يبدأ فحص الأسنان اليوم.

يبدأ means begins or starts.

It is the imperfect verb form in Arabic, which often covers both:

• the present: begins / is beginning
• the future: will begin

In this sentence, اليوم (today) makes the time clear, so the natural meaning is something like:

• The dental examination begins today
• The dental checkup starts today

Because the subject is فحص (examination/checkup), and فحص is a masculine singular noun.

So the verb agrees with it:

• يبدأ = he/it begins for a masculine singular subject
• تبدأ would be used for a feminine singular subject

Even though الأسنان (the teeth) appears in the sentence, it is not the main subject of the verb. The real subject is فحص الأسنان = the examination of the teeth.

The subject is فحص الأسنان.

More literally, this means:

• فحص = examination / checkup
• الأسنان = the teeth

Together, فحص الأسنان means:

• the examination of the teeth
• more naturally in English: the dental examination or the dental checkup

So the thing that begins is the exam/checkup, not the teeth.

This is because فحص الأسنان is an iḍāfa construction, often called a genitive construction or noun-noun phrase.

In an iḍāfa:

• the first noun usually does not take الـ
• the whole phrase becomes definite if the second noun is definite

So:

• فحص أسنان = an examination of teeth / a dental exam
• فحص الأسنان = the examination of the teeth / the dental exam

Because الأسنان is definite, the whole phrase فحص الأسنان is definite.

الأسنان means the teeth.

It is the plural of سِنّ (tooth).

So:

• سِنّ = tooth
• أسنان = teeth
• الأسنان = the teeth

In this sentence, it is the second part of the iḍāfa:

• فحص الأسنان = examination of the teeth

Arabic often likes to begin sentences with the verb, especially in formal written style.

So:

• يبدأ فحص الأسنان اليوم = The dental examination begins today

This is a very normal verb-subject order in Arabic.

You could also say:

• فحص الأسنان يبدأ اليوم

That is also understandable, but it gives the subject a bit more emphasis. The version with the verb first sounds very natural in Modern Standard Arabic.

اليوم means today.

Here it functions as a time expression:

• يبدأ فحص الأسنان اليوم = The dental exam begins today

It tells you when the action happens.

Arabic often places time words like this at the end, but they can also move:

• اليوم يبدأ فحص الأسنان = Today, the dental exam begins

Both are possible; the meaning stays basically the same, though the emphasis changes slightly.

A careful pronunciation is:

yabdaʾu faḥṣu l-asnāni al-yawma

A few notes:

• يبدأ = yabdaʾu
• فحص = faḥṣ
• الأسنان = al-asnān
• اليوم = al-yawm

In connected reading with case endings, it can sound like:

• yabdaʾu faḥṣu l-asnāni al-yawma

In everyday reading, learners often say something simpler like:

• yabdaʾ faḥs al-asnān al-yawm

In fully vocalized formal Arabic, it would be:

يبدأُ فحصُ الأسنانِ اليومَ

Here is why:

• يبدأُ: the verb is in the indicative, so it ends in ـُ
• فحصُ: this is the subject, so it is nominative
• الأسنانِ: second term of the iḍāfa, so it is genitive
• اليومَ: used as an adverb of time, so it is often accusative

Many written texts leave these endings unwritten, so you will usually just see: يبدأ فحص الأسنان اليوم

It can be understood as either present or near future, depending on context.

Because of اليوم, English may translate it in different ways:

• begins today
• starts today
• is starting today

Arabic does not always need a separate future marker if the context already makes the time clear.

If you wanted to make the future more explicit, you could say:

• سيبدأ فحص الأسنان اليوم = The dental examination will begin today

Yes, literally it is something like:

• examination of the teeth

But in natural English, we would usually say:

• dental examination
• dental exam
• dental checkup

So the Arabic is structurally more literal, while the English translation is usually more idiomatic.

Grammatically, yes, that is the literal structure. But in natural English, the teeth examination sounds awkward.

A better translation is:

• The dental examination begins today
• The dental exam starts today
• The dental checkup begins today

So when reading Arabic, it is often better to translate the meaning naturally rather than word-for-word.