Smalțul este atât de sensibil, încât nu putem folosi ața dentară.

Because Romanian usually puts the definite article at the end of the noun.

• smalț = enamel
• smalțul = the enamel

So -ul here is the masculine/neuter singular definite article.

A useful thing to know: smalț is a neuter noun. In Romanian, neuter nouns usually behave like:

• masculine in the singular
• feminine in the plural

That is why the singular definite form is smalțul.

This is a very common Romanian structure meaning so ... that.

In this sentence:

• atât de sensibil = so sensitive
• încât = that / to such an extent that

So the pattern is:

• atât de + adjective + încât + result

Example:

• Este atât de obosit, încât adoarme imediat. = He is so tired that he falls asleep immediately.

This is one of the most important things to notice in the sentence.

Because the adjective has to agree with smalțul.

Since smalțul is:

• singular
• neuter

its adjective in the singular looks like the masculine singular form:

• sensibil

So:

• smalț sensibil
• smalțul este sensibil

If it were plural, a neuter noun would usually take the feminine plural adjective form:

• sensibile

That masculine-singular / feminine-plural behavior is typical of Romanian neuter nouns.

Because:

• putem = we can
• nu putem = we cannot / we can’t
• folosi = to use

So nu putem folosi means we cannot use.

A few useful grammar points:

1. nu goes before the conjugated verb:

   • putem → nu putem

2. After a putea (to be able to / can), Romanian normally uses the infinitive:

   • putem folosi
   • nu putem folosi

So this works very much like English can use / cannot use.

Yes. folosi is the infinitive form of a folosi = to use.

After a putea, Romanian commonly uses the infinitive directly:

• pot pleca = I can leave
• putem folosi = we can use

So in this sentence:

• putem is the conjugated verb
• folosi stays in the infinitive

That is why you do not see a form like folosim here.

This is a noun + adjective phrase.

• ață = thread / floss
• ața = the thread / the floss
• dentară = dental

So:

• ața dentară = the dental floss

A few things to notice:

1. ață is a feminine noun.
2. Its definite article is -a:
   • ață → ața
3. The adjective comes after the noun in normal Romanian word order.
4. The adjective must agree with the noun, so we get feminine singular:
   • dentară

You may also hear ață de dinți, which is another common way to say dental floss.

Because încât introduces a subordinate clause, and in standard Romanian it is normally separated by a comma.

So the sentence is divided like this:

• Smalțul este atât de sensibil,
• încât nu putem folosi ața dentară.

This is very similar to how English often separates so ..., that ... structures in writing, especially when the sentence is long enough to benefit from the pause.

So the comma here is normal and expected.

Grammatically, yes: putem is the 1st person plural form, so it literally means we can.

But in real usage, Romanian sometimes uses we in a broader or more general sense, just like English can:

• We can’t use this here
• meaning something like people can’t / one can’t / in this situation we can’t

So depending on context, nu putem may mean:

• literally we cannot
• or more generally it’s not possible for us / in this case we can’t

This sentence contains several Romanian letters with diacritics:

• ț in smalțul, ața
• ă in atât, ața, dentară
• â in atât
• î in încât

A quick guide:

• ț = ts as in cats
• ă = a short neutral vowel, somewhat like the a in sofa
• â and î represent the same sound, a close central vowel that English does not really have; learners usually just need practice hearing and repeating it

Approximate pronunciations:

• smalțul ≈ smaltsul
• atât ≈ uh-TUHT (very approximate)
• încât ≈ in-KUHT (very approximate)
• ața ≈ AT-sa
• dentară ≈ den-TA-rə

The exact vowel quality takes listening practice, but getting ț = ts right is especially important.

The sentence is natural as it stands, but Romanian does allow some flexibility.

The standard order here is:

• Smalțul este atât de sensibil, încât nu putem folosi ața dentară.

This is natural because it presents:

1. the situation
2. then the consequence

You could rephrase the idea in other ways, for example:

• Nu putem folosi ața dentară, fiindcă smalțul este foarte sensibil.
• Din cauza sensibilității smalțului, nu putem folosi ața dentară.

But with the exact atât de ... încât structure, the original order is the normal one.