Monteiro Marco Antônio de Oliveira, Antunes Alberto Nogueira da Gama, Basting Roberta Tarkany
Faculdade São Leopoldo Mandic, Campinas, São Paulo, Brazil.
Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
J Dent Anesth Pain Med. 2021 Apr;21(2):139-153. doi: 10.17245/jdapm.2021.21.2.139. Epub 2021 Mar 31.
In anesthetic techniques, touching bones can cause needle bending. Theoretically, a needle should support such deflection without fracturing. However, it is possible that a needle may fracture depending on the quality and type of needle used. This study evaluated the physical, chemical, and micromorphological characteristics of long and short dental anesthetic needles, as well as the mechanical properties of flexural load and bending resistance when needles are subjected to different bending angles.
Long and short needles (30G, Jets, Misawa, Selekto, Terumo, Unoject and 27G, Dencojet, Injex, Jets, Misawa, Procare, Setoject XL, Terumo) were evaluated. Scanning electron microscopy was used to evaluate the needle bevels and energy-dispersive X-ray spectroscopy was used for the chemical analysis of needle compositions. Flexural loading and bending strength assessments were performed using a universal testing machine by bending the needles (n = 5) to angles of 30°, 60°, or 90°, or until fracture occurred.
The Injex 27G, Jets 27G, and Septoject XL 27G needles were all less than 30 mm in length. There were small percentage variations in the chemical compositions of the needles. Superior smoothness was observed for the Unoject 30G needle, which exhibited the highest fracture resistance at 60°. The Jets 30G needle exhibited greater resistance to fractures at 90°. The Procare 27G needle exhibited the highest load resistance to bending, followed by the Septoject XL 27G needle, and both needles were tied for the lowest fracture resistance. No needle fractured when bent to 30° or at less than three bends to 60° or 90°.
Greater needle resistance to bending increases the probability of early fracturing. Thinner and shorter needles are more resistant than longer and thicker needles. Performing a single bend does not result in any significant risk of fracture or obliterate the lumen, allowing for the continued passage of anesthetic liquid.
在麻醉技术中，触碰骨头可能导致针头弯曲。理论上，一根针头应能承受这种弯曲而不折断。然而，根据所用针头的质量和类型，针头有可能会折断。本研究评估了长短牙科麻醉针头的物理、化学和微观形态特征，以及针头在不同弯曲角度下的弯曲载荷和抗弯曲机械性能。
对长短针头（30G，Jets、Misawa、Selekto、Terumo、Unoject；27G，Dencojet、Injex、Jets、Misawa、Procare、Setoject XL、Terumo）进行评估。使用扫描电子显微镜评估针头斜面，使用能量色散X射线光谱仪对针头成分进行化学分析。使用万能试验机通过将针头（n = 5）弯曲至30°、60°或90°角，或直至折断来进行弯曲载荷和弯曲强度评估。
Injex 27G、Jets 27G和Septoject XL 27G针头的长度均小于30 mm。针头的化学成分存在小百分比差异。观察到Unoject 30G针头具有卓越的光滑度，在60°时表现出最高的抗折断性。Jets 30G针头在90°时表现出更大的抗折断性。Procare 27G针头表现出最高的抗弯曲载荷，其次是Septoject XL 27G针头，且这两种针头的抗折断性并列最低。当弯曲至30°或弯曲至60°或90°少于三次时，没有针头折断。
更大的针头抗弯曲性会增加早期折断的可能性。更细更短的针头比更长更粗的针头更具抗折断性。进行单次弯曲不会导致任何显著的折断风险或使管腔闭塞，从而允许麻醉液体持续通过。
