La prescription de psychotropes touche environ un quart de la population. Les anxiolytiques, les antidépresseurs, les hypnotiques et les neuroleptiques représentent les catégories les plus utilisées. Après un rappel concernant la pharmacodynamie, la pharmacocinétique et le métabolisme des principales classes de psychotropes, leurs répercussions odontostomatologiques et leur contrôle sont envisagés. Les effets secondaires buccodentaires des psychotropes résultent surtout des altérations quantitatives et qualitatives de la sécrétion salivaire. Un examen régulier de la cavité buccale est nécessaire chez tout patient recevant ce type de traitement. La xérostomie est responsable d'altérations des tissus durs et mous (caries, parodontopathies, mycoses…). Des recommandations hygiénodiététiques et une thérapeutique sialagogue appropriée permettent de lutter efficacement contre ces inconvénients. Enfin, la prise de psychotropes impose des précautions anesthésiologiques particulières.

The evolution of the devices used for the fracture fixation is now oriented toward the bioresorbable materials (PLA, PGA, PDX) which should gradually replace the metallic materials (titanium, SS) in the next 10‐15 years. The osteosynthesis devices will have to fulfil more precise biomechanical criteria, in certain anatomical zones (i.e. trapezoidal plates for the mandibular condyle).

Les anti-inflammatoires appartiennent à des classes chimiques très variées et agissent de façon purement symptomatique sur la réaction aspécifique des tissus à un agent agresseur. Les glucocorticoïdes, anti-inflammatoires stéroïdiens, ont tous une activité hormonale, concernant principalement les régulations métaboliques, et exercent un effet freinateur sur l’axe hypothalamo-hypophyso-surrénalien. Certains états pathologiques demandent une attention particulière mais ne contre-indiquent pas forcément une corticothérapie en cure courte. Les extractions de dents de sagesse incluses et la dermatologie buccale figurent parmi leurs indications avec des modalités propres d’administration. Les anti-inflammatoires non stéroïdiens (AINS) regroupent différentes classes chimiques, mais sans structure stéroïdienne. L’inhibition de la biosynthèse des prostanoïdes par les AINS est responsable de bon nombre de leurs propriétés pharmacologiques mais aussi de leurs effets indésirables (principalement digestifs, rénaux et cutanés). Ils peuvent être prescrits en odontostomatologie, soit pour leurs propriétés antalgiques, soit pour leurs propriétés antiœdémateuses et anti-inflammatoires, après analyse soigneuse du rapport bénéfice/risques. Les nouveaux anti-inflammatoires (coxibs, inhibiteurs sélectifs de la cyclo-oxygénase 2) sont, dans la pratique clinique actuelle, surtout utilisés en rhumatologie, mais ils n’apportent toutefois pas d’avantage notable quant à la survenue d’effets secondaires comparés aux autres AINS. Les enzymes sont des anti-inflammatoires d’efficacité modeste, utilisés surtout comme antiœdémateux.

Ce texte presente les caracteristiques de differents materiaux susceptibles d'etre inclus dans l'organisme humain. Il a pour objectif de constituer une reference destinee a etre consultee par tous les praticiens qui souhaitent s'informer sur la nature physique et chimique ainsi que sur les criteres de tolerance des produits qu'ils sont susceptibles d'utiliser. Ces informations concernent aussi bien les implants dentaires que les materiaux de comblement ou les greffes d'apposition.

This chapter provides a summary of the operating cycle of an industrial gas turbine and associated plant. The characteristics of the materials and integrated materials systems used in a gas turbine are considered. The conditions under which industrial gas turbines operate, and the impact these operating conditions have on materials behavior, are described. The materials selection criteria for individual components and component sections are discussed. The key material properties for designing critical components and the approach for conducting a life assessment are considered. The major limitations to the performance of current superalloys, coatings and steels and the challenges facing the introduction of new materials are discussed. An overview is given of current trends in materials development and future materials technologies.

Qu'ils soient a la base de metaux, de polymeres, de ceramiques, de carbones ou de substances naturelles, les biomateriaux constituent un apport capital a la reparation ou a la construction des tissus durs et mous de la sphere dento-maxillo-faciale. Pour eviter les echecs, ces materiaux doivent realiser une integration tissulaire satisfaisante sans qu'une colonisation bacterienne ne vienne compromettre la cooperation finalisee tissu-biomateriau au niveau du site d'accueil. L'evolution de la science et de la technologie des biomateriaux devrait permettre d'obtenir des materiaux a la fois depourvus de toxicite pour les tissus et empechant l'adherence des microorganismes, l'infectabilite devenant dans certains cas un critere aussi important que la biocompatibilite

Oxygen consumption of carp acclimated at 10 and 20° C has been measured under routine conditions. Some complications and precautions necessary in continuous flow respirometry are discussed. Routine Vo2 at different levels of hypoxia have been determined. Individual variation leads to scatter in the data and different methods of plotting the relationship between Vo2 and Po2 are proposed; attention is drawn to differences between inlet (or ambient) Po2 and inspired Po2. Using certain criteria a ‘critical’ oxygen tension of about 95 mm Hg was found at 20° C; Q10 values are about 2 at normoxia and some suggestions of an increase near to the critical oxygen tension were found. Blood samples from the dorsal aorta showed rising Pa,o2 of 16 mm Hg which increased to 70–80 mm Hg when Pinsp was 90 and they then fall as the inspired oxygen is lowered. During periods of deep hypoxia (25 mm Hg) blood lactate concentration increases steadily and indicates an increasing dependence on anaerobic mechanisms.

The authors investigated the corrosion mechanism of metallic implants inserted into the human body in contact with bone. It was shown that a significant degree of corrosion occurred after several months. The dissolution seems to be non-selective but can be different for each individual. The corrosion mechanism is complex, starting with an inter-granular process, but pitting also occurred . The oxidation of Fe2+ to Fe3+ favours the elimination of iron oxides and is followed by the destruction of the local alloy structure. An estimation of the quantity of each type of element released in the organism was also realized.

Dans cet article, nous avons abordé le problème de la stabilité et de la tolérance des prothèses par une voie originale qui consiste à étudier par croissance in situ les facteurs qui régissent cette stabilité et cette tolérance.

The bonding mechanism between bone and metallic implants has been studied using specific surface techniques (ESCA, RHEED) and X-ray diffraction methods.

Commercial total hip prostheses often show certain metallurgical faults (porosities, coarse grains, growth dendrites, carbide networks). In order to investigate more accurately the role played by these different parameters in prostheses failure we performed a large number of systematic corrosion, fatigue and fatigue - corrosion tests on these materials and on commercial total hip prostheses. Ultimate strengthes seem to be reached for cast cobalt alloys, whereas titanium alloys, such as Ta 6 V, present very high fatigue limit under corrosion. Thus, rotative bending fatigue - corrosion tests in biological environment provide values about 50 DaN/mm2. This value, is nevertheless appreciably higher than those obtained with stellites and stainless steel. Titanium alloys, because of their mechanical performances, their weak Young's modulus (11000 DaN/mm2) and their relative lightness (4.5. g/cm3), which are associated with a good biocompatibility, seem very promising for permanent implants realisation.

Until recently use of adhesives was confined to cases in which glued areas could be pre-treated or at least cleaned. Thus, grease or oil contaminated surfaces could not be joined together by glueing. More recently, some adhesives have been developed which allow previous treatment of greasy surfaces to be avoided. Among these we find epoxy resins, acrylics and polyurethances. These adhesives have been used until now in various industries. We have begun a research program with these products and in aiming to design an adhesive which would enable immediate and strong bone bonding and avoid problems of metallic fixation, this study is a continuation of our previous research. Thus we tested - currently available surgical and dental adhesives - original mixtures developed in our laboratory. Mechanical assays were performed on bone samples from human femurs in different conditions : dried, cleaned, fresh, or after immersion in physiological solution. They consist essentially of tensile tests on Lhomargy and Zwick's machine wherein the stress is directed perpendicular to the interface. Variations of tensile strength (in h bar) are related to hardening time and to mixture composition. The specimens are joined together either in monolayers or in multilayers. The use of adequate catalysts ensures setting at room temperature. Torsion tests and fatigue tests are carried out concomitantly. Standardized bevel fermoral osteotomies were performed on mice with a dental saw after I.P. Nembutal anesthesia in order to test biological tolerance : - for the control group we study the evolution of bone repair after circumferential wiring - for the animals under test, bones are glued together with one of the proposed adhesives. Radiological and histological studies (using classical Azantrichrome staining after demineralization) are carried out at regular time intervals. In the control animals particular attention is paid to the time course of the formation, constitution and evolution of callus. In the test animals, we can observe callus formation, bone growth into the adhesive material and glue resorption, and look for specific antigenic phenomena. Despite expected improvements, bone glueing remains a challenge and only restricted clinical applications can be proposed.