In vitro examination of oral tissue conditioners potential toxicity

Abstract

The oral tissue conditioners are applied temporarily to the gingival surface of a denture for the purpose of reconditioning the abused denture supporting tissues, allowing them to return to a normal, healthy state. According to chemical composition they can be classified into methacrylic and silicon conditioners. The objective of this research was to examine the potential toxicity of one, seven and thirty day extracts of different concentrations. Different effective concentrations (5, 12.5, 25 and 50%) of two silicone and four methacrylic conditioners extracts were used after extraction period of one, seven and thirty days. Amount of toxic substances and dynamics of their release were monitored by high-pressure liquid chromatography (HPLC). HPLC analysis could not be applied to the silicone conditioners because they consist of polymeric and inorganic 19 substances. Evaluation of cell proliferation, as cytotoxic parameters, was done by Mosmann’s MTT assay based on reduction of yellow tetrazole (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide - MTT) to purple formazan by mitochondrial succinate dehydrogenase of metabolic active cells. With increasing of extraction period, the amount of released potential toxic substances increased. The cytotoxicity of tested materials significantly increased with extract concentration increase and duration of extraction period. To improve the biological characteristics of mobile dentures relined by soft materials, soaking in water the day before insertion into patient’s mouth was recommended. Silicone conditioners showed less cytotoxicity compared to the methacrylic conditioners, so they are more appropriate for daily dental practice

Denture base resins biocompatibility testing in vivo

“…Cold polymerized acrylates induced the most intensive granulomatous reaction after both implantation procedures, which is in accordance with the results of examination of their cytotoxic effect [25][26][27] . The results of this study are in positive correlation with the findings of in vitro studies that proved stronger cytotoxic effect of soft and hard cold polymerized acrylates as compared to hot polymerized acrylates [28][29][30][31] .…”

Effects of water boiling, microwave, and water bath post-polymerization on mechanical properties of acrylic denture resins

“…Author's earlier studies have shown possibilities for decreasing the amount of residual monomer and other potentially toxic substances in acrylic material samples by additional polymerization and immersion in a water bath [20,50]. Kostic et al investigated the effects of residual monomer reduction by immersion in a water bath on pressure yields stress and superficial structure of acrylic materials [26].…”

A release of potentially toxic components from the acrylic resins for soft relining dentures

“…Komponente koje ulaze u sastav mekih akrilata u literaturi mogu biti toksične za oralna tkiva ukoliko se u potpunosti ne neutralizuju u procesu polimerizacije [8][9][10][11] . Kako ne postoji apsolutno vezivanje materijala u toku njegove pripreme i izrade zubnih proteza, u istraživanju se krenulo od pretpostavke da će u vremenu korišćenja mekih akrilata kao lajnera doći i do oslobađanja komponenti u okolni tečni medijum.…”