What kind of thread is buried needle and thread carved? What's the difference?

Generally there are PPDO, PDO and protein line, we commonly use the PPDO line. In theory, it is only divided into two kinds: one is toothed, one is smooth, smooth line is divided into: spiral, multiple roots, long and short, thick and thin, and so on. The reason why so many lines are designed is that each line acts on different parts and can achieve different results.
These lines are fundamentally different. Protein lines are mostly purified from animal proteins, and they have sensitive sources. The PDO and PPDO lines, on the other hand, are purely chemical, not derived from animals, more complete. PPDO is a further upgrade from PDO.