Use of x-ray microanalysis to monitor diffusion of Zn from a cement into human dentin.

Energy dispersive x-ray spectrometry (EDAX system), with scanning electron microscopy was used to detect diffusion of Zn from a source in human dentin and the system was tested for sensitivity and reproducibility. Sections of human teeth in which a ZnO-eugenol cement had been placed in a cavity in the dentin in vivo were prepared and x-ray microanalytical measurements carried out. We found that values of counts for Zn, Ca and P in the same field were linear up to a total counting time of 60 sec. We further found that reproducibility of values between repeat examinations of the same specimens on different days was excellent. The concentration of Zn in the dentin decreased exponentially with distance from source within the distance tested. We conclude that the system can be used to detect trace concentrations of Zn, and that accordingly the diffusion behavior of a variety of ions in dentin could be monitored.

[Pulp and dentin responses to topical dexamethasone application]. / Risposte pulop-dentinali alla applicazione topica di desametazone.

The Authors have proposed to develop this research employing a preparation containing exclusively a cortisonic, the desametazone, in order to evaluate the alterations of the dentinogenesis to be attributed to such component. 32 cavities have been carefully drilled in dogs' cuspids. The 16 experimental cavities were dressed with desametazone, asbestos and amalgam in successive strata while in the 16 control cavities only asbestos and amalgam were used. Stainless steel bands were cemented on the processed teeth. The animals received 9 I.V. injections of tetracycline (10 mg per kg) each at 7 days interval. In the observation of the tetracycline markings under the experimental cavities (with desametazone) alterations of the dentinogenesis were not observed. Consequently, it seems that the action of desametazone is not to be considered harmful for the pulp tissue under the freshly cut dentine, as far as duration of the experiment is concerned.

The effect on bone repair of aspirin cones placed in extraction sockets in dogs: a histopathologic study.

Four canines of eight 2-year-old dogs were extracted surgically, a mucoperiosteal flap being raised. A standardized pair of the post-extraction cavities were filled with three aspirin cones, the other pair being used as controls. The flaps were sutured with surgical gut. The dogs were killed at intervals of 2, 4, 6 and 8 weeks; bone blocks including the cavities were resected and decalcified for histologic examination; serial sections were stained with hematoxylin and eosisin. Microscopic observation on 2 week samples showed an inflammatory response with granulation tissue in both experimental and control cavities with delayed bone apposition in cavities filled with aspirin cones. The 4, 6 and 8 week samples did not show any major difference between the experimental and control cavities. We observed a decrease in infiltrating of cells followed in both by a similarly increasing amount of fibrous tissue and bone remodeling. These results were due perhaps to the details of the experimental method as the suture allowed aspirin to stay in the cavities for only a short time (2--3 days), as occurs in clinical practice.

Bone changes incident to blade-vent implants.

This research was undertaken to study the dynamics of bone changes in relation to endosseous blade-vent implants with vital labeling technique. Three mandibular premolars were bilaterally extracted in six two years old dogs. Subsequently each healed edentulous space was implanted with a titanium endosteal blade. One blade in each dog had the post extending into the mouth; the other had the post cut at the level of the neck and covered by the mucoperiosteal flap. The animals received I.V. Pyrrolidin-Methyl-Tetracycline and Alizarine Red S labelings at 15 and 30 days intervals. Dogs 1, 3 and 5 were sacrificed on the 97th day; dogs 2, 4 and 6 on the 52nd day. On ground sections of the mandibular bone which included the blades under U.V. light, it was observed that the implants were surrounded by remodeled trabecular bone of cancellous nature containing the labeling lines of Tetracycline (yellow) and Alizarine (red). The bone-metal interface consisted mainly of a thick layer of non mineralized tissue of about 70 micrometer. The labeling results showed that the new bone apposition began early (at least by the 15th day) and continued for a long time, being still present at the moment of the last injection (90th day). No difference was recognized between the bone responses to the implants jutting out and those submerged. This confirms that implant failure is mainly linked to irregular traumatism and inflammatory infiltration which occurs over a more prolonged duration.

[Value of the use of a cement containing a combination of triamcinolone and tetracycline in cavity preparations]. / Significato dell'impiego di un cemento contenente una associazione di triamicinolone e tetraciclina nelle preparazioni cavitarie.

Odontomix (reg'd) cement was used at the bottom of cavities prepared in healthy dog canines in a attempt to prevent pulp and dentine alterations caused by the preparation and filling of cavities. 24 dogs were used along with 24 controls. I.v. tetracycline was afterwards given 10 times at weekly intervals. Examination of tetracycline labelling under the cavities showed that the cement caused pulp and dentine changes in confined areas, though it has not yet been possible to determine whether these are due to the corticosteroid, the antibiotic, or the excipient employed in the preparation.