Background

Woodcast® is a wood-plastic composite casting material that becomes pliable and self-adhesive when heated to 65 °C and returns to being weightbearing as it cools down. The present study aims to test whether this novel non-toxic casting material is strong enough for clinical use by comparing its strength against materials that are already used in weightbearing casting applications such as total contact casts.

Methods

The strength of Woodcast® samples was compared against the strength of two commonly used synthetic casting materials (Delta-Cast®, OrthoTape). The effect of environmental factors such as cooling, prolonged heating and exposure to water was also assessed.

Findings

The results of this study indicated that Woodcast® is stronger than the synthetic casting materials in compression but weaker in tension. The flexural strength of Woodcast® was 14.24 MPa (±1.25 MPa) while the respective strength of Delta-Cast® and OrthoTape was 18.96 MPa (±7.46 MPa) and 12.93 MPa (±1.93 MPa). Independent samples t-test indicated that the difference between Woodcast® and the other two materials was not statistically significant (P > .05). Woodcast® recovered 90% and 78% of its tensile or flexural strength respectively after 15 min of cooling at ambient temperature and its strength was not reduced by prolonged heating. On average, exposure to water reduced the flexural strength of Delta-Cast® by 6% and of OrthoTape by 44%. The strength of Woodcast® was not affected by exposure to water.

Interpretation

The comparison between Woodcast® and commonly used synthetic casting materials indicated that Woodcast® is indeed strong enough to be safely used in weightbearing casting applications.

中文翻译：

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新型木塑复合材料和常用合成铸造材料的强度特性比较研究。

背景

Woodcast®是一种木塑复合铸造材料，在加热到65°C时会变得柔韧性和自粘性，并且在冷却后恢复承重。本研究旨在通过将这种无毒铸造材料的强度与承重铸造应用（例如全接触铸造）中使用的材料进行比较，来测试这种无毒铸造材料是否足以用于临床。

方法

将Woodcast®样品的强度与两种常用的合成铸造材料（Delta-Cast®，OrthoTape）的强度进行了比较。还评估了诸如冷却，长时间加热和暴露于水等环境因素的影响。

发现

这项研究的结果表明，Woodcast®在压缩方面比合成铸造材料强，但拉伸强度却弱。Woodcast®的抗弯强度为14.24 MPa（±1.25 MPa），而Delta-Cast®和OrthoTape的抗弯强度分别为18.96 MPa（±7.46 MPa）和12.93 MPa（±1.93 MPa）。独立样本t检验表明Woodcast®与其他两种材料之间的差异无统计学意义（P > .05）。在环境温度下冷却15分钟后，Woodcast®分别恢复了其拉伸强度或弯曲强度的90％和78％，并且长时间加热不会降低其强度。平均而言，接触水会使Delta-Cast®的抗弯强度降低6％，而OrthoTape的抗弯强度降低44％。Woodcast®的强度不受暴露于水的影响。

解释

Woodcast®与常用合成铸造材料之间的比较表明，Woodcast®确实足够坚固，可以安全地用于承重铸造应用中。