Wall J G, Cipra D L
Department of Prosthodontics, Ohio State University, College of Dentistry, Columbus.
Dent Clin North Am. 1992 Jul;36(3):765-82.
The metal-ceramic crown system still is selected the most frequently because of its strength and versatility. The ability to select metals for color or strength for single units or fixed partial dentures gives great flexibility, but when esthetics of the anterior region are a prime concern, the all-ceramic crown is still an excellent choice. Choice of which all-ceramic system to use is dependent on the strength demands, esthetic needs, amount of tooth structure that can be preserved, and laboratory support available. Where good tooth structure remains but some color, contour, or incisal length changes are desired, the porcelain laminate veneer is an outstanding esthetic and restorative choice. When good labial tooth structure remains but lingual structure is inadequate, a partial veneer gold crown can be an excellent esthetic choice. If moderate tooth structure is lost or moderate staining is present, the Dicor crown is a superb choice. In those instances in which heavy staining is present, a foil or core system should be considered to completely block out the background colors. As the occlusal forces become more of a factor, selection of a restorative system will depend more on strength than esthetic demands. The aluminous porcelain jacket crown still offers great strength and esthetics at a reasonable price. When most of the color is on the surface of the teeth, or when there is a high translucency to the teeth, Dicor can provide very esthetic results, and the Dicor Plus crown offers the opportunity to develop intrinsic shading. When greater strength is required, selection of a foil and core system is suggested, as might be a system that provides a stronger core material, like Alceram or Inceram. These stronger core materials will render improved flexural and compressive strengths, but some increases in brightness may occur with the increased alumina content of the cores. The future in ceramic restorative dentistry may be in the computer-generated crown if ways to develop internal coloring and layered building can be developed and cost can be controlled. Ceramic crowns are best limited to the anterior region of the mouth where occlusal forces normally are less than those found in the posterior region. In selected cases, in which there is no evidence of parafunctional habits, and when the dentist and technician are well versed in functional occlusion and have maximum restorative control of the occlusion, posterior ceramic restorations will be successful. It is important to remember in these cases that porcelain is harder than enamel and very strong in compression.(ABSTRACT TRUNCATED AT 400 WORDS)
金属烤瓷冠系统因其强度和多功能性仍是最常被选用的。对于单颗牙或固定局部义齿,能够选择具有特定颜色或强度的金属,这提供了很大的灵活性。然而,当美观是前牙区的首要考虑因素时,全瓷冠仍是绝佳选择。选择使用哪种全瓷系统取决于强度要求、美观需求、可保留的牙体组织量以及现有的实验室支持。当剩余牙体组织良好,但希望改变一些颜色、外形或切缘长度时,瓷贴面是出色的美观和修复选择。当唇面牙体组织良好但舌面组织不足时,部分贴面金冠可能是很好的美观选择。如果牙体组织中度丧失或存在中度染色,Dicor全瓷冠是极佳选择。在存在重度染色的情况下,应考虑使用箔或核系统以完全遮盖底色。随着咬合力成为更重要的因素,修复系统的选择将更多地取决于强度而非美观需求。氧化铝烤瓷全冠仍然以合理的价格提供了出色的强度和美观性。当大部分颜色位于牙齿表面或牙齿具有高透明度时,Dicor全瓷冠能提供非常美观的效果,而Dicor Plus全瓷冠提供了形成内部色泽的机会。当需要更高强度时,建议选择箔和核系统,或者提供更强核材料的系统,如Alceram或Inceram。这些更强的核材料将提高弯曲强度和抗压强度,但随着核材料中氧化铝含量的增加,亮度可能会有所增加。如果能够开发出内部着色和分层构建的方法并控制成本,计算机生成的全瓷冠可能是陶瓷修复牙科的未来发展方向。陶瓷全冠最好仅限于口腔前牙区,因为该区域的咬合力通常小于后牙区。在某些选定的病例中,若没有异常功能习惯的证据,并且牙医和技师精通功能性咬合且对咬合具有最大程度的修复控制,后牙陶瓷修复也会成功。在这些情况下,重要的是要记住,瓷比釉质硬,并且抗压性很强。(摘要截选至400字)