Journal of Dental Research

Compressed apatite disks were used as models for tooth enamel. Their permselective properties were studied as functions of the pH of the gradient solutions, the composition of the apatites, and the pretreatments with anionic phosphate compounds and cationic proteins. The results are discussed in relation to the caries mechanisms.

The acid resistance of powdered human dentin increased linearly after pretreatments in 2.5, 25, 250, and 1,000 mM NaF in water. The acid resistance was not directly correlated to the F content of the dentin. The results indicated F uptake by the dentin to be a result of chemical reaction and of adsorption .

An optical test was developed for amalgam alloys by condensing amalgams against stainless steel blocks with regularly spaced grooves forming diffraction gratings. The quality of the diffraction pattern obtained with a He-Ne laser from these amalgams is a measure of the adaptation to the grooves.

The immunosuppresive effects of topically applied 9, 10 dimethyl 1, 2 benzanthracene (DMBA) were investigated in the Syrian Golden hamster. Tri-weekly doses of DMBA were administered, zith some hamsters receiving both DMBA and X-radiation. DMBA and DMBA-plus-radiation groups demonstrated decreased immune responsiveness relative to their control counterparts. Potential immuntosuppressive effects of carcinogen and carcinoma are discussed.