1.What are the commonly used materials for full crowns in restorative dentistry? What are the advantages of these materials in clinical use? What are the disadvantages? Suitable for restoration of which position of the tooth? A: commonly used oral restoration of full crown materials are mainly porcelain crowns, all-ceramic crowns and metal crowns of three categories. (1) Porcelain metal crown: refers to the first production of metal inner crown, as a bracket, on its surface with the natural tooth color similar to the porcelain powder to restore the shape of the tooth, sintered in a vacuum porcelain furnace, so that the porcelain fused with the metal alloy to form a porcelain crown. According to the different metal materials of the inner crown, porcelain teeth are divided into non-precious metal porcelain teeth (such as nickel-chromium alloy, cobalt-chromium alloy), semi-precious metal porcelain teeth (such as palladium-silver alloy, palladium-gold alloy), precious metal porcelain teeth (such as gold alloy), titanium and titanium alloy porcelain teeth. Advantages: Well-made porcelain teeth have a realistic appearance, beautiful, strong and durable, the color is similar to natural teeth, which can restore the function of the teeth and also have the effect of increasing the aesthetics, which is an ideal denture. Disadvantages: the amount of tooth cutting; porcelain layer brittle, easy to crack, metal corrosion, biocompatibility limitations. (2) All-ceramic crowns: refers to the full crowns made of ceramic materials without metal. Advantages: natural and realistic color stability, low thermal conductivity, non-conductive, wear-resistant, biocompatibility is the best. Disadvantages: the amount of tooth cutting more, the price is higher. (3) Metal crowns: full crowns made of metal, commonly known as “steel teeth”. Advantages: less abraded tooth tissue, high strength. Disadvantages: poor aesthetics, metal corrosion, poor biocompatibility, etc., the basic clinical abandonment. Porcelain metal crowns and all-ceramic crowns can be used on both anterior and posterior teeth, while metal crowns are mainly used on posterior teeth. A good full crown with high service life should be composed of the following elements: firstly, the physician should have a scientific design plan; secondly, the preparation of the dental system should be strictly standardized; thirdly, the model should be taken accurately; fourthly, the level of the production technician should be high; fifthly, the material should be good; and sixthly, it should be reasonably used. Ring interlocking, mutual influence. So repair teeth should go to the regular hospital after the doctor’s examination to choose the appropriate restorations. 2.What are the commonly used oral restoration methods for missing individual teeth? What are the indications for each? A: Commonly used methods of individual missing teeth are: implants, fixed bridges, removable movable denture repair. (1) Dental implants: Dental implants are dentures that are placed on artificial tooth roots. The implant (i.e. artificial tooth root), which is biocompatible with the human body, is surgically implanted into the bed of the missing teeth, and after a period of time when the wound has healed, a denture (false tooth) is set on the artificial tooth root to repair the missing teeth. Generally speaking, with the development of various complex dental implant surgical techniques, as long as the teeth are defective or missing teeth, patients can rebuild the function of the bite and jaw through dental implants. However, the successful premise of dental implant is that it must have better economic conditions, good oral environment, good healing ability and anti-infection ability. (2) Fixed bridge: If the number of missing teeth is small, and there are solid remaining teeth before and after the missing teeth area, and if the general health condition and economic conditions permit, fixed bridge restoration can be considered. This kind of dentures feel comfortable, chewing powerful, which “all-ceramic teeth” safe and harmless, “porcelain teeth” beautiful and realistic, “steel teeth” economical and practical. (3) Activity denture: from a single missing tooth to the maxillary, mandibular only a single remaining tooth of a wide range of missing or even accompanied by soft and hard tissue loss can be used activity denture repair. Activity denture has the advantages of easy to clean, beautiful and inexpensive, at present, activity denture has the traditional “plastic bracket teeth”, high-strength “stainless steel bracket teeth” and no wire “invisible denture”. 3.What kind of oral restoration method has the least damage to the adjacent teeth? A: Dental implant restoration. 4.From the point of view of comfort and practicality, which restorative material is the best with which restorative method? From the point of view of aesthetics, which material is the best with which restoration method? A: At present, the best restoration method for missing teeth is dental implant, which has the following advantages:1 During the process of using, the occlusal force is transmitted to the alveolar bone through the implant, which can stimulate the alveolar bone and gingiva, and maintain the height and width of the alveolar bone and gingiva to prevent them from shrinking prematurely.2 It restores the function and aesthetics of the missing teeth by almost 100% without damaging the neighboring teeth.3 It is also a good restoration material for the teeth, which is the best restoration material for the teeth. Dental implant + all-ceramic crown restoration is regarded as an ideal restoration method and is the development direction of dental restoration. If you can not make dental implant restoration, fixed denture restoration is also a more comfortable and beautiful restoration method. 5.What is the process of restorative dentistry? Do I have to take pictures? How long does it take to complete the restoration? How many times do I need to visit the doctor during the period? A: The general process of restorative dentistry is to check the oral condition (such as missing teeth, abutment teeth, occlusal relationship, mucosa and alveolar ridge resorption, etc.), make a diagnosis, and then make a reasonable treatment process and restorative design program. For example, the residual crowns and roots that can not be retained and loose teeth are extracted in time, and the endodontically diseased teeth with periapical disease are treated with perfect root canal therapy. After dealing with the preparatory work before restoration, according to the restoration plan to carry out tooth preparation, taking molds, making denture, wearing teeth and other steps. It is not necessary to take radiographs for restoration, but it is necessary to take radiographs for implant or casting. Fixed and removable dentures generally take 1-2 weeks to complete, 2-3 times to complete. Implantation time is longer, usually 3-6 months, 2-3 times to complete. 6. What is all-ceramic crown? What is the difference between all-ceramic crowns and porcelain crowns? Which type of patients are suitable for all-ceramic crowns? A: All-ceramic crowns are restorations made of ceramic materials that cover the entire surface of the crown. Compared with ordinary porcelain teeth, all-ceramic crowns have the following advantages: (a) good transparency and more realistic color. This is the ordinary baked teeth can not be achieved. Because the metal crown of the porcelain tooth is opaque, which directly affects its transparency, so that the color of the porcelain tooth into a chalky white. All-ceramic crowns replace the metal crowns with high-strength sub-crowns that have good transparency and refractive properties, making the color of all-ceramic crowns closer to natural teeth. (ii) No discoloration of the gums. All-ceramic crowns do not contain metal, and the inner crown is a porcelain crown. So it will not cause discoloration of the gums. (C) good combination of inner and outer crowns. Ordinary porcelain teeth metal and porcelain combination is a weak link, often see porcelain and metal stripping, chipping phenomenon. All-ceramic crown is inside and outside the crown are porcelain, can reduce the occurrence of chipping phenomenon. (D) health: porcelain on the human body has excellent compatibility and stability. Very few people are allergic to porcelain, the possible future head nuclear porcelain resonance also has no effect. While ordinary metal such as nickel-chromium alloy, the oral cavity can release metal ions, easy to cause discoloration of the gums and allergies, especially women’s allergy rate is higher, while the casting of ordinary metal is less accurate, easy to cause redness and bleeding of the gums, the aesthetic appearance of the front teeth also adversely affect. Porcelain full crowns can change the color, shape and position of the teeth to the greatest extent possible, and have a good restorative effect on severely discolored, chipped and misshapen teeth. High aesthetic requirements, or allergic to metal is particularly suitable for porcelain crowns. 7, all porcelain crowns use what materials? What harm to neighboring teeth? A: All-ceramic crown materials are feldspar porcelain crowns, cast vitreous china crowns, alumina porcelain crowns, garnet-enhanced porcelain crowns, heat-pressing-enhanced porcelain crowns, zirconia CAD/CAM all-ceramic crowns and so on. In short, cast porcelain crowns, alumina glass permeable porcelain crowns, zirconia CAD/CAM all-ceramic crowns. Regular operation will not cause harm to the neighboring teeth.