Sterilization

1. Sterilization • Defined as destruction of all living organisms, (including highly resistant bacterial spores) • Goal of instrument sterilization is to kill all potentially harmful organisms to prevent direct cross contamination

2. Beginnings of sterilization… • Ancient Greeks used boiling water • End of 19th century • Koch and Lister discoveries lead to infection control

3. First Autoclave • Steam pressure cooker- invented by Denis Papin in 1679 • Louis Pasteur- confirms germ theory of disease • Charles Chamberland 1879 reformed steam digester into medical device

4. Details of Sterilization • Interferes with infectious diseases • Instruments can transmit infectious diseases • High heat destroys microbes • Follow manufacturer’s directions • Sterility of packets maintained until opened chair side

5. 3 autoclaves in clinic • Proper disinfection required before sterilization (supported by studies) • Carbon steel instruments - only use dry heat because of rusting Midmark Autoclave

6. Steps for using the autoclaves • Don PPE • Remove instruments from Miele • Wrap instruments • Indicator strip • Write date and autoclave number on tape • Check water level • Refill with distilled water • Load the autoclave • Do not stack packets • Place tape side down and blue side down • Select setting for contents and press start

7. Steps for using the autoclaves (cont.) • Change sign to “clean” • End of cycle door pops open • Leave contents to dry • Use oven mitts if items hot • Empty contents into cubbies • Never leave for the day if autoclave is in a cycle • Don’t start a cycle after 2:45 pm • Unplug autoclaves at end of the day

8. Safety with the autoclaves and additional details • Potential to burn oneself if trays have not cooled fully before touching with bare hands.

9. Heat Sterilization • CriticalInstruments • Penetrate soft tissue or bone • Probes • Explorers • Scaling & root planinginstruments • SemicriticalInstruments • Contact oral fluids/mucous membranes • Mouth mirrors • Impression trays

10. Autoclave • Mode of action • High pressure and steam • 250 degrees F, 15 psi, 15-20 min. • Advantage • Non toxic, inexpensive, quick • Drawback • Instrument corrosion • Types • Prevacuum • Gravity Displacement Midmark M9 Autoclave

11. Influence of sterilization on the retention properties of magnetic attachments for dental implants Study performed in 2009 states sterilization using autoclave does not effect magnetic properties of implants.

12. Unsaturated Chemical Vapor Sterilizer • Mode of action • High pressure and chemical vapor • 20 psi, 20-40 minutes, 270 degrees F • Advantage • Does not rust or corrode instruments • Drawback • Toxic chemical vapors

13. Dry-heat Sterilizer • Mode of action • High heat • 300-340 degrees F, 60-350 min. • Advantage • Low cost • Does not corrode instruments • Drawback • Time-consuming • Damage heat-sensitive items Henry Schein –Model 200 • Types • Static-air (oven type) • Forced air

14. Flash Sterilizer • Instruments for immediate use • Mode of action • High pressure and steam • 270 degrees F, 3 minutes, 27-28 psi. Midmark M3 • Drawback • Instruments are unwrapped, so contaminated upon removal. * Investigations - Increased incidence of neurosurgical infections. Patient burns.

15. Low Temperature Sterilization, Ethylene Oxide gas (ETO) • Mode of action • Exposure to gas for 10-48 hours • Advantage • No heat or moisture damage • Drawback • Time consuming • Potential health/safety hazards Andersen AN74ix * Better for large health-care facilities

16. Testing • Chemical indicators - Tests for certain element • External indicator - Outside of package • Internal indicator - Inside of package (i.e. strips) Hu-Friedy Sterilization Steam Indicator Strips • Single Parameter - One variable • Multiparameter - Multiple variables

17. Testing (cont.) • Biological Indicators (a.k.a. spore tests) • Strip is embedded with spores * • Place strip in sterilizer with instruments • Send to lab Henry Schein MaxiTest * Nonpathogenic Bacillus spores are used

18. Efficacy • 2011 Study published in World Journal of Dentistry • 30 rotary nickel-titanium files divided into 4 separate groups. All were exposed to Bacillus stearothermophilus. Vs.

19. One of the observational studies performed in Scotland showed that effectiveness of bench top autoclaves is often compromised due to: • Lack of adequate training of an operator • Improper packaging of the instruments • Using poor quality water • Not following maintenance guidelines Smith AJ, Bagg J, Hurrell D, McHugh S. Sterilization of re-usable instruments in general dental practice. Br Dent J. 2007 Oct 27 203(8): E16

20. Maintenance Procedures Weekly • Wipe external surfaces • Clean internal surfaces • Drain water to prevent malfunction • Wash inside chamber • Refill reservoir with distilled water

21. Maintenance Procedures Monthly • Drain reservoir and fill water • Add 1oz. of speed-clean sterilizer cleaner to a cool chamber • Run one pouch cycle • Run one unwrapped cycle • Drain reservoir and allow sterilizer to cool • Clean channel gaskets and filter • Refill reservoir

22. Biological Spore Testing • Spore test every Thursday • Each spore test envelope contains 2 strips • One spore test per sterilizer • Fill out back of the spore test envelope • Give to Truc for mailing • Record in sterilization binder • Date of spore test • Student performing spore test • Individual who mailed spore test • Date spore test was mailed

23. OSHA Regulations There is no specific OSHA standard on the autoclaving of instruments. Centers for Disease Control and Prevention (CDC) have developed guidelines and recommendations on the use and monitoring of sterilization equipment in dental healthcare settings, and the Food and Drug Administration (FDA) also have relevant information in connection with that agency's approval of autoclaves. 

24. CDC Recommendations Ensure that the autoclave/sterilizer door is closed and locked before beginning the cycle. Do not remove items from an autoclave/sterilizer until they have cooled. Avoid handling the sharp ends of instruments. Use forceps or other tools to remove sharp instruments from baskets and autoclaves.

25. References • Darby ML, Walsh MM, editors. Dental hygiene theory and practice. 3rd ed. St. Louis (MO): Saunders Elsevier; 2010. p. 92-94. • Rutala WA, Weber DJ. Guideline for disinfection and sterilization in healthcare facilities, 2008 [Internet]. Atlanta (GA): Department of Health and Human Services –Centers for Disease Control and Prevention; 2008 [cited 2012 Nov 2]. p. 58-69. Available from http://www.cdc.gov/hicpac/pdf/guidelines/Disinfection_Nov_2008.pdf • Kohn WG, Collins AS, Cleveland JL, Harte JA, Eklund KJ, Malvitz DM. Guidelines for infection control in dental health-care settings – 2003 [Internet]. Department of Health and Human Services –Centers for Disease Control and Prevention. MMWR. 2003 Dec; 52(RR17);1-61 [cited 2012 Nov 2]. Available from: http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5217a1.htm • Halebathi RG, Dodwad PK, Uppin VM, Ghandi B, Sarangi P, Sahni N. Comparative evaluation of the efficacy of two methods of sterilization for rotary nickel-titanium files: an in vitro study. World J Dent. 2011 July;2(3):193-198. • Foucaud E, The book of illustrious mechanics of Europe and America [Internet].Google e-books [cited 2012 Nov 20]. Available from http://www.ehow.com/about_5641799_autoclave-history.html • “Pressure Cooker.” Encyclopedia Britannica. 2012. Web. 02. 2012 [Internet] Available from http://www.britannica.com/EBchecked/topic/475443/pressure-cooker/475443rellinks/Related-Links • Smith AJ, Bagg J, Hurrell D, McHugh S. Sterilization of re-usable instruments in general dental practice. Br Dent J. 2007 Oct 27 203(8): E16 • BoecklerAF, Morton D, Ehring C, Setz JM. Influence of sterilization on the retention properties of magnetic attachments for dental implants. Clin Oral Implants Res. 2009 Nov;20(11):1206-11. • Fairfax RE. OSHA standards on the autoclaving of instruments, 2004 [internet]. Directorate of Enforcement Programs – OSHA; 2004 [cited 2012 Nov 15]. Available from: http://www.osha.gov/law-regs.html • Bolyard EA, Tablan OC, Williams WW, Pearson ML, Shapiro CN, Deitchman SD, The Hospital Infection Control Practices Advisory Committee. Guideline for infection control in health care personnel. Guidelines for infection control in healthcare personnel. Centers for disease control and prevention public health services; 1998 [cited 2012 Nov 15]. Available from: http://www.cdc.gov/HAI/prevent/sd_medicalDevices.html • Burnett, George Wesley. Oral microbiology and infectious disease. Student ed. Baltimore (Md.): Williams & Wilkins Co.; 1978. • Bagg, Jeremy. Essentials of microbiology for dental students. Oxford (NY): Oxford University Press; 1999. Ch. 10. • Gasic, J., Petrovic, A., Popovic, J., Radicevic, G., Zivkovic, S.. “Evaluation of biological debris on endodontic instruments after cleaning and sterilization procedures.” IntEndod J. April 2010 (cited 2012 November 4); 43 (4): 336-341. Available from www.ebsco.com or Foothill Library Database to EBSCO.