There is a clearly defined and substantial role for free radicals or reactive oxygen species ( ROS ) in periodontitis , but little research has been performed in this area .
there is a clearly defined and substantial role for free radicals or reactive oxygen species ( ros ) in periodontitis , but little research has been performed in this area .
O O O O O O O O O B-other_organic_compound I-other_organic_compound O B-other_organic_compound I-other_organic_compound I-other_organic_compound O B-other_organic_compound O O B-tissue O O O O O O O O O O O