Stomatolog daje anesteziju injekcijom.

Because it is the direct object of the verb daje (gives), so it goes into the accusative case.

• Dictionary form: anestezija
• Accusative singular: anesteziju

So:

• Stomatolog daje anesteziju. = The dentist gives/administers anesthesia.

This is very common in Serbian: the thing being given usually goes in the accusative.

Because Serbian uses the instrumental case to show the means or tool used to do something.

• Dictionary form: injekcija
• Instrumental singular: injekcijom

So injekcijom means:

• by injection
• with an injection

The sentence is literally something like:

• The dentist gives anesthesia by means of an injection.

Because in Serbian, the instrumental case can be used without a preposition to express the instrument or method.

So:

• injekcijom = by injection / with an injection

This is the natural way to express the tool or means here.

Using sa injekcijom would usually sound more like together with an injection or would feel less natural in this sentence. For pure instrument/method, bare instrumental is preferred.

Daje is the 3rd person singular present tense of the imperfective verb davati / daje.

It is used for:

• an action happening now: is giving
• a general or habitual action: gives

So Stomatolog daje anesteziju injekcijom can mean either:

• The dentist is administering anesthesia by injection
• The dentist administers anesthesia by injection

depending on context.

The form da belongs to the perfective verb dati, and it is not the normal choice for a plain ongoing present action like this.

It can mean both.

Serbian present tense often covers both:

• simple present: gives
• present continuous: is giving

So without more context, the sentence may describe:

1. a general fact or usual practice
   
   • A dentist gives anesthesia by injection.
2. something happening right now
   
   • The dentist is giving anesthesia by injection.

Context tells you which meaning is intended.

Yes, but it is a bit more formal/professional.

Two common words are:

• stomatolog = more formal, medical/official
• zubar = more everyday, colloquial

So both of these can work:

• Stomatolog daje anesteziju injekcijom.
• Zubar daje anesteziju injekcijom.

The first sounds more professional; the second sounds more conversational.

Because Serbian does not have articles like English a/an/the.

So:

• stomatolog can mean a dentist or the dentist
• anesteziju can mean anesthesia / the anesthesia
• injekcijom can mean with an injection / by injection

Serbian relies on context instead of articles.

If needed, speakers can add words like:

• taj = that/the specific one
• jedan = one / a certain

But in a normal sentence like this, no article is used.

Yes. Serbian word order is more flexible than English because case endings show what each noun is doing.

The neutral order here is:

• Stomatolog daje anesteziju injekcijom.

But you could also hear:

• Anesteziju stomatolog daje injekcijom.
• Injekcijom stomatolog daje anesteziju.

These versions shift the focus or emphasis, but the core meaning stays the same.

English depends much more on word order; Serbian depends more on case endings.

In context, it usually refers to the anesthetic/anesthesia being administered, especially the numbing medication used at the dentist.

In natural English, you might translate the whole sentence as:

• The dentist administers anesthetic by injection.
• The dentist gives anesthesia with an injection.

At the dentist, this would normally imply local anesthetic, not necessarily general anesthesia.

Yes, but it means something slightly different.

• Stomatolog daje anesteziju injekcijom. = The focus is on anesthesia/anesthetic, and the method is by injection.

• Stomatolog daje injekciju. = The focus is on the injection itself. = The dentist gives an injection.

So both are correct, but they highlight different things.

You can use a feminine noun if you want to specify that:

• Stomatološkinja daje anesteziju injekcijom.
• Zubarka daje anesteziju injekcijom.

The rest of the sentence stays the same because the verb form daje is still 3rd person singular.

So only the noun for dentist changes.