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.
Dental Crowns and Dental Bridges. A dental crown and dental bridge is an area seen above the gums. Usually, when a dental crown is needed, the natural crown on your tooth has been chipped, fractured, broken, or even in some cases a large silver filling has broken off. Sometimes root canal therapy is necessary.