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Dentin is classified into three types: primary, secondary, and tertiary. [24] [25] Secondary dentin is a layer of dentin formed after the tooth's root has fully formed. Tertiary dentin develops as a result of a stimulus, such as a carious attack or wear. [26]
Tertiary dentin on the surface of a gorilla tooth. The darker area indicated by the white arrow is tertiary dentin and has formed as a response to tooth wear. Wear on the surface of a tooth can lead to the exposure of the underlying dentin. When wear is severe tertiary dentin may form to help protect the pulp chamber. [4]
The mammalian heart has two atrioventricular valves separating the upper atria from the lower ventricles: the mitral valve in the left heart, and the tricuspid valve in the right heart. The two semilunar valves are at the entrance of the arteries leaving the heart. These are the aortic valve at the aorta, and the pulmonary valve at the ...
Reactionary dentin is formed by odontoblasts when the injury does not damage the odontoblast layer. Reparative dentin is formed by replacement odontoblasts when the injury is so severe that it damages a part of the primary odontoblast layer. Thus a type of tertiary dentin forms in reaction to stimuli, such as attrition or dental caries.
Dr. Davis emphasizes that valve damage is not only caused by poor dietary habits, explaining, “Diet is often talked about in connection to heart disease, but valve damage has different causes.
Odontoblasts also secrete tertiary dentin when irritated. Tertiary dentin secreted by odontoblasts is often due to chemical attack, either by chemicals diffusing through the dentin and insulting the odontoblasts, or by diffusion of toxic bacterial metabolites down the dentinal tubules in the instance of a carious attack with dental decay. This ...
There are three types of dentin, primary, secondary and tertiary. [19] Secondary dentin is a layer of dentin produced after root formation and continues to form with age. Tertiary dentin is created in response to stimulus, such as cavities and tooth wear. [20]
The heart's cardiac skeleton comprises four dense connective tissue rings that encircle the mitral and tricuspid atrioventricular (AV) canals and extend to the origins of the pulmonary trunk and aorta. This provides crucial support and structure to the heart while also serving to electrically isolate the atria from the ventricles. [1]