Department of Prosthodontics, Institute of Odontology, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
Digitorum LAB, Vilnius, Lithuania.
J Dent. 2022 Nov;126:104267. doi: 10.1016/j.jdent.2022.104267. Epub 2022 Aug 24.
Splinting of impression copings is generally recommended for complex implant-supported restorations. It can also be used in the digital workflow when a control model is needed to improve the fit of the prosthesis. However, there is a lack of knowledge on how dimensional accuracy is affected by different splinting techniques and time factors.
To evaluate the time factor on the dimensional stability of different implant impression splinting techniques used in the conventional and digital workflow.
Ten pairs of implant analogs were fixed to a stainless steel bar. Modified impression copings were connected to the analogs and eight splinting strategies evaluated (n=10): (1) type I impression plaster (PLA), (2) autopolymerizing acrylic resin, cut and rejoin technique (PTR), (3) light-cured acrylic resin, cut and rejoin technique (ILC), (4) light-cured acrylic resin, no cutting and rejoining (ILN), (5) VPS bite registration material (SBR), (6) bis-acryl bite registration material (LXB), (7) bis-acryl composite resin (PTP), (8) 3D printed splint (3DP). In each group, the position of modified impression copings was scanned with a laboratory scanner at different time points: (1) unsplinted impression copings (baseline), (2) 2 h after splinting, (3) 24 h after splinting. Modified impression coping design allowed using metrology software to measure and compare distance, vertical, angle and rotational deviations between impression copings.
All types of splints showed dimensional deviations. After 2 h of splinting, the lowest distance deviation was recorded in PTR (15.4±6.15µm), vertical deviation - in ILC (19.2±27.37µm), angle deviation - in ILC (0.08±0.1°), rotation - in LXB (0.2±0.24°) groups. Comparing results 2 and 24 h after connection of impression copings, statistically significant deviations in the distance were recorded in groups PLA (-5.6±5.95 µm), PTR (5.5±7.01µm), ILN (19.2±14.26µm), PTP (23.8±12.55µm).
The best dimensional accuracy was observed in the ILC group, followed by PTR and 3DP groups.
Proper selection of splinting technique and polymerization time can increase the accuracy of conventional or digital impressions. Splinting techniques with rigid materials, proper polymerization and compensating for material shrinkage seem to produce the best results.
对于复杂的种植体支持修复体，通常建议使用夹板固定印模。当需要控制模型来提高修复体的适配度时，这种方法也可以用于数字化工作流程中。然而，目前对于不同夹板技术和时间因素如何影响尺寸精度的了解还很有限。
评估不同种植体印模夹板技术在传统和数字化工作流程中的时间因素对尺寸稳定性的影响。
将十对种植体模拟体固定在不锈钢棒上。将改良的印模托盘连接到模拟体上，并评估了八种夹板策略（n=10）：（1）I 型印模石膏（PLA），（2）自聚物丙烯酸树脂，切割后再连接技术（PTR），（3）光固化丙烯酸树脂，切割后再连接技术（ILC），（4）光固化丙烯酸树脂，不切割再连接技术（ILN），（5）VPS 咬合记录材料（SBR），（6）双丙烯酸咬合记录材料（LXB），（7）双丙烯酸复合材料（PTP），（8）3D 打印夹板（3DP）。在每组中，使用实验室扫描仪在不同时间点扫描改良后的印模托盘位置：（1）未夹板的印模托盘（基线），（2）夹板后 2 小时，（3）夹板后 24 小时。改良后的印模托盘设计允许使用计量软件测量和比较印模托盘之间的距离、垂直、角度和旋转偏差。
所有类型的夹板都显示出尺寸偏差。在夹板后 2 小时，PTR 组的距离偏差最小（15.4±6.15μm），垂直偏差最小在 ILC 组（19.2±27.37μm），角度偏差最小在 ILC 组（0.08±0.1°），旋转偏差最小在 LXB 组（0.2±0.24°）。比较印模托盘连接后 2 小时和 24 小时的结果，在 PLA（-5.6±5.95μm）、PTR（5.5±7.01μm）、ILN（19.2±14.26μm）和 PTP（23.8±12.55μm）组中记录到距离的统计学显著偏差。
在 ILC 组中观察到最佳的尺寸精度，其次是 PTR 和 3DP 组。
适当选择夹板技术和聚合时间可以提高传统或数字化印模的精度。使用刚性材料、适当聚合和补偿材料收缩的夹板技术似乎可以产生最佳效果。
