treatment why the original treatment failed .
If it is simply a case of poorly executed treatment ( poorly obturated , missed anatomy , etc .) a single visit treatment may be possible . In more complicated failed treatment , such as teeth with perforations , teeth with large periapical areas of longstanding , periapical areas which are increasing rapidly and failed silver point root fillings , it is sensible to consider dressing the tooth prior to obturation .
Teeth with symptoms of acute infection at the time of treatment ( e . g . marked swelling or marked tenderness to pressure ) are more likely to flare up and again it is wise to consider a 2-visit approach . If the tooth is dressed , it does of course allow for easier access to the apical tissues if there is a flare up and further treatment is indicated .
A ‘ crown down ’ technique will help the chances of comfortable single visit treatment as it reduces the tendency to carry infected material to the apical end of the canal . With a rubber dam applied , the pulp chamber and coronial part of the crown should be thoroughly disinfected prior to further access into the canals .
It is widely accepting that the gold standard for root canal disinfection is regular sodium hypochlorite ( NaOCl ), commonly used at a concentration of anywhere between 1 and 5 %. There is much debate about what concentration should be used , or whether the hypochlorite should be heated . What seems to be important is the amount of irrigant used ( copious amounts should be used , 10s of mls per canal ) as well as the use of ultrasonic agitation to ‘ activate ’ the irritant . This ‘ Passive Ultrasonic Irrigation ( PUI ) uses non-cutting ultrasonic tips which help to create steaming within the irrigant , which increases the mechanical cleaning of the irrigant as well as increasing the chemical activity ( Gutarts et al 2005 ).
The recommendation for PUI from Van der Sluis ( 2006 ) is to use 3x 2ml 2 % NaOCl with 20 seconds ultrasonic agitation per canal . This helps to remove organic and inorganic debris by physical irrigation , cavitation ( the effect of ‘ bubbles ’) as well as gently heating the hypochlorite . It is felt that this regime is as effective as the use of 50mls of irrigant .
The advent of rotary Nickel Titanium ( NiTi ) files has helped to improve the efficiency of canal shaping as well as helping to achieve deep tapers that correctly follow the canal anatomy and aid irrigant action . The increase in efficiency increases the amount of time that the irrigant can be where it needs to be working , but it is obviously still important that all the anatomy is identified and cleaned and that sufficient irrigant is used and crucially that enough time is allowed .
The correct identification of anatomy requires magnification and this is one of the most important aids to success of endodontic treatment of any description
Fig 1 ( preop radiograph ) Fig 2 ( 4 week follow up ) Fig 3 ( 4 month follow up )
FIGS 1-3 : Single visit endodontic treatment in a tooth with a large periapical area . FIG 4 : Some teeth even have more canals ( 6 canals in a lower molar !) FIG 5 : Root-filled lower first molar ’.
and particularly when we try to achieve this in a single visit . It has been shown that most upper first molars have 4 canals ( 93 % according to Stropko amongst others ) but so too do a high proportion of second molars ( over 60 %) and even lower incisors are likely to have 2 canals ( 32 %). Magnification ( ideally a microscope ) is crucial to identify this as again is sufficient time and expertise . Magnification is also crucial for retreatment cases , as well as checking that the canal is as clean and dry as possible prior to obturation .
Once the canals have been thoroughly cleaned and completely obturated ( with a system that will fill the canals in 3 dimensions , such as is achieved with warm vertical compaction ), it is important that the pulp chamber is sealed to prevent the reintroduction of bacteria . It has been shown that placing a good base ( such as glass ionomer ) in the pulp chamber at the time of obturation will help with success
Fig 4
Fig 5
rates ( Hommez 2002 ). Similarly it has been shown that long term coronal restoration is very important to the long term success ( Ray and Trope showed it to be more important that the quality of the endodontic treatment alone !) and this should therefore be carried out as quickly as practical after endo treatment is completed .
This is all in keeping with basic tenets of endodontic treatment . However technical and mechanical endodontic treatment seems , it is actually all about bugs . Whether treatment is carried out in a single visit or multiple visits , we need to do everything we can to thoroughly clean the whole canal system and prevent the reintroduction of bacteria . If this is done in a careful and controlled way , allowing enough time for thorough mechanical and chemical cleaning , with care of the delicate apical tissues , single visit endodontics will be successful and comfortable in most cases .
38 Dental Practice Magazine