Rigidity of dental local anaesthetic injection needles.
The objective of this study was to determine the rigidity of 11 different types (4 brands) of dental local anaesthetic injection needles available in South Africa. Twenty needles of each type were attached to a Zwick material testing apparatus and subjected to pressure testing. Stress vs deformation curves were obtained for each needle. The data obtained was logarithmically converted and subjected to an analysis of covariance. The results from this study showed that there were statistically significant differences in the rigidity of dental needles available on the South African market.