Development of a compact induction-heated autoclave with a dramatically shortened sterilization cycle in orthodontic clinics

PurposeThis article reviews the development of a compact autoclave with a dramatically shortened running time that did not compromise the quality of its sterilization properties including orthodontic appliances, orthodontic mini-implants (anchor screws), instruments and other dental items.Materials and methodsInduction heating (IH) mechanisms were employed to produce a more compact machine and shorten sterilization sufficiently so that it could be used at chair-side. Intravessel pressure was estimated by a pressure gauge mounted in the lid of the sterilization vessel. A digital multimeter with a K thermocouple set in the lid of the vessel was used to monitor this intravessel temperature.The level of sterilization achieved with a conventional autoclave and an IH autoclave was quantified by the biological indicator containing vials of Geobacillus stearothermophilus bacteria in growth media.ResultsWe found that the minimum effective sterilizing time after reaching the operating pressure was 25, 15, 12.5, 10 and 5 min at 0.20, 0.25, 0.30, 0.35 and 0.50 MPa with a compact IH mechanism, respectively. Combining the values with (i) the time taken to achieve the operating pressure and (ii) ∼2–3 min for cooling and removal of sterilized items gave the total sterilization cycle time, which were, on average, 30, 22, 19, 18 and 13 min at 0.20, 0.25, 0.30, 0.35 and 0.50 MPa, respectively.ConclusionsIH mechanism is useful for compact and speedy autoclave, which reduce total sterilisation time by 40–80% compared with conventional autoclaves.