bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of LRAP on Enamel Organ Epithelial Cell Differentiation
Authors: Le T.Q. , Zhang Y. , Li W. , DenBesten P.K.
Published: January 2009

Leucine-rich amelogenin peptide (LRAP) is an alternatively spliced amelogenin found in the developing enamel organ. LRAP functions to regulate the development of mesenchymal-derived cells; however, its effect on cells of the enamel organ remains unclear. The hypothesis tested in this study is that LRAP also regulates human enamel organ epithelial cells. Recombinant human LRAP (rH58) was synthesized in E. coli, purified, and exogenously added to cultures of human primary enamel epithelial cells, which were analyzed for changes in cell proliferation and differentiation. rH58 had no effect on cell proliferation, but altered enamel epithelial cell morphology, resulting in larger, more rounded cells. Immunofluorescence showed that rH58 treatment increased amelogenin synthesis, but down-regulated Notch1 expression in enamel epithelial cells. LAMP-1, a membrane receptor for LRAP in mesenchymal cells, was identified and was up-regulated in the presence of rH58. These results suggest that rH58 promotes differentiation of human enamel organ epithelial cells.
Stimulation of Cells Derived from Nifedipine-induced Gingival Overgrowth with Porphyromonas gingivalis, Lipopolysaccharide, and Interleukin-1β
Authors: Lu H.-K. , Chou H.-P. , Li C.-L. , Wang M.-Y. , Wang L.-F.
Published: January 2009

The purpose of this study was to clarify the main contributory factor of nifedipine-induced gingival overgrowth either by Porphyromonas gingivalis lipopolysaccharide ( Pg-LPS) or interleukin-1beta (IL-1β). Human gingival fibroblasts from healthy tissues and nifedipine-induced gingival overgrowth tissues were stimulated with nifedipine, IL-1β, Escherichia coli lipopolysaccharide ( Ec-LPS), and Pg-LPS, and the gene expressions were analyzed by RT-PCR. Analysis of the data showed no strong evidence of a synergistic effect of nifedipine and Pg-LPS on IL-6, connective tissue growth factor (CTGF), and type 1 collagen gene expression of either healthy cells or nifedipine-induced gingival overgrowth cells. Among the three stimulants—IL-1β, Pg-LPS, and Ec-LPS—androgen receptor and IL-6 gene expressions in both the healthy and nifedipine-induced gingival overgrowth groups were strongly up-regulated by the presence of IL-1β only. Furthermore, the responses to IL-1β in the nifedipine-induced gingival overgrowth group were stronger than those of the healthy group. It can be concluded that IL-1β is an important mediator responsible for the higher IL-6 and androgen receptor expression of nifedipine-induced gingival overgrowth cells.
Longitudinal Study of Bone Density and Periodontal Disease in Men
Authors: Phipps K.R. , Chan B.K.S. , Madden T.E. , Geurs N.C. , Reddy M.S. , Lewis C.E. , Orwoll E.S.
Published: January 2009

Bone loss is a feature of both periodontitis and osteoporosis, and periodontal destruction may be influenced by systemic bone loss. This study evaluated the association between periodontal disease and bone mineral density (BMD) in a cohort of 1347 (137 edentulous) older men followed for an average of 2.7 years. Participants were recruited from the Osteoporotic Fractures in Men Study. Random half-mouth dental measures included clinical attachment loss (CAL), pocket depth (PD), calculus, plaque, and bleeding. BMD was measured at the hip, spine, and whole-body, by dual-energy x-ray absorptiometry, and at the heel by ultrasound. After adjustment for age, smoking, race, education, body mass index, and calculus, there was no association between number of teeth, periodontitis, periodontal disease progression, and either BMD or annualized rate of BMD change. We found little evidence of an association between periodontitis and skeletal BMD among older men.
Longitudinal Relationship between Root Caries and Serum Albumin
Authors: Yoshihara A. , Takano N. , Hirotomi T. , Ogawa H. , Hanada N. , Miyazaki H.
Published: January 2009

Serum albumin levels are a practical marker of general health status in the elderly and have been used to determine the severity of an underlying disease and the risk for death. This longitudinal study evaluated the relationship between serum albumin levels and root caries. A total of 266 persons with at least 1 tooth at baseline underwent a baseline examination and then annual investigations for 6 years. Multiple linear regression analysis was used to assess the relationship between changes in serum albumin levels and the number of root caries lesions over 6 years, after adjustment for confounding factors. Change in the number of root caries lesions was significantly associated with change in serum albumin concentrations. The standardized coefficient was −0.148 ( p = 0.024). We can confirm that serum albumin concentration correlates with root caries events. From these data, we conclude that persons with hypoalbuminemia are at high risk for root caries.
Strong Genetic Control of Emergence of Human Primary Incisors
Authors: Hughes T.E. , Bockmann M.R. , Seow K. , Gotjamanos T. , Gully N. , Richards L.C. , Townsend G.C.
Published: January 2009

Our understanding of tooth eruption in humans remains incomplete. We hypothesized that genetic factors contribute significantly to phenotypic variation in the emergence of primary incisors. We applied model-fitting to data from Australian twins to quantify contributions of genetic and environmental factors to variation in timing of the emergence of human primary incisors. There were no significant differences in incisor emergence times between zygosity groups or sexes. Emergence times of maxillary central incisors and mandibular lateral incisors were less variable than those of maxillary lateral incisors and mandibular central incisors. Maxillary lateral incisors displayed significant directional asymmetry, the left side emerging earlier than the right. Variation in timing of the emergence of the primary incisors was under strong genetic control, with a small but significant contribution from the external environment. Estimates of narrow-sense heritability ranged from 82 to 94% in males and 71 to 96% in females.
Numbers of Natural Teeth, Diet, and Nutritional Status in US Adults
Authors: Nowjack-Raymer R.E. , Sheiham A.
Published: January 2009

Evidence that dental status affects diet is equivocal. The hypothesis of this study was that diet was affected by dental status. The objective was to assess the relationship between numbers of teeth and diet and nutritional status in US adult civilians without prostheses. We examined 6985 NHANES (1988–1994) participants. Data included socio-economics, demographics, dental status, and diet and nutritional status. Dietary data were obtained from food frequency questionnaires and 24-hour dietary recall. Serum levels of beta carotene, folate, and vitamin C were measured with isocratic high-performance liquid chromatography. The population was classified by numbers of teeth. Covariance and Satterthwaite F-adjusted statistical comparisons were made between tooth groupings and the fully dentate population. Multilinear regression models adjusted for covariates. People with fewer than 28 teeth had significantly lower intakes of carrots, tossed salads, and dietary fiber than did fully dentate people, and lower serum levels for beta carotene, folate, and vitamin C. Dental status significantly affects diet and nutrition.
Predictors of Obstructive Sleep Apnea-Hypopnea Treatment Outcome
Authors: Hoekema A. , Doff M.H.J. , de Bont L.G.M. , van der Hoeven J.H. , Wijkstra P.J. , Pasma H.R. , Stegenga B.
Published: January 2009

Oral appliance therapy is an alternative to continuous positive airway pressure (CPAP) for treating the obstructive sleep apnea-hypopnea syndrome. However, the ability to pre-select suitable candidates for either treatment is limited. The aim of this study was to assess the value of relevant variables that can predict the outcome of oral appliance and CPAP therapy. Fifty-one patients treated with oral appliance therapy and 52 patients treated with CPAP were included. Relevant clinical, polysomnographic, and cephalometric variables were determined at baseline. The predictive value of variables for treatment outcome was evaluated in univariate and multivariate analyses. The outcome of oral appliance therapy was favorable, especially in less obese patients with milder sleep apnea and with certain craniofacial characteristics (mandibular retrognathism in particular). Neither univariate nor multivariate analyses yielded variables that reliably predicted the outcome of CPAP. We conclude that the variables found in this study are valuable for pre-selecting suitable candidates for oral-appliance therapy.
Hypersensitivity to Mechanical and Intra-articular Electrical Stimuli in Persons with Painful Temporomandibular Joints
Authors: Ayesh E.E. , Jensen T.S. , Svensson P.
Published: January 2009

This study tested whether persons with TMJ arthralgia have a modality-specific and site-specific hypersensitivity to somatosensory stimuli assessed by quantitative sensory tests (QST). Forty-three healthy persons and 20 with TMJ arthralgia participated. The QST consisted of: sensory and pain detection thresholds and summation threshold to intra-articular electrical stimulation, tactile and pin-prick sensitivity in the TMJ area, pressure-pain threshold and tolerance on the lateral side of the TMJ and on the finger. Persons with TMJ arthralgia had lower pain detection and summation thresholds (P < 0.001), higher ratings of tactile and pin-prick stimuli (P < 0.05), and markedly lower pressure thresholds on the TMJ and finger (P <0.001) than did healthy individuals. Correlation analysis revealed associations between several QST and clinical pain measures. This study provides new evidence of sensitization of the TMJs as well as central nociceptive pathways. QST may facilitate a mechanism-based classification of temporomandibular disorders.
Healing Cranial Defects with AdRunx2-transduced Marrow Stromal Cells
Authors: Zhao Z. , Wang Z. , Ge C. , Krebsbach P. , Franceschi R.T.
Published: January 2009

Marrow stromal cells (MSCs) include stem cells capable of forming all mesenchymal tissues, including bone. However, before MSCs can be successfully used in regeneration procedures, methods must be developed to stimulate their differentiation selectively to osteoblasts. Runx2, a bone-specific transcription factor, is known to stimulate osteoblast differentiation. In the present study, we tested the hypothesis that Runx2 gene therapy can be used to heal a critical-sized defect in mouse calvaria. Runx2-engineered MSCs displayed enhanced osteogenic potential and osteoblast-specific gene expression in vitro and in vivo. Runx2-expressing cells also dramatically enhanced the healing of critical-sized calvarial defects and increased both bone volume fraction and bone mineral density. These studies provide a novel route for enhancing osteogenesis that may have future therapeutic applications for craniofacial bone regeneration.
The Effects of Social Class and Dental Attendance on Oral Health
Authors: Donaldson A.N. , Everitt B. , Newton T. , Steele J. , Sherriff M. , Bower E.
Published: January 2009

The relationship between socio-economic status (SES) and oral health is well-established. We investigated whether the association between SES and the number of sound teeth in adults is explained by dental attendance patterns, in turn determined by the effect of SES on barriers to dental attendance. Data on 3817 participants from the 1998 Adult Dental Health Survey in the UK were analyzed. Using structural equation modeling, we found a model with 4 factors (aging, SES, attendance-profile, and barriers-to-dental-attendance) providing an adequate fit to the covariance matrix of the 9 covariates. The final model suggests that the association between SES and the number of sound teeth in adults in the UK is partially explained by the pathway [SES → barriers-to-dental-attendance → dental-attendance-profile → number-of-sound-teeth]. A direct relationship, SES → number-of-sound-teeth, is also significant.
Microtensile Specimen Attachment and Shape—Finite Element Analysis
Authors: Soares C.J. , Soares P.V. , Santos-Filho P.C.F. , Armstrong S.R.
Published: January 2009

Microtensile bond strength values are influenced by specimen shape and attachment method to the gripping device during testing. We hypothesized that stress distribution inside the testing specimen is affected by microtensile specimen shape and attachment method. Rectangular, hourglass-, and dumbbell-shaped specimens, all with a 1 mm2 cross-sectional testing region, were modeled as indirect ceramic restorations luted to dentin. Three specimen attachments were investigated: (1) posterior surface; (2) posterior, superior, and lateral surfaces; and (3) all surfaces. Qualitative and quantitative analyses were carried out according to von Mises’ criteria. Stress analysis showed a direct correlation between attachment modes and stress distribution, with shear stresses observed in models with less surface attachment. Increasing the number of faces for specimen attachment to the metallic gripping device resulted in a more homogeneous and regular distribution of stress, with tensile stress concentrated at the adhesive interface. Dumbbell-shaped specimens showed improved stress distribution compared with rectangular and hourglass-shaped specimens.
Modulation of CaV2.3 Calcium Channel Currents by Eugenol
Authors: Chung G. , Rhee J.N. , Jung S.J. , Kim J.S. , Oh S.B.
Published: January 2009

Eugenol, a natural congener of capsaicin, is a routine analgesic agent in dentistry. We have recently demonstrated the inhibition of CaV2.2 calcium channel and sodium channel currents to be molecular mechanisms underlying the analgesic effect of eugenol. We hypothesized that CaV2.3 channels are also modulated by eugenol and investigated its mode of action using the whole-cell patch-clamp technique in a heterologous expression system. Eugenol inhibited calcium currents in the E52 cell line, stably expressing the human CaV2.3 calcium channels, where TRPV1 is not endogenously expressed. The extent of current inhibition was not significantly different between naïve E52 cells and TRPV1-expressing E52 cells, suggesting no involvement of TRPV1. In contrast, TRPV1 activation is prerequisite for the inhibition of CaV2.3 calcium channels by capsaicin. The results indicate that eugenol has mechanisms distinct from those of capsaicin for modulating CaV2.3 channels. We suggest that inhibition of CaV2.3 channels by eugenol might contribute to its analgesic effect.
HUGO (FNDC3A): a New Gene Overexpressed in Human Odontoblasts
Authors: Carrouel F. , Couble M.-L. , Vanbelle C. , Staquet M.-J. , Magloire H. , Bleicher F.
Published: January 2009

Previously, we established a subtractive cDNA library enriched in odontoblast-specific genes and hypothesized that new, previously unidentified, markers would be present, associated with the odontoblast phenotype. In this paper, we report the first characterization of a new gene we have named HUGO, and its associated deduced protein sequence. This gene expression is under the control of two alternative promoters, resulting in the synthesis of two proteins, one of which, HUGO2, is included in the other, HUGO1. HUGO proteins are mainly composed of a proline-rich region at the N-terminus, 8 type III-fibronectin modules, and a transmembranous helix at the C-terminus. In odontoblasts, the proteins are located in Golgi vesicles. However, they display a broader expression pattern, since they are also expressed by nerve fibers in the dental pulp and other tissues ( e.g., trachea, brain, kidney), as demonstrated by immunohistochemistry and qPCR, respectively. Their location in odontoblasts suggests a role in collagen and glycosaminoglycan synthesis.
The Effectiveness of Sealants in Managing Caries Lesions
Authors: Griffin S.O. , Oong E. , Kohn W. , Vidakovic B. , Gooch B.F. ,   CDC Dental Sealant Systematic Review Work Group, Bader J. , Clarkson J. , Fontana M.R. , Meyer D.M. , Rozier R.G. , Weintraub J.A. , Zero D.T.
Published: January 2009

A barrier to providing sealants is concern about inadvertently sealing over caries. This meta-analysis examined the effectiveness of sealants in preventing caries progression. We searched electronic databases for comparative studies examining caries progression in sealed permanent teeth. We used a random-effects model to estimate percentage reduction in the probability of caries progression in sealed vs. unsealed carious teeth. Six studies, including 4 randomized-controlled trials (RCT) judged to be of fair quality, were included in the analysis (384 persons, 840 teeth, and 1090 surfaces). The median annual percentage of non-cavitated lesions progressing was 2.6% for sealed and 12.6% for unsealed carious teeth. The summary prevented fraction for RCT was 71.3% (95%CI: 52.8%–82.5, no heterogeneity) up to 5 years after placement. Despite variation among studies in design and conduct, sensitivity analysis found the effect to be consistent in size and direction. Sealing non-cavitated caries in permanent teeth is effective in reducing caries progression.
Estrogen Modulates Cytokine Expression in Human Periodontal Ligament Cells
Authors: Shu L. , Guan S.-M. , Fu S.-M. , Guo T. , Cao M. , Ding Y.
Published: January 2009

Although systemic bone loss accompanying estrogen deficiency has been proposed as a risk factor for periodontal disease in post-menopausal women, the mechanisms involved remain unclear. The objective of this study was to elucidate the potential bone-sparing effect of estrogen (17β-estradiol, E2) via modulation of inflammatory cytokine production in human periodontal ligament (hPDL) cells. E. coli lipopolysaccharide (LPS) increased the production of pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and receptor activator of NF- B ligand (RANKL) by hPDL cells at both mRNA and protein levels. E2 treatment reversed the stimulatory effects of LPS on pro-inflammatory cytokine expression by hPDL cells. Moreover, E2 up-regulated osteoprotegerin (OPG) expression and therefore attenuated the reduction of the OPG vs. RANKL ratio. Our results suggested that estrogen may play a significant role in modulating periodontal tissue responses to LPS, and may exert its bone-sparing effects on periodontal tissues via altering the expression of inflammatory cytokines in hPDL cells.
Insulin-like Growth Factor I Regulates Apoptosis in Condylar Cartilage
Authors: Yokota T. , Shimokawa H. , Shibata S. , Itoh K. , Baba Y. , Ohya K. , Ohyama K. , Suzuki S.
Published: January 2009

Endogenous insulin-like growth factor-I (IGF-I) is known to affect the growth and development of condylar cartilage. However, the critical effect of IGF-I on cell survival is still unknown. We hypothesized that endogenous IGF-I could regulate the survival of cells of the mandibular condylar cartilage. Mandibular condyles dissected from 12-day-old rats were cultured for 1, 3, and 5 days in medium containing antisense oligodeoxynucleotide (AS-ODN) for IGF-I. Real-time RT-PCR analysis showed that the levels of IGF-I and IGF binding protein (IGFBP)3 mRNAs in the AS-ODN group were significantly decreased. After 3 days’ culture, the number of necrotic cells was observed in the undifferentiated mesenchymal cell layer. These cells were TUNEL-positive and confirmed to be apoptotic by electron microscopic observation. Immunoblotting revealed that expression of cleaved caspase3 was increased with AS-ODN. These results may suggest that the cells in the undifferentiated mesenchymal cell layer of the mandibular condyle require IGF-I for survival.
Beyond Good and Evil in the Oral Cavity: Insights into Host-Microbe Relationships Derived from Transcriptional Profiling of Gingival Cells
Authors: Handfield M. , Baker H.V. , Lamont R.J.
Published: January 2009

In many instances, the encounter between host and microbial cells, through a long-standing evolutionary association, can be a balanced interaction whereby both cell types co-exist and inflict a minimal degree of harm on each other. In the oral cavity, despite the presence of large numbers of diverse organisms, health is the most frequent status. Disease will ensue only when the host-microbe balance is disrupted on a cellular and molecular level. With the advent of microarrays, it is now possible to monitor the responses of host cells to bacterial challenge on a global scale. However, microarray data are known to be inherently noisy, which is caused in part by their great sensitivity. Hence, we will address several important general considerations required to maximize the significance of microarray analysis in depicting relevant host-microbe interactions faithfully. Several advantages and limitations of microarray analysis that may have a direct impact on the significance of array data are highlighted and discussed. Further, this review revisits and contextualizes recent transcriptional profiles that were originally generated for the specific study of intricate cellular interactions between gingival cells and 4 important plaque micro-organisms. To our knowledge, this is the first report that systematically investigates the cellular responses of a cell line to challenge by 4 different micro-organisms. Of particular relevance to the oral cavity, the model bacteria span the entire spectrum of documented pathogenic potential, from commensal to opportunistic to overtly pathogenic. These studies provide a molecular basis for the complex and dynamic interaction between the oral microflora and its host, which may lead, ultimately, to the development of novel, rational, and practical therapeutic, prophylactic, and diagnostic applications.
Different Roles of Odontoblasts and Fibroblasts in Immunity
Authors: Staquet M.-J. , Durand S.H. , Colomb E. , Roméas A. , Vincent C. , Bleicher F. , Lebecque S. , Farges J.-C.
Published: January 2009

Odontoblasts and fibroblasts are suspected to influence the innate immune response triggered in the dental pulp by micro-organisms that progressively invade the human tooth during the caries process. To determine whether they differ in their responses to oral pathogens, we performed a systematic comparative analysis of odontoblast-like cell and pulp fibroblast responses to TLR2-, TLR3-, and TLR4-specific agonists (lipoteichoic acid [LTA], double-stranded RNA, and lipopolysaccharide [LPS], respectively). Cells responded to these agonists by differential up-regulation of chemokine gene expression. CXCL2 and CXCL10 were thus increased by LTA only in odontoblast-like cells, while LPS increased CCL7, CCL26, and CXCL11 only in fibroblasts. Supernatants of stimulated cultures increased migration of immature dendritic cells compared with controls, odontoblast-like cells being more potent attractants than fibroblasts. Analysis of these data suggests that odontoblasts and pulp fibroblasts differ in their innate immune responses to oral micro-organisms that invade the pulp tissue.
Trigeminal Nociceptors Express Prostaglandin Receptors
Authors: Patwardhan A.M. , Vela J. , Farugia J. , Vela K. , Hargreaves K.M.
Published: January 2009

Orofacial inflammation is associated with prostaglandin release and the sensitization of nociceptive receptors such as the transient receptor potential subtype V1(TRPV1). We hypothesized that certain PGE2receptor subtypes (EP1–EP4) are co-expressed with TRPV1in trigeminal nociceptors and sensitize responses to a TRPV1agonist, capsaicin. Accordingly, combined in situ hybridization was performed with immunohistochemistry on rat trigeminal ganglia. We next evaluated the effects of specific EP2 and EP3 agonists (butaprost and sulprostone) in cultured trigeminal ganglia neurons. The results showed that EP2 and EP3 are expressed in trigeminal neurons (58% and 53% of total neurons, respectively) and are co-expressed in TRPV1-positive neurons (64% and 67 % of TRPV1-positive neurons, respectively). Moreover, most of the cells expressing EP2 or EP3 mRNA were of small to medium diameter (< 30 μm). The application of butaprost and sulprostone triggered neuropeptide exocytosis, and butaprost sensitized capsaicin responses. Analysis of these data, collectively, supports the hypothesis that prostaglandins regulate trigeminal TRPV1nociceptors via activation of the EP2 and EP3 receptors.
Wnt/β-catenin Signaling Regulates Cranial Base Development and Growth
Authors: Nagayama M. , Iwamoto M. , Hargett A. , Kamiya N. , Tamamura Y. , Young B. , Morrison T. , Takeuchi H. , Pacifici M. , Enomoto-Iwamoto M. , Koyama E.
Published: January 2009

Wnt proteins and β-catenin signaling regulate major processes during embryonic development, and we hypothesized that they regulate cranial base synchondrosis development and growth. To address this issue, we analyzed cartilage-specific β -catenin-deficient mice. Mutant synchondroses lacked typical growth plate zones, and endochondral ossification was delayed. In reciprocal transgenic experiments, cartilage overexpression of a constitutive active Lef1, a transcriptional mediator of Wnt/β-catenin signaling, caused precocious chondrocyte hypertrophy and intermingling of immature and mature chondrocytes. The developmental changes seen in β -catenin-deficient synchondroses were accompanied by marked reductions in Ihh and PTHrP as well as sFRP-1, an endogenous Wnt signaling antagonist and a potential Ihh signaling target. Thus, Wnt/β-catenin signaling is essential for cranial base development and synchondrosis growth plate function. This pathway promotes chondrocyte maturation and ossification events, and may exert this important role by dampening the effects of Ihh-PTHrP together with sFRP-1.
Inhibition of Human Dental Pulp Stem Cell Differentiation by Notch Signaling
Authors: Zhang C. , Chang J. , Sonoyama W. , Shi S. , Wang C.-Y.
Published: January 2009

Notch signaling plays a critical role in development and cell fate specification. Notch receptors and ligands have been found to be expressed in dental epithelium or mesenchyme in the developing tooth, suggesting that Notch signaling may regulate odontogenesis. Post-natal human dental pulp stem cells (DPSCs) isolated from the dental pulp have characteristics of mesenchymal stem cells and can differentiate into odontoblasts. In this study, we examined whether Notch signaling regulated the odontoblastic differentiation of DPSCs. We found that over-expression of the Notch ligand, Jagged-1, activated the Notch signaling pathway in DPSCs. Jagged-1 inhibited the odontoblastic differentiation of DPSCs in vitro. Jagged-1-expressing DPSCs could not form mineralized tissues in vivo. Moreover, over-expression of the constitutively activated Notch1 intracellular domain (Notch-ICD) also inhibited odontoblastic differentiation of DPSCs. Taken together, our results demonstrate that Notch signaling can inhibit the odontoblastic differentiation of DPSCs.
Effects of IL-17 on Human Gingival Fibroblasts
Authors: Mahanonda R. , Jitprasertwong P. , Sa-Ard-Iam N. , Rerkyen P. , Charatkulangkun O. , Jansisyanont P. , Nisapakultorn K. , Yongvanichit K. , Pichyangkul S.
Published: January 2009

Interleukin (IL)-17 is present in inflammatory periodontal lesions, thus suggesting a role in mediating inflammation. We tested the hypothesis that IL-17, especially when combined with interferon (IFN)-γ, may modulate the responses of human gingival fibroblasts (HGFs). IL-17 induced IL-8 and minimal intercellular adhesion molecule (ICAM)-1 expression. It had no effect on expression of HLA-DR, CD40, or the immune-suppressive enzyme indoleamine 2,3-dioxygenase (IDO). The effects of IL-17 on HGFs were compared with those of IFN-γ. Unlike IL-17, IFN-γ augmented the expression of HLA-DR, ICAM-1, and IDO, but not IL-8. Thus, IL-17 and IFN-γ induce different HGF responses when administered separately. Interestingly, when IL-17 and IFN-γ were combined, marked enhancement of ICAM-1, IL-8, and IDO expression by HGFs was observed. These findings suggest that IL-17, especially when combined with IFN-γ, could play an important role in immune modulation through stimulation of HGFs in periodontal disease.
Osteoporosis and Oral Infection: Independent Risk Factors for Oral Bone Loss
Authors: Brennan-Calanan R.M. , Genco R.J. , Wilding G.E. , Hovey K.M. , Trevisan M. , Wactawski-Wende J.
Published: January 2009

Studies have suggested that oral bone loss is independently influenced by local and systemic factors, including osteoporosis. This cross-sectional study of 1256 post-menopausal women, recruited from the Buffalo center of the Women’s Health Initiative Observational Study, evaluated the influence of oral infection and age on the associations between osteoporosis and oral bone loss. Systemic bone density was measured by dual-energy x-ray absorptiometry. Alveolar crestal height was measured from standardized dental radiographs. Oral infection was assessed from subgingival plaque samples. Total forearm density [β (SE) = −0.931 (0.447), p = 0.038] and presence of Tannerella forsythensis [β (SE) = 0.125 (0.051), p = 0.015] were independently associated with mean alveolar height among women aged < 70 years after confounder adjustment. Women aged 70+ years had worse oral bone loss, in general, but neither bone density nor oral infection was significantly associated with mean alveolar height in this age group. Systemic bone density and oral infection independently influenced oral bone loss in post-menopausal women aged < 70 years.
An Anti-c-Fms Antibody Inhibits Orthodontic Tooth Movement
Authors: Kitaura H. , Yoshimatsu M. , Fujimura Y. , Eguchi T. , Kohara H. , Yamaguchi A. , Yoshida N.
Published: January 2009

Orthodontic force induces osteoclastogenesis in vivo. It has recently been reported that administration of an antibody against the macrophage-colony-stimulating factor (M-CSF) receptor c-Fms blocks osteoclastogenesis and bone erosion induced by tumor necrosis factor-α (TNF-α) administration. This study aimed to examine the effect of an anti-c-Fms antibody on mechanical loading-induced osteoclastogenesis and osteolysis in an orthodontic tooth movement model in mice. Using TNF receptor 1- and 2-deficient mice, we showed that orthodontic tooth movement was mediated by TNF-α. We injected anti-c-Fms antibody daily into a local site, for 12 days, during mechanical loading. The anti-c-Fms antibody significantly inhibited orthodontic tooth movement, markedly reduced the number of osteoclasts in vivo, and inhibited TNF-α-induced osteoclastogenesis in vitro. These findings suggest that M-CSF plays an important role in mechanical loading-induced osteoclastogenesis and bone resorption during orthodontic tooth movement mediated by TNF-α.
Degenerative Disorders of the Temporomandibular Joint: Etiology, Diagnosis, and Treatment
Authors: Tanaka E. , Detamore M.S. , Mercuri L.G.
Published: January 2009

Temporomandibular joint (TMJ) disorders have complex and sometimes controversial etiologies. Also, under similar circumstances, one person’s TMJ may appear to deteriorate, while another’s does not. However, once degenerative changes start in the TMJ, this pathology can be crippling, leading to a variety of morphological and functional deformities. Primarily, TMJ disorders have a non-inflammatory origin. The pathological process is characterized by deterioration and abrasion of articular cartilage and local thickening. These changes are accompanied by the superimposition of secondary inflammatory changes. Therefore, appreciating the pathophysiology of the TMJ degenerative disorders is important to an understanding of the etiology, diagnosis, and treatment of internal derangement and osteoarthrosis of the TMJ. The degenerative changes in the TMJ are believed to result from dysfunctional remodeling, due to a decreased host-adaptive capacity of the articulating surfaces and/or functional overloading of the joint that exceeds the normal adaptive capacity. This paper reviews etiologies that involve biomechanical and biochemical factors associated with functional overloading of the joint and the clinical, radiographic, and biochemical findings important in the diagnosis of TMJ-osteoarthrosis. In addition, non-invasive and invasive modalities utilized in TMJ-osteoarthrosis management, and the possibility of tissue engineering, are discussed.
Optimal Drinking Water Composition for Caries Control in Populations
Authors: Bruvo M. , Ekstrand K. , Arvin E. , Spliid H. , Moe D. , Kirkeby S. , Bardow A.
Published: January 2009

Apart from the well-documented effect of fluoride in drinking water on dental caries, little is known about other chemical effects. Since other ions in drinking water may also theoretically influence caries, as well as binding of fluoride in the oral environment, we hypothesized that the effect of drinking water on caries may not be limited to fluoride only. Among 22 standard chemical variables, including 15 ions and trace elements as well as gases, organic compounds, and physical measures, iterative search and testing identified that calcium and fluoride together explained 45% of the variations in the numbers of decayed, filled, and missing tooth surfaces (DMF-S) among 52,057 15-year-old schoolchildren in 249 Danish municipalities. Both ions had reducing effects on DMF-S independently of each other, and could be used in combination for the design of optimal drinking water for caries control in populations.
Treatment of Health Complaints Attributed to Amalgam
Authors: Melchart D. , Vogt S. , Köhler W. , Streng A. , Weidenhammer W. , Kremers L. , Hickel R. , Felgenhauer N. , Zilker T. , Wühr E. , Halbach S.
Published: January 2009

The aim of the present study was to compare the reduction of subjective complaints by 3 treatment strategies in 90 “amalgam patients” whose complaints could not be explained by a medical or psychological disorder. The individuals were randomly assigned either to removal of dental amalgam only (removal group), or removal in combination with a “biological detoxification” therapy with high doses of vitamins and trace elements (removal-plus group), or participation in a health promotion program without removal of dental amalgam (no-removal group). Between baseline and month 12, the sum score of main complaints decreased by 3.5 (SD = 2.2) points on average in the removal group as well as in the removal-plus group, and by 2.5 (SD = 2.4) points in the no-removal group (p = 0.152). Both removal groups showed a significant decrease in steady-state levels of inorganic mercury compared with the no-removal group. Thus, all 3 interventions were associated with clinically relevant improvements.
Nano-mechanical Properties of Fluoride-treated Enamel Surfaces
Authors: Jeng Y.-R. , Lin T.-T. , Wong T.-Y. , Chang H.-J. , Shieh D.-B.
Published: January 2009

Calcium-fluoride-like deposits play a key role in caries prevention by topical fluoride. Previous microhardness analyses have introduced errors due to a substrate effect, and thereby could not substantiate the early loss of these deposits. To address this question, we applied Atomic Force Microscopy (AFM) and a nano-indentation technique in this study to characterize the nano-mechanical properties and topographic structure of enamel surfaces following topical fluoride treatment. The deposits were found to have a low nano-hardness and a high nano-wear depth, which explains the early loss of calcium-fluoride-like deposits. However, a 22% increase in the fluoride concentration could still be detected on the treated enamel surface following the removal of the surface deposits, justifying the long-term effectiveness of topical fluoride treatment.
Role of NBCe1 and AE2 in Secretory Ameloblasts
Authors: Paine M.L. , Snead M.L. , Wang H.J. , Abuladze N. , Pushkin A. , Liu W. , Kao L.Y. , Wall S.M. , Kim Y.-H. , Kurtz I.
Published: January 2009

The H+/base transport processes that control the pH of the microenvironment adjacent to ameloblasts are not currently well-understood. Mice null for the AE2 anion exchanger have abnormal enamel. In addition, persons with mutations in the electrogenic sodium bicarbonate co-transporter NBCe1 and mice lacking NBCe1 have enamel abnormalities. These observations suggest that AE2 and NBCe1 play important roles in amelogenesis. In the present study, we aimed to understand the roles of AE2 and NBCe1 in ameloblasts. Analysis of the data showed that NBCe1 is expressed at the basolateral membrane of secretory ameloblasts, whereas AE2 is expressed at the apical membrane. Transcripts for AE2a and NBCe1-B were detected in RNA isolated from cultured ameloblast-like LS8 cells. Our data are the first evidence that AE2 and NBCe1 are expressed in ameloblasts in vivo in a polarized fashion, thereby providing a mechanism for ameloblast transcellular bicarbonate secretion in the process of enamel formation and maturation.
Serum Levels of Resistin and Adiponectin in Women with Periodontitis: the Hisayama Study
Authors: Saito T. , Yamaguchi N. , Shimazaki Y. , Hayashida H. , Yonemoto K. , Doi Y. , Kiyohara Y. , Iida M. , Yamashita Y.
Published: January 2009

Resistin and adiponectin, recently discovered adipokines, are secreted from adipose tissue, with postulated opposing functions in insulin resistance and inflammation. More recently, an abundance of resistin was detected in macrophages, which suggests its important role in inflammation. The aim of this study was to clarify circulating serum adipokine levels in women with periodontitis. Thirty-four women with moderate to severe periodontitis and 42 control individuals with healthy gingiva (50- to 59-year-old women) were selected. The serum level of adipokines was analyzed between groups, along with the obesity index, smoking status, and age. Having periodontitis was significantly associated with an increased level of resistin, both in bivariate (OR, 3.0; 95% CI, 1.2–7.6) and multivariate (adjusted OR, 3.1; 95% CI, 1.1–8.6) analyses. The association of periodontitis with a decreased level of adiponectin did not reach statistical significance. It was concluded that an increased serum resistin level in middle-aged Japanese women with periodontitis may affect systemic health.
N-acetyl Cysteine (NAC)-assisted Detoxification of PMMA Resin
Authors: Yamada M. , Kojima N. , Paranjpe A. , Att W. , Aita H. , Jewett A. , Ogawa T.
Published: January 2009

Despite its proven cytotoxicity, poly-methyl methacrylate (PMMA) resin is one of the most frequently and extensively used materials in dental practice. This study hypothesized that an anti-oxidant amino acid, N-acetyl cysteine (NAC), has the potential to detoxify this material. Ten percent of the rat dental pulp cells were viable when cultured on the PMMA resin for 24 hours, while over 70% of the cells were viable on the NAC-added resin. Nearly all suppressed alkaline phosphatase activity, matrix mineralizing capability, and odontoblastic gene expression, such as dentin sialoprotein, on the untreated control resin was recovered by NAC in a concentration-dependent manner. A Ca/P ratio of 1.65 was found in the extracellular matrix of cultures on NAC-added resin, while that in the untreated resin culture was 0.70. The addition of NAC to PMMA resin significantly ameliorated its cytotoxicity to the dental pulp cells and restored their odontoblast-like cell phenotype to a biologically significant degree.
Biomechanical Properties of the Condyle Created by Osteodistraction
Authors: Zhu S. , Hu J. , Zou S. , Kakudo K. , Tsunokuma M.
Published: January 2009

A new condyle can be reconstructed by osteodistraction, but the biomechanical properties of the neocondyle remain unknown. This study examined the hypothesis that the biomechanical properties of neocondylar cancellous bone could reach control levels 24 weeks after its creation by osteodistraction. The right mandibular condyles were removed and reconstructed by osteo-distraction in 16 adult goats. Their contralateral condyles served as controls. Microstructural and mechanical properties were examined by microcomputed tomography and mechanical testing. At 24 weeks after distraction, the neocondyle grew larger in size, but the shape and histological features were similar to those of the controls. The cancellous bone of the neocondyle even appeared to be more dense and stiffer in comparison with the control condyle. The results of this study suggest that the neocondyle created by osteodistraction develops nearly normal biomechanical properties for functional loading by 24 weeks after creation.
Dental Amalgam and Psychosocial Status: The New England Children’s Amalgam Trial
Authors: Bellinger D.C. , Trachtenberg F. , Zhang A. , Tavares M. , Daniel D. , McKinlay S.
Published: January 2009

High-dose exposures to elemental mercury vapor cause emotional dysfunction, but it is uncertain whether the levels of exposure that result from having dental amalgam restorations do so. As part of the New England Children’s Amalgam Trial, a randomized trial involving 6- to 10-year-old children, we evaluated the hypothesis that restoration of caries using dental amalgam resulted in worse psychosocial outcomes than restoration using mercury-free composite resin. The primary outcome was the parent-completed Child Behavior Checklist. The secondary outcome was children’s self-reports using the Behavior Assessment System for Children. Children’s psychosocial status was evaluated in relation to three indices of mercury exposure: treatment assignment, surface-years of amalgam, and urinary mercury excretion. All significant associations favored the amalgam group. No evidence was found that exposure to mercury from dental amalgams was associated with adverse psychosocial outcomes over the five-year period following initial placement of amalgams.
Favoring Trauma as an Etiological Factor in Denture Stomatitis
Authors: Emami E. , de Grandmont P. , Rompré P.H. , Barbeau J. , Pan S. , Feine J.S.
Published: January 2009

The etiology of denture stomatitis remains controversial. Trauma due to unstable dentures has been suggested as an etiological factor. Therefore, we tested the hypothesis that the prevalence of denture stomatitis is reduced when mandibular dentures are stabilized by implants. Data were collected at a one-year follow-up from 173 edentulous elders who had randomly received mandibular implant overdentures or conventional dentures. The diagnosis of denture stomatitis was determined according to the Newton classification. Elders wearing conventional dentures were almost 5 times more likely to have denture stomatitis than those wearing mandibular two-implant overdentures ( P < 0.0001, Fisher’s exact test). Adjusted odds ratios showed that only the type of the prosthesis (AOR = 4.54, 95% CI 2.20 to 9.40) and nocturnal wear (AOR = 3.03, 95% CI 1.24 to 7.40) predict the frequency of denture stomatitis. Thus, implant overdentures may reduce oral mucosal trauma and control denture stomatitis.
Salivary Lysozyme and Prevalent Hypertension
Authors: Qvarnstrom M. , Janket S. , Jones J.A. , Nuutinen P. , Baird A.E. , Nunn M.E. , Van Dyke T.E. , Meurman J.H.
Published: January 2009

Although the etiology of essential hypertension is not clearly understood, endothelial dysfunction from chronic infection and/or impaired glucose metabolism may be involved. We hypothesized that salivary lysozyme, a marker for oral infection and hyperglycemia, might display a significant relationship with hypertension, an early stage of cardiovascular disease. Logistic regression analyses of the Kuopio Oral Health and Heart Study demonstrated that persons with higher lysozyme levels were more likely to have hypertension, after adjustment for age, gender, smoking, BMI, diabetes, the ratio of total cholesterol to HDL cholesterol, and C-reactive protein. The exposure to increasing quartiles of lysozyme was associated with adjusted Odds Ratios for the outcome, hypertension, 1.00 (referent), 1.25, 1.42, and 2.56 (linear trend p < 0.003). When we restricted the sample to the individuals without heart disease (N = 250), we observed a non-significant trend for increasing odds. Our hypothesis—“high salivary lysozyme levels are associated with the odds of hypertension”—was confirmed.
Oral Symptoms Predict Mortality: a Prospective Study in Japan
Authors: Ide R. , Mizoue T. , Fujino Y. , Kubo T. , Pham T.-M. , Shirane K. , Ogimoto I. , Tokui N. , Yoshimura T.
Published: January 2009

Several studies have reported positive associations between oral infections and systemic diseases. The purpose of the present study was to evaluate the effects of oral symptoms on mortality from cardiovascular disease (CVD) and pneumonia. Using data from a cohort study in Japan, we analyzed 4,139 individuals aged 40–79 years. The baseline questionnaire included the following items related to oral symptoms: ‘sensitive teeth’, ‘difficulty in chewing tough food substances’, ‘bleeding gums’, and ‘mouth feels sticky’. We used the Cox proportional hazard model to estimate hazard ratios (HRs) and 95% confidence intervals (95%CIs) for mortality, after adjustments for lifestyle, socio-economic factors, and history of diseases. Persons complaining that their ‘mouth feels sticky’ had a two-fold higher risk of pneumonia (HR = 2.1; 95%CI, 1.2–3.6), while those complaining of ‘sensitive teeth’ had a lower risk of CVD (HR = 0.4; 95%CI, 0.2–0.9). Some oral symptoms may be predictors of mortality from pneumonia and CVD.
Color Adjustment Potential of Resin Composites
Authors: Paravina R.D. , Westland S. , Johnston W.M. , Powers J.M.
Published: January 2009

The study objective was to explore a new method for quantifying the color adjustment potential originating from physical translucency on a set of 7 resin composites, and then for testing the hypothesis that color adjustment potential is dependent on the composites and shades studied. Two-composite specimens (an outer base shade with an inner hole filled with inner test shades) and single-composite specimens of all shades were made. A 1-mm circular area, with its center in the middle of the specimen (P0mm), was measured by means of spectroradiometry. A newly developed equation for quantification of the color adjustment potential was tested. Color adjustment potential at P0mm ranged from −0.19 (negative color adjustment/contrast) to 0.61. Within the limitations of this study, a newly developed concept and equation have proved the existence of the physical component of color adjustment of translucent dental materials. Color adjustment potential was dependent on composite and shade.
Reduced Amelogenin-MMP20 Interactions in Amelogenesis Imperfecta
Authors: Tanimoto K. , Le T. , Zhu L. , Witkowska H.E. , Robinson S. , Hall S. , Hwang P. , DenBesten P. , Li W.
Published: January 2009

Amelogenin with a proline 41 to threonine mutation (P41T) is hydrolyzed at a lower rate by matrix metalloproteinase 20 (MMP20), resulting in an inherited tooth enamel defect, amelogenesis imperfecta (AI). The aim of this study was to elucidate the effect of P41T on the interactions between amelogenin and MMP20, which may contribute to the formation of this type of AI. The interactions of a recombinant wild-type human amelogenin and its P41T mutant with recombinant human MMP20 were compared by substrate competition assay, pull-down assay, and surface plasmon resonance (SPR). The results showed that the binding of the P41T mutant amelogenin for MMP20 was significantly lower than that of wild-type amelogenin. Our study supports a model in which the P41T mutation reduces the interactions between amelogenin and MMP20, leading to decreased degradation of amelogenin by MMP20, and resulting in AI.