Irrigation in Endodontics - The Endoexperience
Irrigation in Endodontics - The Endoexperience
Irrigation in Endodontics - The Endoexperience
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Haapasalo et al<br />
dissolve tissue either. <strong>The</strong>refore there is no good reason for their use <strong>in</strong> canal irrigation<br />
<strong>in</strong> rout<strong>in</strong>e cases. In addition, water and sal<strong>in</strong>e solutions bear the risk of contam<strong>in</strong>ation if<br />
used from conta<strong>in</strong>ers that have been opened more than once. Iod<strong>in</strong>e potassium iodide<br />
(eg, 2% and 4%, respectively) has considerable antimicrobial activity but no tissuedissolv<strong>in</strong>g<br />
capability 38,39 and it could be used at the end of the chemomechanical<br />
preparation like CHX. However, some patients are allergic to iod<strong>in</strong>e, which must be<br />
taken <strong>in</strong>to consideration.<br />
Interactions Between Irrigat<strong>in</strong>g Solutions<br />
Hypochlorite and EDTA are the 2 most commonly used irrigat<strong>in</strong>g solutions. As they<br />
have different characteristics and tasks, it has been tempt<strong>in</strong>g to use them as a mixture.<br />
However, EDTA (and CA) <strong>in</strong>stantaneously reduces the amount of chlor<strong>in</strong>e when mixed<br />
with sodium hypochlorite, result<strong>in</strong>g <strong>in</strong> the loss of NaOCl activity. Thus, these solutions<br />
should not be mixed. 40<br />
CHX has no tissue-dissolv<strong>in</strong>g activity and there have been efforts to comb<strong>in</strong>e CHX<br />
with hypochlorite for added benefits from the 2 solutions. However, CHX and NaOCl<br />
are not soluble <strong>in</strong> each other; a brownish-orange precipitate is formed when they are<br />
mixed (Fig. 4). <strong>The</strong> characteristics of the precipitate and the liquid phase have not<br />
been thoroughly exam<strong>in</strong>ed, but the precipitate prevents the cl<strong>in</strong>ical use of the mixture.<br />
Atomic absorption spectrophotometry has <strong>in</strong>dicated that the precipitate conta<strong>in</strong>s iron,<br />
which may be the reason for the orange development. 41 Presence of parachloroanil<strong>in</strong>e,<br />
which may have mutagenic potential, has also been demonstrated <strong>in</strong> the<br />
precipitate. 42,43<br />
Mix<strong>in</strong>g CHX and EDTA immediately produces a white precipitate (Fig. 5). Although<br />
the properties of the mixture and the cleared supernatant have not been thoroughly<br />
studied, it seems that the ability of EDTA to remove the smear layer is reduced.<br />
Many cl<strong>in</strong>icians mix NaOCl with hydrogen peroxide for root-canal irrigation. Despite<br />
more vigorous bubbl<strong>in</strong>g, the effectiveness of the mixture has not been shown to be<br />
Fig. 4. Orange precipitate formed by mix<strong>in</strong>g chlorhexid<strong>in</strong>e with sodium hypochlorite.