Statement of problem

Redesigned mixing tips, promising less impression material waste, have been marketed. However, whether their use adversely affects the dimensional stability and detail reproduction of the impression material is unclear.

Purpose

The purpose of this in vitro study was to evaluate the dimensional stability, detail reproduction, and material waste of different polyvinyl siloxane impression materials (regular and light-body) mixed with 2 different mixing tips (MIXPAC T-Mixer mixing tip and MIXPAC helical mixing tip).

Material and methods

Six different polyvinyl siloxane impression materials were used in 2 different consistencies: Virtual Monophase and Virtual Light Body (Ivoclar Vivadent AG), Express XT Regular and Express XT Light Body (3M ESPE), and Panasil initial contact Regular and Panasil initial contact Light (Kettenbach). The polyvinyl siloxane impression materials were mixed with 2 different mixing tips: conventional helical and T-Mixer (n=10). The specimens were prepared in a metal matrix as per specification #19 of the American National Standards Institute/American Dental Association (ANSI/ADA) and International Organization for Standardization (ISO) 4823:2015. The materials were mixed with both mixing tips as per the manufacturer’s instructions, inserted into a perforated custom tray on the matrix, and allowed to polymerize completely. The dimensional stability was calculated based on the measurement of the reproduction of lines engraved in the metal matrix. Detail reproduction was evaluated through analysis of continuity and reproducibility of those lines, immediately, 7 days, and 14 days after polymerization. Material waste was assessed by the difference between the initial (before mixing) and final weight (after complete polymerization) of both mixing tips. The data on dimensional stability and detail reproduction among the materials were submitted to the Kruskal-Wallis test, followed by the Student-Newman-Keuls test (α=.05). Comparison between the mixing tips was carried out with the Mann-Whitney test (α=.05), while the comparison among the periods of analysis (immediate, 7 days, and 14 days) was carried out with the Friedman test (α=.05). The data on material waste between the mixing tips were submitted to 1-way ANOVA, followed by the Tukey honestly significant difference tests (α=.05).

Results

The T-Mixer mixing tip resulted in reduced material waste. For dimensional stability, Virtual Light mixed with T-Mixer resulted in lower dimensional change (0.53 ±0.58%) compared with the helical mixing tip (1.09 ±0.43%). Among the materials, Panasil Light presented higher values of dimensional change at immediate and 7-day analysis when mixed with T-Mixer tip with a statistical difference compared with Express Light, Virtual Light, and Panasil Regular (P<.05). In general, both mixing tips provided similar results in all periods of analysis (P>.05) for qualitative analysis of detail reproduction.

Conclusions

The T-Mixer tip resulted in less material waste compared with the helical mixing tip. In general, light-body materials showed higher dimensional stability when the T-Mixer tip was used compared with the conventional tip. In general, reduced detail reproduction was observed after periods longer than 7 days after impression making.

中文翻译：

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评估与不同混合头混合的聚乙烯基硅氧烷印模材料的材料浪费、尺寸稳定性和细节再现

问题陈述

重新设计的混合头，承诺减少印模材料的浪费，已经上市。然而，它们的使用是否会对印模材料的尺寸稳定性和细节再现产生不利影响尚不清楚。

目的

本体外研究的目的是评估不同聚乙烯硅氧烷印模材料（常规和轻体）与 2 种不同混合头（MIXPAC T-Mixer 混合头和 MIXPAC 螺旋混合头）混合后的尺寸稳定性、细节再现和材料浪费小费）。

材料与方法

六种不同的聚乙烯硅氧烷印模材料用于 2 种不同的稠度：Virtual Monophase 和 Virtual Light Body (Ivoclar Vivadent AG)、Express XT Regular 和 Express XT Light Body (3M ESPE)，以及 Panasil initial contact Regular 和 Panasil initial contact Light (Kettenbach ）。聚乙烯硅氧烷印模材料与 2 种不同的混合尖端混合：传统的螺旋和 T 型混合器 (n=10)。根据美国国家标准协会/美国牙科协会 (ANSI/ADA) 和国际标准化组织 (ISO) 4823:2015 的规范 #19 在金属基质中制备样品。根据制造商的说明将材料与两种混合尖端混合，插入基质上的穿孔定制托盘中，并使其完全聚合。尺寸稳定性是基于对刻在金属基质中的线条的再现性的测量来计算的。通过分析聚合后立即、7 天和 14 天这些线的连续性和再现性来评估细节再现性。通过两个混合尖端的初始（混合前）和最终重量（完全聚合后）之间的差异来评估材料浪费。材料之间尺寸稳定性和细节再现的数据提交给 Kruskal-Wallis 测试，然后是 Student-Newman-Keuls 测试 (α=.05)。混合尖端之间的比较采用 Mann-Whitney 检验 (α=.05)，而分析周期之间的比较（立即、7 天和 14 天）采用弗里德曼检验 (α=.05) 进行比较。 05)。

结果

T-Mixer 混合头减少了材料浪费。对于尺寸稳定性，与螺旋混合尖端 (1.09 ±0.43%) 相比，Virtual Light 与 T-Mixer 混合导致较小的尺寸变化 (0.53 ±0.58%)。在这些材料中，与 Express Light、Virtual Light 和 Panasil Regular 相比，Panasil Light 与 T-Mixer 吸头混合时在即时和 7 天分析时呈现更高的尺寸变化值，具有统计学差异 ( P <.05)。一般来说，两个混合技巧在所有分析阶段都提供了相似的结果 ( P >.05)，用于细节再现的定性分析。

结论

与螺旋混合头相比，T-Mixer 头产生的材料浪费更少。一般来说，与传统的尖端相比，使用 T-Mixer 尖端时，轻体材料表现出更高的尺寸稳定性。一般来说，在印模制作超过 7 天后，观察到细节再现减少。