yangchihago naseo chisildo sseo bonikka deo kkaekkeushan neukkimi deureosseoyo.

양치 is a common shortened noun referring to brushing your teeth. The verb is 양치하다, so 양치하고 나서 means after brushing my teeth.

You could also say 이를 닦고 나서, which is more literally after brushing my teeth. The difference is mostly style:

• 양치하다 = a very common everyday expression for toothbrushing
• 이를 닦다 = also correct, a bit more literal

So this sentence is natural casual everyday Korean.

-고 나서 means after doing... and shows that one action happens first, then another happens afterward.

So:

• 양치하고 나서 = after brushing my teeth

Structure:

• verb stem + -고 나서

Examples:

• 밥 먹고 나서 공부했어요. = After eating, I studied.
• 샤워하고 나서 잤어요. = After showering, I slept.

In your sentence, it sets up the order:

1. brush teeth
2. use floss
3. realize it feels cleaner

The particle 도 means also, too, or even.

So 치실도 써 보니까 means:

• when I also tried using floss
• or when I tried floss too

This suggests something like:

• I already brushed my teeth, and
• I used floss in addition

If you said 치실을 써 보니까, it would simply mean when I tried using floss, without emphasizing the also/too meaning.

Yes, 쓰다 can mean to write, but it also means to use.

So here:

• 치실을 쓰다 = to use floss

The form 써 is the -아/어 connective form of 쓰다:

• 쓰다 → 써

That same verb appears in many contexts:

• 안경을 쓰다 = to wear glasses
• 돈을 쓰다 = to spend money
• 펜을 쓰다 = to use a pen / to write with a pen

So in this sentence, 치실도 써 보니까 means when I tried using floss too.

This combines two grammar points:

1. -아/어 보다 = to try doing something

   • 써 보다 = to try using

2. -니까 here gives a meaning like:

   • when I did it and found out...
   • after trying it, I realized...
   • sometimes loosely because I tried it...

So 써 보니까 means something like:

• when I tried using it
• after trying to use it
• once I tried using it, I found that...

In this sentence, it leads to a discovered result:

• When I tried using floss too, it felt cleaner.

Not exactly. It can sometimes feel similar to because, but its core nuance is more like:

• when I tried/did it, I discovered...
• after doing it, I found that...

So 써 보니까 더 깨끗한 느낌이 들었어요 is not just a simple logical cause like because I used floss. It has a more experiential meaning:

• After trying floss, I found that it felt cleaner.

That discovery nuance is important.

깨끗하다 is an adjective meaning to be clean. When Korean adjectives modify a noun, they change form.

So:

• 깨끗하다 = to be clean
• 깨끗한 = clean ... / a clean ...

Then:

• 느낌 = feeling

So:

• 깨끗한 느낌 = a clean feeling or more naturally a feeling of cleanliness

This is just the normal adjective-modifying form:

• adjective stem + -ㄴ / -은 / 한

Because 깨끗하다 is a 하다-adjective, it becomes 깨끗한 before a noun.

더 means more.

So:

• 더 깨끗한 느낌 = a cleaner feeling / a feeling of being cleaner

It compares the result with not using floss, or with brushing alone.

The implied meaning is:

• brushing alone feels clean,
• but brushing plus floss feels even cleaner.

Literally, 느낌이 들다 means something like:

• a feeling arises
• I get the feeling that...
• it feels like...

So:

• 더 깨끗한 느낌이 들었어요 = I got the feeling that it was cleaner
• more naturally: it felt cleaner

This expression is very common in Korean. It often sounds a bit softer and more natural than a direct statement.

Examples:

• 좋은 느낌이 들어요. = I have a good feeling.
• 이상한 느낌이 들었어요. = I had a strange feeling.

Both are possible, but they feel a little different.

• 더 깨끗한 느낌이 들었어요 = it felt cleaner / I got a cleaner feeling
• 더 깨끗하다고 느꼈어요 = I felt that it was cleaner

The original sentence sounds a bit softer and more natural in everyday speech. It focuses on the sense/impression rather than making a firm judgment.

So 느낌이 들었어요 is a very natural way to describe a personal impression.

No, that’s normal. 양치하다 already contains the idea of brushing the teeth, so you usually do not need an object.

Compare:

• 양치했어요. = I brushed my teeth.
• 이를 닦았어요. = I brushed my teeth.

With 이를 닦다, the object 이 can appear. With 양치하다, the object is usually unnecessary.

들었어요 is in the polite informal style, often called the -아요/어요 style.

So the whole sentence is polite and natural for everyday conversation:

• polite enough for most normal situations
• not stiff or highly formal

A more formal version might be:

• 양치하고 나서 치실도 써 보니까 더 깨끗한 느낌이 들었습니다.

A casual version might be:

• 양치하고 나서 치실도 써 보니까 더 깨끗한 느낌이 들었어.

A natural translation would be:

• After brushing my teeth, I tried using floss too, and it felt cleaner.
• After brushing my teeth, I also tried flossing, and it felt cleaner.
• After brushing, I tried using floss too, and I felt like my teeth were cleaner.

The key nuance is:

• first brushing,
• then also flossing,
• then noticing a cleaner feeling as a result.

Yes. Because of 써 보다, the sentence has a trying it out nuance.

So it is not just:

• I used floss

It is more like:

• I tried using floss
• I gave floss a try

That makes sense especially if the speaker is talking about a new habit or experimenting to see whether floss helps.