Abstract
To understand the pathology of caries lesions, it is important that the earliest stage of destruction in the surface layer of enamel and also the point of attack at the superficial layer of the enamel should be directly demonstrated. For this reason the progress of destruction in caries-like lesions produced on thin sections of teeth should be successively followed up.
While histopathological evidence on incipient caries lesions has been accumulated by numerous researchers, little has been published concerning a direct demonstration of structural changes.
This paper, then, deals with a successful new method for continuous observation of changes in lesions produced on ground thin sections of teeth under the microscope. Plano-parallel thin sections of approximately 20μ in thickness were prepared from undecalcified teeth according to procedures previously published. The sections were cemented with 3% toluene solution of polyvinylmethylether between two pieces of glass, leaving intact only the small area of the enamel surface to be observed (Fig. 1).
The area thus prepared was exposed to the attack solution running at a constant flow rate through the apparatus assembling on the microscope as shown in Fig. 2 and 3.
The changes were observed and recorded by microscopic photography for long periods of time. In particular, 16 mm. cine-automatic photography was most useful in following details of the changes.
As can be seen in Fig. 4, in which changes on the enamel section produced by N/10 acetic acid buffered to pH 5.0 were sucessively shown for 67 hours according to the method described here, the reliability and availability of this method was confirmed. The method will be helpful for getting further information on the pathology of enamel caries.
