Torsion and linear accuracy in intraoral scans obtained with different scanning principles

PurposeFew investigations have examined the production of single restorations using intraoral scanners (IOS). Data on full-arch scans are rare, and data regarding torsion within the entire arch are very sparsely reported. Therefore, the aim of this study was to examine the deviations of torsion and linear distances in full-arch scans of three IOS based on different scanning principles.MethodsA cobalt-chrome-molybdenum alloy master model (CCMM) with four hemispheres was fabricated by laser sintering. The CCMM was digitized using a laboratory scanner (ATOS-Core/GOM) and scanned with three IOS (Omnicam/Sirona(OC); True Definition/3M(TD); TriosII/Cara-Version/Kulzer(TR)). All scan data were exported in a standard STL-file format and were analyzed with GOM Inspect software (V7.5/GOM). Torsion between the right and left side of the arch and linear accuracy (trueness and precision) were evaluated. After normality was confirmed, all data were subjected to parametric statistical analyses.ResultsThe torsion ranged from 0.07 ± 0.03°(OC) to 0.29 ± 0.14°(TD). Pairwise comparisons showed significant differences between the OC and TD scanners and between the TR and TD scanners. The linear distances ranged from 6 ± 5 μm(OC) to 298 ± 317 μm(TD). Significant differences were observed among all investigated IOS (p = 0.05).ConclusionsAlthough the highest torsion was observed for the TD scanner, it is still not clear whether the differences between the IOS are related to the scanning principle or to the scanning algorithm. Due to the high clinical relevance of full-arch restorations, future studies should consider torsion. Regarding linear accuracy, no general difference related to the scanning principles of the IOSs was observed.     

Evaluating the accuracy (trueness and precision) of interim crowns manufactured using digital light processing according to post-curing time: An in vitro study

PURPOSEThis study aimed to compare the accuracy (trueness and precision) of interim crowns fabricated using DLP (digital light processing) according to post-curing time.MATERIALS AND METHODSA virtual stone study die of the upper right first molar was created using a dental laboratory scanner. After designing interim crowns on the virtual study die and saving them as Standard Triangulated Language files, 30 interim crowns were fabricated using a DLP-type 3D printer. Additively manufactured interim crowns were post-cured using three different time conditions-10-minute post-curing interim crown (10-MPCI), 20-minute post-curing interim crown (20-MPCI), and 30-minute post-curing interim crown (30-MPCI) (n = 10 per group). The scan data of the external and intaglio surfaces were overlapped with reference crown data, and trueness was measured using the best-fit alignment method. In the external and intaglio surface groups (n = 45 per group), precision was measured using a combination formula exclusive to scan data (₁₀C₂). Significant differences in accuracy (trueness and precision) data were analyzed using the Kruskal-Wallis H test, and post hoc analysis was performed using the Mann-Whitney U test with Bonferroni correction (α=.05).RESULTSIn the 10-MPCI, 20-MPCI, and 30-MPCI groups, there was a statistically significant difference in the accuracy of the external and intaglio surfaces (P <.05). On the external and intaglio surfaces, the root mean square (RMS) values of trueness and precision were the lowest in the 10-MPCI group.CONCLUSIONInterim crowns with 10-minute post-curing showed high accuracy.     

临床化学检测的标准化现状

实验室的质量管理和检验结果标准化是临床化学检测项目实现结果互认的2个重要基础。开展标准化工作,建立检验项目的标准化体系可为检验质量提供准确性依据,是确保检验结果准确、具有可比性的最有效措施。实现检验结果准确、可比的重要方法之一是建立和保证检验结果的溯源性。国际组织一般通过建立参考测量程序、参考物质和一致性方案等来解决不同项目的量值溯源性问题。正确度验证计划和能力验证的开展为临床化学检验项目的结果互认提供了依据。文章对临床化学检测标准化的现状进行综述,以期为临床实验室质量管理提供参考。     

全冠预备体终止线局部扫描正确度对整体的影响

目的: 探讨影响数字化印模中全冠预备体终止线扫描正确度的因素。方法: 在树脂牙列模型上制备右上第一磨牙标准全冠预备体,分别进行牙列内全冠预备体和孤立全冠预备体终止线的扫描正确度检测。牙列内全冠预备体终止线的扫描正确度检测:(1)应用Imetric扫描仪扫描全冠预备体,获得STL格式数据作为参考真值;(2)应用 CERE...     

血清游离脂肪酸酶法测定的方法学评价及生物学变异研究

目的评价血清游离脂肪酸(FFA)酶学比色法(简称酶法)的精密度和正确度,并且研究血清FFA个体间和个体内生物学变异。方法采用美国临床和实验室标准化协会(CLSI)EP5-A2和EP15-A文件评价酶法测定血清FFA的精密度和正确度。生物学变异的研究对象为13名健康志愿者,在6周时间内每2周测定1次血清FFA浓度,利用SAS9.1软件中MIXED分析过程计算个体间生物学变异和个体内生物学变异。结果精密度实验样品的血清FFA浓度总均数为0.796 mmol/L,批内、批间、日间和室内不精密度分别为2.15%、3.44%、3.67%和5.46%。测定3个室间质评样品的百分比偏差分别为24.20%、-0.90%、-1.50%。血清FFA个体间和个体内生物学变异分别为8.43%、19.36%。结论酶法测定血清FFA的精密度和正确度能满足相关实验室质量控制要求。血清FFA的个体间和个体内生物学变异可为制定实验室质量规范和临床课题的科研设计提供参考依据。     

Trueness and precision of digital impressions obtained using an intraoral scanner with different head size in the partially edentulous mandible

Purpose

It remains unclear whether digital impressions obtained using an intraoral scanner are sufficiently accurate for use in fabrication of removable partial dentures. We therefore compared the trueness and precision between conventional and digital impressions in the partially edentulous mandible.

Effects of inter-implant distance on the accuracy of intraoral scanner: An in vitro study

PURPOSESeveral studies focused on the accuracy of intra-oral scanners in implant dentistry, but the data of inter-implant distances were not widely mentioned. Therefore, this study aimed to evaluate the effect of distance between two implants on the surface distortion of scanned models generated by intra-oral scanners.MATERIALS AND METHODSThree models with the distances between two fixed scan bodies of 7, 14, and 21 mm were fabricated and scanned with a highly precise D900L dental laboratory scanner as reference models. Fifteen scans were performed with TRIOS3 and CEREC Omnicam intra-oral scanners. Trueness, precision, and angle deviation of the test models were analyzed (α=.05).RESULTSThere was a significant difference among inter-implant distances in both intraoral scanners (P <.001). The error of trueness and precision increased with the increasing inter-implant length, while the angle deviation did not show the same trend. A significant difference in the angle deviation was found among the inter-implant distance. The greatest angle deviation was reported in the 14-mm group of both scanners (P <.05). In contrast, the lowest angle deviation in the 21-mm group of the TR scanner and the 7-mm of the CR scanner was reported (P <.001).CONCLUSIONThe inter-implant distance affected the accuracy of intra-oral scanner. The error of trueness and precision increased along with the increasing distance between two implants. However, the distortions were not clinically significant. Regarding angle deviation, the clinically significant angle deviation may be possible when using intra-oral scanners in the partially edentulous arch.     

血清SCC在非配套免疫检测系统中的性能验证

目的验证上海透景公司生产的化学发光法血清鳞状上皮细胞癌相关抗原(SCC)定量测定试剂盒在非配套免疫检测系统中的性能,并初步评价其临床应用价值。方法参考CLSI EP15-A2及EP9-A2方案,在雅培全自动免疫分析仪i2000SR上验证上海透景化学发光法SCC定量测定试剂盒,主要评价试剂盒的精密度、正确度、线性范围和生物参考区间。采用上海透景公司提供的多项肿瘤标志物质控品进行精密度的评价;同时,收集雅培化学发光法SCC检测结果均匀分布在测量范围内的冻存血清标本进行比对试验和线性范围的评价。另外,选取120例表观健康体检人员的新鲜血清标本进行生物参考区间的评价。将所得的结果与厂家提供的数值进行比较,判断其是否一致。结果测定多项肿瘤标志物质控品,血清SCC低值和高值质控品实验室内CV分别为5.37%和4.02%,均小于厂家提供的数值(≤10%),精密度验证通过。40例标本进行比对试验时,透景与雅培试剂盒SCC检测结果相关性良好,说明二者之间具有一致性。线性范围验证时,血清SCC的线性范围为0.1~70.0 ng/mL,决定系数R^2大于0.995。120例表观健康体检人员的血清SCC检测结果均在厂家提供的参考区间范围之内。结论上海透景化学发光法血清SCC定量测定试剂盒在非配套免疫检测系统(雅培全自动免疫分析仪i2000SR)中具有良好的精密度,与雅培化学发光法SCC试剂盒的检测结果和线性范围一致,可初步满足临床需要。     

Accuracy of 14 intraoral scanners for the All-on-4 treatment concept: a comparative in vitro study

PURPOSEThis in vitro study aimed to evaluate the accuracy of 14 different intraoral scanners for the All-on-4 treatment concept.MATERIALS AND METHODSFour implants were placed in regions 13, 16, 23, and 26 of an edentulous maxillary model that was poured with scannable Type 4 gypsum to imitate the All-on-4 concept. The cast was scanned 10 times for each of 14 intraoral scanners (Primescan, iTero 2, iTero 5D, Virtuo Vivo, Trios 3, Trios 4, CS3600, CS3700, Emerald, Emerald S, Medit i500, BenQ BIS-I, Heron IOS, and Aadva IOS 100P) after the polyether ether ketone scanbody was placed. For the control group, the gypsum model was scanned 10 times with an industrial scanner. The first of the 10 virtual models obtained from the industrial model was chosen as the reference model. For trueness, the data of the 14 dental scanners were superimposed with the reference model; for precision, the data of all 14 scanners were superimposed within the groups. Statistical analyses were performed using the Kolmogorov-Smirnov, Shapiro-Wilks, and Dunn’s tests.RESULTSPrimescan showed the highest trueness and precision values (P < .005), followed by the iTero 5D scanner (P < .005).CONCLUSIONSome of these digital scanners can be used to make impressions within the All-on-4 concept. However, the possibility of data loss due to artifacts, reflections, and the inability to combine the data should be considered.     

Comparing the accuracy (trueness and precision) of models of fixed dental prostheses fabricated by digital and conventional workflows

Purpose

This study aimed to evaluate and compare the accuracy.