A Study on a Composite Resin Material Containing a New Filler for Pulp Response

Abstract

Fluoride-releasing composite resin and bonding materials have recently been developed for application during the glass-ionomer cement phase of treatment, This new generation of fillers exploits the acid-base reactions of fluoride re-charge and release. In this study, we applied these new bonding materials in dog to histopathologically investigate pulp response and evaluate cytotoxicity. This study was conducted based on the guidelines for animal experiments issued by Tokyo Dental College. A total of 71 test teeth were obtained from dogs aged older than one year including maxillary and mandibular incisors, canines, premolars and post-molar teeth. The test teeth were divided into two groups, an IB group, which underwent restoration with the new fluoride-releasing composite, and an LC group, which underwent restoration with resin-modified glass-ionomer cement. Teeth were collected after a short term '7 days) or a long term (90 days), subjected to hematoxylin-eosin doublestaining by the usual procedures, and then investigated histopathologically under a microscope to assess dentin and pulp responses. In addition, Hucker-Conn staining was conducted to determine the presence or absence of microbes in the cavities and dentinal tubules. We used the Millipore filter method to determine cytotoxicity. The new fluoride-release composite resin system demonstrated favorable pathological results confirming its safety in relation to dentin. The non-polymerization resin showed only a mild cytotoxic response. These results indicate that the new fluoride-releasing composite resin system can be applied as a restorative material with superior safety.