behav Biomed Mater, 2017, 74: 245-250.
[20] Ortiz AL, Borrero-LO, Guiberteau F, et al.Microstructural development during heat treatment of a commercially available dental-grade lithium disilicate glass-ceramic[J]. Dent Mater, 2019, 35(5): 697-708.
[21] Rifat G, Ender K, Yasemin O.Flexural properties of leucite and lithium disilicate ceramic materials after repeated firing cycles[J]. J Dent Sci, 2014,9(2):144-150.