Ahmed Yousra, Hameed Shereen Moselhy Abdul, Sharkawy Zainab Refaey El, Alshahrani Faris A, Mahmoud Tarek AbdAllah, M Mohamed Inas, Taymour Noha
Department of Prosthetic Dentistry, Removable Prosthodontic Division, Faculty of Dentistry, King Salman International University, El Tur 45615, Egypt.
Department of Crowns and Bridges, Faculty of Dental Medicine for Girls, Al Azhar University, Cairo 11765, Egypt.
Dent J (Basel). 2025 Sep 12;13(9):421. doi: 10.3390/dj13090421.
To assess the impact of PVS impression material viscosity and implant angulation on the three-dimensional accuracy of implant casts in a partially edentulous situation using the closed-tray technique. : Three epoxy resin mandibular partially edentulous models (Kennedy Class I) were fabricated, each with four implant analogues placed at teeth positions 35, 37, 45, and 47. The anterior analogues were positioned parallel (0), while the posterior analogues were placed at different angulations: Group 1, 30° mesiodistal; Group 2, 20° mesiodistal; Group 3, 20° buccolingual. All analogues were placed 2 mm subgingivally. Closed-tray impressions (n = 8 per subgroup) were made using either heavy + light body PVS or monophase PVS. Resulting stone casts were scanned, and STL files were processed and analyzed using reverse engineering software (Geomagic Control X). Three-dimensional deviations (root mean square, RMS) between reference and test models were calculated by superimposition and best-fit algorithm. With monophase PVS, implant angulation significantly influenced cast accuracy ( < 0.001). The 30° MD group exhibited the highest deviation (96 ± 7 µm), followed by the 20° BL group (81 ± 6 µm), then the 20° MD group (75 ± 6 µm). In contrast, no statistically significant difference in accuracy was observed among angulation groups when using heavy + light body PVS (77 ± 3 µm, 82 ± 13 µm, and 79 ± 8 µm for 30° MD, 20° BL, and 20° MD, respectively; = 0.550). Both monophase and heavy + light body PVS impression materials produced clinically acceptable accuracy for closed-tray implant impressions. However, the heavy + light body PVS demonstrated greater consistency across various implant angulations and is recommended for multiple angulated subgingival posterior implants when using the closed-tray technique.
使用封闭托盘技术评估聚醚砜（PVS）印模材料粘度和种植体角度对部分牙列缺损情况下种植体模型三维精度的影响。：制作了三个环氧树脂下颌部分牙列缺损模型（肯氏I类），每个模型在35、37、45和47号牙位放置四个种植体代型。前部代型平行放置（0°），而后部代型以不同角度放置：第1组，近远中向30°；第2组，近远中向20°；第3组，颊舌向20°。所有代型均放置在龈下2mm处。使用重体+轻体PVS或单相PVS制作封闭托盘印模（每个亚组8个）。对所得石膏模型进行扫描，并使用逆向工程软件（Geomagic Control X）对STL文件进行处理和分析。通过叠加和最佳拟合算法计算参考模型和测试模型之间的三维偏差（均方根，RMS）。使用单相PVS时，种植体角度对模型精度有显著影响（P<0.001）。30°近远中向组偏差最大（96±7μm），其次是20°颊舌向组（81±6μm），然后是20°近远中向组（75±6μm）。相比之下，使用重体+轻体PVS时，各角度组在精度上未观察到统计学显著差异（30°近远中向、20°颊舌向和20°近远中向分别为77±3μm、82±13μm和79±8μm；P = 0.550）。单相和重体+轻体PVS印模材料在封闭托盘种植体印模方面均产生了临床可接受的精度。然而，重体+轻体PVS在各种种植体角度下表现出更大的一致性，建议在使用封闭托盘技术时用于多个有角度的龈下后部种植体。
