A 2% quaternary ammonium compound polymerised with a denture acrylic resin displayed antiseptic properties after a 4-week soaking period in artificial saliva. Such antiseptic denture base could help geriatric patients to improve their oral health.

Aims: To develop an in vitro protocol in order to assess the antiseptic properties of a quaternary ammonium compound polymerized with acrylic denture resin base, using experimental resin discs and dialysis membranes. Methods and Results: Experimental acrylic resin discs were polymerized with Poly 202063A, an ammonium compound (2-50%). Antiseptic properties were assayed against two reference strains (Escherichia coli, Staphylococcus aureus) and a laboratory strain (Candida albicans), using three different conditions (test A, B and C). In test A, according to classical protocols the resin discs were first soaked in large volumes of microbial inoculum (45 ml). An original dialysis protocol was then designed to recreate the small biofilm volume on the prosthetic surface. In test B, discs and bacterial inoculum (600 ll) were introduced in a dialysis bag and dialysed against a sterile buffer. A bactericidal effect was observed against E. coli and Staph. aureus (<0AE1% viable cells in initial bacterial suspension). A dose-dependent fungistatic effect was observed against C. albicans. Finally, in test C discs and sterile buffer (600 ll) were introduced in a dialysis bag and dialysed against microbial inoculum. Reduced activity was found outside the dialysis bag, demonstrating that free ammonium was able to diffuse through the dialysis membrane, displaying antiseptic properties.Conclusions: The present protocol demonstrated that a quaternary ammonium compound remains efficient after heat polymerization with an acrylic denture base resin, both in immediate and distant microbial environments. Significance and Impact of the Study: Such removable prosthetic devices with intrinsic antiseptic properties would contribute to improve the long-term management of denture stomatitis.

La systématisation et la généralisation des traitements phytosanitaires peuvent avoir des répercussions Biocénose, secondaires indésirables et graves sur les équilibres fauniques déjà précaires de ces milieux artificiels que sont Entomofaune , tes agrosystèmes céréaliers qui représentent en France 9 000 000 ha en 1980. Céréales, ' Nous avons engagé, en 1978 et 1979, des recherches sur l'action de traitements insecticides (parathion méthyl Effets secondaires, + phosalone et dim éthoate) en végétation sur l'entomofaune des champs de blé. Insecticides, ' Si tes niveaux de populations d'insectes sont très bas dans les régions traitées intensément depuis plusieurs Ravageurs. ' années, ce sont Ics espèces nuisibles qui occupent une place prépondérante. avageurs, ' Les captures journalières accusent une chute de l'ordre de 60 à 80 p. 100 après traitement. La faune détruite représente, à cette période, en majeure partie des insectes utiles. L'analyse du matériel capturé avant et après traitement montre que les groupes les plus touchés sont les Carabidae, les Staphylinidae, les Collemboles, les Hyménoptères. Les captures augmentent à nouveau après 12 à 15 jours. La rccolonisation par l'entomofaune, constatée actuellement, n'est possible que grâce à la faible proportion des surfaces traitées. Une évolution dans le sens de l'intensification et la généralisation des interventions avec des produits à large champ d'activité ne pourrait qu'aggraver la situation et déboucher sur de nouveaux problèmes phytosanitaires. SUMMARY Studies on the cereal agroecosystem-11.-Side-effects of insecticide treatrnents on the entomofauna Biocenosis , We have attracted growers' attention to the fact that insecticide treatments can have major sidc-cffccts on the Entomofauna, faunal balance. Cereals, This risk is increased by the size of the areas concerned (9 000 000 ha of cereals in France), and by the more Side-effects, regular and general use of these treatments. Insecticides, This is the reason why we have put forward the idea of the « slice of life » which can be killed by treatments. Pests. For this reason, we started research in 1978-79 on the effect of insecticide treatments on the entomofauna during cercal growth. Two insecticidcs : mcthylparathion + phosalonc and dimethoate were used at normal application rates. It appears in the first instance, that in heavily treated areas, after several years, the level of insect populations are very low, but pest species become more numerous. Comparison of daily catches before and after treatment shows that catches decreased about 60-70 % after treatment with dimethoate and about 70-80 % with methyl parathion + phosalonc. Since, according to our observations, there was very few pests at this period. The killed fauna must have been constituted for the greater part of useful insects in the widest sense of the word. Analysis of catches before and after treatment confirms this, the most affected groups being Carabidae, Staphylinidae. Collembola, Hymeuoptera. Catches increased again after 12-15 days, pos...

No abstract