Doktor gigi membersihkan karang gigi agar tidak merosakkan gusi.

Yes. Doktor gigi literally means tooth doctor, and it is the normal Malay way to say dentist.

This is very common in Malay: instead of always using a single special word, Malay often uses a short descriptive noun phrase.

• doktor = doctor
• gigi = tooth / teeth

So doktor gigi = a doctor for teeth = dentist.

You may also sometimes see dentis, but doktor gigi is very common and natural.

Because it is part of two different noun phrases:

• doktor gigi = dentist
• karang gigi = dental tartar / calculus

So the repeated gigi is not redundant in the grammar. It is just doing two separate jobs.

Also, in Malay, a noun modifying another noun often comes after it:

• doktor gigi = doctor of teeth
• karang gigi = tartar of the teeth

This is a normal Malay noun order pattern.

Karang gigi means tartar or dental calculus, the hardened deposit that forms on teeth.

Word by word:

• karang can refer to a hard crust, deposit, or coral-like buildup in certain contexts
• gigi = teeth

So karang gigi is specifically the hardened buildup on teeth.

A learner might first guess it means something like tooth coral, but in actual usage it means tartar.

Because bersih is an adjective meaning clean, while membersihkan is a verb meaning to clean or to make clean.

Here is the pattern:

• bersih = clean
• membersihkan = to clean something

So:

• Gigi itu bersih. = The tooth/teeth are clean.
• Doktor gigi membersihkan karang gigi. = The dentist cleans the tartar.

The form membersihkan is built from bersih with affixes that turn it into an active transitive verb.

In this sentence, membersihkan is a transitive verb, meaning it takes an object:

• membersihkan karang gigi = clean the tartar

Very roughly:

• meN- often marks an active verb
• -kan often helps form a verb meaning to cause/make/do something to something

So membersihkan means something like to make clean or to clean.

You do not always need to analyze every affix every time, but it helps to recognize that membersihkan is the normal verbal form, not just a random long word.

Agar here means so that, in order that, or so as not to.

In this sentence:

• agar tidak merosakkan gusi = so that it does not damage the gums / in order not to damage the gums

Yes, agar and supaya are often very close in meaning, and in many contexts either one would work.

For example:

• ... agar tidak merosakkan gusi
• ... supaya tidak merosakkan gusi

Both can mean so that it does not damage the gums.

Sometimes agar can feel a little more formal or written, but both are common.

This is a very good question, because Malay often leaves some things implied.

In this sentence, the most natural interpretation is:

• the dentist cleans the tartar so that the tartar will not damage the gums
• or more naturally in English: to prevent it from damaging the gums

So the understood idea is that karang gigi is the thing that can damage the gums.

Malay often allows this kind of compact phrasing without repeating the noun or pronoun.

If someone translated it very literally as so as not to damage the gums, it might sound as if the dentist is trying not to damage the gums. But in context, the intended meaning is usually about preventing the tartar from harming the gums.

Rosak means broken, damaged, or spoiled.

Examples:

• Gigi itu rosak. = The tooth is damaged.
• Mesin itu rosak. = The machine is broken.

Merosakkan means to damage or to cause damage to something.

Examples:

• Gula boleh merosakkan gigi. = Sugar can damage teeth.
• Karang gigi merosakkan gusi. = Tartar damages the gums.

So the difference is:

• rosak = be damaged / broken
• merosakkan = damage something

Malay does not use articles the same way English does. There is no direct equivalent that must appear before nouns in most ordinary sentences.

So:

• Doktor gigi can mean the dentist or a dentist
• karang gigi can mean the tartar or tartar
• gusi can mean the gums or gums

The exact meaning depends on context.

This is very normal in Malay. English learners of Malay have to get used to nouns appearing without articles.

Gusi usually refers to the gums as a body part, so in English it is often translated with a plural-looking form: gums.

Malay nouns usually do not have separate singular and plural forms in the same way English does. Very often, context tells you whether one or more is meant.

So gusi can function as a general body-part noun. In natural English, gums is the best translation here.

This is standard Malay word order:

• Doktor gigi = subject
• membersihkan = verb
• karang gigi = object

So it follows a basic Subject–Verb–Object pattern, just like English:

• The dentist cleans tartar

That makes this sentence fairly straightforward structurally. The main challenge is usually the vocabulary and the affixes, not the word order.

Yes. A few possible alternatives are:

• Doktor gigi membersihkan karang gigi supaya tidak merosakkan gusi.
• Doktor gigi membuang karang gigi agar gusi tidak rosak.

These are not exactly identical word for word, but they are close in meaning.

Differences:

• membersihkan = clean
• membuang = remove
• gusi tidak rosak = the gums are not damaged

The original sentence is already natural, but Malay often allows several similar ways to express the same idea.