MLD is usually caused by the lack of an important enzyme called arylsulfatase A. Because this enzyme is missing, chemicals called sulfatides build up in and damage the nervous system, kidneys, gallbladder, and other organs. In particular, the chemicals damage the protective sheaths that surround nerve cells.
What is a dental crown? The anatomy of a tooth can be divided into two basic parts -- the root and the crown. In a person with healthy gums and bone, the root of the tooth is covered by the gums and bone. The part of the tooth that is visible in the mouth, above the gum line on lower teeth and below the gum line on upper teeth, is called the clinical crown. A cemented restoration that partially or completely covers the outside of the clinical crown is referred to as a dental crown or cap.
Crowns are made by taking an impression of the tooth or teeth they'll be covering. Before this impression is created, your dentist must first reduce your tooth's size so that the crown fits properly. Your dentist may also place a temporary crown while the permanent one is being made. Types of Dental Crowns. There are four different types of dental crowns. Ceramic â These are used for restoring front teeth, and are popular in this area for their ability to blend with your natural tooth color. The crown is made of a porcelain-based material.