[Overlay prosthetic solution in subtotal edentation treatment]. / Supraprotezarea--solutie de tratament în edentatiile subtotale.

The preservation of the natural dental roots represents a big advantage for the overdenture prosthetic appliances. The realization of an overdenture needs a perfect correlation of all the clinical and technological factors, in all the prosthetics steps. Another important aspect is represented by the possibility of a correct treatment of the remaining roots. The remaining roots will be correctly endodontically treated. The root section will be prepared with two inclines bucally and orally located. A metallic cup will cover the root section. On the inner surface of the overdenture the dental technician will realize specific preparations corresponding to this cups. This kind of prosthetic treatment is indicated only for patients with a very good oral hygiene and a good general health.

[Moiré effect. Application in medicine and dental technology]. / Fenomenul moiré. Aplicatii în medicina si în tehnologia protezelor dentare.

Moiré effect is an optical phenomenon that occurs when two similar arrays of alternately opaque and transparent lines or dots are superimposed upon each other. Superimposition of two such similar, but slightly different, line arrays causes interference between the arrays; the interference results in the formation of moiré fringes. There is a definite relationship between the pitches of the two arrays and the spacing of the fringes. Therefore, given the pitch of one of the arrays and the distance between the moiré fringes, the pitch of the other array can be calculated. The moiré effect can be used to determine the development of cutaneous tumors in a very short time-frame and to assess the measurement of dental eruption within 20 minutes. The 3-D facial, palatal and dental morphology can thus be evaluated very accurately. The CAD/CAM dental technology is actually possible due to the moiré effect.

[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.

[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.

[CAD/CAM technology-elaboration of electronic model through optical impression in the fabrication of the dental prostheses by a computer assisted device]. / Tehnologia CAD/CAM--elaborarea modelului electronic prin amprentarea optica în cadrul technologiei de realizare a protezelor dentare asistate de computer.

In modern CAD/CAM technology of dental prosthetics, the "optical impression" taken by special video cameras deploying 3D-recording of the oral situation (Cerec 1, Cerec 2) initiates the computer-generated production of a digital model. The computer receives and renders the digital data obtained through "optical impression" i.e. data acquisition not as a "negative" of the oral situation but as a "positive" copy of it, namely as a digital model in a virtual environment which can be displayed on the screen and be further used in the fabrication of dental prostheses by means of a computer-assisted device (CAM or CIM).

[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.

Technical and biophysical aspects in prosthetic occlusal rehabilitation for edentulous teenagers.

The loss of anterior teeth may be transient solved by temporary adhesive bridges (Oslo bridge, Rochette, Ellmann, Neumann, Tschemitscheck, Armatron systems). Provisional crowns and bridges could be used for Brackets fixing. Anterior bridge with subocclusal connector permits transversal expansion. When a successful orthodontic treatment is followed by a prosthetic treatment, it is not important to change the achieved occlusion, by the occlusal framework morphology. The framework design of the metal component can contribute to the improvement of the aesthetic aspect and reduce the cost by using a small quantity of expensive alloy. Cytocompatibility of the used Cr-Co alloy is confirmed by cell culture test.