Albergo G, Bedini R, Pane S, Majori M, Gallottini L
Department of Technology and Health, Italian Institute of Health, Rome, Italy.
Minerva Stomatol. 2008 Jan-Feb;57(1-2):9-16, 16-20.
In this study Authors want to evaluate the static and dynamic flexural behaviour of innovative injection needles for dental anaesthesia comparing to the traditional needles.
Four kinds of innovative injection needles (Carpule Free Flow-Heraeus Kulzer), different for length and external diameter, have been evaluated in comparison with the traditional ones (Carpule-Heraeus Kulzer), dimensions being equal except for the internal diameter. Static stiffness tests (10 for each kind of needles, resulting in a totality of 80 tests) and fatigue bending test (10 for each kind of needles, each tested at 3 different bending angles, resulting in a totality of 240 tests) have been conducted following the ISO 9626 norms. The final comparison among the obtained data have been conducted using a one way statistical analysis of variance (ANOVA).
After stiffness tests the Carpule Free Flow injection needles and the traditional ones showed the same static behaviour, resulting in statistical comparable values of mean deflection at the maximum load allowed by ISO norms tests, whereas the 0.4 mm external diameter showed a statistically significant difference because the Carpule Free Flow needles achieved lower deflection values. After dynamic bending tests at 20 degrees both needle types showed the same behaviour, whereas at 30 degrees bending the Carpule Free Flow injection needles showed a higher number of breaks comparing to normal type, up to a maximum value of breaks (10 out of 10) for the 0.4 mm external diameter needles. After 50 degrees fatigue bending tests the Carpule Free Flow needles came to the break point after lower number of cycles than the Carpule needles.
This study pointed out that, among anaesthesia injection needles, the Carpule Free Flow needles not only showed better clinical characteristics but also a mechanical behaviour, both static and dynamic, statistically similar to traditional ones, according to international standards. After fatigue bending higher than 20 degrees, exclusively made in this research in order to simulate critical or extreme conditions, all analysed Carpule Free Flow needles have been broken after a lower number of cycles. It is concluded that it is recommended not to repeatedly bend this kind of needles at more than 90 degrees. At the end of this study it may be suggested that this kind of needles cannot be repeatedly bended at angles more than 90 degrees.
在本研究中，作者希望评估用于牙科麻醉的创新型注射针与传统针相比的静态和动态弯曲行为。
已对四种长度和外径不同的创新型注射针（卡普乐自由流动针 - 贺利氏库尔泽）与传统针（卡普乐针 - 贺利氏库尔泽）进行了评估，除内径外尺寸相同。按照ISO 9626标准进行了静态刚度测试（每种针10次，共80次测试）和疲劳弯曲测试（每种针10次，每次在3个不同弯曲角度下测试，共240次测试）。使用单向方差分析（ANOVA）对所得数据进行最终比较。
刚度测试后，卡普乐自由流动注射针和传统针表现出相同的静态行为，在ISO标准测试允许的最大负载下，平均挠度的统计值具有可比性，而外径0.4毫米的针表现出统计学上的显著差异，因为卡普乐自由流动针的挠度值较低。在20度动态弯曲测试后，两种针表现相同，而在30度弯曲时，卡普乐自由流动注射针的断裂次数比普通型多，外径0.4毫米的针断裂次数最多达到10次（共10次测试）。在50度疲劳弯曲测试后，卡普乐自由流动针在比卡普乐针更少的循环次数后达到断裂点。
本研究指出，在麻醉注射针中，卡普乐自由流动针不仅具有更好的临床特性，而且根据国际标准，其静态和动态机械行为在统计学上与传统针相似。在高于20度的疲劳弯曲后（本研究专门为模拟临界或极端条件而进行），所有分析的卡普乐自由流动针在较少的循环次数后均已断裂。得出的结论是，建议不要将这种针反复弯曲超过90度。在本研究结束时，可以建议这种针不能反复弯曲超过90度。
