Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit Van Amsterdam and Vrije Universiteit, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, Noord-Holland, The Netherlands.
Department of Reconstructive Oral Care, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit Van Amsterdam and Vrije Universiteit, Amsterdam, The Netherlands.
Clin Oral Investig. 2023 Nov;27(11):6429-6438. doi: 10.1007/s00784-023-05246-1. Epub 2023 Sep 20.
To study the influence of glazing on strength repair of lithium disilicate glass-ceramics after defect incorporation in different production processing phases.
Bar-shaped specimens (1 × 1 × 12 mm, n = 280; 20/group) made from different lithium disilicate ceramics (IPS e.max CAD, Ivoclar, "LD" or advanced lithium disilicate CEREC Tessera, Dentsply Sirona, "ALD") were exposed to 7 different protocols: crystallized without (c) and with glaze layer (cg), with a defect incorporated before crystallization without (ic) and with glaze layer (icg), with a defect after crystallization without (ci) or with glaze layer (cig), and defect incorporated after the glaze layer (cgi). The flexural strength was determined using the three-point bending test. Analysis of indented areas and fractured specimens was performed by scanning electron microscopy. Flexural strength data were evaluated by two-way ANOVA followed by Tukey tests (α = 5%).
Two-way ANOVA revealed a significant influence of ceramic (p < 0.001; F = 55.45), protocol (p < 0.001; F = 56.94), and the interaction protocol*ceramic (p < 0.001; F = 13.86). Regardless of ceramics, defect incorporation as final step resulted in the worst strength, while defects introduced before crystallization did not reduce strength. Glaze firing after defect incorporation led to strength repair for ALD, whereas such an effect was not evident for LD.
The advanced lithium disilicate must receive a glaze layer to achieve its highest strength. Defects incorporated in the pre-crystallized stage can be healed during crystallization. Defects should not be incorporated after glazing.
Clinical adjustments should be performed on pre-crystallized or crystalized restorations that receive a glazer layer afterwards.
研究在不同生产加工阶段缺陷形成后，上釉对锂硅玻璃陶瓷强度修复的影响。
由不同的锂硅陶瓷（义获嘉维他，“LD”或 CAD 高级锂硅 CEREC Tessera，登士柏西诺德，“ALD”）制成的棒状试件（1×1×12mm，n=280；每组 20 个），暴露于 7 种不同的方案中：不结晶（无釉层）和结晶后上釉层（有釉层）、在结晶前有缺陷但不上釉层（无釉层）和结晶后有缺陷但上釉层（有釉层）、在结晶后有缺陷但不上釉层（无釉层）和结晶后有缺陷且上釉层（有釉层）、缺陷在上釉层之后形成（有釉层）。采用三点弯曲试验测定抗弯强度。通过扫描电子显微镜对压痕区和断裂试件进行分析。采用双因素方差分析（α=5%）对抗弯强度数据进行评估。
双因素方差分析显示，陶瓷（p<0.001；F=55.45）、方案（p<0.001；F=56.94）和方案*陶瓷交互作用（p<0.001；F=13.86）有显著影响。无论陶瓷类型如何，作为最后一步引入的缺陷会导致强度最差，而在结晶前引入的缺陷不会降低强度。在缺陷形成后上釉会导致 ALD 的强度修复，而 LD 则没有这种效果。
高级锂硅玻璃陶瓷必须上釉层才能达到最高强度。在结晶前阶段形成的缺陷可以在结晶过程中得到修复。缺陷不应在上釉后形成。
临床调整应在随后上釉的预结晶或结晶修复体上进行。
