Pulp irritants:lec 13

Operative
Lec.13 دعبدالمنعم الخفاجي
Pulp irritants:
Like other soft tissues, the pulp reacts to irritants with an inflammatory response. The pulp irritants can be classified according to the cause of irritant:
1-bacterial
2-Physical
3-Irradiation
4-Chemical
5-Idiopathic
I-Bacterial irritant:
1-Caries:
Carious dentin and enamel contain numerous bacteria such as Streptococcus mutans, Lactobacilli, and Actinomyces. The population of microorganisms decreases to few or none in the deepest layers of carious dentin. Many studies have been shown that even early enamel caries lesions that extend less than one fourth of the way to the dentinoenamel junction induce pulpal reaction especially when the caries lesion has advanced rapidly. This is may be related to an increase in the permeability of enamel, allowing the transmission of stimuli along enamel rods. However, direct pulp exposure to microorganisms is not a prerequisite for pulpal response and inflammation. Microorganisms in caries produce toxins that penetrate to the pulp through tubules. As a result of microorganisms and their by products in dentin, pulp is infiltrated locally primarily by chronic inflammatory cells. As a lesion progresses deeper into the tooth, pulpal reaction increases and the intension and character of infiltrate change. The outward flow of fluid through dentinal tubules does not prevent bacteria or their toxins from reaching the pulp and initiating pulpal inflammation. The extent of pulpal inflammation beneath a carious lesion depends on the depth of bacterial invasion as well as the degree to which dentin permeability has been reduced by dentinal sclerosis and reparative dentin formation and the time of irritant.