Candida is the most significant species among fungi, because it is not only a member of the normal microbiota of oral cavity, skin, gastrointestinal tract and vagina, but also one of the pathogens for opportunistic infections（candidiasis）. Recently incidence and prevalence of candidiasis have increased in large populations of compromised hosts.

Studies of poly-microbial Candida biofilms suggest that the hyphae of Candida provides the scaffold for oral bacteria in biofilms and show the interactions with many oral infections such as dental caries, periodontal disease, endodontic infection, and denture stomatitis.

Candida has a number of virulence factors, the most important is aspartic proteinase （Sap）. Sap plays a central role in the pathogenicity of Candida destroying human proteins and invading tissues.

The gold standard of diagnosis for candidiasis is based on clinical findings and confirmed by identification of colonies cultured on the media for Candida. However, microscopic examinations of staining smear samples are faster and simpler methods than culture methods, if the staining is sufficiently accurate. We compared staining methods of candidiasis smear samples, and suggest that Fungiflora Y staining is useful for the diagnosis of oral erythematous candidiasis.

Right now, we are doing both, basic and clinical research to reduce Candida colonization in the oral cavity. Basic research includes the development of probiotics with lactobacilli as well as biogenic products of lactobacilli for controlling Candida colonization in the oral cavity. Clinical research comprises of reducing the number of Candida in the oral cavity by gargling with a diluted antifungal drug（amphotericin B）.

The goal of our studies is to improve QOL, not restricted to the oral cavity, but for the entire body by eliminating Candida from the oral cavity.

When oral administration is possible, penicillin agents are recommended for infectious endocarditis in the antibacterial prophylaxis method during dental treatment. If the patient is allergic to penicillin, first-generation cephem agents are recommended. As of 2003, the antibacterial activities of cepfalexin（CEX） and cefaclor（CCL） against oral Streptococci from odontogenic infections were as follows：CEX –MIC₉₀ was ＞ 100μg/mL；CCL– MIC₉₀ was 100μg/mL. We measured the antibacterial activities of CEX, CCL, cefditoren and amoxicillin（AMPC） with respect to the 50 respective shares of the Streptococcus mitis group and the Sterptococcus anginosus group for each fiscal year from 2005 to 2015.

The annual changes of MIC₉₀ value of each agents for S. mitis group were found to be as follows：For CEX, it was 16〜64μg/mL； for CCL, 4〜32μg/mL；for AMPC, 0.12〜0.5μg/mL. The annual changes of the MIC₉₀ value of each agent in the S. anginosus group were found to be as follows：For CEX, it was 8〜16μg/mL；for CCL, 4〜8μg/mL；for AMPC, 0.12〜0.25μg/mL.

Salubrinal and guanabenz are two known inhibitors of dephosphorylation of eukaryotic translation initiation factor 2 alpha (eIF2α), and they suppress osteoclastogenesis through downregulating nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), a master molecule of osteoclastogenesis. The mechanism of NFATc1 suppression is not well understood. Using genome-wide microarray analysis, we investigated molecular regulators of osteoclastogenesis, in particular, in response to salubrinal and guanabenz. We identified two sets of genes: a set of genes that were upregulated by receptor activator of nuclear factor kappa-B ligand (RANKL) and downregulated by salubrinal and guanabenz; and the other set of genes that were downregulated by RANKL and upregulated by salubrinal and guanabenz. The microarray and qPCR result revealed that a zinc finger protein, FYVE domain containing 21 (Zfyve21), as well as DNA-damage-inducible transcript 4 (Ddit4), were suppressed by RANKL and upregulated by salubrinal and guanabenz. A partial silencing of Zfyve21 or Ddit4 attenuated salubrinal- and guanabenz-driven suppression of NFATc1. Collectively, this study demonstrates that Zfyve21 and Ddit4 are two inhibitors of osteoclastogenesis. We expect that they may potentially serve as novel targets for preventing bone loss from skeletal diseases such as osteoporosis.

The objective of this study was to identify the properties of oral moisturizing gels under experimental conditions that simulate the oral cavity.Oral moisturizing gels were studied under the following three conditions: (1) a drying experiment that tests the water-retention properties of emollients which reduce water loss from evaporation; (2) an dissolution of the gel`s protective layer to assess the hydration properties of oral gel moisturizers in relation to its elution from the oral mucosa; (3) A filtration test to assess an oral moisturizing gel`s degradation in the oral cavity. Three oral gel moisturizers were studied: Peptisal gentle mouth gel (T&K Corporation, Tokyo), Refre-care H (EN Otsuka Pharmaceutical Corporation, Iwate), and Concool mouth gel (Welltec Corporation, Osaka).

The results of the gel drying test using a dried filter paper showed that Refre-care had a higher drying rate than Peptisal and Concool, however, in the moist filter experiment no major difference were observed between the three gel moisturizers. Based on these results, it was shown that every gel moisturizer has emollient properties . The gel dissolution test showed that the retention residue % of the cream after elution increased initially due to water absorption; however, it was observed that, over time, the retention residue % decreased until the cream dissolved into water. Of the oral moisturizing creams tested, Peptisal gentle mouthgel maintained a high retention residue % after elution with high water absorption property, high adhesion property, low disintegration and dissolution property. In the filtration tests, Peptisal gentle mouthgel was retained in a net basket with a 8～14mesh sieve at a higher rate which may explain the results of the dissolution experiments.These results show that Peptisal gentle mouthgel has the potential of providing a long term moisturizing effect.