Comparison of biofilm formation and migration of Streptococcus mutans on tooth roots and titanium miniscrews

Periodontitis and peri-implantitis are inflammatory diseases caused by periodontal pathogenic bacteria leading to destruction of supporting periodontal/peri-implant tissue. However, the progression of inflammatory process of these two diseases is different. The bacterial biofilm is the source of bacteria during the inflammatory process. As the bacteria migrate down the surface of tooth or titanium implant, the inflammation spreads along with it. Streptococcus mutans has an important role in oral bacterial biofilm formation in early stage biofilm before the microbiota shift to late stage and become more virulent. The other major difference is the existence of periodontal ligament (PDL) cells in normal teeth but not in peri-implant tissue. This study aims to compare the S. mutans bacterial biofilm formation and migration on 2 different surfaces, tooth root and titanium miniscrew. The biofilm was grown with a flow cells system to imitate the oral dynamic system with PDL cells. The migration distances were measured, and the biofilm morphology was observed. Data showed that the biofilm formation on miniscrew was slower than those on tooth root at 24 hr. However, there were no difference in the morphology of the biofilm formed on the tooth root with those formed on the miniscrew at both 24 and 48 hr. The biofilm migration rate was significantly faster on miniscrew surface compare with those on tooth root when observe at 48 hr (p <.001). There are no significant differences in biofilm migration within miniscrew group and tooth root group despite the exiting of PDL cell (p >.05). The biofilm's migration rate differences on various surfaces could be one of the factors accounting for the different inflammatory progression between periodontitis and peri-implantitis disease.