动物模型,牙齿激发痛 z-bo 2020-08-08 491

　　(1) Reproduction method Use a cat with healthy and complete lower canine teeth and anesthesia by intraperitoneal injection of pentobarbital sodium at a dose of 45 mg/kg body weight. The hind limb saphenous vein is injected with 5% glucose at a rate of 6 drops/min. And through this route, 5mg/kg body weight was injected with sodium pentobarbital to maintain anesthesia; then the animal underwent tracheotomy and intubation, fixed the head and open jaws, made an incision in the masseter muscle area and peeled it to the mandible, then chiseled The bone is exposed to the alveolar vascular nerve bundle, the vascular nerve bundle capsule is stripped, the nerve fiber is exposed, the edge of the skin incision is sutured and fixed on the ring metal of the experimental bench to form an oil groove, and paraffin oil at 35-40°C is dripped. Using the two-stage electrical stimulation method of tooth tip and tooth neck, insert the tip of the cat canine into the bottle through the small hole at the bottom of the liquid adding bottle, and form the tip of the tooth through the physiological saline in the bottle and the platinum wire with the inner wall of the bottle with a diameter of 200μm. electrode. Then use a No. 700 split drill to drill a hole 2 to 3 mm away from the gingival margin of the canine tooth to the surface of the dentin. Use the same platinum wire and conductive glue to fix it in the hole with EB composite resin to form a tooth neck electrode. The isolator is connected to the electronic stimulator. A single platinum wire recording electrode with a diameter of 30μm is connected to a DC preamplifier through a shielding box, and this output terminal is connected to the input terminal of the oscilloscope and the audio amplifier monitor. The signal is input into the computer by the oscilloscope, and then processed by the frequency recording and processing software, and the histogram curve formed by the discharge frequency every 10s is statistically drawn. Use hairspring forceps to separate the nerve bundles from the inferior alveolar nerve bundles under a microscope, tear off the central and axial ends, and place the outer peripheral ends on the recording electrodes; under a stimulus pulse with a frequency of 0.1 Hz, a delay of 7 to 8 ms, and a wave width of 1 ms , Gradually increase the stimulation intensity, and separate the single pulp nerve (SPN) that innervates the lower canine according to whether the action potential occurs. Use a high-speed gas turbine dental drill to smooth the tooth tip to expose the dentin, and apply temperature (0～4℃ and 60～80℃ normal saline) stimulation and airflow (using the jet of the turbine) to the middle layer (3mm) and deep layer (5mm) of the dentin. , Water spray device, control the air pressure at 143.8kPa, observe the dry air flow 15cm away from the tooth surface and the aerosol of 5, 10, 15cm away from the tooth surface acting on the surface of the dentin) irritation, hypertonic solution (2.5mol/L NaCl solution) ) Stimulate and record the number of discharges.

　　(2) Model characteristics Model animals show that the number of unit discharges induced by repeated hypertonic solution stimulation is relatively stable, while the temperature and aerosol stimulation require repeated stimulation at an interval of 2 minutes to achieve a stable number of discharges. It proves that most of the dental pulp nerves of the selected model animals (cats) respond to hypertonic solution and airflow stimulation. It is easy to guide and easy to obtain test models, but this model is difficult to guide temperature-sensitive fibers, especially heat-sensitive fibers and teeth. The essential middle layer of sensitive fibers, and the tooth age and body temperature of the model animals can also affect the results of the experiment. This model uses computer software to record the number of discharges, and the experimental results obtained are accurate, reliable, and comparable. The results of the number of discharges are related to the stimulation intensity, interval and duration.

　　(3) Comparative medicine. So far, the research on dentin sensitivity, pain during dentin cutting, and mitigation methods are mostly clinical experimental studies. Such studies are always affected by subjective factors and can cause unpredictable results in human trials. harm. Previous studies have shown that compared with human teeth, cat teeth are similar to humans in terms of the structure of dentin and dentin cells, the types and distribution of pulp nerves, and their functions are also similar; electrophysiological experiments prove that cat pulp nerves The law of fiber discharge has a good correlation with the pain of human teeth. Because clinical research is restricted by the research object (human), the effect of certain strong noxious stimuli, analgesic methods whose mechanism is not clear, and the use of drugs can only rely on animal model experiments to confirm their effects. The several stimulation methods selected in this model can cause human teeth to stimulate pain clinically, so it is an ideal animal model.