The Demineralization of Human Dental Roots in the Presence of Fluoride

1987 ◽  
Vol 66 (8) ◽  
pp. 1370-1374 ◽  
Author(s):  
P.M.M. Hoppenbrouwers ◽  
F.C.M. Driessens ◽  
J.M.P.M. Borggreven
Keyword(s):  
Surface Layer ◽  
Outer Surface ◽  
Fluoride Concentration ◽  
Root Surface ◽  
Buffer Solution ◽  
Buffer Solutions ◽  
Ionic Product ◽  
Oral Environment ◽  
Root Surface Caries ◽  
Intact Roots

Intact roots of human molars, which had not been exposed to the oral environment, were exposed to buffer solutions of pH 5.5, which contained, besides calcium and phosphate, various concentrations offluoride. Densitometric measurements on contact-microradiograms of transverse sections of these roots produced data which were used to calculate the rate of demineralization ( Vdem). Vdem appeared to be reduced with increasing fluoride concentration and with decreasing pIOHA (i.e., the negative logarithm of the ionic product of hydroxyapatite) of the buffer solution. In addition, it was observed that, after some days of exposure, remineralization started to occur within the surface layer at some μm from the outer surface and that the region within which remineralization took place was extended inward with increasing time of exposure. These data suggest that fluoride is effective in the prevention of root surface caries. The mechanism of the interaction of fluoride with the root mineral is discussed.

Rumination in sheep. III. Experimentally induced variations on the circadian pattern of rumination

1965 ◽  
Vol 16 (4) ◽  
pp. 649 ◽  
Author(s):  
GR Pearce
Keyword(s):  
Extended Period ◽  
High Protein ◽  
Circadian Pattern ◽  
Buffer Solution ◽  
Buffer Solutions ◽  
Experimentally Induced

The circadian (24-hr) pattern of rumination of caged sheep was found to be affected: (a) by the administration of a roughage ration per fistulam; (b) by the emptying of the rumen and the subsequent return of the rumen contents; (c) by the emptying of the rumen and the replacement of the contents by a buffer solution plus roughage. The period during which no rumination occurred following feeding was progressively shortened when increasing proportions of a ration of oaten chaff and lucerne chaff were administered per fistulam. The effect was much reduced when high protein sheep cubes were added to the chaff ration. The removal of the rumen contents after voluntary feeding and then their immediate return to the rumen tended to cause an early commencement of rumination. When the rumen contents were "pasteurized" before return, however, rumination did not occur for an extended period afterwards. When the rumen contents were replaced with buffer solutions plus roughage, variable rumination responses occurred. In one instance apparently uninhibited rumination resulted.

scholarly journals ULTRACENTRIFUGATION STUDIES ON THE ELEMENTARY BODIES OF VACCINE VIRUS

1938 ◽  
Vol 68 (4) ◽  
pp. 607-627 ◽  
Author(s):  
Joseph E. Smadel ◽  
Edward G. Pickels ◽  
Theodore Shedlovsky
Keyword(s):  
Sedimentation Rate ◽  
Vaccine Virus ◽  
Normal Rate ◽  
Buffer Solution ◽  
Buffer Solutions ◽  
Original Volume ◽  
Sucrose Solutions ◽  
Rate Of Sedimentation

Ultracentrifugal studies of the CL dermal strain of vaccine virus warrant the following conclusions: 1. When suspended in increasing concentrations of sucrose, glycerol, or urea solutions, elementary bodies of vaccinia show variations in sedimentation rate which indicate changes in the density or size of the particles. For a given change in the density of the medium these changes are smallest with sucrose and most marked with urea. The normal rate of sedimentation of Paschen bodies may be restored by resuspending them in dilute buffer solution. 2. The density of elementary bodies of vaccinia suspended in dilute buffer solutions is estimated to be 1.16 gm. per cc. Higher values for the density are found if the particles are suspended in solutions containing sucrose, glycerol, or urea. In 53 per cent sucrose, for example, the density is 1.25 gm. per cc. 3. Paschen bodies appear to be quite permeable to water and urea, less so to glycerol, and only slightly, if at all, to sucrose. 4. The increased density of the elementary bodies of vaccinia in sucrose solutions may be accounted for by an osmotic extraction of water from the particles. On this basis the water which can be thus extracted corresponds to at least a third of the original volume of the particles.

Root Surface Caries: A Cinical, Histopathologic and Microradiographic Investigation

1974 ◽  
Vol 8 (3) ◽  
pp. 249-255 ◽  
Author(s):  
John L. Westbrook ◽  
Arthur S. Miller ◽  
Neal W. Chilton ◽  
Frank L. Williams ◽  
Richard D. Mumma, jr.
Keyword(s):  
Root Surface ◽  
Root Surface Caries

Comparison of two Scoring Methods for Root Surface Caries in Hamsters

1988 ◽  
Vol 67 (1) ◽  
pp. 44-45 ◽  
Author(s):  
A.R. Firestone ◽  
F.F. Feagin ◽  
C.N. Graves ◽  
G.K. Stookey ◽  
C. Rodlun ◽  
...  
Keyword(s):  
Root Surface ◽  
Scoring Methods ◽  
Root Surface Caries

Root surface caries among older Australians

2018 ◽  
Vol 46 (6) ◽  
pp. 535-544 ◽  
Author(s):  
Ninuk Hariyani ◽  
A. John Spencer ◽  
Liana Luzzi ◽  
Loc Giang Do
Keyword(s):  
Root Surface ◽  
Root Surface Caries
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