[Relative concentration of phosphorus and calcium in the ameloblastic layer and in the enamel. Preliminary study (author's transl)]. / Concentration relative du phosphore et du calcium dans la couche améloblastique et dans l'émail. Etude préliminaire.

It may be inferred from this observation, that all of the phosphorus necessary to the formation of the enamel, reaches it, during its formation process, by way of compounds, formed in the ameloblastic layer, and containing only part of the calcium necessary to the crystallisation of the hydroxyapatite. The remainder of the calcium may attain, by another route, the enamel under formation where the hydroxyapatite crystallises.

[Superficial structure of dental cement as shown by acid etching and scanning electron microscope]. / Contribution á l'étude de la structure superficielle du cément dentaire par attaque acide et observation au microscope électronique á balayage (M.E.B.).

The superficial layer of the cement is made up of a mineralised structure in which are included organic fibres which would seem to serve as the intracemental anchorage of Sharpey's fibre. The appearance seen on sweep electron microscopy after acid demineralisation confirm those seen using the electron microscope by Selvig. These fibres included in the cement have a variable diameter ranging from a few microns and 45 microns on our pictures (10 microns according to Selvig). They consist of a numerous fibrils with a diameter of the order of 0.3 microns. In the cement these fibers are parallel to the surface of the tooth, this confirming Selvig's finding. Finally, our observations show that, in the superficial part of the cement, these fibres form a markedly flattened three-dimensional network.

[Acid application on dental tartar as preliminary treatment before mechanical scaling]. / Contribution à l'étude de l'attaque acide du tartre dentaire, en tant que traitement préliminaire au détartrage mécanique.

The action of the preparation studied, containing 20% hydrochloric acid in an alcohol-chloroform medium: 1) affected both white tartar as well as the submucosal tartar, progressively replacing the phosphorus radicles of tricalcium phosphate by CL ions, transforming the insoluble tricalcium phosphate into soluble calcium chloride; 2) was practically complete in 2 minutes; 3) was more rapid on tartar than on enamel or even cement; 4) did not appear to alter the superficial structure of the tooth in 4 minutes whilst, for the same period of time, the superficial structure of the cement was deeply attacked with 50% preparations of citric acid or phosphoric acid; 5) in our trials, carried out after 4 minutes treatment, caused the tartar to undergo a relatively superficial but adequate chemical action to facilitate its removel, whilst leaving the underlying hard tissue, enamel or cement, unharmed. It would thus appear that such a substance may be used for the preparation and speeding of mechanical descaling.