what is the effect of over itching???

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Dental Source

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i wonder if someone can help me and give me a full scientific answer for that question, and the one who will answer the most right answer will have a great prize
 
for ahmedhish, do i know u man?
i have a scientific question and i need an answer, if u can help me it is ok and u will get ur prize if u can't don't bother me or others here, and i couldn't read what u wrote, in which language did u write it, is that spanich?
 
Dental Source said:
i wonder if someone can help me and give me a full scientific answer for that question, and the one who will answer the most right answer will have a great prize

A scratch
 
Dental Source said:
i wonder if someone can help me and give me a full scientific answer for that question, and the one who will answer the most right answer will have a great prize

This, in sharp contradistinction, leads to larger and more numerous microporosities in the enamel surface than are required for bonding. Fluids can percolate down to the dentinal tubules and lead to sensitivity.
 
only that? my prof said that it is a long answer and it causes many things, so if u know more plz send it and don't worry u will get ur prize :clap:
and what about under itching? what is its effect???
 
"Itching"... seriously? Twice? This may be part of the reason you are having a difficult time getting an answer.
 
oh "etching".. I didn't understand when the OP typed itching 🙂
 
:laugh:
the most funny part in all that, that everyone made laugh on (Itching) and after knowing that it is etching not (itching) he/she didn't give an answer 🙂
 
oh c'mon...

etching is done so that you can increase the surface area of the available enamel or dentine for greater bonding. you expose more enamel rods and dentinal tubules.

if you were to over-etch... i guess you would most likely dehydrate the tooth very very much. i do not think that bonding will be jeapordised though.

does that answer your question? 🙂
 
To answer your question:
My understanding is that it is difficult to over-etch enamel, but very possible to over-etch dentin.

You can etch w/ 37% phosphoric acid for greater than 15 seconds on enamel with no negative effects to the tooth or bonding. Etching more than 15 seconds in dentin is, however, detrimental. This is because over-etching dentin demineralizes too much of the inorganic components and denatures the collagen too much, leading to decreased micromechanical retention (when the bonding agent is applied) because there are no longer the well defined opened tubules for the resin to interdigitate with to make the hybridized zone (because they were destroyed by over-etching), and also may lead to increased risk of post-operative sensitivity due to opening the dentinal tubules too much and essentially exposing the pulp.

I'm sorry for making fun of your misuse of the word, I didn't realize you were not a US student. Although, the answer "a scratch" was dead on, to your initial question. 😉 I hope this helps.
 
in addition to wild-cat's correct answer..

you must note that you can etch enamel though - it is a selective dissolution of the calcium salts that the acid removes.
 
CALALILY said:
in addition to wild-cat's correct answer..

you must note that you can etch enamel though - it is a selective dissolution of the calcium salts that the acid removes.

Oh, yeah, I re-read my post, it wasn't very clear. Yes, the enamel is definitely etched. Either the interrod or rod enamel is more readily dissolved (I think there have been scanning and transmission electron micrographs showing both of these to be the case in different enamel, i.e. sometimes interrod and sometimes rod enamel is more readily dissolved) leading to microporosities in the enamel surface. Longer term etching (within reason) still leads to these microporosities and not to a less retentive surface in enamel(which is what I meant by no negative effects of etching greater than 15 seconds for enamel).
 
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