title: Pressures generated in vitro during Stabident intraosseous injections.
abstract: OBJECTIVE
  To test the hypothesis that the Stabident intraosseous injection is a potentially high-pressure technique, which carries serious risks of anaesthetic cartridge failure.
  
  
  METHODS
  A standard Astra dental syringe was modified to measure the internal pressure of local anaesthetic cartridges during injection. Intra-cartridge pressures were measured at 1 s intervals during slow (approximately 15 s) and rapid (<10 s) injections of 2% Xylocaine with 1:80,000 adrenaline (0.25 cartridge volumes) into air (no tissue resistance), or into freshly prepared Stabident perforation sites in the anterior mandible of freshly culled young and old sheep (against tissue resistance). Each injection was repeated 10 times over 3 days. Absolute maximum pressures generated by each category of injection, mean pressures at 1 s intervals in each series of injections, and standard deviations were calculated. Curves of mean maximum intra-cartridge pressure development with time were plotted for slow and rapid injections, and one-way anova (P<0.05) conducted to determine significant differences between categories of injection.
  
  
  RESULTS
  Pressures created when injecting into air were less than those needed to inject into tissue (P<0.001). Fast injection produced greater intra-cartridge pressures than slow delivery (P<0.05). Injection pressures rose more quickly and to higher levels in small, young sheep mandibles than in larger, old sheep mandibles. The absolute maximum intra-cartridge pressure developed during the study was 3.31 MPa which is less than that needed to fracture glass cartridges.
  
  
  CONCLUSIONS
  Stabident intraosseous injection conducted in accordance with the manufacturer's instructions does not present a serious risk of dangerous pressure build-up in local anaesthetic cartridges.
authors.affiliation: School of Dental Sciences, Newcastle University, Newcastle upon Tyne, UK. j.m.whitworth@ncl.ac.uk
authors.forename: J M
authors.initials: JM
authors.lastname: Whitworth
authors.forename: R A M
authors.initials: RA
authors.lastname: Ramlee
authors.forename: J G
authors.initials: JG
authors.lastname: Meechan
mesh_terms: D000367:Age Factors; D000388:Air; D000772:Anesthesia, Local / Q000295:instrumentation*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D000818:Animals; D004837:Epinephrine / Q000008:administration & dosage; D007267:Injections / Q000295:instrumentation; D008012:Lidocaine / Q000008:administration & dosage; D008334:Mandible; D011312:Pressure; D012756:Sheep; D013594:Syringes; D013997:Time Factors; D014160:Transducers, Pressure; D014662:Vasoconstrictor Agents / Q000008:administration & dosage
chemical_list: D000779:Anesthetics, Local; D014662:Vasoconstrictor Agents; D008012:Lidocaine; D004837:Epinephrine