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Endo Tribune Middle East & Africa Edition No. 5, 2017

PUBLISHED IN DUBAI www.dental-tribune.me September-October 2017 | No. 5, Vol. 7 Cleaning is key By Aws Alani, UK Completely disinfecting the canal system is challenging when all fac- tors are considered. If we are looking at the nano level there are approxi- mately 76,000 dentinal tubules per square millimetre of dentine. Each of which can harbour a colony of bacteria. Then there may be inacces- sible anatomy such as lateral canals, apical deltas or fi ns. These are factors that need considering outside of ca- nal curvatures that may or may not be entirely visible in the plane of the radiograph. It is clear that outside of the contact our fi les make with the walls of the root canal there needs to be chemical disinfection to further reduce bacterial load. Irrigants disin- fect as well as lubricate instruments and they dissolve the pulp. Sodium hypochlorite has been the mainstay irrigant for decades. During the 1980s, Bystrom and col- leagues investigated the effect of me- chanical instrumentation with and without adjunctive use of hypochlo- rite. They found, unsurprisingly so, that when compared to pure me- chanical instrumentation, the use of hypochlorite in combination with hand fi ling signifi cantly reduced bac- terial load. As such chemomechani- cal instrumentation was shown to be crucial for endodontic success. They compared irrigation with saline, 0.5 % and 5 % hypochlorite over a se- quence of 5 appointments. Interest- ingly they found no difference in the reduction of bacterial load between 0.5 and 5 % hypochlorite. Despite what was likely to be a comprehen- sive protocol for these teeth, 7 of the 15 specimens in this study still had bacteria that they could grow at the end of treatment. The presence of cultivable bacteria does not necessar- ily mean we have failure—it merely means that there may be a cohort of bacteria that have resisted treat- ment. Mechanical instrumentation does reduce bacterial load by itself— this is by way of physical removal of tissues where bacteria reside, while also facilitating the dispersal of the irrigant into the canal. Siquiera and colleagues found that enlarging the canal from size 30 to 40 resulted in a signifi cant decrease in endodontic pathogens. It seems that irrigation and instru- mentation are both highly inter- related in canal disinfection. Take washing your car for instance, purely covering it with soapy water and rinsing won’t remove the motorway bugs and bird produced projectiles. A good scrubbing with a sponge is needed, or if you are really serious about cleaning, a pressure washer! This begs a further question—how would your patients feel if they knew that, more or less, the same or very similar liquid they use to clean bathroom suites is the same that we use to clean the inside of their teeth? On recent evidence of a dentist to the “stars” appearance on national TV not much—he advocated using charcoal to whiten teeth, which you may be able to buy from your local petrol station for barbecues. Annareichel/Shutterstock.com Hypochlorite is an effective bacteri- cidal but does not remove the smear layer. The smear layer is a mix of organic material (protein, pulp rem- nants, saliva, microorganisms) with an inorganic components consist- ing of minerals from the dentine. The smear layer prevents bacteria residing in the dentinal tubules from being exposed to the irrigant as well as reducing the contact between the dentine and sealant during obtura- ÿPage A2 3D agility_ The One to Shape your Success Anatomical root canal preparation Exclusive Adaptive Core™ Technology Superelasticity and expansion capacity Remarkable cyclic fatigue resistance Excellent debris removal FKG Dentaire SA www.fkg.ch

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