bluuebunny/crossref_metadata_2025 huggingface dataset:
Cyclosporin A Specifically Affects Nuclear PLCβ1 in Immunodepressed Heart Transplant Patients with Gingival Overgrowth
Authors: Ruggeri A. , Montebugnoli L. , Matteucci A. , Zini N. , Solimando L. , Servidio D. , Suppa P. , Cadenaro M. , Cocco L. , Breschi L.
Published: January 2009

One of the most commonly observed adverse effects of cyclosporin A (CsA) is the development of gingival overgrowth (GO). Fibroblasts are involved in GO, but the question why only a percentage of patients undergoing CsA treatment shows this side-effect remains unanswered. In a previous study, CsA has been demonstrated to induce over-expression of phospholipase C (PLC) β1 in fibroblasts of patients with clinical GO, in cells from both enlarged and clinically healthy gingival sites. In this work, we assessed the expression of PLCβ isoforms to investigate whether the exaggerated fibroblast response to CsA related to increased PLCβ1 expression could also be detected in CsA-treated patients without clinical signs of GO. Our results support the hypothesis of a multi-factorial origin of gingival overgrowth, including specific changes within the gingival tissues orchestrating fibroblastic hyper-responsiveness as a consequence of a long-term in vivo exposure to cyclosporin A.
Bayesian Analysis of Clustered Interval-censored Data
Authors: Wong M.C.M. , Lam K.F. , Lo E.C.M.
Published: January 2009

The recording of multiple interval-censored failure times is common in dental research. Modeling multilevel data has been a difficult task. This paper aims to use the Bayesian approach to analyze a set of multilevel clustered interval-censored data from a clinical study to investigate the effectiveness of silver diamine fluoride and sodium fluoride varnish in arresting active dentin caries in Chinese pre-school children. The time to arrest dentin caries on a surface was measured. A three-level random-effects Weibull regression model was used. Analysis was performed with WinBUGS. Results revealed a strong positive correlation (0.596) among the caries lesions’ arrest times on different surfaces from the same child. The software WinBUGS made the above complicated estimation simple. In conclusion, the annual application of silver diamine fluoride on caries lesions, and caries removal before the application, were found to shorten the arrest time.
Eugenol Inhibits Calcium Currents in Dental Afferent Neurons
Authors: Lee M.H. , Yeon K.-Y. , Park C.-K. , Li H.-Y. , Fang Z. , Kim M.S. , Choi S.-Y. , Lee S.J. , Lee S. , Park K. , Lee J.-H. , Kim J.S. , Oh S.B.
Published: January 2009

Eugenol is a topical analgesic agent widely used in the dental clinic. To elucidate the molecular mechanism underlying its analgesic action, we investigated the effect of eugenol on high-voltage-activated calcium channel (HVACC) currents in dental primary afferent neurons, and with a heterologous expression system. Dental primary afferent neurons were identified by retrograde labeling with a fluorescent dye, DiI. Eugenol inhibited HVACC currents in both capsaicin-sensitive and capsaicin-insensitive dental primary afferent neurons. The HVACC inhibition by eugenol was not blocked by capsazepine, a competitive transient receptor potential vanilloid 1 (TRPV1) antagonist. Eugenol inhibited N-type calcium currents in the cell line C2D7, stably expressing the human N-type calcium channels, where TRPV1 was not endogenously expressed. Our results suggest that the HVACC inhibition by eugenol in dental primary afferent neurons, which is not mediated by TRPV1 activation, might contribute to eugenol’s analgesic effect. Abbreviations: high-voltage-activated calcium channel, HVACC; transient receptor potential vanilloid 1, TRPV1; trigeminal ganglion, TG; dorsal root ganglion, DRG; capsazepine, CZP.
Myofibroblasts in Palatal Wound Healing: Prospects for the Reduction of Wound Contraction after Cleft Palate Repair
Authors: van Beurden H.E. , Von den Hoff J.W. , Torensma R. , Maltha J.C. , Kuijpers-Jagtman A.M.
Published: January 2009

The surgical closure of orofacial clefts is considered to impair maxillary growth and dento-alveolar development. Wound contraction and subsequent scar tissue formation, during healing of these surgical wounds, contribute largely to these growth disturbances. The potential to minimize wound contraction and subsequent scarring by clinical interventions depends on the surgeon’s knowledge of the events responsible for these phenomena. Fibroblasts initiate wound contraction, but proto-myofibroblasts and mature myofibroblasts are by far the most important cells in this process. Myofibroblasts are characterized by their cytoskeleton, which contains alpha-smooth-muscle actin. Additionally, their contractile apparatus contains bundles of actin microfilaments and associated contractile proteins, such as non-muscle myosin. This contractile apparatus is thought to be the major force-generating element involved in wound contraction. After closure of the wound, the myofibroblasts disappear by apoptosis, and a less cellular scar is formed. A reduction of contraction and scarring might be obtained by inhibition of myofibroblast differentiation, stimulation of their de-differentiation, stimulation of myofibroblast apoptosis, or impairment of myofibroblast function. In this review, we will discuss all of these possibilities, which ultimately may lead to a better outcome of cleft palate surgery.
Effects of Positive Pressure in Odontogenic Keratocysts
Authors: Oka S. , Kubota Y. , Yamashiro T. , Ogata S. , Ninomiya T. , Ito S. , Shirasuna K.
Published: January 2009

Intracystic fluid pressure is thought to be involved in odontogenic cyst growth. In this study, we investigated the effects of positive pressure on the expression of interleukin-1α (IL-1α), matrix metalloproteinases (MMPs), and prostaglandin E2 (PGE2) in odontogenic keratocysts to determine whether this pressure stimulates inflammatory cytokine production and signaling of osteoclastogenic events. Positive pressure enhanced the expression of IL-1α mRNA and protein in odontogenic keratocyst epithelial cells, and increased the secretion of MMP-1, MMP-2, MMP-3, and PGE2 in a co-culture of odontogenic keratocyst fibroblasts and the epithelial cells. The pressure-induced secretions were inhibited by an interleukin-1 receptor antagonist. Recombinant human interleukin-1α (rhIL-1α) increased the secretion of MMP-1, MMP-2, MMP-3, and PGE2 in the fibroblasts. Furthermore, in the fibroblasts, rhIL-1α enhanced the expression of macrophage colony-stimulating factor (M-CSF) mRNA, and rhIL-1α-induced PGE2 increased the expression of nuclear factor κB ligand (RANKL) mRNA. Thus, positive pressure may play a crucial role in odontogenic keratocyst growth via stimulating the expression of IL-1α in epithelial cells.
Possible Link between Glycolysis and Apoptosis Induced by Sodium Fluoride
Authors: Otsuki S. , Morshed S.R.M. , Chowdhury S.A. , Takayama F. , Satoh T. , Hashimoto K. , Sugiyama K. , Amano O. , Yasui T. , Yokote Y. , Akahane K. , Sakagami H.
Published: January 2009

Fluoride has been used to prevent caries in the dentition, but the possible underlying mechanisms of cytotoxicity induction by this compound are still unclear. Since fluoride is known as an inhibitor of glycolytic enzymes, we investigated the possible connection between NaF-induced apoptosis and glycolysis in human promyelocytic leukemia HL-60 cells. NaF-induced apoptotic cell death is characterized by caspase activation, internucleosomal DNA fragmentation, loss of mitochondrial membrane potential, and production of apoptotic bodies. Higher activation of caspases-3 and -9, as compared with that of caspase-8, suggested the involvement of an extrinsic pathway. Utilization of glucose was nearly halted by NaF, whereas that of glutamine was rather enhanced. NaF enhanced the expression of Bad protein, but not that of Bcl-2 and Bax proteins, and reduced HIF-1α mRNA expression. Analysis of these data suggests a possible link between glycolysis and apoptosis.
Addressing Selection Bias in Dental Health Services Research
Authors: Lee J.Y. , Rozier R.G. , Norton E.C. , Vann W.F.
Published: January 2009

When randomization is not possible, researchers must control for non-random assignment to experimental groups. One technique for statistical adjustment for non-random assignment is through the use of a two-stage analytical technique. The purpose of this study was to demonstrate the use of this technique to control for selection bias in examining the effects of the The Supplemental Program for Women, Infants, and Children’s (WIC) on dental visits. From 5 data sources, an analysis file was constructed for 49,512 children ages 1–5 years. The two-stage technique was used to control for selection bias in WIC participation, the potentially endogenous variable. Specification tests showed that WIC participation was not random and that selection bias was present. The effects of the WIC on dental use differed by 36% after adjustment for selection bias by means of the two-stage technique. This technique can be used to control for potential selection bias in dental research when randomization is not possible.
Experience with Dental Pain and Fear of Dental Pain
Authors: van Wijk A.J. , Hoogstraten J.
Published: January 2009

Anxious people tend to overestimate the intensity of aversive events such as fear and pain. When an aversive event has been experienced personally, prediction is based on experience and is possibly less subject to bias due to anxiety. Therefore, it was hypothesized that subjects will overestimate fear of specific dental pains relative to subjects who experienced the pain or procedure personally. Samples of highly anxious dental patients (n = 48), patients waiting for periodontal treatment (n = 56), and psychology freshmen (n = 262) completed a measure of dental anxiety and the Fear of Dental Pain (FDP) questionnaire. All FDP items were extended with the question whether the subject ever experienced the pain personally (yes or no). Less fear was reported when the pain had been experienced personally, with the exception of the sample of highly anxious dental patients. The results suggest that fear of dental pain is a highly important covariate in dental pain research.
Double-blind Study on Materials Testing with Applied Kinesiology
Authors: Staehle H.-J. , Koch M.J. , Pioch T.
Published: January 2009

Applied Kinesiology (AK) is a scientifically unproven method used in complementary medicine to recognize the (in)tolerance of dental materials. Test-retest reliability of AK was examined. The working hypothesis was the assumption that the reliability of AK would not exceed random chance. Two dentists qualified in AK examined 112 volunteers to determine individual (in)tolerance toward two dental composite materials. After the first examination, 31 subjects were excluded from further testing. At the end of the open test phase, 34 of 81 participants had been classified as “tolerant”, and seven as “intolerant” to both materials. The remaining 40 individuals showed a combination of either tolerant (to material I)/intolerant (to material II), or the reverse (n = 20 each). Retrieval rate was tested under blind conditions. In 14 cases, the results of the open and blinded tests matched, whereas in 26 cases they did not (95% confidence interval, 21%-52%; p = 0.98). This outcome confirmed our working hypothesis.
Apatite/Amelogenin Coating on Titanium Promotes Osteogenic Gene Expression
Authors: Du C. , Schneider G.B. , Zaharias R. , Abbott C. , Seabold D. , Stanford C. , Moradian-Oldak J.
Published: January 2009

Osteoblast differentiation and extracellular matrix production are pivotal processes for implant osseointegration or bone tissue engineering. We hypothesized that a biomimetic coating on titanium surfaces, consisting of apatite and amelogenin, would promote such processes. Human Embryonic Palatal Mesenchymal pre-osteoblasts were used as a model for the evaluation of cell adhesion and spreading patterns, as well as mRNA expression of certain osteoblastic gene products. Real-time PCR showed significant (p < 0.05) increase in expression of type I collagen, alkaline phosphatase, and osteocalcin from cells grown on titanium with an apatite/amelogenin composite, as compared with that from cells grown on a pure titanium or apatite coating only. Osteocalcin expression was specifically stimulated by amelogenin added to the culture media. Enhanced attachment and cell spreading were also observed. The biomimetic coating promoting cell adhesion and osteoblast differentiation may have great potential for future dental and biomedical applications.
Genes and Related Proteins Involved in Amelogenesis Imperfecta
Authors: Stephanopoulos G. , Garefalaki M.-E. , Lyroudia K.
Published: January 2009

Dental enamel formation is a remarkable example of a biomineralization process. The exact mechanisms involved in this process remain partly obscure. Some of the genes encoding specific enamel proteins have been indicated as candidate genes for amelogenesis imperfecta. Mutational analyses within studied families have supported this hypothesis. Mutations in the amelogenin gene ( AMELX) cause X-linked amelogenesis imperfecta, while mutations in the enamelin gene ( ENAM) cause autosomal-inherited forms of amelogenesis imperfecta. Recent reports involve kallikrein-4 ( KLK4), MMP-20, and DLX3 genes in the etiologies of some cases. This paper focuses mainly on the candidate genes involved in amelogenesis imperfecta and the proteins derived from them, and reviews current knowledge on their structure, localization within the tissue, and correlation with the various types of this disorder.
Effectiveness of 4 Pulpotomy Techniques—Randomized Controlled Trial
Authors: Huth K.C. , Paschos E. , Hajek-Al-Khatar N. , Hollweck R. , Crispin A. , Hickel R. , Folwaczny M.
Published: January 2009

Pulpotomy is the accepted therapy for the management of cariously exposed pulps in symptom-free primary molars; however, evidence is lacking about the most appropriate technique. The aim of this study was to compare the relative effectiveness of the Er:YAG laser, calcium hydroxide, and ferric sulfate techniques with that of dilute formocresol in retaining such molars symptom-free. Two hundred primary molars in 107 healthy children were included and randomly allocated to one of the techniques. The treated teeth were blindly re-evaluated after 6, 12, 18, and 24 months. Descriptive data analysis and logistic regression analysis, accounting for each patient’s effect by a generalized estimating equation (GEE), were used. After 24 months, the following total and clinical success rates were determined (%): formocresol 85 (96), laser 78 (93), calcium hydroxide 53 (87), and ferric sulfate 86 (100). Only calcium hydroxide performed significantly worse than formocresol (p = 0.001, odds ratio = 5.6, 95% confidence interval 2.0–15.5). In conclusion, calcium hydroxide is less appropriate for pulpotomies than is formocresol.
Role of TNF-α and Its Receptors in Pericoronitis
Authors: Beklen A. , Laine M. , Ventä I. , Hyrkäs T. , Konttinen Y.T.
Published: January 2009

The classic stimulus for cellular cytokine production is bacterial lipopolysaccharide (endotoxin). It was therefore hypothesized that tumor necrosis factor-α (TNF-α) may be responsible for pericoronitis. TNF-α and its receptors were detected by immunohistochemical staining in third molar pericoronitis in ten patients and ten healthy control samples. The percentage of TNF-α positive cells was high in pericoronitis (p = 0.0317). TNF receptors TNF-R1 and TNF-R2 were found in macrophage- and fibroblast-like cells, vascular endothelial cells in post-capillary venules, and basal epithelial cells in pericoronitis, but were only weakly expressed in controls. Increased expression of interleukin-1β and vascular cell adhesion molecule-1 was found as a biological indicator of TNF-α ligand-receptor interaction. Explanted tissues acquired destructive potential upon TNF-α stimulation, whereas TNF-α blockers controlled it in inflamed tissues. These findings suggest that, in pericoronitis, inflammatory and resident cells produce and respond to potent pro-inflammatory cytokine TNF-α, with pathogenic and potential therapeutic relevance.
Influence of Biosurfactant on Interactive Forces between Mutans Streptococci and Enamel Measured by Atomic Force Microscopy
Authors: van Hoogmoed C.G. , Dijkstra R.J.B. , van der Mei H.C. , Busscher H.J.
Published: January 2009

Although interactive forces, influenced by environmental conditions, between oral bacteria and tooth surfaces are important for the development of plaque, they have never been estimated. It is hypothesized that interactive forces, as measured by atomic force microscopy, between enamel with or without a pellicle and two strains of mutans streptococci become less attractive by the application of a Streptococcus mitis BMS biosurfactant coating. Upon approach of each of the strains toward bare and pellicle-coated enamel, adsorbed biosurfactant increased the range of the repulsive forces. Upon retraction of the enamel surface, small adhesion forces (0.8–0.9 nN) were measured for bare enamel that almost disappeared after biosurfactant coating. The prevalence and magnitude of the adhesion forces also decreased upon pellicle-coating of the enamel, with a minor effect of adsorbed biosurfactant. These findings indicate that adsorbed S. mitis BMS biosurfactant changes the interactive forces between the mutans streptococci studied and enamel, explaining the effects of biosurfactant on adhesion.
Full-mouth Tooth Extraction Lowers Systemic Inflammatory and Thrombotic Markers of Cardiovascular Risk
Authors: Taylor B.A. , Tofler G.H. , Carey H.M.R. , Morel-Kopp M.-C. , Philcox S. , Carter T.R. , Elliott M.J. , Kull A.D. , Ward C. , Schenck K.
Published: January 2009

Prior studies of a link between periodontal and cardiovascular disease have been limited by being predominantly observational. We used a treatment intervention model to study the relationship between periodontitis and systemic inflammatory and thrombotic cardiovascular indicators of risk. We studied 67 adults with advanced periodontitis requiring full-mouth tooth extraction. Blood samples were obtained: (1) at initial presentation, immediately prior to treatment of presenting symptoms; (2) one to two weeks later, before all teeth were removed; and (3) 12 weeks after full-mouth tooth extraction. After full-mouth tooth extraction, there was a significant decrease in C-reactive protein, plasminogen activator inhibitor-1 and fibrinogen, and white cell and platelet counts. This study shows that elimination of advanced periodontitis by full-mouth tooth extraction reduces systemic inflammatory and thrombotic markers of cardiovascular risk. Analysis of the data supports the hypothesis that treatment of periodontal disease may lower cardiovascular risk, and provides a rationale for further randomized studies.
Radiographic Assessment of Dental Health in Middle-aged Men Following Sudden Cardiac Death
Authors: Karhunen V. , Forss H. , Goebeler S. , Huhtala H. , Ilveskoski E. , Kajander O. , Mikkelsson J. , Penttilä A. , Perola M. , Ranta H. , Meurman J.H. , Karhunen P.J.
Published: January 2009

Poor oral health has been suggested to be a risk factor for myocardial infarction. To study if dental pathology might predispose to pre-hospital sudden cardiac death, and using a sum index of panoramic tomography findings, we compared the oral health of middle-aged (33–69 yrs) male victims (Helsinki Sudden Death Study) of sudden cardiac death (n = 117) with that of controls, who died of non-cardiac diseases (n = 63) or suffered unnatural sudden death (n = 120). The mean number of teeth was 15.2, and 17.4% of the men were edentulous. Frequent age-associated findings in dentate victims were fillings (79.9%), horizontal bone loss (72.1%), periapical lesions (45.6%), residual roots (38.2%), and vertical pockets (30.9%). In multivariate analysis with coronary heart disease risk factors and number of teeth as covariates, poor oral health was associated (p = 0.053) with the risk of sudden cardiac death along with age, smoking, and body mass index. This association was especially strong (p = 0.009) among victims < 50 yrs.
Cloning, Sequencing, and Expression of the Amelogenin Gene in Two Scincid Lizards
Authors: Delgado S. , Couble M.-L. , Magloire H. , Sire J.-Y.
Published: January 2009

Our knowledge of the gene coding for amelogenin, the major enamel protein, is mainly based on mammalian sequences. Only two sequences are available in reptiles. To know whether the snake sequence is representative of the amelogenin condition in squamates, we have studied amelogenin in two scincid lizards. Lizard amelogenin possesses numerous conserved residues in the N- and C-terminal regions, but its central region is highly variable, even when compared with the snake sequence. This rapid evolution rate indicates that a single squamate sequence was not representative, and that comparative studies of reptilian amelogenins might be useful to detect the residues which are really important for amelogenin structure and function. Reptilian and mammalian enamel structure is roughly similar, but no data support amelogenin being similarly expressed during amelogenesis. By performing in situ hybridization using a specific probe, we showed that lizard ameloblasts express amelogenin as described during mammalian amelogenesis. However, we have not found amelogenin transcripts in odontoblasts. This indicates that full-length amelogenin is specific to enamel matrix, at least in this lizard.
The Transmission of Anaerobic Periodontopathic Organisms
Authors: Lee Y. , Straffon L.H. , Welch K.B. , Loesche W.J.
Published: January 2009

The oral microbial flora is unique, and available evidence indicates that it is passed vertically from parents to children. In this investigation, we used a chairside assay for the N-benzoyl-DL-arginine-2-naphthylamide (BANA)-sensitive enzyme found in Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythensis, to determine the prevalence of these BANA-positive species in young children and their caregivers. We predicted that if the BANA enzyme was found in plaque samples of children, it would also be present in the plaque samples of the caregivers. Forty-four percent of 150 children had at least one plaque sample positive for the BANA enzyme. If the caregiver was BANA-positive, the odds of the child also being BANA-positive was 35 times more than for a child with a BANA-negative caregiver, after adjustment for the child’s age and papillary bleeding score (PBS). Other significant predictors were the PBS of children (p < 0.001), a history of periodontal disease, and the ages of the caregivers (p < 0.001).
Protective and Destructive Immunity in the Periodontium: Part 2—T-cell-mediated Immunity in the Periodontium
Authors: Teng Y.-T.A.
Published: January 2009

Based on the results of recent research in the field and Part 1 of this article (in this issue), the present paper will discuss the protective and destructive aspects of the T-cell-mediated adaptive immunity associated with the bacterial virulent factors or antigenic determinants during periodontal pathogenesis. Attention will be focused on: (i) osteoimmunology and periodontal disease; (ii) some molecular techniques developed and applied to identify critical microbial virulence factors or antigens associated with host immunity (with Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis as the model species); and (iii) summarizing the identified virulence factors/antigens associated with periodontal immunity. Thus, further understanding of the molecular mechanisms of the host’s T-cell-mediated immune responses and the critical microbial antigens related to disease pathogenesis will facilitate the development of novel therapeutics or protocols for future periodontal treatments. Abbreviations used in the paper are as follows: A. actinomycetemcomitans ( Aa), Actinobacillus actinomycetemcomitans; Ab, antibody; DC, dendritic cells; mAb, monoclonal antibody; pAb, polyclonal antibody; OC, osteoclast; PAMP, pathogen-associated molecular patterns; P. gingivalis ( Pg), Porphyromonas gingivalis; RANK, receptor activator of NF-κB; RANKL, receptor activator of NF-κB ligand; OPG, osteoprotegerin; TCR, T-cell-receptors; TLR, Toll-like receptors.
Immediate Erosive Potential of Cola Drinks and Orange Juices
Authors: Jensdottir T. , Holbrook P. , Nauntofte B. , Buchwald C. , Bardow A.
Published: January 2009

Little is known about the erosive potential of soft drinks within the first minutes of exposure to teeth, and about the potentially protective role of salivary proteins. We hypothesized that the erosive potential is determined primarily by pH and decreases in the presence of salivary proteins. To investigate this, we first added uncoated hydroxyapatite crystals and, second, salivary-protein-coated hydroxyapatite crystals to 20 commercially available cola drinks and orange juices simultaneously, with pH recordings every 15 sec for 3 min. The amount of apatite lost per liter of soft drink per sec was calculated from titratable acidity values to each pH obtained by crystal addition. The erosive potential within the first minutes of exposure was determined solely by the pH of the drink, and the erosive potential was ten-fold higher in cola drinks compared with juices. However, salivary proteins reduced the erosive potential of cola drinks by up to 50%.
Anti-inflammatory Activity of a High-molecular-weight Cranberry Fraction on Macrophages Stimulated by Lipopolysaccharides from Periodontopathogens
Authors: Bodet C. , Chandad F. , Grenier D.
Published: January 2009

Periodontitis is a chronic inflammatory disease affecting oral tissues. The continuous, high production of cytokines by host cells triggered by periodontopathogens is thought to be responsible for the destruction of tooth-supporting tissues. Macrophages play a critical role in this host inflammatory response to periodontopathogens. The aim of this study was to investigate the effect of non-dialyzable material prepared from cranberry juice concentrate on the pro-inflammatory cytokine response of macrophages induced by lipopolysaccharides (LPS) from Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum subsp. nucleatum, Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, and Escherichia coli. Interleukin-1 beta (IL-1β), IL-6, IL-8, tumor necrosis factor alpha (TNF-α), and Regulated on Activation Normal T-cell Expressed and Secreted (RANTES) production by macrophages treated with the cranberry fraction prior to stimulation by LPS was evaluated by ELISA. Our results clearly indicate that the cranberry fraction was a potent inhibitor of the pro-inflammatory cytokine and chemokine responses induced by LPS. This suggests that cranberry constituents may offer perspectives for the development of a new therapeutic approach to the prevention and treatment of periodontitis.
How Do Factors at Different Stages of the Lifecourse Contribute to Oral-health-related Quality of Life in Middle Age for Men and Women?
Authors: Mason J. , Pearce M.S. , Walls A.W.G. , Parker L. , Steele J.G.
Published: January 2009

The relative contributions of factors operating in fetal life, childhood, and adulthood to the risk of disease in middle age have become important research issues, but self-perceived oral health has rarely been considered in this context. This study investigated the impact of risk factors operating throughout life on self-perceived oral health, according to the Oral Health Impact Profile (OHIP), at age 50 yrs in 305 individuals from the Newcastle Thousand Families cohort. Factors from early and adult life contributed to the OHIP scores, but in men, self-perceived oral health was mostly explained by factors operating early in life. In women, the number of teeth retained in adulthood had a more prominent impact. Lifecourse influences on oral-health-related quality of life appear different for men and women, which may have implications for the effectiveness of public health interventions and health promotion.
Carbonated Soft Drinks and Dental Caries in the Primary Dentition
Authors: Sohn W. , Burt B.A. , Sowers M.R.
Published: January 2009

We analyzed fluid intake data among children aged 2–10 years from a 24-hour dietary recall interview in the NHANES III (1988–94) to investigate the effect of high consumption of carbonated soft drinks on caries in the primary dentition. We used cluster analysis to determine fluid consumption patterns. Four distinct fluid consumption patterns were identified: high carbonated soft drinks, high juice, high milk, and high water. About 13% of children had a high carbonated soft drink consumption pattern; they also had a significantly higher dental caries experience in the primary dentition than did children with other fluid consumption patterns. A fluid intake pattern comprised mainly of milk, water, or juice was less likely to be associated with dental caries. Findings of this study suggest that high consumption of carbonated soft drinks by young children is a risk indicator for dental caries in the primary dentition and should be discouraged.
Cigarette Smoking Increases the Risk of Root Canal Treatment
Authors: Krall E.A. , Sosa C. Abreu , Garcia C. , Nunn M.E. , Caplan D.J. , Garcia R.I.
Published: January 2009

Few studies have investigated smoking as a risk factor for root canal treatment. We studied the effect of smoking on the incidence of root canal treatment, controlling for recognized risk factors, in 811 dentate male participants in the VA Dental Longitudinal Study. Participants were not VA patients. Follow-up ranged from 2 to 28 years. Root canal treatment was verified on radiographs and evaluated with proportional hazards regression models. Compared with never-smokers, current cigarette smokers were 1.7 times as likely to have root canal treatment (p < 0.001), but cigar and/or pipe use was not significantly associated with root canal treatment. The risk among cigarette smokers increased with more years of exposure and decreased with length of abstinence. These findings suggest that there is a dose-response relationship between cigarette smoking and the risk of root canal treatment.
Finger Osteoarthritis and Differences in Dental Work Tasks
Authors: Solovieva S. , Vehmas T. , Riihimäki H. , Takala E.-P. , Murtomaa H. , Luoma K. , Leino-Arjas P.
Published: January 2009

Mechanical load has been proposed as a risk factor for hand osteoarthritis. Dentists produce high manual forces in their work tasks. We studied whether the pattern of dental work tasks was associated with finger osteoarthritis. Radiographs of both hands of 291 middle-aged female dentists were examined for the presence of osteoarthritis. Patterns of dental work tasks during work history were empirically defined by cluster analysis. Three patterns emerged reflecting high, moderate, and mild task variation. Age, specialization, years in clinical work, various activities requiring hand use, family history of Heberden’s nodes, body mass index, and smoking were accounted for in logistic regression analyses. The dentists with a history of low task variation had a greater prevalence of osteoarthritis in the thumb, index, and middle fingers compared with dentists with high variation (OR 2.22; 95%CI 1.04–4.91). The pattern of dental work task history is associated with the localization of osteoarthritis in the fingers.
Effects of Isoflurane on Parasympathetic Vasodilatation in the Rat Submandibular Gland
Authors: Mizuta K. , Mizuta F. , Takahashi M. , Ishii H. , Niioka T. , Izumi H.
Published: January 2009

Volatile anesthetics have been known to suppress parasympathetic reflex vasodilatation in the lower lip and palate. However, in the submandibular gland, little is known about the effects of these anesthetics on the parasympathetic vasodilatation elicited by reflex and direct ( i.e., non-reflex) activation of the parasympathetic vasodilator mechanisms. Although both parasympathetic vasodilatations were inhibited by isoflurane in a concentration- and time-dependent manner, the effects of continuous administration of the α1-adrenoceptor agonist methoxamine were markedly different: The reflex vasodilatation was not affected by methoxamine, while the direct vasodilatation was significantly reduced. Picrotoxin (GABAAreceptor antagonist) attenuated the inhibitory effect of isoflurane on direct vasodilatation and the systemic arterial blood pressure. These findings suggest that the isoflurane-induced inhibitory effects on direct vasodilatation are produced by a decrease of peripheral vascular tone by GABAergic mechanisms, whereas those on the reflex vasodilatation are produced exclusively by the inhibition of the reflex center.
Responses of Rat Pulp Cells to Heat Stress in vitro
Authors: Amano T. , Muramatsu T. , Amemiya K. , Kubo K. , Shimono M.
Published: January 2009

Although heat stress can cause irritation in the dentin/pulp complex, little is known about the thermotolerance of pulp cells and their response to heat stress. We investigated cultured rat pulp cell responses to heat stress. Cells were subjected to a temperature of 42°C for 30 minutes, and HSPs, alkaline phosphatase activity, and gap-junctional communication were determined at various time points. Although only low levels of HSP70 expression were detected before heat treatment, heat shock markedly induced HSP70 expression, with it gradually increasing at 1 hour after being heated. HSP25, however, showed no dramatic change. Gap junction protein connexin43 rapidly degraded after heat treatment, recovering to normal levels within the following 6 hours. Alkaline phosphatase activity decreased immediately after heat stress, recovering after 1 hour. These results indicate that dental pulp possesses protective factors, including HSPs, and that it can recover viability of intercellular communication and alkaline phosphatase activity after heat stress.
Edema in Oral Mucosa after LPS or Cytokine Exposure
Authors: Bletsa A. , Nedrebø T. , Heyeraas K.J. , Berggreen E.
Published: January 2009

Lowering of interstitial fluid pressure (Pif) is an important factor that explains the rapid edema formation in acute inflammation in loose connective tissues. Lipopolysaccharide (LPS) and the pro-inflammatory cytokines interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) are pathogenetic in gingivitis. To test if these substances induce lowering of Pif in rat oral mucosa, we measured Pif with a micropuncture technique. IL-1β and TNF-α caused lowering of Pif, whereas LPS induced an immediate increase in Pif, followed by lowering after 40 min. Measurements of fluid volume distribution showed a significant change in interstitial fluid volume (Vi) 1.5 hr after LPS exposure as Vi changed from 0.41 ± 0.02 to 0.51 ± 0.03 mL/g wet weight ( p < 0.05), confirming edema. These findings show that LPS, IL-1β, and TNF-α induce lowering of Pif in the rat oral mucosa and contribute to edema formation in LPS-induced gingivitis.
Peri-implant Inflammation Defined by the Implant-Abutment Interface
Authors: Broggini N. , McManus L.M. , Hermann J.S. , Medina R. , Schenk R.K. , Buser D. , Cochran D.L.
Published: January 2009

An implant-abutment interface at the alveolar bone crest is associated with sustained peri-implant inflammation; however, whether magnitude of inflammation is proportionally dependent upon interface position remains unknown. This study compared the distribution and density of inflammatory cells surrounding implants with a supracrestal, crestal, or subcrestal implant-abutment interface. All implants developed a similar pattern of peri-implant inflammation: neutrophilic polymorphonuclear leukocytes (neutrophils) maximally accumulated at or immediately coronal to the interface. However, peri-implant neutrophil accrual increased progressively as the implant-abutment interface depth increased, i.e., subcrestal interfaces promoted a significantly greater maximum density of neutrophils than did supracrestal interfaces (10,512 ± 691 vs. 2398 ± 1077 neutrophils/mm2). Moreover, inflammatory cell accumulation below the original bone crest was significantly correlated with bone loss. Thus, the implant-abutment interface dictates the intensity and location of peri-implant inflammatory cell accumulation, a potential contributing component in the extent of implant-associated alveolar bone loss.
Modulation of Dental Inflammation by the Sympathetic Nervous System
Authors: Haug S.R. , Heyeraas K.J.
Published: January 2009

Recent findings have indicated that immune responses are subjected to modulation by the sympathetic nervous system (SNS). Moreover, the findings show that the SNS inhibits the production of pro-inflammatory cytokines, while stimulating the production of anti-inflammatory cytokines. The present review is an attempt to summarize the current results on how the SNS affects inflammation in dental tissues. In dental tissues, it has been found that the SNS is significant for recruitment of inflammatory cells such as CD 43+ granulocytes. Sympathetic nerves appear to have an inhibitory effect on osteoclasts, odontoclasts, and on IL-1α production. The SNS stimulates reparative dentin production, since reparative dentin formation was reduced after sympathectomy. Sprouting of sympathetic nerve fibers occurs in chronically inflamed dental pulp, and neural imbalance caused by unilateral sympathectomy recruits immunoglobulin-producing cells to the dental pulp. In conclusion, this article presents evidence in support of interactions between the sympathetic nervous system and dental inflammation.
Toll-like Receptors, NOD1, and NOD2 in Oral Epithelial Cells
Authors: Sugawara Y. , Uehara A. , Fujimoto Y. , Kusumoto S. , Fukase K. , Shibata K. , Sugawara S. , Sasano T. , Takada H.
Published: January 2009

Oral epithelium might be the first barrier against oral bacteria in periodontal tissue. We hypothesized that oral epithelium is endowed with innate immune receptors for bacterial components, which play roles in host defense against bacterial infection without being accompanied by excessive inflammatory responses. We found clear expression of Toll-like receptor (TLR)4 as well as TLR2, and strong expression of NOD1 and NOD2 in normal oral epithelial tissues by immunohistochemical analysis. We also showed that primary oral epithelial cells in culture expressed these molecules using PCR, flow cytometry, and immunostaining. In inflamed oral epithelium, cell-surface localizations of TLR2 and TLR4 were more clearly observed than in healthy tissue. Upon stimulation with synthetic ligands for these receptors, the expression of β-defensin 2 was markedly up-regulated. These findings indicate that these molecules in oral epithelial cells are functional receptors that induce antibacterial responses.
Size and Orientation of Masticatory Muscles in Patients with Mandibular Laterognathism
Authors: Goto T.K. , Nishida S. , Yahagi M. , Langenbach G.E.J. , Nakamura Y. , Tokumori K. , Sakai S. , Yabuuchi H. , Yoshiura K.
Published: January 2009

Size measurements of jaw muscles reflect their force capabilities and correlate with facial morphology. Using MRI, we examined the size and orientation of jaw muscles in patients with mandibular laterognathism in comparison with a control group. We hypothesized that the muscles of the deviated side would be smaller than those of the non-deviated side, and that the muscles of both sides would be smaller than in controls. In patients, a comparison of deviated and non-deviated sides showed, in orientation, differences for masseter and medial pterygoid muscles, but, in size, differences only for the masseter muscle. Nevertheless, muscle sizes in patients were much smaller than in controls. Lateral displacement of the mandible can explain the orientation differences, but not the smaller muscle size, in patients. It is possible that the laterodeviation initiates an adaptive process in the entire jaw system, resulting in extensive atrophy of the jaw muscles.
Protective Effect of the Dental Pellicle against Erosive Challenges in situ
Authors: Hara A.T. , Ando M. , González-Cabezas C. , Cury J.A. , Serra M.C. , Zero D.T.
Published: January 2009

The acquired dental pellicle helps prevent erosion, but the protection level is unknown. This in situ study tested whether a two-hour pellicle protects against different erosive challenges by orange juice. Subjects wore palatal appliances loaded with either enamel or dentin specimens. Pellicle was allowed to form, or not (control), on the surfaces of the specimens intra-orally for 2 hrs before the erosive challenges of 0 (control), 10, 20, and 30 minutes’ duration. Specimens were randomly removed from the appliances after each challenge. Percentage of surface microhardness change (%SMC) was determined for the enamel specimens, and that of mineral loss and lesion depth for the dentin specimens. Enamel specimens with the pellicle showed a significantly lower %SMC, only after the 10-minute challenge. No protection was found for dentin. It was concluded that the acquired pellicle reduced dental erosion, but that this effect was limited to the less severe erosive challenge on enamel surfaces.
Survival of ART and Amalgam Restorations in Permanent Teeth of Children after 6.3 Years
Authors: Frencken J.E. , Taifour D. , van ’t Hof M.A.
Published: January 2009

The null hypothesis tested was that there is no difference in the survival percentages of all restorations placed through the Atraumatic Restorative Treatment (ART) approach, with high-viscosity glass ionomer, and those produced through the traditional approach, with amalgam (TA), in the permanent dentitions of children after 6.3 years. Using a parallel group design, we randomly assigned a total of 370 children, aged 6 to 9 years, to the ART group and 311 children, also aged 6 to 9 years, to the TA group. Eight dentists placed a total of 1117 single- and multiple-surface restorations. The cumulative survival percentages for ART glass-ionomer restorations were statistically significantly higher than those of amalgam restorations at all time intervals except the first (p ≤ 0.044). After 6.3 years, the cumulative survival percentages of ART and amalgam restorations were 66.1% (SE = 3.1%) and 57.0% (SE = 3.3%), respectively. We concluded that the restorations produced with the ART approach, with high-viscosity glass ionomer, survived longer than those produced with the traditional approach, with amalgam, in the permanent teeth of young children.
Gelled Calcium Polyphosphate Matrices Delay Antibiotic Release
Authors: Schofield S.C. , Berno B. , Langman M. , Hall G. , Filiaggi M.J.
Published: January 2009

Introducing a gelling step during antibiotic incorporation has previously been found to delay vancomycin delivery from a calcium polyphosphate matrix intended for local treatment of bone infections. This study examined the general applicability of this approach using cefuroxime, a lower-molecular-weight antibiotic with different charge characteristics compared with those of vancomycin. A calcium polyphosphate/cefuroxime paste was “gelled” in disk form in a humid environment for 5 or 24 hours prior to drying. Antibiotic release in Tris-buffered saline under gentle agitation was monitored over a seven-day period. While non-gelled samples clearly exhibited a burst release, the gelling process significantly retarded early antibiotic release from five- and 24-hour gelled matrices, yielding a constant release rate over the first four days. Cefuroxime incorporation did not appear to alter matrix structure or degradation. Overall, this non-aggressive process effectively trapped cefuroxime and reduced its release rate, suggesting its potential applicability with molecularly diverse therapeutic agents.
Single-channel Recordings of TREK-1 K+ Channels in Periodontal Ligament Fibroblasts
Authors: Ohara A. , Saeki Y. , Nishikawa M. , Yamamoto Y. , Yamamoto G.
Published: January 2009

The periodontal ligament (PDL) works as a suspensory ligament when external mechanical stress is placed on the teeth. PDL fibroblasts, the principal cells in the PDL, are responsible for many PDL functions. We hypothesized that mechanosensitive ion channels are present in human PDL fibroblasts, which are capable of responding to mechanical stress during normal function of the tissue. Using patch-clamp techniques, we detected mechanosensitive TREK-1 K+ channels (a member of the two-pore-domain K+ channel family), whose single-channel conductance was 104 pS in symmetrical K+-rich solutions. The open probability of the channel was low in the quiescent state, but it was strongly increased by the induction of membrane stretch. Arachidonic acid also enhanced the channel activity. RT-PCR and immunocytochemical observations showed the expression of TREK-1 K+ channels in PDL fibroblasts. The results suggest that the activation of TREK-1 K+ channels by masticatory stress contributes to the hyperpolarization of PDL fibroblasts.
Clodronate Inhibits PGE2Production in Compressed Periodontal Ligament Cells
Authors: Liu L. , Igarashi K. , Kanzaki H. , Chiba M. , Shinoda H. , Mitani H.
Published: January 2009

Periodontal ligament (PDL) cells play an essential role in orthodontic tooth movement. We recently reported that clodronate, a non-N-containing bisphosphonate, strongly inhibited tooth movement in rats, and thus could be a useful adjunct for orthodontic treatment. However, it is not clear how clodronate affects the responses of PDL cells to orthodontic force. In this study, we hypothesized that clodronate prevents the mechanical stress-induced production of prostaglandin E2(PGE2), interleukin-1β (IL-1β), and nitric oxide (NO) in human PDL cells. A compressive stimulus caused a striking increase in PGE2production, while the responses of IL-1β and NO were less marked. Clodronate concentration-dependently inhibited the stress-induced production of PGE2. Clodronate also strongly inhibited stress-induced gene expression for COX-2 and RANKL. These results suggest that the inhibitory effects of clodronate on tooth movement and osteoclasts may be due, at least in part, to the inhibition of COX-2-dependent PGE2production and RANKL expression in PDL cells.
Amelogenins in Human Developing and Mature Dental Pulp
Authors: Ye L. , Le T.Q. , Zhu L. , Butcher K. , Schneider R.A. , Li W. , Besten P.K. Den
Published: January 2009

Amelogenins are a group of heterogenous proteins first identified in developing tooth enamel and reported to be present in odontoblasts. The objective of this study was to elucidate the expression and function of amelogenins in the human dentin-pulp complex. Developing human tooth buds were immunostained for amelogenin, and mRNA was detected by in situ hybridization. The effects of recombinant amelogenins on pulp and papilla cell proliferation were measured by Brd U immunoassay, and differentiation was monitored by alkaline phosphatase expression. Amelogenin protein was found in the forming dentin matrix, and amelogenin mRNA was localized in the dentin, presumably in the odontoblast processes. Proliferation of papilla cells was enhanced by recombinant human amelogenin rH72 (LRAP+ exon 4), while pulp cells responded to both rH72 and rH58 (LRAP), with no effect by rH174. These studies suggest that odontoblasts actively synthesize and secrete amelogenin protein during human tooth development, and that low-molecular-weight amelogenins can enhance pulp cell proliferation.