More types of mobile phones, and the structure can be divided according to speed and low-speed high-speed mobile phones, high-speed mobile dental handpiece using high pressure air driven turbine handpiece for micro turbine speed can be up to 300,000 to 500,000 r / min, bur cutting speed can be up to 15m / s, while the low-speed mobile dental handpiece because it is gear, speed can be transferred per minute for thousands of 30000 rpm.
2013年8月6日星期二
why pulpitis unbearable toothache
Dental pulp bit dry central location, the outer layer from the enamel, dentin and cementum encircled the only hole in the very tip associated with periapical tissue; pulp nerve from the trigeminal nerve, medullary cavity nerve fiber stress threshold is low, its susceptibility to strong pressure, and pulp tissue itself inherently tissue pressure than other organs tissue pressure is high. When the pulp first arterial vasodilatation inflammation, congestion, resulting pulp increased internal pressure in the cavity, so that the apical hole by compression of the vein, causing venous Dental Autoclave congestion, so that the exudate accumulation, due to the very tip through a small hole contact with the outside, so that poor drainage, poor blood supply, resulting pulp nutritional disorders, can cause pulp necrosis. Necrotic tissue and releases more inflammatory product, to make more vascular leakage increased intramedullary pressure is further increased, coupled with the pulp is enclosed in a rigid cavity inelastic, that is surrounded by the pulp tissue solid tooth structure, medullary cavity space capacity is constant, with no room for a buffer, increased oppression of pulp nerve pressure, it will have severe pain, with the pulp cavity pressure increases, further aggravating the pain, and thus This pain is really unbearable, the majority of patients have painful toothache Jane up vital experience.
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