DNA profiling of Streptococcus mutans in children with and without black tooth stains: A polymerase chain reaction analysis

Abstract

Background: The purpose of this study was to identify the genetic patterns of
Streptococcus mutans by DNA finger printing among caries‑active, caries‑free, and in children
with black tooth stains.
Materials and Methods: In this in vitro study Ten children with black tooth stains and ten
caries‑free and caries‑active children between 3 and 6 years of age were recruited. Saliva samples
were collected using a sterile tube, followed by microbial culture of S. mutans, DNA isolation, and
polymerase chain reaction amplification. The molecular weights of each band were converted into
binary data, and data were entered into SPSS to generate similarity dendrograms.
Results: Dendrogram interpretation of black tooth stain and caries‑free samples revealed
an identical genetic pattern in 15 samples with high genetic similarity. Dendrogram
interpretation of black tooth stain and caries‑active samples exhibited a greater genetic
diversity.
Conclusion: This study concludes that identical genotypes and high genetic similarity among
isolates of the caries‑free and black tooth stains. Polymorphism and genetic diversity exist between
the black tooth stain and caries‑active samples.
Key Words: DNA profiling, stains, Streptococcus mutans