Dokter gigi melihat karies, akar gigi, dan mahkota gigi pada rontgen.

In Indonesian, the main noun usually comes first, and the describing noun comes after it. So dokter gigi is literally something like doctor of teeth or tooth doctor, which is the normal way to say dentist.

So:

• dokter = doctor
• gigi = tooth / teeth

Together, dokter gigi means dentist.

For the same reason: Indonesian usually puts the head noun first and the modifier after it.

So:

• akar gigi = tooth root literally root of the tooth
• mahkota gigi = tooth crown literally crown of the tooth

This noun + noun pattern is very common in Indonesian.

Karies is a medical or technical word meaning caries, usually referring to tooth decay or cavities.

A learner should know that:

• karies sounds more clinical or dental
• everyday speech often uses gigi berlubang for a cavity / cavities

So in a dental context, karies is very natural.

Indonesian usually does not use articles the way English does. Very often, nouns appear without anything like a or the, and the listener understands from context.

So:

• dokter gigi can mean the dentist or a dentist
• karies can mean caries, the caries, or a cavity/cavities, depending on context

If Indonesian needs to be more specific, it uses other words, but very often it simply leaves articles out.

Indonesian often does not mark plural unless it is important to do so. Number is frequently understood from context.

So:

• gigi can mean tooth or teeth
• akar gigi can mean tooth root or tooth roots
• mahkota gigi can mean tooth crown or tooth crowns

If the speaker wants to be explicit, they can add something like:

• beberapa akar gigi = several tooth roots
• dua mahkota gigi = two tooth crowns

The basic root is lihat, which is related to see or look. The form melihat is the standard active verb form.

So:

• lihat = see / look
• melihat = to see

This meN- prefix is very common in Indonesian and often forms active verbs. In casual speech, people may say lihat, but in standard written Indonesian, melihat is the normal form here.

Here pada rontgen means something like on the X-ray or in the X-ray image.

Pada can be used in a somewhat formal style to mean on, in, at, or with reference to, especially when talking about what appears in a source, image, text, or record.

A learner should know:

• pada rontgen = on the X-ray / in the X-ray
• di rontgen is also possible in some contexts, but it may sound more like at the X-ray place or be a less precise choice
• if you want to be very explicit, pada foto rontgen or di foto rontgen can be clearer

So in this sentence, pada rontgen tells you where the dentist sees those things: in the X-ray image.

Rontgen is a common Indonesian word for X-ray. Depending on context, it can refer to:

• the X-ray procedure
• the X-ray image
• X-ray technology in general

In this sentence, it most naturally means the X-ray image.

The word comes from Röntgen, the name associated with the discovery of X-rays.

Because they form a list after the transitive verb melihat.

The structure is:

• Dokter gigi = subject
• melihat = verb
• karies, akar gigi, dan mahkota gigi = objects in a list
• pada rontgen = where/in what medium the seeing happens

So the meaning is that the dentist sees all three of these on the X-ray:

• caries
• the tooth root
• the tooth crown

It can mean either one, depending on context.

Most basically, mahkota gigi means the crown of the tooth, especially the visible upper part of a tooth in anatomy. In dentistry, it can also refer to an artificial crown placed over a tooth.

In this sentence, since it is listed with karies and akar gigi on an X-ray, it most likely refers to the anatomical crown of the tooth.

Yes. Indonesian word order is somewhat flexible, especially with adverbial phrases like pada rontgen.

These are both possible:

• Dokter gigi melihat karies, akar gigi, dan mahkota gigi pada rontgen.
• Pada rontgen, dokter gigi melihat karies, akar gigi, dan mahkota gigi.

The second version emphasizes the X-ray first. The basic meaning stays the same.