Cell responses to Hydron by a new in‐vitro method

Abstract

An in-vitro biotoxicity test system, suitable for the assessment of endodontic filling materials, has been developed and used to test cell responses to Hydron, AH26 and Tubliseal. A robust, well-characterized and stable cell line (L-cells) which was grown as uniform cultures on Millipore filters, has been used as indicator cells. As they approached confluence they were exposed to test substances for 24 h and biosynthetic activities were measured. The test system is a modification of that described by Wennberg et al. (1979). By inverting the cultures on organ-culture rafts, cells were separated from the test material, which was placed on top of the Millipore filters. Freshly mixed polymerizing Hydron and prepolymerized Hydron were tested. The cell responses were compared with those of cultures exposed to freshly mixed AH26 and Tubliseal. Polymerizing and prepolymerized Hydron depressed both cell division, assessed by 3H-thymidine incorporation, and the synthesis and secretion of matrix material as measured by precipitable 35S-sulphate. Prepolymerized Hydron decreased cell functions by 59% and 56% of live cell controls, respectively, while the freshly mixed polymerizing Hydron inhibited biosynthesis by 89% and 94%, respectively. The data for polymerizing Hydron were compared with results for other root-filling materials and showed similar values to those for Tubliseal (92% and 95%), but greater inhibition of biosynthesis than for AH26 (53% and 50%). The AH26 values were similar to those obtained from cultures exposed to the prepolymerized Hydron. Recovery of biosynthetic capacity by these cultures after removal of all endodontic material was also assessed. Partial biosynthetic recovery of cell cultures was observed 24 h after removal of preopolymerized Hydron.(ABSTRACT TRUNCATED AT 250 WORDS)

Methodology for Morphometric Analysis of Modern Human Contralateral Premolars

“…Their conclusion regarding lack of conformity to root canal regularities and shrinkage resulted in the histological study of three experimental root canal materials; root filling consisting of silicone elastomer and adhesive (Silastic 382 elastomer and Silastic Medical Adhesive type A) or a pure polyhydroxy-ethyl-methacrylate root filling (Hydron, Hydron Technologies, FL, USA ) (185). The in vitro & in vivo preliminary findings for Hydron were very promising [192][193][194], but a subsequent long-term study showed poorer results with Hydron versus gutta-percha and AH-26 [195]. Furthermore, other independent studies on histological responses and leakage found that Hydron did not fulfill the manufactures promises concerning physical/clinical properties as it elicited severe inflammatory responses, demonstrated more leakage than conventional root filling materials, and was resorbable [196][197][198].…”

Biocompatibility of dental materials used in contemporary endodontic therapy: a review. Part 1. Intracanal drugs and substances

“…Various biological endpoints are used for these investigations. They include growth inhibition, determination of the effective dose 50 (ED 50 ), membrane integrity, DNA, RNA or protein synthesis and/or the determination of alterations of cellular morphology by light or electron microscopy (Matsumoto et al . 1989, Al‐Nazhan & Spångberg 1990, McNamara et al .…”

Comparative cytotoxicity of five root canal sealers on cultured human periodontal ligament fibroblasts

“…1995). Tubliseal (Kerr Manufacturing Company, Romulus, MI, USA) was shown to be highly toxic to L929 cells (McNamara et al. 1992).…”