Failure of dental local anaesthetic cartridges under pressure.

The objective of this study was to determine the pressures that caused cartridge failure (leakage or fracture) of six different dental local anaesthetics available in South Africa. Forty glass cartridges of each local anaesthetic were placed in an apparatus and subjected to pressure testing using two different plungers. Failure of the cartridges was observed visually as well as on the computer screen of the testing apparatus. In addition the compressibility of local anaesthetic rubber stoppers (bungs) was measured. The data obtained was analysed by means of a two-way analysis of variance and a chi-square test. The results from this study showed that there were statistically significant differences in the mean pressures that caused failure of local anaesthetic cartridges available on the South African market.