ABSTRACT
BACKGROUND:Nano-size inorganic filling greatly improves mechanic characteristic of composite resin.However,its effects on pulp tissue remain unclear.OBJECTIVE:To evaluate the biocompatibility of FiltekTM Z350 nano-composite resin on dog pulp tissue by means of histology observation.DESIGN,TIME AND SETTING:Randomized control animal experiment was performed at the animal experiment center of Fuzhou General Hospital,Nanjing Military Area Command of Chinese PLA from April 2007 to April 2008.MATERIALS:Sixty healthy teeth from three adult male beagle dogs were recruited in this study.METHODS:Buccal Class V deep cavities were prepared in beagle dogs,which were then divided into four groups at random.FiltekTM Z350 resin,Dyract AP compomer and TPH resin were used to restore the cavities in three testing groups and glass ionomer cement was used as control.All cavities were treated with Clearfil SE BOND before filling.Intact healthy teeth were used as blank control.MAIN OUTCOME MEASURES:The pulp condition of each tooth was studied histologically.The remaining dentine thickness of each cavity was measured.RESULTS:After 7 days,mild inflammatory response was observed in most of the specimens.After 30 and 90 days,normal histological characteristics were observed in almost all specimens except TPH resin group.The histological structure disturbance of dentin cell layer emerged in some specimens of TPH group,which was higher than other testing groups(P 0.05).CONCLUSION:FiltekTM Z350 nano-composite resin has similar biocompatibility as Dyract AP compomer and glass ionomer cement,better than TPH resin.