With the advances of personal computer and application, data analysis has been familiar. Clinicians can easily analyze their own data. As an editor and reviewer for the submitted manuscripts, I often faces fundamental misuse of statistical analysis. In this manuscript, basic concepts of statistics are described to prevent common errors and misuse. For the application of regression analysis, advanced description are presented.

The human race is under constant threat from infections, including emerging infectious diseases such as outbreaks of new influenza viruses and Ebola hemorrhagic fever, epidemics of AIDS, and re-emergence of tuberculosis. The outbreak of the coronavirus disease 2019（COVID-2019）caused by a novel coronavirus has forced humans to change social lifestyles drastically. Furthermore, measures against infections caused by resident bacteria in the oral cavity, such as aspiration pneumonia, as well as opportunistic/nosocomial infections are urgently required in Japan, where the population is aging. Infectious diseases are caused by bacteria or viruses that enter and proliferate within the body. Some bacteria and viruses are capable of infecting hosts persistently for the rest of their lives and manifesting as symptoms when the hosts’ immunity weakens. In addition to microorganism-host interactions, intricately meshed bacteria-virus interactions are involved. Negative chain reactions between bacteria and viruses have increasingly been shown to play an important role in the onset of periodontal diseases that were previously attributed solely to bacterial infections. It is difficult to understand the whole picture of infectious diseases through conventional studies focusing solely on the oral cavity or a single microorganism.

We believe that elucidation of diverse microorganism-microorganism and microorganism-host crosstalk in pathogenicity, i.e., “bacteria-virus-host interactions,” will open a path to a new understanding of infectious diseases and development of new therapeutic and prophylactic means.

In the super-aged society, practice of oral care as a dental approach and prevention of oral flail will be essential in the future, and the importance of dental needs is attracting attention in the field of medical and nursing care for the elderly. In cases where it is difficult to rely on mechanical cleaning with a toothbrush alone, the combination of chemical cleaning with chemical solutions would be effective. Currently, the use of mouthwashes and mouthwashes at the discretion of dentists, dental hygienists, caregivers, and nurses is practiced based on their knowledge of the antimicrobial action of the products and empirical clinical experience. In the mechanism of action of mouthwashes and rinses, we have only studied the antimicrobial effects of mouthwashes and rinses on the bacteria that cause infection, but we have also studied the reactive oxygen species（ROS）from inflammatory cells that play an important role in oral inflammation and defense against bacterial infection. It is only reported that the antioxidant effects of ROS to reduce the oxidative stress caused by ROS has been investigated indirectly. Evidence for oral health care products that protect against oral infections should include not only antimicrobial activity but also antioxidant activity that reduces oxidative stress caused by ROS. Therefore, evidence for oral health care products that implement oral care to protect against oral infections requires not only an examination of antimicrobial action, but also an examination of antioxidant action by ROS. Since we have established an antioxidant evaluation method by electron spin resonance（ESR）method for the development of drugs, food and beverage products, and supplements, we used the antioxidant evaluation of mouthwashes and mouthwashes to investigate the antioxidant evaluation. The antimicrobial activity of Listerine^® natural care（Listerine NC）and Neustelline^® Green Gargle（Neostelline）, which are widely used as mouth rinses and mouthwashes, was confirmed in this study, but the antimicrobial effect of Listerine NC and Neosterine in the concentrations used was more than sufficient and comparable to that of hydrogen peroxide（H₂O₂）, which is used as a disinfectant. In the antioxidant effects of mouthwashes and rinses, some were found to have excellent antioxidant effects, such as Listerine NC and sodium bicarbonate, but others, such as Neustelin, did not have strong antioxidant effects. In this study, Listerine NC and sodium bicarbonate were found to have a coordinated effect on the antibacterial and antioxidant effects of mouthwashes and rinses. In addition, from the viewpoint of safe antimicrobial action, further evidence of appropriate concentration of antimicrobial action in the oral environment will be needed in the future by examining the effects of excessive concentrations of mouthwashes and rinses on the oral flora. We hope to develop mouthwashes and rinses based on these evidences in the future.

Since there are many ways of mouthwash and types of mouthwash products, they are often used in oral care and nursing situations without clear evidence of their use. It is very useful to select an appropriate mouthwash and to provide safe and efficient oral care in facilities and hospitals with limited time and human resources if it is possible to use the mouthwash not only according not only to the type of bacteria causing oral diseases but also to the stage of the disease. In this study, we report a comparison of the antibacterial, bactericidal, and ROS scavenging effects of Neostelin Green 0.2 ％ mouthwash solution^® and sodium bicarbonate, which are clinically used as mouthwashes, against periodontal pathogens, caries-causing bacteria, and Candida. The direct scavenging effects of ROS, hydroxyl radicals（HO^•）and superoxide（O₂^•－）, was measured by the electron spin resonance（ESR）method. Antimicrobial activity was estimated in reference to minimum inhibitory concentration（MIC）and minimum bactericidal concentration（MBC）using five bacteria, Candida albicans（C. albicans）, Streptococcus mutans（S. mutans）, Aggregatibacter actinomycetemcomitans（A. actinomycetemcomitans）, Porphyromonas gingivalis（P. gingivalis）, and Prevotella intermedia（P. intermedia）. HO^• scavenging effects of Neostelin were significantly lower than those of sodium bicarbonate. O₂^•－ scavenging effects were significantly higher in Neostelin compared to sodium bicarbonate. For Neostelin, the antimicrobial and fungicidal effects to both species were confirmed to be sufficient within the range of concentrations indicated for pharmaceutical use. Although sodium bicarbonate showed high concentrations of MBC against S. mutans and P. gingivalis, while MIC was 2 w/v％, a concentration usually applied in clinical practice. MBC and MIC against A. actinomycetemcomitans and P. intermedia were both less than 2 w/v％；MBC against C. albicans was not effective unless the concentration of sodium bicarbonate was high（10 w/v％）. In this study, the differences in antioxidant and antibacterial effects were confirmed between Neostelin and sodium bicarbonate. Therefore, the present results could contribute to the clinical practice of oral care in the near future.

PURPOSE：The repair of bone defects has received much attention in dental implant treatment and orthopedics. In recent years, fibroblast growth factor-2（FGF-2）and hydroxyapatite（HA）ceramic has been shown to enhance bone regeneration；therefore, we prepared a composite of FGF-2 and interconnected porous calcium hydroxyapatite ceramics（IP-CHA）for bone tissue engineering. The scaffolding role of FGF-2/IP-CHA granules in an MC3T3-E1 cell population and in osteogenic differentiation was investigated in vitro. The purpose of this study was to evaluate the in vitro combined effect of FGF-2 and IP-CHA ceramic on the bioactivity of osteoblasts and initial bone differentiation.

MATERIALS & METHODS：MC3T3-E1 cells were treated with FGF-2/IP-CHA, saline/IP-CHA or FGF-2 and measured using assays for alkaline phosphatase（ALP）activity and cell proliferation.

RESULTS：FGF-2 and FGF-2/IP-CHA increased cell proliferation on day 4 compared to saline/IP-CHA；however, this difference did not reach statistical significance. On day 7, a significant difference was observed between FGF-2/IP-CHA and saline/IP-CHA, FGF-2 and FGF-2/IP-CHA. Increased ALP activity was observed from day 7 to day 21 in all groups, although there was no significant difference between groups

CONCLUSION：FGF-2/IP-CHA may be clinically applicable as a novel method for bone regeneration.

Dipeptidyl peptidase（DPP）-4 inhibitors are widely used for the treatment of type 2 diabetes mellitus. Recently, several reports have described oral ulceration associated with relatively new drugs such as nicorandil, low-dose methotrexate, and bisphosphonate. We herein report a case of a patient who developed oral ulceration as a result of taking the DPP-4 inhibitor, sitagliptin. The patient was a 64-year-old woman with oral ulceration of the left palate. Topical steroid treatment was ineffective. After sitagliptin cessation, the lesion epithelialized within 3 weeks. To our knowledge, this is only the second case report of oral ulceration induced by DPP-4.