The Influence Of Two Types Of Cements On The Caries Bacteria Colonized On The Edge Of PFM Crown

Objective: To determine the different cements that impact on the changes of caries bacteria colonized on the edge of PFM crown before and after restoration by applying different cements,provide theoretical foundation for PFM crown prevent from caries. Methods: Randomly select thirty patients whom mandibular first molar palladium needs to be repaired by the silver alloy PFM crown. And then, we use self control method and double blind method, numbered the patients and divided them into groups. We collecte patients’ supragingival plaque of PFM crown margin,then measured the quantitative values of streptococcus mutans before and after restoration in one month and three months by using quantitative fluorescence of polymerase chain reaction.Result: Compared with those before restoration, the quantity of S. mutans in glass ionomer cemens group is getting lower in one and three months after restoration; the quantity of S. mutans in the group of polycarboxylic cements is getting higher in one and three months after restoration(P<0.05). Conclusion: Glass-ion cement may be more active to reduce the caries risk of repaired-abutment teeth compared with polycarboxylic cements.