. The Dental cosmos. that thiscalcified area (see a) has been decalcifiedto a lesser extent than the surroundingdentin, showing a marked retarding ac-tion on the part of the solidified dentin. 162 THE DENTAL COSMOS. In many cases of caries, then, when itsprogress has been slow, the pulp has beenhealthy, and the dentinal calcificationshave been complete, these secondarychanges have a marked effect upon theadvance of the carious process, inhibitingits progress toward the pulp. This maybe illustrated by Fig. 4, in which we seea cavity of caries in the occlusal surface ofa molar, the cavity having
. The Dental cosmos. that thiscalcified area (see a) has been decalcifiedto a lesser extent than the surroundingdentin, showing a marked retarding ac-tion on the part of the solidified dentin. 162 THE DENTAL COSMOS. In many cases of caries, then, when itsprogress has been slow, the pulp has beenhealthy, and the dentinal calcificationshave been complete, these secondarychanges have a marked effect upon theadvance of the carious process, inhibitingits progress toward the pulp. This maybe illustrated by Fig. 4, in which we seea cavity of caries in the occlusal surface ofa molar, the cavity having extended some face of the tooth to the pulp. Consider-able irritation is set up in the pulp bya large number of filling materials whichwe commonly use in the repair of cariousteeth. All the metals conduct heat moreor less readily, and a filling with a highconductivity, if placed in a cavity whichapproaches the pulp, will constantly irri-tate the latter by undue irritation will be less severe if the. distance laterally beneath the enamel, thecaries process, however, having advanceda relatively short distance toward thepulp. It seems very possible that thisimpeding of the progress of caries pulp-ward is due to the heavy secondary calci-fications formed in the dentinal tubuliwhich have been attacked. The trans-parent zone is therefore of great benefitto the tooth, in that it conserves the den-tin from loss and delays or prevents theexposure of the pulp. It also has an-other influence of a beneficial characterin that the dentin which is thus calcifiedoffers an increased resistance to the trans-mission of thermal stimuli from the sur- dentin overlying the pulp is dense, hav-ing undergone sclerotic changes. Thisprinciple will also apply to all filling ma-terials which by their nature are irrita-ting to the pulp. Such fillings as theoxyphosphates of copper and zinc, whichcontain an excess of acid, are intenselyirritating, but if calcification has takenplace, the pulp
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectdentist, bookyear1912
