The presence of yeasts in periodontal pockets is well documented and Candida albicans is the species most commonly isolated from the oral cavity. The immune response and anticandidal activity of oral epithelial cells play a key role in host defense against C. albicans infection. Human gingival epithelial cells were primarily cultured from healthy human gingival tissues and challenged with C. albicans ATCC90029. After 8 hours, total RNA was extracted and mRNA levels were analyzed using Affymetrix GeneChip (Human Genome U133 plus 2.0 Array, ca. 47,000 genes). Numerous genes showed altered gene expression, and among these, a pro-inflammatory cytokine, tumor necrotizing factor alpha (TNF-α), was up-regulated by more than two-fold over normal levels after C. albicans infection. Altered mRNA levels on GeneChip results were confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR. Rat gingiva was infected with C. albicans cells and immunohistochemical examination for TNF-α production was then carried out. Stronger immunoreactivity against TNF-α was observed in rat gingival epithelium infected with C. albicans.

Down syndrome (DS) is the most common chromosomal disorder resulting in various abnormalities such as mental retardation, immunodeficiency and physical abnormities. Especially, abnormality of the immune function is important pathological features in this syndrome, and leads to increased susceptibility to viral or bacterial infections. Interestingly, several studies have showed that they have high susceptibility of severe periodontal disease, even though they have lower or equal prevalence of dental caries. Many studies have attempted to clarify this phenomenon but it remains unsolved. It is also well known that DS is a premature ageing syndrome. DS has been considered as a model of precocious, abnormal ageing of immune function in human. Age-related declines in immune function cause more susceptibility to infections in the elderly. In addition, it is well known that ageing is related with telomere shortening. Furthermore, DS has an accelerated telomere shortening. However, there are only a few reports that focus on the relations among ageing, telomere length and high susceptibility of oral infectious disease in individuals with DS. Therefore, we summarize our current knowledge on the relations between the oral disease and immunodeficiency in individuals with DS taking account of telomere shortening and ageing.

Special Care in DentistryVolume 27, Issue 4 p. 125-126 Custom-made mouth guards for Special Olympics athletes Hiroshi Suzuki DDS, PhD, Corresponding Author Hiroshi Suzuki DDS, PhD Department of Clinical Oral Physiology, Nihon University School of Dentistry at Matsudo*e-mail: [email protected]Search for more papers by this authorMisao Kawara DDS, PhD, Misao Kawara DDS, PhD Department of Clinical Oral Physiology, Nihon University School of Dentistry at MatsudoSearch for more papers by this authorYoko Tanaka DDS, PhD, Yoko Tanaka DDS, PhD Department of Dentistry for the Disabled Nihon University School of Dentistry at MatsudoSearch for more papers by this authorJunichi Mega DDS, PhD, Junichi Mega DDS, PhD Department of Dentistry for the Disabled Nihon University School of Dentistry at MatsudoSearch for more papers by this authorHisao Takahashi DDS, Hisao Takahashi DDS Commitee Member, Healthy Athlete Program Committee of Special Olympics Nippon, Special Smiles Clinical Director of Special Olympics InternationalSearch for more papers by this author Hiroshi Suzuki DDS, PhD, Corresponding Author Hiroshi Suzuki DDS, PhD Department of Clinical Oral Physiology, Nihon University School of Dentistry at Matsudo*e-mail: [email protected]Search for more papers by this authorMisao Kawara DDS, PhD, Misao Kawara DDS, PhD Department of Clinical Oral Physiology, Nihon University School of Dentistry at MatsudoSearch for more papers by this authorYoko Tanaka DDS, PhD, Yoko Tanaka DDS, PhD Department of Dentistry for the Disabled Nihon University School of Dentistry at MatsudoSearch for more papers by this authorJunichi Mega DDS, PhD, Junichi Mega DDS, PhD Department of Dentistry for the Disabled Nihon University School of Dentistry at MatsudoSearch for more papers by this authorHisao Takahashi DDS, Hisao Takahashi DDS Commitee Member, Healthy Athlete Program Committee of Special Olympics Nippon, Special Smiles Clinical Director of Special Olympics InternationalSearch for more papers by this author First published: 12 March 2008 https://doi.org/10.1111/j.1754-4505.2007.tb00333.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. REFERENCES 1 White JA, Beltrán ED, Malvitz DM, Perlman SP. Oral health status of special athletes in the San Francisco Bay Area. J Calif Dent Assoc 1998; 26: 347–54. 2 Official Report of 2005 Special Olympics World Winter Games Nagano Japan. 2005: 22–5. 3 Castaldi CR. Preventton of craniofacial injuries in ice hockey. Dent Clin North Am 1991; 35: 647–56. 4 Feldman CA, Giniger M, Sanders M, et al Special Olympics, special smiles: assessing the feasibility of epidemiologic data collection. J Am Dent Assoc 1997; 128: 1687–96. 5 Reid BC, Chenette R, Macek MD. Prevalence and predictors of untreated caries and oral pain among Special Olympic athletes. Spec Care Dentist 2003; 23: 139–42. 6 Perlman S. Helping Special Olympics athletes sport good smiles. An effort to reach out to people with special needs. Dent Clin North Am 2000; 44: 221–9. 7 Jensen GM, Cleall JF, Yip AS. Dentoalveolar morphology and developmental Changes in Down's syndrome (trisomy 21). Am J Orthod 1973; 64: 607–18. 8 Dennis N. Ranalli. Advance Sports Dentistry. Igaku jouhousha 2001: 181–183. 9 SO Winter Sports Rules 20032006. Chapter 5, Floor Hockey, 1–20. Citing Literature Volume27, Issue4July 2007Pages 125-126 ReferencesRelatedInformation

This study examined the influence of carbon chain length of fluorinated alkyl acrylate on bacterial adhesion to the surface of test specimens. Perfluorobutylethyl acrylate (C4F), perfluorohexylethyl acrylate (C6F), perfluorooctylethyl acrylate (C8F), and perfluorodecylethyl acrylate (C10F) were used as fluorinated alkyl acrylate monomers. All specimens with the fluoro-monomer added exhibited significantly higher water-shedding and oil-shedding surface characteristics when compared to control (MMA/PMMA). Furthermore, contact angle for droplets of water and dodecane on the fluoromonomer-added specimens increased with carbon chain length of the perfluoroalkyl groups. Bacterial adhesion was significantly suppressed on the fluoromonomer-added specimens, both the saliva-uncoated and -coated specimens. In addition, the number of Candida albicans adhering to both the saliva-uncoated and -coated fluoromonomer-added specimens decreased with an increase in perfluoroalkyl carbon chain length. The results suggest that the application of fluorinated alkyl acrylate to denture base resin can modify the surface characteristics, and that fluorinated alkyl acrylate with long carbon chains of C8F and C10F successfully inhibit bacterial adherence to the resin surface.

The ability of osteoblasts to form bone greatly diminishes with aging, which may be due to the rise of oxygen-derived free radical formation. However, changes that occur in the mineral crystallinity of bone nodules formed by osteoblasts under conditions of oxidative stress have not been sufficiently clarified. The aim of this study was to elucidate the effects of oxidative stress on osteogenesis. We investigated bone nodule formation in an osteoblast-like cell line, MC3T3-E1, using von Kossa staining and micro-X-ray diffraction (micro-XRD). For the micro-XRD examinations, the bone nodules were analyzed after removal from the culture plate and placed on a slide glass or a silver membrane filter. We found that nodule formation was lower on day 30 following treatment with H2O2 and mineral crystallinity in H2O2-treated cells was also lower than in the controls. These results suggest that osteoblasts damaged by oxygen free radicals produced during the aging process show a decline in their bone nodule formation ability.

Trauma to oral soft tissues in comatose patients may be more widespread than reported, as no extensive study of this problem has been conducted. Various appliances for the prevention of self-inflicted injuries to oral tissues particularly in children and the physically and mentally challenged have been documented, but there is little information on their use in adult comatose patients. Because comatose patients lack cerebral control of the masticatory cycle, they can easily injure themselves. Although it is not uncommon for patients with a decreased level of consciousness and in need of intensive care to be restrained to prevent injury due to involuntary movement of the limbs, head and neck restraint is often difficult and may be dangerous to the patient. This case report presents a simple solution to the problem of self-inflicted trauma to oral tissues.

It is well known that bone formation steadily declines with age, resulting in a significant loss of bone mass. Cellular senescence-elevated oxidative stress has been shown to be related to the regulation of cellular functions in physiological and pathological conditions, and it has been clearly demonstrated that oxidative stress inhibits osteoblast differentiation and leads to a reduction in bone formation. However, the precise mechanism of the effect of reactive oxygen species (ROS) on the function of osteoblastic cells involved in bone nodule formation is not clear. In an attempt to establish a useful cell culture experimental model, we examined the effects of H2O2 on bone nodule formation in an established cell line, MC3T3-E1, following treatment with H2O2 using von Kossa staining. We found that cell viability was not affected by H2O2, though 400 μM suppressed the total number, as well total area and bone nodule area in MC3T3-E1 cells. Thus, a cell culture experimental model of bone formation during the aging process was successfully established using MC3T3-E1 cells with an H2O2 challenge without the damaging effects of proliferation or cell death. The present experimental model may be useful for studying the mechanism of decline of bone formation that accompanies aging.

Hayashi et al. recently succeeded in preparing a filling polymer composed of methyl methacrylate and perfluorooctylethyl acrylate (C8F). They suggested that the addition of C8F-added polymer beads could inhibit bacterial adherence to the surface of denture base resin. The objective of this study was to examine the influence of carbon chain length of fluorinated alkyl acrylate on mechanical properties of test specimens ; perfluorobutylethyl acrylate (C4F), perfluorohexylethyl acrylate (C6F), C8F and perfluorodecylethyl acrylate (C10F) were used as fluorinated alkyl acrylates. The glass transition temperature of test specimens appeared to be greater as carbon chain length of fluorinated alkyl acrylate increased. Knoop hardness was lowest in C6F-added specimens (C6FA), while all test specimens gave lower values than the control. The direct tensile strengths of fluoromonomer-added specimens were lower than the control, while relatively lower strengths were seen in C6FA or C8F-added specimens (C8FA). Although Knoop hardness and direct tensile strength decreased after addition of fluorinated alkyl acrylates, these mechanical properties remained within the limits recommended by the Japanese Society for Dental Materials and Devices for denture base resin. This study suggests that the new denture base resin is clinically acceptable with regard to mechanical properties.

Bone formation steadily declines with age resulting in a significant loss of bone mass, while reactive oxygen species (ROS) are thought to be major contributors to the aging process. In the present study, we attempted to identify which gene had an altered transcription level when osteoblasts were treated with ROS, H 2 O 2 , using a subtraction gene cloning technique. A gene clone was obtained from cDNA of cells from the osteoblastic cell line MC3T3-E1 after subtraction of the cDNA of H 2 O 2 -treated cells and designated as MC- ROS-7. To confirm the gene product, the DNA sequence of MC-ROS-7 was determined and homology was assessed using a nucleotide-nucleotide BLAST (BLASTN) search of the NCBI database, which revealed a 99.7% homology with fibronectin 1 (FN) gene. A significant lower level of FN mRNA was found in H 2 O 2 - treated cells when compared to that in non-treated cells using endpoint RT-PCR and real-time PCR assays. Our results suggest that a reduction of FN gene expression by ROS is involved in the decline of bone formation in osteoblasts during the ageing process.

There have been many studies on the relationships among various methods for determining whole salivary volume and these methods' effectiveness. The methods of determining this volume include those that determine the salivary volume of a subject at rest and during salivary stimulation. The convention method uses both the spitting method at rest and the paraffin mastication method. In the present study, we compared the reproducibility of the salivary volumes determined by the modified ion dilution method (the modified fluoride dilution method) and conventional methods. Salivary volumes in decreasing order were sour stimulation with the modified fluoride dilution (MFD) method, during mastication, under tasteless stimulation with the MFD method, and at rest. Higher correlations were found between the salivary volumes at rest and during mastication determined by the conventional method (r=0.57, p<0.001) and between salivary volumes under tasteless stimulation and sour stimulation by the MFD method (r=0.56, p<0.001). With a collection time of 1 minute, the MFD method featured a smaller coefficient of variation and higher reproducibility than those of the spitting and paraffin mastication methods, indicating its usefulness.

In the current study, we used the modified ion dilution method to evaluate the influence of the circadian rhythm on the salivary volume in response to varying sour concentrations. We found that the salivary volume changed depending on when the sample was taken and on the sour concentration. Specifically, there was a definite trend for the salivary volume to be low in the morning and to increase from around lunchtime to evening. In addition, the influence of the circadian rhythm on salivary volume tended to be reduced by a strong taste stimulation (high sour concentration). These results suggest that the greater the amount of stimulation (sour stimulation), the smaller the effect of circadian rhythm on the salivary volume.

Since the periodontal ligament (PDL) contains a heterogeneous cell population, it is challenging to identify all cell types within the tissue and to determine whether they function alone to produce tissue components or interact with other cell types. Further, it is difficult to isolate and expand single cell clones from PDL cells, as normal cells have a limited life span and are phenotypically unstable. In the present study, we inserted the human telomerase reverse transcriptase (hTERT) gene, which encodes the catalytic subunit of the telomerase holoenzyme, into normal human periodontal ligament (HPL) cells and successfully obtained single cell clones. Expression of the inserted gene and telomerase activity in each of the clones was confirmed. Unlike the original HPL cells, at the end of the study (day 120), clone populations continued to actively double without phenotypic alteration. Osteogenic characteristics were present in some but not all clones. In conclusion, immortalization of HPL cells was successfully accomplished by transduction with the hTERT gene. This is the first report of immortalization of different cell types derived from PDL.

The objective of the present study is to make a resin by using fluoroalkyl acrylate monomer for the suppression of the adhesion of microbes to dentures surfaces and plaque formation, since it is thought that fluoroalkyl acrylate monomer might develop a denture base material having low affinity for microbes. Here, we could produce polymer beads by adding perfluorooctylethyl acrylate (C8F) to methyl methacrylate (MMA) in order to modify the surface characteristics of the denture base resin, and then investigated microbial adhesion to test specimens.The water contact angle for C8F-added specimens (C8FA) was higher than that for control specimens (MMA/PMMA), although the surface hardness and tensile strength of the C8FA were slightly lower than those of the control. In addition, the maximum fluorine concentration for the C8FA was at a depth of 0.2 mm. Furthermore, bacterial adhesion to test specimens using Candida albicans was lower for the C8FA, when compared to the control. These findings suggest that the surface characteristics of dentures may be improved by adding a fluoroalkyl acrylate monomer to the filling polymer used in denture base resins.

Recently, the concept of hygiene has been promoted, and many sanitary goods that contain antimicrobial reagents have been produced. Such reagents are divided into organic and inorganic ones. Some literature has pointed out that these reagents have many disadvantages, such as short-time durability of antibacterial effect, degeneration by heating operation, and physical irritation. Furthermore, the organic antimicrobial reagents have intensive antimicrobial action, but long use of these reagents may cause microbial substitution and teratogenicity.We aimed to put inorganic antimicrobial reagent into practical use, and the effects of silver-inorganic antimicrobial reagents (IONPURETM and NOVARON AG 300TM) on oral microorganisms were examined.1. Minimum inhibitory concentrations (MICs) of antimicrobial reagents (IONPURE and NOVARON) for Streptococcus mutans were 7.5 mg/m/ and 1.3 mg/m/. The antimicrobial action was bacteriostatic. The microorganisms on resin plates that contained both antimicrobial reagents were remarkably reduced.2. MICs for Streptococcus mutans on resin plates that contained antimicrobial reagents were 5 wt%(IONPURE) and 10 wt%(NOVARON).3. Insoluble glucan synthesis was inhibited on NOVARON-containing resin plates. On the other hand, IONPURE was not so noticeable.4. The surviving microorganisms of Streptococcus mutans on resin plates that contained both antimicrobial reagents (3 wt%) were remarkably decreased.These results suggest that IONPURE and NOVARON were effectual antimicrobial reagents against Streptococcus mutans, and that they were useful for antimicrobial prosthesis.

Hitherto, many kinds of anti-bacterial reagents have been developed. Those anti-bacterial reagents could be divided into two groups such as organic and inorganic reagents. The silver-inorganic reagents have been interesting as a substitute for the organic reagent, since those inorganic reagents might resolve the problems of organic reagents such as the short-term durability of anti-bacterial effect, degeneration by proceeding or heating operation, and physical irritation. The purpose of this study was to investigate whether or not the silver-inorganic reagents could be applied biologically to dental materials. IonpureTMwas used as the silver-inorganic anti-bacterial reagent. Biological reactions of Ionpure were measured by the standard biological tests such as the toxic tests proposed by OECD and patch test by Kawai's method.The results were as follows1. In acute toxicity testing by oral ingestion of Ionpure, no mortality of mice was observed by the single dose of 5, 000 mg/kg. Lethal dose by oral ingestion of Ionpure was estimated to be more than 5, 000 mg/kg. The general condition, including the average weight, did not indicate abnormal signs during the experimental period. Furthermore, no pathological finding was observed in the internal organs by dissection after testing.2. In the dermal sensitization by modified Draize test, the eye irritation test, and the mutagenesis test, Ionpure was evaluated to be negative, whereas the evaluation of the patch test by Kawai's method was semi-negative.