Human tooth decays more rapidly and is subject to severe cavities if not properly treated, but dentin still acts as a protective layer and supports the crown of the tooth. Dentin is a mineralized connective tissue with an organic matrix of collagenous proteins. Dentin has microscopic channels, called dentinal tubules, which radiate outward through the dentin from the pulp cavity to the exterior cementum or enamel border. The diameter of these tubules range from 2.5 μm near the pulp, to 1.2 μm in the midportion, and 900 nm near the dentino-enamel junction. Although they may have tiny side-branches, the tubules do not
Human tooth ligaments attached to a tooth moving away from it has a high number of osteoblasts, resulting in bone formation. The gingiva ("gums") is the mucosal tissue that overlays the jaws. There are three different types of epithelium associated with the gingiva: gingival, junctional, and sulcular epithelium. These three types form from a mass of epithelial cells known as the epithelial cuff between the tooth and the mouth. The gingival epithelium is not associated directly with tooth attachment and is visible in the mouth. The junctional epithelium, composed of the basal lamina and hemidesmosomes, forms an attachment to the tooth. The