Preformed stainless steel crowns are used in pediatric dentistry to obtain full crown restoration of primary molar teeth. They are consider the best restoration in terms of durability and effectiveness. The purpose of this study is to evaluate microbial, cytological and physio-chemical properties to determine whereas stainless steel crown are biocompatible, safe for surrounding tissue and helpful in avoiding micro-organisms influence on the tooth tissue. Based on the results, it was determined that stainless steel crowns used in pediatric dentistry represent no cytotoxic risk to the surrounding tissues, have a low probability of developing hypersensitivity to the coronal material and also that their biological properties make them suitable to use in pediatric dentistry for the reconstruction of damaged primary molar tissue.