All the vital teeth specimens and 9 pulpless specimens were immerged in 0.9% sodium chloride solution, and another 9 pulpless specimens were air-dried.

• 所有活髓牙标本和9个无髓牙标本浸泡于0.；9%25生理盐水中，9个无髓牙标本则在空气中干燥。