Bersihkan plak gigi; kalau tidak, ia merosakkan enamel gigi.

Because this sentence begins with a command. In Malay, direct commands often use the verb without the meN- prefix. So Bersihkan plak gigi means Clean the dental plaque.

By contrast, membersihkan is the normal active verb form used in statements, for example:

• Anda perlu membersihkan plak gigi. = You need to clean dental plaque.

So bersihkan fits an imperative, while membersihkan fits a statement.

Malay often omits the subject in commands because it is understood. In Bersihkan plak gigi, the hidden subject is you.

This is very similar to English imperatives:

• Sit down.
• Brush your teeth.
• Clean the plaque.

You could add anda or awak, but it would usually sound more explicit or emphatic than necessary.

Malay usually puts the main noun first and the describing noun second.

So:

• plak gigi = plaque of the teeth = dental plaque
• enamel gigi = enamel of the teeth = tooth enamel

This is the reverse of common English noun order. English often says tooth enamel, while Malay says enamel gigi.

Kalau tidak means if not or otherwise.

It links the command to the consequence:

• Clean the plaque; otherwise...

A very common spoken version is:

• kalau tak

A more formal version is:

• jika tidak

So all of these are related, but kalau tidak is a standard, natural choice.

Here, ia refers back to plak gigi. It means it.

So the idea is:

• if you do not clean the plaque, it damages the tooth enamel.

Malay often uses ia in writing or more formal language. In everyday speech, many people would more often use dia or simply repeat the noun instead.

Because rosak by itself usually means something like damaged, broken, or spoiled, and it is not the best form for saying that one thing damages another thing.

merosakkan is the transitive verb meaning to damage something.

Compare:

• Enamel gigi rosak. = The tooth enamel is damaged.
• Plak gigi merosakkan enamel gigi. = Dental plaque damages tooth enamel.

So merosakkan is used because the verb has a direct object: enamel gigi.

In many cases, -kan helps form a verb that means cause something to become X or do X to something.

For example:

• bersih = clean
• bersihkan = clean something / make something clean

And:

• rosak = damaged, spoiled
• merosakkan = damage something / cause something to become damaged

So in this sentence, -kan helps make both verbs act on an object.

Yes. They are loanwords used in health or scientific contexts.

Malay uses many borrowed technical terms, especially in medicine, science, and dentistry. So it is normal to see words that look familiar to an English speaker. Even when the spelling looks similar, they still function as ordinary Malay words inside the sentence.

Because the sentence contains two separate noun phrases:

• plak gigi
• enamel gigi

Each one needs its own modifier. Repeating gigi makes the meaning clear and specific:

• the plaque is tooth plaque
• the enamel is tooth enamel

This kind of repetition is completely normal in Malay, especially in clear explanatory or medical language.

Yes. The semicolon separates:

1. the command
2. the result if you do not follow it

It works much like in English:

• Clean the plaque; otherwise, it damages the enamel.

Malay punctuation is generally similar to English punctuation. A writer might also use a full stop, or sometimes a comma, depending on style. The semicolon simply shows a strong connection between the two parts.