Domani mattina vado dal dentista prima di andare in ufficio.

In Italian, the present tense is very often used for the future when the time is already clear from the context.

Here, Domani mattina tells you the action happens in the future, so vado is perfectly natural.

• Domani mattina vado dal dentista = Tomorrow morning I’m going to the dentist
• You could also say andrò, using the future tense, but in everyday Italian the present is extremely common.

Italian usually says domani mattina with no article and no extra preposition.

This is just the normal way to say tomorrow morning:

• domani = tomorrow
• mattina = morning

Together they function like a time expression.

Compare:

• stasera = tonight
• domani pomeriggio = tomorrow afternoon
• domani sera = tomorrow evening

So domani mattina is just the standard idiomatic form.

Dal is a contraction of da + il.

In Italian, with many professionals, andare da + person/article means to go to someone’s place / to go see someone professionally.

So:

• vado dal dentista = I’m going to the dentist / dentist’s office
• vado dal medico = I’m going to the doctor
• vado dal parrucchiere = I’m going to the hairdresser

Using al dentista is generally not the normal choice here. Dal dentista is the idiomatic expression.

It can imply both, depending on how you think about it.

Literally, dal dentista means to the dentist / at the dentist’s place. In practice, English often says to the dentist, while Italian uses da because the idea is going to the professional’s office or going to see that person.

So the sentence naturally means:

• I’m going to the dentist
• or more literally, I’m going to the dentist’s office

Because the sentence means before going to the office / before I go to the office.

After prima di, Italian normally uses an infinitive when the subject is the same as in the main clause.

So:

• vado dal dentista = I go / I’m going
• prima di andare in ufficio = before going to the office

This is very common:

• prima di uscire = before going out
• prima di mangiare = before eating
• prima di partire = before leaving

Because prima needs di before an infinitive.

So the pattern is:

• prima di + infinitive

Examples:

• prima di dormire = before sleeping
• prima di studiare = before studying
• prima di andare in ufficio = before going to the office

Without di, the sentence would be ungrammatical.

In Italian, andare in ufficio is the normal way to say to go to the office in the sense of going there for work.

Italian often uses in with certain places:

• in ufficio = to/in the office
• in banca = to/in the bank
• in ospedale = to/in the hospital

All’ufficio can exist in some contexts, but in ufficio is much more natural when talking about going to work or being at the office.

Because Italian usually drops subject pronouns when they are not needed.

The verb ending already tells you the subject:

• vado = I go / I’m going

So io is optional. You would add io mainly for emphasis, contrast, or clarity:

• Io vado dal dentista, tu vai in ufficio.
  I’m going to the dentist, you’re going to the office.

In a normal sentence, vado by itself is enough.

Yes, Italian word order is fairly flexible, especially with time expressions.

These are all possible, with slightly different emphasis:

• Domani mattina vado dal dentista prima di andare in ufficio.
• Vado dal dentista domani mattina prima di andare in ufficio.
• Prima di andare in ufficio, domani mattina vado dal dentista.

The original version is very natural because it starts with the time frame, which is common in everyday Italian.

Not exactly.

• domani mattina = tomorrow morning
• di mattina = in the morning / during the morning, more as a habitual or general time expression

Examples:

• Domani mattina studio. = I’m studying tomorrow morning.
• Di mattina studio sempre. = I always study in the morning.

So in your sentence, domani mattina is the correct form because it refers to a specific upcoming morning.

Grammatically, you might hear forms with all’ufficio in certain specific situations, but in this sentence in ufficio is the most natural and standard choice.

For everyday Italian, especially when talking about work, remember:

• andare in ufficio
• essere in ufficio

So prima di andare in ufficio is the version learners should treat as the normal one.

Dal is a combined form of:

• da
  • il = dal

These are called articulated prepositions in Italian.

Some other examples:

• a + il = al
• di + il = del
• in + il = nel
• su + il = sul

In your sentence:

• dal dentista = da + il dentista

Even though English does not usually say to the from-the dentist, Italian naturally uses this combined form.

Yes. In Italian, the simple present often covers both meanings.

So vado can correspond to:

• I go
• I’m going

In this sentence, because it refers to a planned event tomorrow morning, English would usually translate it as:

• I’m going to the dentist tomorrow morning...

But grammatically, Italian is just using the present tense vado.