Visiting Researcher, Section Medical Materials Science & Technology, University Hospital Tübingen, Tübingen, Germany; Lecturer, Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt.
Associate Professor, Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt; Head of Fixed prosthodontics department, Faculty of Dentistry, British University, Cairo, Egypt.
J Prosthet Dent. 2021 Jul;126(1):93.e1-93.e9. doi: 10.1016/j.prosdent.2021.03.016. Epub 2021 Apr 29.
Although force-damping behavior that matches natural teeth may be unobtainable, an optimal combination of crown material and luting agent might have a beneficial effect on the force absorption capacity of implant-supported restorations. However, the force-absorbing behavior of various restorative materials has not yet been satisfactorily investigated.
The purpose of this in vitro study was to evaluate the material dependent force-damping behavior of implant-supported crowns fabricated from different computer-aided design and computer-aided manufacturing (CAD-CAM) materials luted to implant abutments under different conditions.
Titanium inserts (N=84) were screwed to implant analogs, scanned to design zirconia abutments, and divided into 4 groups to receive CAD-CAM fabricated crowns in 4 materials: zirconia, polyetheretherketone (PEEK), polymer-infiltrated ceramics (VITA ENAMIC), and lithium disilicate (e.max). The crowns were subdivided as per the luting agent: none, interim cement, and adhesive resin cement. Measurements were performed by loading specimens in a universal testing machine with an increasing force and measuring the resulting force with a digital forcemeter, followed by image processing and data acquisition. Two-way multivariate analysis of variance (MANOVA) was used to assess all interactions with multiple pairwise comparisons (α=.05).
The curve progression of the applied and resulting forces varied significantly among the investigated materials, resulting in differently inclined slopes for each material (P<.001). With no cementation, the mean slope values of the resulting force curves ranged from 77.5 ±0.03 degrees for zirconia, followed by 71.8 ±0.03 degrees for lithium disilicate, 56.2 ±0.1 degrees for polymer-infiltrated ceramics, and 51.1 ±0.01 degrees for polyetheretherketone. With interim cementation, the mean slope values ranged from 75.4 ±0.01 degrees for zirconia, followed by 70.05 ±0.02 degrees for lithium disilicate, 56.1 ±0.02 degrees for polymer-infiltrated ceramics, and 52.2 ±0.1 degrees for polyetheretherketone. As with adhesive cementation, curve slopes ranged from 73.2 ±0.02 degrees for zirconia, followed by 70.5 ±0.2 degrees for lithium disilicate, 55.9 ±0.04 degrees for polymer-infiltrated ceramics, and 52.3 ±0.1 degrees for polyetheretherketone. Slope loss was significant after the cementation of zirconia and lithium disilicate crowns but less significant for polymer-infiltrated ceramics and polyetheretherketone.
Force damping is generally material dependent, yet implant-supported crowns fabricated from resilient materials such as polymer-infiltrated ceramics and PEEK show better force absorption than rigid materials such as zirconia and lithium disilicate ceramics. Furthermore, cementation of rigid materials significantly increased slope loss, indicating enhancement in their force-damping behavior, whereas less-rigid materials benefit less from cementation. Further studies are essential to investigate the effect of prosthetic materials on the stress distribution to the peri-implant bone in the crown-abutment-implant complex.
虽然无法获得与天然牙齿相匹配的力阻尼行为，但冠材料和粘固剂的最佳组合可能对种植体支持修复体的力吸收能力产生有益的影响。然而，各种修复材料的力吸收行为尚未得到令人满意的研究。
本体外研究的目的是评估不同 CAD-CAM 材料制成的种植体支持冠在不同条件下粘接到种植体基台上的材料依赖性力阻尼行为。
将钛插入物（N=84）拧到种植体模拟物上，扫描以设计氧化锆基台，并将其分为 4 组，用 4 种材料制造 CAD-CAM 冠：氧化锆、聚醚醚酮（PEEK）、聚合物渗透陶瓷（VITA ENAMIC）和锂二硅（e.max）。根据粘固剂将冠分为无粘固剂、临时粘固剂和粘合树脂粘固剂。通过在万能试验机上以递增的力加载试件并使用数字测力仪测量产生的力来进行测量，然后进行图像处理和数据采集。使用双向多元方差分析（MANOVA）评估所有相互作用和多个两两比较（α=0.05）。
所研究材料的施加力和产生力的曲线进展差异显著，导致每种材料的斜率不同（P<.001）。无粘固剂时，产生力曲线的平均斜率值范围为氧化锆 77.5±0.03 度，其次是锂二硅 71.8±0.03 度，聚合物渗透陶瓷 56.2±0.1 度，聚醚醚酮 51.1±0.01 度。临时粘固剂时，平均斜率值范围为氧化锆 75.4±0.01 度，其次是锂二硅 70.05±0.02 度，聚合物渗透陶瓷 56.1±0.02 度，聚醚醚酮 52.2±0.1 度。与粘合粘固剂一样，曲线斜率范围为氧化锆 73.2±0.02 度，其次是锂二硅 70.5±0.2 度，聚合物渗透陶瓷 55.9±0.04 度，聚醚醚酮 52.3±0.1 度。氧化锆和锂二硅冠粘固后斜率损失明显，但聚合物渗透陶瓷和聚醚醚酮的斜率损失较小。
力阻尼通常是材料依赖性的，但由聚合物渗透陶瓷和 PEEK 等弹性材料制成的种植体支持冠比氧化锆和锂二硅陶瓷等刚性材料具有更好的力吸收能力。此外，刚性材料的粘固显著增加了斜率损失，表明其力阻尼行为增强，而较不刚性的材料受益于粘固的程度较小。需要进一步研究以调查修复材料对冠-基台-种植体复合体中种植体周围骨的应力分布的影响。
