1, not skull position
Porcelain teeth are embedded in the teeth, which are located in the maxillary position of the skull. Therefore, MRI can be done without considering the influence of tooth vibration and non-skull position.
2. Ordinary porcelain teeth
(1) Ordinary porcelain teeth are generally made of metals, including precious metals and non-precious metals. Most of them can't be vibrated by magnetic resonance, because the metal will be moved by a strong alternating magnetic field in the examination room, which will damage the adjacent teeth nerves and oral blood vessels in the process of moving, so it is taboo to vibrate porcelain teeth by magnetic resonance.
(2) However, pure titanium porcelain teeth are the most special kind of porcelain teeth, which can be used for cranial MRI. Because titanium is the only nonmagnetic porcelain tooth metal, it will not be magnetized in the strong magnetic field of nuclear magnetic resonance, and it has good compatibility with teeth, so it is widely used in medical field.
3. All-ceramic porcelain teeth
All-ceramic porcelain teeth include zirconia, alumina and cast porcelain teeth. Biocompatibility is very good, and they are all non-metallic materials. It is no problem to do MRI, but the cost will be more expensive than ordinary porcelain teeth.
4. What if I can't do it?
When you have to have an MRI instead of an MRI to check the condition of your head, you should take the porcelain teeth out of your mouth first. This operation should be performed in a professional hospital, and porcelain teeth should not be pulled out at home. After the MRI vibration, the porcelain teeth can be put back under the doctor's operation without affecting the appearance.
5, nuclear magnetic resonance principle
The human body is rich in water, and the water content of different tissues is different. If we can detect the distribution information of these waters, we can draw a relatively complete picture of the internal structure of the human body. The basic principle of magnetic resonance imaging is to put the human body in a special magnetic field, and excite the hydrogen nuclei in water molecules in the human body by radio frequency pulses, so that the hydrogen nuclei vibrate and absorb energy. After stopping the radio frequency pulse, the hydrogen nucleus sends out a radio signal at a specific frequency, and releases the absorbed energy, which is collected by a receiver in vitro and processed by an electronic computer to obtain an image, which is called nuclear magnetic resonance imaging.
6. Pay attention to nuclear magnetic vibration.
1. There is a strong magnetic field around the vibrating equipment (within 5 meters). It is forbidden for patients and their accompanying families to bring all ferromagnetic items and electronic products near or into the examination room. These projects include: all communication projects; Various magnetic storage media projects; Watches, heart cards and their accessories; Electronic products such as PDA and calculator; Ferromagnetic products such as keys, lighters, metal coins, knives, pens, needles, nails and screws; Hairpins, hairpins, glasses, artificial eyes, metal ornaments and items of unknown materials; Flammable and explosive materials, corrosive or chemical materials, ointment, plaster, damp and liquid leakage materials, etc. Beds and wheelchairs are not allowed to enter the magnet room.
2. Patients (including accompanying family members) who install and carry the following items and devices in the body are considered as contraindications for magnetic vibration inspection, and cannot enter the magnet room, otherwise their lives will be in danger. Including pacemakers, defibrillators, cardiac stents, artificial heart valves, metal clips after aneurysm surgery, drug infusion devices implanted in the body, any electronic devices implanted in the body, nerve stimulators, bone growth stimulators, other biological stimulators of any kind, intravascular embolization steel rings, filters, inferior vena cava filters, ECG recording monitors, metal sutures, bullets, shrapnel or iron sand particles in the body, etc. After fracture surgery, fixed steel plates, steel nails, screws, prostheses or joints, Tintin prostheses, hearing AIDS, cochlear implants, middle ear implants, intraocular metal foreign bodies, artificial eyes, removable dentures, head and face implants, etc.
3. Critically ill patients who are claustrophobic, pregnant and need life support and rescue can't do magnetic resonance examination. Patients and their families who have a history of various operations (especially organ transplantation and heart and kidney surgery) need to make a special statement before the examination to ensure safety.
4. Patients with fixed dentures, tattoos, intrauterine devices, tattooed eyeliner, and titanium alloy objects left in the body (such as titanium alloy fixation devices in the spine) should inform the doctor before the examination, and decide whether magnetic resonance examination can be carried out according to the specific situation.
5. Patients who undergo magnetic vibration examination of neck, chest, waist, abdomen, buttocks and other parts should first take off clothes, underwear, chemical fiber fabrics, belts and other decorative items with iron hooks, iron buckles and zippers, and wear cotton clothes when checking; Patients undergoing abdominal examination are forbidden to take drugs containing metal ions within three days before the examination, and fasting and drinking water are forbidden 12 hours before the examination.
6. Magnetic vibration flaw detection is a nondestructive flaw detection, which has no radiation damage to human body. But it is normal for the machine to be noisy when checking. Please make psychological preparations for patients and their families, don't panic and remain absolutely still.
7. Please take good care of your valuables. If you lose them, you will bear the consequences.
8. Due to the different location and nature of the lesion, the required examination time will be different, and your examination time may be advanced or delayed, so please be sure to arrive on time or fifteen minutes in advance. If you can't come on time after making an appointment, make an appointment for inspection.