312 Proceedings Columbia Biochemical Association [Jan. 



ii8. A further study of dental caries.^^ Alfred P. Lothrop 

 AND William J. Gies. The effect of vinegar as a dentifrice was 

 determined. Natural extracted teeth (i6), nearly all of which 

 contained typical fillings of gutta percha, Silicate cement, oxy-phos- 

 phate of zinc, synthetic porcelain, red copper cement, alloy, amal- 

 gam, cast gold inlay and malleted gold,^^ were embedded in blocks 

 of paraffin about three-fourths of an inch Square, in such a way as 

 to completely cover the roots with the paraffin, leaving only the 

 enamel surfaces with the fillings exposed. These blocks, containing 

 the teeth, were then placed in a narrow zinc box about 8 in. long and 

 I in. deep, in such a way that the lower edges of the exposed sur- 

 faces were on a line with the edges of the box. The box was then 

 completely filled with melted paraffin which, after hardening, made 

 an " artificial jaw " in which the teeth were firmly fixed. 



An ordinary flat toothbrush with tufted bristles was used for 

 the application of dentifrices. At each application the brush was 

 held a moment in running water, the bulk of the suspended water 

 dislodged with a jerk, and then ten drops of diluted vinegar ( i : i ) 

 or of a populär, slightly alkaline, antiseptic dentifrice were allowed 

 to fall on the wet brush from a dropping bottle. The teeth were 

 vigorously and systematically brushed for a period of lo to 15 

 seconds. The brush was then rinsed in running water, and the 

 teeth washed with the water that remained in the brush. The teeth 

 were washed in this way with three fresh supplies of water. Finally, 

 after residual water had been drained from the teeth by simply 

 tilting the box, saliva was expectorated on the teeth and distributed 

 over them with the clean brush. During the intervals between 

 brushings (which occurred twice daily), each box of teeth was kept 

 in a moist Chamber, for which purpose the senior author's glass 

 device for the preservation of hashed meat by the cold-storage 



^* Conducted under the auspices of the First District Dental Society of the 

 State of New York. See the Journal of the Allied Dental Societies, 1913, viii, 

 p. 283. 



^^ The teeth were obtained for us and the filHngs inserted by Drs. J. Morgan 

 Howe and C. C. Linton. Before the experiment was begun, Drs. A. H. Merritt 

 and C. C. Linton made critical examinations of the teeth with special reference 

 to the detection by them, subsequently, of any unfavorable change as a result 

 of our intended treatment of the teeth. 



