Effectiveness and safety of a new dental plaque removal device utilizing micro mist spray for removing oral biofilm in vitro.

BACKGROUND: Removal of oral biofilm from the oral mucosa is essential for preventing risk of respiratory and gastrointestinal infection in elderly people. Currently, no device is available which can remove oral biofilm from oral mucosa effectively and safely. Therefore, the effectiveness and safety of the Micro Scale Mist UNIT (MSM-UNIT), a newly developed dental plaque removal device utilizing high speed sprays of fine water droplets, were evaluated for biofilm removal, including the rate and surface roughness for simulated tooth surface and mucous membrane. METHODS: Simulated tooth and oral mucosa coated with an artificial biofilm of Streptococcus mutans were used for evaluation of effectiveness, with uncoated substrates as the controls. The MSM-UNIT and a conventional air ablation device were operated under recommended instructions. The effectiveness was evaluated from the rate of removal of the biofilm, and the safety was evaluated from the damage observed by scanning electron microscope and surface roughness. RESULTS: The biofilm removal rate of the MSM-UNIT was significantly higher than that of AIRFLOW. Little damage was observed in the area treated by the MSM-UNIT. The surface roughness of the MSM-UNIT treated area on simulated tooth surface and oral mucosa showed no significant difference to the control area. In contrast, cracks and powder were observed in the area treated by AIRFLOW. In particular, the surface roughness of the AIRFLOW treated area for Toughsilon was significantly larger than that of the control. CONCLUSIONS: The MSM-UNIT could be used safely and effectively for removing biofilm not only on simulated tooth surfaces but also simulated mucous membrane. The MSM-UNIT has no harmful effect on teeth or oral mucosa, and may be used for comprehensive oral care for patients during nursing care and the perioperative period.

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.

Reduced heart rate variability and increased saliva cortisol in patients with TMD.

Temporomandibular disorders (TMD) are the most common source of non-dental pain. The pathogenesis of TMD is multifactorial, involving biological, psychological and behavioral factors. Those factors are involved with alterations of the autonomic nervous system (ANS) and stressful conditions. Heart rate variability (HRV) has been used as a marker of ANS function. Increased cortisol level (a stress indicator), has been found in chronic pain. Therefore, the present study aimed to compare pain intensity, HRV, psychological factors, and salivary cortisol level between TMD patients and a control group. Twenty-one TMD patients and twenty-three healthy control subjects participated in the study. All participants underwent 24-h-Holter monitoring to record HRV. Morning unstimulated saliva samples were collected from each participant for cortisol analysis. The pain intensity was assessed using a visual analog scale. The participants were evaluated for anxiety and depression via the Hospital Anxiety and Depression Scales. We found that pain intensity and psychological distress in the TMD group were significantly greater than those of the control (p < 0.01). Pain intensity showed a positive correlation with psychological distress (p < 0.01). HRV parameters in the TMD group were significantly lower than those in the control, suggesting reduced HRV in TMD patients. Pain intensity was negatively associated with HRV. Salivary cortisol level of the TMD group was greater than that of control. Our findings indicate that reduced HRV with higher psychological distress and increased salivary cortisol levels were observed in the TMD group. Therefore, TMD patients may benefit from interventions that can restore ANS function and stress balance.