Thoughts on 'Toxicity'
A few thoughts on the 'toxicity' of ZOE.
Any foreign material introduced to the body can be said to be 'toxic' in the sense that the body reacts to it adversely. Thus all sealers that we might choose to use are 'toxic' to a certain degree. The big question is this, "Is the level of 'toxicity' tolerable in relation to the good that it does. I.e. Is it worth it given the good that it does.
- The toxic part of the ZOE cement is not the ZO but the E.
- After ZO combines chemically with E it becomes ZOE which is neither ZO nor E. Just as when chlorine and sodium are combined into sodium chloride, it is not as toxic as either of it's components.
- ZOE is not nearly as toxic as E
- When ZO is mixed with E it is still ZO suspended in E and after it sets it's ZOE
- In a chemical reaction if one ZO combines with one E and you have two E's then when it sets you have one ZOE plus one E
- The E is still toxic but neither the ZO nor the E that combined with it is, because now it is ZOE
- Hypothesis: We could practially eliminate the toxicity of ZOE by mixing no more E with the ZO than can combine with it forming ZOE limiting the toxic countdown time to the setting time of the mix.
- Conclusion: Mix the ZOE as thick as humanly possible will minimize the toxicity to the point of it being negligible in a clinical sense.
- Further conclusion, since ZOE used with solid core filling materials must be mixed thin, using ZOE by itself can be less toxic.
- Since ZOE mixed thick is syringeable, and thick ZOE is less toxic, syringe endo produces a less toxic overfill( puff, if you will ) than ZOE used with gutta percha.
- Any research that purports to compare the toxicity of ZOE with any other material has to explain the amount of ZO and the amount of E to be a valid comparison.
- Total weight of powder ( which contains things that E doesn't combine with ) doesn't count. Total liquid (which contains things that ZO doesn't combine with) doesn't count either.