The Effect of Crown Restorations on The Types and Counts of Cariogenic Bacteria

This study investigated the effect of crown restorations on the numbers and types of cariogenic bacteria. Plaque samples were collected from thirty eight individuals who had crown restoration (crown or fixed partial denture) and an adjacent normal tooth by using sterile curettes. The bacterial counts (Colony Forming Unit/ ml) were obtained by the cultivation of plaque samples on certain selective media that were used for the cultivation of Streptococcus mutans, Lactobacillus species, and Actinomyces species. The number of Lactobacillus species were higher in the samples obtained from crown restorations than the samples obtained from natural teeth (P=.02). Also, it was found that the metal-acrylic crown restorations have higher number of lactobacillus species compared to the metal-ceramic (P =.003) and the crowns with subgingival margin has the highest counts of Streptococcus (P=.001) and Actinomyces species (P= .032). Moreover, the number of the cariogenic bacteria was found to be significantly associated with the periodontal conditions of the person and the age of crown restorations. It can be concluded that high counts of cariogenic bacteria was found to be associated with; crowns, metal acrylic crowns, placing the crown margin subgingivally, as well as the age of the crown restoration.