2.2 Preparation of Specimens
The mandibles, labial papules and mandibular papules prepared as above
were cleaned three times in an ultrasonic bath JP-010T (Skymen Cleaning
Equipment CO., Ltd., Shenzhen, China) at 250 W for 350 s each time. The
mandibles, labial papules and mandibular papules were fixed with 3%
glutaraldehyde at 5℃ for 15 h, and dehydrated with 60%, 70%, 80%,
90%, and 100% liters of ethanol, with an interval of 8 min. The
prepared mandibles, labial papules and mandibular papules were stored in
glass containers which was already cleared and dried for 36 h. After
drying, the specimens were mounted on a holder using double-sided sticky
tape (dorsal, ventral), sputter coated with gold-palladium.
Subsequently, the prepared were scanned by using an electron microscope
(model S-3400N, Hitachi, Ibaraki, Japan) at an accelerating voltage of
3-10 kV. The images were named separately and stored on a computer.