Dental Tribune United Kingdom Edition

15Endo TribuneNovember 2013United Kingdom Edition Find out how Objet 3D printers from Stratasys can make digital orthodontics a reality for your lab. stratasysdental.com | marketing.emea@stratasys.com | +49 7229 777 2-0 Exclusively designed for smaller labs and clinics, the new Objet30 OrthoDesk is office-friendly, affordable and easy to use. It is the first solution that puts cutting-edge, 3D printing technology on your desktop. Now you can digitally manufacture stone models, orthodontic appliances, delivery and positioning trays, clear aligners and retainers faster than ever. Transition to a digital workflow and do away with bulky physical model storage. Take the leap to digital orthodontics today, and: • Increase your production capacity and accuracy • Accelerate production times • Eliminate traditional stone model storage • Stay ahead of the competition • Eliminate the inconvenience of physical impressions The Future of Orthodontics Fits on Your Desktop Objet30 OrthoDesk The Secret to Dental Lab Survival Go Digital In vitro and in vivo studies have demonstrated greater removal of debris from the apical walls and a statistically cleaner result using apical negative-pressure irrigation in closed root canal systems with sealed apices. In an in vivo study of 22 teeth by Siu and Baumgartner, less debris re- mained at 1mm from working length using apical negative pres- sure compared to use of tradition- al needle irrigation, while Shin et al. found in an in vitro study of 69 teeth comparing traditional nee- dle irrigation with apical nega- tive pressure that these methods both resulted in clean root canals, but that apical negative pressure resulted in less debris remaining at 1.5 and 3.5mm from working length.46,104,116 When comparing root canal debridement using manual-dy- namic agitation or the EndoVac for final irrigation in a closed system and an open system, it was found that the presence of a sealed apical foramen adversely affected debridement efficacy when manual-dynamic agitation was used, but did not adversely affect results when the Endo- Vac was used. Apical negative- pressure irrigation is an effective method to overcome the fluid- dynamic challenges inherent in closed root canal systems.117 Microbial control Hockett et al. tested the abil- ity of apical negative pressure to remove a thick biofilm of E. Faecalis, finding that these speci- mens rendered negative cultures obtained within 48 hours, while those irrigated using traditional positive-pressure irrigation were positive at 48 hours.99 One study found that api- cal negative-pressure irrigation resulted in similar bacterial re- duction to use of apical positive- pressure irrigation and a triple antibiotic in immature teeth.118 In a study comparing the use of apical positive-pressure irriga- tion and a triple antibiotic that has been utilised for pulpal regen- eration/revascularisation in teeth with incompletely formed apices (Trimix = Cipro, Minocin, Flagyl) versus use of apical negative- pressure irrigation with NaOCl, it was found that the results were statistically equivalent for min- eralised tissue formation and the repair process.119 Using apical negative pressure and NaOCl also avoids the risk of drug resistance, tooth discoloration, and allergic reactions.120,121 Conclusion Since the dawn of contemporary endodontics, dentists have been syringing NaOCl into the root canal space and then proceed- ing to place endodontic instru- ments down the canal in the be- lief that they were carrying the irrigant to the apical termination. Biological, scanning electron mi- croscopy, light microscopy, and other studies have proven this belief to be in error. NaOCl reacts with organic material in the root canal and quickly forms micro- bubbles at the apical termina- tion that coalesce into a single large apical vapour bubble with subsequent instrumentation. Since the apical vapour lock can- not be displaced via mechani- cal means, it prevents further NaOCl flow into the apical area. The safest method yet dis- covered to provide fresh NaOCl safely to the apical terminus to eliminate the apical vapour lock is to evacuate it via apical nega- tive pressure. This method has also been proven to be safe be- cause it always draws irrigants to the source via suction - down the canal and simultaneously away from the apical tissue in abundant quantities.122 When the proper irrigating agents are delivered safely to the full extent of the root canal terminus, thereby removing 100 per cent of organic tissue and 100 per cent of the microbial con- taminants, success in endodontic treatment may be taken to levels never seen before. DT Editorial note: A complete list of references is available from the publisher. This article has been reprinted in part from G. Glass- man, Safety and Efficacy Consid- erations in Endodontic Irrigation (PenWell, January 2011). About the author Dr Gary Glassman graduated from the University of Toronto Faculty of Dentistry in 1984 and graduated from the Endodontology Program at Temple University in 1987, where he received the Louis I. Grossman Study Club Award for academic and clinical proficiency in endodontics. The au- thor of numerous publications, he lec- tures globally on endodontics and is on the staff at the University of Toron- to Faculty of Dentistry in the Graduate Department of Endodontics. He is a fellow of the Royal College of Dentists of Canada, and the endodontic editor for the Oral Health journal. He main- tains a private practice, Endodontic Specialists, in Toronto, Ontario, Can- ada. He can be reached through his website, www.rootcanals.ca