Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran, Associate Professor, Department of Prosthodontics, School of Dentistry, International Campus, Tehran University of Medical Sciences, Tehran, Iran.
Graduate student, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
J Prosthet Dent. 2023 Jul;130(1):132.e1-132.e9. doi: 10.1016/j.prosdent.2023.04.013. Epub 2023 May 17.
Despite the acceptable physical properties of biocompatible high-performance polymer (BioHPP), little is known about the marginal accuracy and fracture strength of restorations made from this material.
This in vitro study assessed the marginal and internal adaptation and fracture strength of teeth restored with lithium disilicate (LD) ceramics and BioHPP monolithic crowns.
Twenty-four extracted premolars were prepared for complete coverage crowns and divided into 2 groups to receive pressed IPS e.max LD, or computer-aided design and computer-aided manufacturing (CAD-CAM) BioHPP monolithic crowns. After adhesive cementation, the marginal and internal adaptations of the restorations were evaluated by microcomputed tomography at 18 points for each crown. Specimens were subjected to 6000 thermal cycles at 5 °C and 55 °C and 200 000 load cycles of 100 N at a frequency of 1.2 Hz. The fracture strength of the restorations was then measured in a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed via an independent-sample t-test (α=.05).
The mean ±standard deviation of marginal gap was 138.8 ±43.6 μm for LD and 242.1 ±70.7 μm for BioHPP groups (P=.001). The mean ±standard deviation value of absolute marginal discrepancy was 193.8 ±60.8 μm for LD and 263.5 ±97.6 μm for BioHPP groups (P=.06). The internal occlusal and axial gap measurements were 547.5 ±253.1 μm and 197.3 ±54.8 μm for LD (P=.03) and 360 ±62.9 μm and 152.8 ±44.8 μm for BioHPP (P=.04). The mean ±standard deviation of internal space volume was 15.3 ±11.8 μm³ for LD and 24.1 ±10.7 μm³ for BioHPP (P=.08). The mean ±standard deviation of fracture strength was 2509.8 ±680 N for BioHPP and 1090.4 ±454.2 MPa for LD groups (P<.05).
The marginal adaptation of pressed lithium disilicate crowns was better, while BioHPP crowns displayed greater fracture strength. Marginal gap width was not correlated with fracture strength in either group.
尽管生物相容性高性能聚合物（BioHPP）具有可接受的物理性能，但对于用这种材料制成的修复体的边缘精度和断裂强度知之甚少。
本体外研究评估了用锂硅玻璃陶瓷（LD）和 BioHPP 整体冠修复的牙齿的边缘和内部适应性以及断裂强度。
将 24 颗提取的前磨牙制备成全冠覆盖，并分为两组，分别接受压制的 IPS e.max LD 或计算机辅助设计和计算机辅助制造（CAD-CAM）BioHPP 整体冠。修复体粘结后，通过微计算机断层扫描在每个冠的 18 个点评估修复体的边缘和内部适应性。样本在 5°C 和 55°C 下进行 6000 次热循环，在 1.2 Hz 的频率下施加 100 N 的 200000 次循环载荷。然后在万能试验机上以 0.5mm/min 的十字头速度测量修复体的断裂强度。数据采用独立样本 t 检验（α=.05）进行分析。
LD 组的平均边缘间隙为 138.8 ±43.6μm，BioHPP 组为 242.1 ±70.7μm（P=.001）。LD 组的平均绝对边缘差异为 193.8 ±60.8μm，BioHPP 组为 263.5 ±97.6μm（P=.06）。LD 组的内部牙合面和轴向间隙测量值为 547.5 ±253.1μm 和 197.3 ±54.8μm（P=.03），BioHPP 组为 360 ±62.9μm 和 152.8 ±44.8μm（P=.04）。LD 组的平均内部空间体积为 15.3 ±11.8μm³，BioHPP 组为 24.1 ±10.7μm³（P=.08）。BioHPP 组的平均断裂强度为 2509.8 ±680N，LD 组为 1090.4 ±454.2MPa（P<.05）。
压制的锂硅玻璃陶瓷冠的边缘适应性更好，而 BioHPP 冠显示出更大的断裂强度。两组的边缘间隙宽度与断裂强度均无相关性。
