[Some aspects concerning the electrochemical corrosion of the Gaudent-S dental alloy]. / Unele aspecte privind coroziunea electrochimica a aliajului dentar Gaudent-S.

The potentiodynamic polarization methods have been employed to evaluate the corrosion resistance of the Gaudent-S dental alloy in a slightly acid artificial saliva (Fusayama's saliva; pH = 6.18), a slightly alkaline artificial saliva (Rondelli's saliva; pH = 7.75) and in an acid saline solution (NaCl/lactic acid; pH = 2.64). The results were compared with those obtained for copper and aluminium--the principal components of the studied alloy. In Fusayama's artificial saliva both the copper and Gaudent alloy exhibit close indentic cyclic voltammograms, typical for pitting corrosion; the pitting potentials being 1550 mV (SCE) for Gaudent-S and 1350 mV (SCE) for copper, while the repassivation potential is 700 mV (SCE), the same for the two analysed metals. In the Rondelli's artificial saliva and in acidic saline solution the passivation domain is considerable reduced; the corrosion potential and the repassivation potential coincides. In the saline acid solution the current densities are two times higher than those obtained in the other two solutions. In the aluminium case it can be noticed that the passivation domain is very reduced, no cathodic peak is observed and much more current densities are registered in the positive potential domain.

[Advances and limits in biomedical stress quantification in dento-periodontal structures]. / Posibilitati si limite în cuantificarea solicitarilor biomecanice în structurile dento-parodontale.

The stress quantification in dento-periodontal structures is an important concept, as stress in the tissue and in surrounding structures. A number of clinical studies have suggested figures for such an optimal stress strange. The clinical experiments can be completed with mathematical analysing methods as finite element method. Once the basics of biomechanics understood laws the treatment goes clearly defined, the computer aided design improve the optimal restorative prosthetic or orthodontic appliance. The finite element method (FEM) makes possible the numerical simulation of different clinical situations. Based upon mathematical modelling and extrapolation from experimental studies, practical conclusions can be drawn concerning the different types of forces and their subsequent induced relationship to the stresses. Clinical and histological experiments confirm the mathematical prediction offered by the FEM.

[Periodontal regeneration with enamel derivate proteins (Emdogain)--clinical evaluation]. / Régénération parodontale a dérivés de la matrice proteique de l'email (Emdogain)--évaluation clinique.

UNLABELLED: The study was undertaken in order to evaluate the effect of Emdogain as an adjuvant in periodontal surgery in promoting bone level gain, compared to bone levels after surgery. METHOD: The study was realised on 6 patients. who had pair test sites and control sites. Two interproximal sites were selected in each patient at a distance from each other, in the same maxilla, with infra-osseous defects with depth > or = 4 mm and width > or = 2 mm. The patients were followed on a long term period, initially and after 8 and 16 months. RESULTS: The average values of the clinical attachment level were evaluated both in the test sites and in the control group at 8 months and 16 months, The radiographic osseous level continued to recede at the group treated with Emdogain, and in the control group it remained at its initial level. The radiographic gain was ascertained after 16 months. CONCLUSION: This study proves that the topic use of Emdogain as an adjuvant, during periodontal defects surgery, on radicular surfaces, determines a gain in the clinical attachment and an osseous gain observed on X-rays.

[Influence of corrosion products of the dental alloys on the excitable tissues]. / Influenta produsilor de coroziune ai aliajelor dentare asupra tesuturilor excitabile.

The surface of dental alloys in contact with well conducting electricity solutions are electrochemically corroded. This phenomenon is determined by a proper electric wave generated by electrochemical phenomena present at the limit between the two phases. Because during dental treatments similar conditions with the generation of corrosion waves are present, we decided to study the electrochemical behaviour of the most commonly used dental alloys. The method used in our study is based on the anodic and catodic reactions developed simultaneously, represented by the global curve of polarization that gives informations on the intensity of corrosion waves. We have also studied the influence of corrosion products on the excitable tissues. The results demonstrate the significant influence of metallic ions on the excitable tissues.

[Comparison on the effects of metronidazole in subgingival application in the treatment of adult periodontitis]. / Studiul comparativ al efectului metronidazolului în aplicatii subgingivale în tratamentul parodontitei adultului.

UNLABELLED: Control of subgingival plaque is the key of the treatment of periodontal diseases. The use of subgingival sustained-release antibiotic therapy is advocated for the beneficial effect on anaerobic flora. A single-blind clinical trial was carried out in 13 patients with adult periodontitis to compare the effects of subgingival application of metronidazole dental gel with those of subgingival scaling. METHOD AND MATERIALS: A split mouth design was used so that each patient received all treatments simultaneously. Randomly selected quadrants were treated with applications of 25% metronidazole gel, subgingival scaling, or a combination of scaling and gel application. The remaining quadrant in each patient was left untreated as a control. RESULTS: All three treatments were effective in significantly reducing bleeding on probing over the 14 weeks observation period. No statistically significant differences were found between scaling alone and combined treatment. Scaling and combined treatment were better than metronidazole. Metronidazole produced transient effects, best noted during the first 4 weeks after treatment. No additive effect of metronidazole was noted in the combined treatment. At week 14, only combined treatment sites and scaled showed statistically greater probing depths reduction than control sites. CONCLUSION: For the treatment of mild to moderate adult periodontitis, subgingival scaling alone is as effective as the combination of scaling and antibiotic therapy.

[The technic for the reoptimization of laryngeal cannulae by recoating them with a silicone material]. / La technologie de reoptimisation des canules laryngiennes par recouvrement d'un materiau siliconique.

In the laryngeal surgical pathology area, the application of a cannula with temporary or long term indications is necessary for ensuring the respiratory function troubled by various causes (inflammatory, tumor or traumatic) that obstruction the respiratory tract. The most frequently used standard cannula is rigid and does not show proper adaptation for every clinical situation, thus leading to local troubles. In this paper, the realization technique of a rigid/flexible and individual cannula applied after the tracheotomy is presented. In order to carry out the cannula, a rigid material is utilized (acrylic resin) for maintaining the shape and dimensions of the laryngeal stoma. It is also utilized an elastically material (acrylic resin with a retard plug--Simpa) that ensures the optimal adaptation, tight close and tissue protection around the stoma. In co-operation with the ORL Clinic--Recuperation Hospital, these cannulae were applied to fifteen patients pursuing their evolution in time.

[The tension induced by orthodontic forces in the dentoperiodontal system studied by the finite element method]. / Cercetari privind tensiunea indusa de fortele ortodontice în sistemul dento-parodontal prin metoda elementului finit.

The aim of this study was to quantify the stress induced in the periodontal ligaments by the orthodontic appliances. A finite element model of an orthodontic system, applied on a lower premolar, was developed in different loading conditions. The maximum stress values depend on the location, direction and the magnitude of force application.