Department of Periodontology, Endodontology and Cariology, University Center for Dental Medicine Basel, University of Basel, Basel, Switzerland.
Centre for Craniofacial and Regenerative Biology, Dental Institute, King's College London, London, UK.
Clin Oral Implants Res. 2018 Feb;29(2):175-184. doi: 10.1111/clr.13075. Epub 2017 Oct 31.
To investigate the fracture behavior and marginal gap region of CAD/CAM fabricated lithium disilicate (L) and zirconium dioxide (Z) crowns using palatal venting (PV), pre-cementation with custom analogs (CA), or conventional cementation technique (SP) with adhesive cement (A) or resin-modified glass ionomer cement (B).
Twelve groups (n = 6) were set according to material (L, Z), cement (A, B), and technique (PV, CA, SP). Specimens were thermo-mechanical aged (TML), loaded until fracture (LF) and fracture patterns recorded. Marginal gap width and quality were assessed and compared to replicas obtained before and after TML.
Crown material significantly influenced LF with a mean of 1037.6 ± 282.4 N in L and 5356.3 ± 1207.0 N in Z groups (p < .001). Neither cement material nor cementation method affected the outcome. Fractures occurred along the mesial-distal central fissure in both materials. Gap width before TML was 22.04 ± 13.42 μm for L and 19.98 ± 12.72 μm for Z specimens, with overall no influence of crown material, cement type, or method. Marginal cleanliness just below the polished implant shoulder reached 66.7%-88.9% with A, and 91.7%-100% with B, and tended to increase in all groups during TML indicating a decrease in excess cement. Implant-crown junctions were cleaner with B compared to A (p ≤ .001) and along Z crown surfaces compared to L (p ≤ .007).
Crown venting of lithium disilicate and zirconium dioxide crowns did not affect the fracture load and patterns. Complete cement removal was rare, and the observed particle ablation requires further clinical attention, particularly with submucosal margins.
研究 CAD/CAM 制作的锂硅（L）和氧化锆（Z）冠采用腭部通风（PV）、预粘固剂（CA）、或传统粘固剂（SP），使用普通粘固剂（A）或树脂改性玻璃离子粘固剂（B）的断裂行为和边缘间隙区域。
根据材料（L、Z）、粘固剂（A、B）和技术（PV、CA、SP），共设置 12 组（n=6）。标本进行热机械老化（TML），直至断裂（LF），记录断裂模式。评估并比较 TML 前后的边缘间隙宽度和质量与复制件。
冠材料显著影响 LF，L 组的平均断裂载荷为 1037.6±282.4 N，Z 组为 5356.3±1207.0 N（p<0.001）。粘固剂材料或粘固方法均不影响结果。两种材料的裂缝均发生在近远中中央裂缝处。TML 前，L 组的间隙宽度为 22.04±13.42 μm，Z 组为 19.98±12.72 μm，总体上不受冠材料、粘固剂类型或方法的影响。在所有组中，边缘清洁度在 TML 期间都有所增加，表明多余粘固剂减少，在抛光的种植体肩下刚好达到 66.7%-88.9%，使用 B 则达到 91.7%-100%，且用 B 比用 A 更清洁（p≤0.001），Z 冠表面比 L 冠更清洁（p≤0.007）。
锂硅和氧化锆冠的腭部通风不影响断裂载荷和模式。完全去除粘固剂很少见，观察到的颗粒烧蚀需要进一步的临床关注，特别是在粘膜下边缘。
