bluuebunny/crossref_metadata_2025 huggingface dataset:
RGD-CAP (βig-h3) Exerts a Negative Regulatory Function on Mineralization in the Human Periodontal Ligament
Authors: Ohno S. , Doi T. , Fujimoto K. , Ijuin C. , Tanaka N. , Tanimoto K. , Honda K. , Nakahara M. , Kato Y. , Tanne K.
Published: January 2009

In our previous studies, RGD-CAP/βig-h3 was isolated from a fiber-rich fraction of cartilage and was found to have a negative function on mineralization of hypertrophic chondrocytes. However, the expression and biological function of RGD-CAP in the periodontal ligament (PDL) are not known. We hypothesized that RGD-CAP could be expressed in the PDL and regulate its mineralization. To test this, we investigated the expression of RGD-CAP in human PDL and the effects of RGD-CAP on mineralization of cultured PDL cells. RGD-CAP was detected in the human PDL as multimeric proteins greater than 200 kDa. The RGD-CAP mRNA level decreased in cultured PDL cells exposed to 10−8 M dexamethasone or 10−8 M 1α,25-dihydroxyvitamin D3 when these steroids increased alkaline phosphatase (ALP) activity. Furthermore, exogenous RGD-CAP suppressed the ALP activity and bone nodule formation of cultured PDL cells. These findings suggest that RGD-CAP in the PDL modulates the mineralization which affects adjacent alveolar bone metabolism.
MMP-9 Activation by Tumor Trypsin-2 Enhances in vivo Invasion of Human Tongue Carcinoma Cells
Authors: Nyberg P. , Moilanen M. , Paju A. , Sarin A. , Stenman U.-H. , Sorsa T. , Salo T.
Published: January 2009

Various human cancer cells express tumor-associated trypsinogen-2 (TAT-2), which can efficiently activate matrix metalloproteinases (MMPs) in vitro. MMP-2 and MMP-9 are particularly associated with the invasive malignant potential of several tumors. To investigate the role of TAT-2 in tumor invasion, we overexpressed TAT-2 in two malignant human squamous cell carcinoma cell lines of tongue and in non-malignant human papilloma virus transformed gingival keratinocytes. The TAT-2 overexpression significantly increased the levels of active MMP-9 in the most malignant cell line. TAT-2-transfected cells intravasated (invaded blood vessels) up to 60% more efficiently than did the control cells in an in vivo chick embryo chorioallantoic membrane invasion model. This increased intravasation was almost completely abolished by a specific tumor-associated trypsin inhibitor (TATI). These results indicate that TAT-2 has a role in the invasive growth of tumors, either alone or in cascade with gelatinases, especially by generating active MMP-9.
Anode Glow Discharge Plasma Treatment Enhances Calcium Phosphate Adsorption onto Titanium Plates
Authors: Shibata Y. , Miyazaki T.
Published: January 2009

Glow discharge plasma (GDP) supplied to a cathode (GDP-) has been applied for cleaning, surface activating, and sterilizing biomaterials, because the kinetic energy in the case of the GDP- is larger than that supplied to the anode (GDP+). However, no comparison between GDP+ and GDP- has been reported. In this study, a titanium surface pre-treated with GDP+ and GDP- was characterized by x-ray photoelectron spectroscopy (XPS). In addition, the wettability of the titanium surface was measured with and without GDP. Furthermore, XPS characterized the adsorption of inorganic ions on titanium surfaces with and without GDP and immersed in an electrolyte solution. The findings suggested that GDP+ enhances calcium phosphate nucleation, due to the accumulation of electrons. In addition, calcium phosphate was not nucleated on the specimen with GDP-. We conclude that GDP+ is more suitable for biomineralization on titanium.
The Path from Studying Masticatory Function to Managing TMD and Pain: A Personal Journey
Authors: De Laat Antoon
Published: January 2009

The author describes his experiences in the evolution of the fields of oral physiology, temporomandibular disorders, and related pain in the masticatory system.
Role of K+ATPChannels, Endothelin A Receptors, and Effect of Angiotensin II on Blood Flow in Oral Tissues
Authors: Berggreen E. , Heyeraas K.J.
Published: January 2009

K+ATPchannels are involved in CGRP-mediated vasodilation and in the vasoconstriction induced by endothelin or angiotensin II. In this study, we examined the effects of a K+ATPchannel antagonist and an ET(A) receptor antagonist on resting blood flow in the pulp and gingiva, and observed their role in the vasodilation induced by tooth stimulation. We also investigated whether receptors for angiotensin II exist in the pulp and gingiva. Blood flow was measured with laser-Doppler flowmetry. Under control conditions, the K+ATPchannel antagonist and angiotensin II caused a significant drop in blood flow in both target tissues. Blocking of ET(A) receptor did not change basal blood flow. The vasodilation observed after tooth stimulation remained unchanged following blockade of K+ATPchannels and ET(A) receptors. Analysis of the data shows that open K+ATPchannels exist during resting conditions in the pulp and gingiva, but that CGRP seems to induce vasodilation mainly via mechanisms other than K+ATPchannels. ET(A) and AT1receptors are found in the pulp and gingiva, but ET(A) receptors are not involved in modulation of a basal vascular tone in these tissues or in the vasodilation observed after tooth stimulation.

Open K+ATPchannels exist during resting conditions in both the dental pulp and gingiva, but calcitonin gene-related peptide seems to induce vasodilation via mechanisms other than the K+ATPchannels.
Age Effect on Orthodontic Tooth Movement in Rats
Authors: Ren Y. , Maltha J.C. , Van ’t Hof M.A. , Kuijpers-Jagtman A.M.
Published: January 2009

Orthodontic procedures seem to be more time-consuming in adults than in juveniles. This might be related to delay in the initial tissue response or to a slower turnover of the bone and periodontal ligament in adults. To study this problem, we studied orthodontic tooth movement in two groups of 30 rats, aged 6 wks and 9–12 mos, respectively. At one side of the maxilla, 3 molars together were moved mesially with a standardized orthodontic appliance delivering a force of 10 cN. The other side served as a control. The results showed a faster initial tooth movement in juvenile than in adult animals. However, once tooth movement had reached the linear phase, the rate of tooth movement was the same in both groups. The results indicate that, besides a delay in the onset of tooth movement in adult animals, tooth movement could be equally efficient in adults once it had started.
Interaction between 2-Ethoxybenzoic Acid (EBA) and Eugenol, and Related Changes in Cytotoxicity
Authors: Fujisawa S. , Atsumi T. , Satoh K. , Sakagami H.
Published: January 2009

The liquid of 2-ethoxybenzoic acid cements is composed of 2-ethoxybenzoic acid and eugenol (4-allyl-2-methoxyphenol). Recently, eugenol was reported to produce radicals at a higher pH, which consequently directly damages cells. We examined here whether eugenol radicals are generated from the mixture of eugenol/calcium hydroxide, and also whether 2-ethoxybenzoic acid or acetylsalicylic acid scavenges radicals, using electron spin resonance spectroscopy. Radicals were generated from the mixture of eugenol/calcium hydroxide in 50% dimethylsulfoxide solution. The radical intensity of eugenol in 50% dimethylsulfoxide with 0.1 M sodium bicarbonate buffer (pH 9.5) was dose-dependently reduced by 2-ethoxybenzoic acid, whereas it was enhanced by acetylsalicylic acid. Next, we investigated the cytotoxic effect of eugenol on 2-ethoxybenzoic acid, acetylsalicylic acid, or calcium hydroxide on human pulp fibroblasts or a human submandibular gland cancer cell line. The cytotoxicity of EBA was decreased, whereas that of acetylsalicylic acid was increased by eugenol. In contrast, that of calcium hydroxide was not affected by eugenol. Human pulp fibroblast but not human submandibular gland cells showed a high resistance against calcium hydroxide. The generation of eugenol radicals in the liquid of 2-ethoxybenzoic acid cements caused by oxidation may be suppressed by 2-ethoxybenzoic acid.
Quality of Marginal Adaptation Evaluation of Posterior Composites in Clinical Trials
Authors: Hayashi M. , Wilson N.H.F. , Watts D.C.
Published: January 2009

The evaluation of margins of restorations in clinical trials relies on the subjective assessment of evaluators, with no instrument having been developed, let alone validated, to assist in the process. The purpose of the present study was to assess the quality of evaluations of marginal adaptation by analyzing the distribution of marginal steps rated according to clinical criteria. Replicas of 435 restorations, the marginal qualities of which had been evaluated according to modified USPHS criteria, were randomly selected from the Occlusin TM multi-center clinical trial program. The marginal step height in the most deteriorated area of each restoration was measured by means of a digital step-height instrument. An overlap between the steps in the restorations with A (Alfa; replacement unnecessary) and B (Bravo; replacement questionable) ratings was found to be in the range of 101 μm to 321 μm. When the steps with a height greater or less than one standard deviation of the mean were excluded, the overlap was reduced to a range of 168 μm to 173 μm. This finding indicates a marginal height boundary between A and B ratings for marginal adaptation of 170 ± 3 μm.
Production of Colony-stimulating Factor in Human Dental Pulp Fibroblasts
Authors: Sawa Y. , Horie Y. , Yamaoka Y. , Ebata N. , Kim T. , Yoshida S.
Published: January 2009

Class II major histocompatilibity complex (MHC)-expressing cells are usually distributed in dental pulp, and it was postulated that the colony-stimulating factor (CSF) derived from dental pulp fibroblasts contributes to the migration of class II MHC-expressing cells into pulp tissue. This study aimed to investigate the CSF production of human dental pulp fibroblasts. In pulp tissue sections, granulocyte (G)-CSF was detected from normal teeth, while G-CSF, macrophage (M)-CSF, and granulocyte-macrophage (GM)-CSF were detected from teeth with dentinal caries. In cultured dental pulp fibroblasts, G-CSF was detected by immunostaining, immunoprecipitation, and ELISA, and mRNAs of G-CSF, M-CSF, and GM-CSF were detected by RT-PCR. The dental pulp fibroblasts cultured with TNF-α were found to increase the G-CSF expression and to produce M-CSF and GM-CSF. These findings suggest that dental pulp fibroblasts usually produce G-CSF. In the presence of TNF-α, dental pulp fibroblast express M-CSF and GM-CSF.
Adjustment of the Occlusal Vertical Dimension in the Bite-raised Guinea Pig
Authors: Yagi T. , Morimoto T. , Hidaka O. , Iwata K. , Masuda Y. , Kobayashi M. , Takada K.
Published: January 2009

In humans, the inappropriate occlusal vertical dimension (OVD) causes several orofacial disorders, such as bruxism and pain in the masticatory muscles and temporomandibular joint. However, it is still unclear how strictly the OVD is adjusted. To answer this question, we studied the temporal change of the OVD in bite-raised young guinea pigs. The OVD was raised by fixation of a bite-raising appliance to the lower incisors, and increased by either 3 or 1.5 mm at the first molars. After the space produced between the upper and lower molars was filled within 10 days due to eruption of the molars, the appliance was removed. In the bite-raised animals, the raised OVD was reduced until it attained that observed in the control animals, after which the OVD increased according to cranial growth. These results show that the OVD is developmentally changed and strictly controlled.
Gene Expression of Growth Differentiation Factors in the Developing Periodontium of Rat Molars
Authors: Sena K. , Morotome Y. , Baba O. , Terashima T. , Takano Y. , Ishikawa I.
Published: January 2009

Growth and differentiation factors (GDF) 5, 6, and 7 are known to play roles in tendon and ligament formation, and are therefore probably involved in the formation of periodontal ligament. In this study, we sought to determine temporal and spatial expression of GDF-5, -6, and -7 mRNA in developing periodontal tissue of rat molars using in situ hybridization. GDF gene expression in the periodontal ligament was first detected in cells associated with the initial process of periodontal ligament fiber bundle formation. Gene signals were also detected in cells located along the alveolar bone and cementum surfaces, the insertion sites of periodontal ligaments, during the course of root formation. GDF expression in these cells were down-regulated after completion of root formation. Our results appeared to suggest the involvement of GDF-5, -6, and -7 in the formation of the dental attachment apparatus.
Expression of Vascular Endothelial Growth Factor and the Effects on Bone Remodeling during Experimental Tooth Movement
Authors: Kohno S. , Kaku M. , Tsutsui K. , Motokawa M. , Ohtani J. , Tenjo K. , Tohma Y. , Tokimasa C. , Fujita T. , Kawata T. , Tanne K.
Published: January 2009

Vascular endothelial growth factor (VEGF) has an ability to induce functional osteoclasts as well as neovascularization. We recently reported that the number of osteoclasts was enhanced by the injection of recombinant human VEGF (rhVEGF) with the application of mechanical force for experimental tooth movement. In this study, the expression of VEGF was detected in osteoblasts on the tension side of the alveolar bone. Moreover, the rate of tooth movement was significantly increased in the rhVEGF injection groups compared with the controls. These results suggested that VEGF, highly expressed by mechanical stimuli, enhances the number of osteoclasts as a paracrine factor, and that the amount of tooth movement is accelerated by both endogenous VEGF and injected rhVEGF.
Unification of the "Burst" and "Linear" Theories of Periodontal Disease Progression: A Multilevel Manifestation of the Same Phenomenon
Authors: Gilthorpe M.S. , Zamzuri A.T. , Griffiths G.S. , Maddick I.H. , Eaton K.A. , Johnson N.W.
Published: January 2009

Previously, burst and linear theories for periodontal disease progression were proposed based on different but limited statistical methods of analysis. Multilevel modeling provides a new approach, yielding a more comprehensive model. Random coefficient models were used to analyze longitudinal periodontal data consisting of repeated measures (level 1), sites (level 2), teeth (level 3), and subjects (level 4). Large negative and highly significant correlations between random linear and quadratic time coefficients indicated that subjects and teeth with greater-than-average linear change experienced decelerated variation. Conversely, subjects and teeth with less-than-average linear change experienced accelerated variation. Change therefore exhibited a dynamic regression to the mean at the tooth and subject levels. Since no equilibrium was attained throughout the study, changes were cyclical. When considered as a multilevel system, the "linear" and "burst" theories of periodontal disease progression are a manifestation of the same phenomenon: Some sites improve while others progress, in a cyclical manner.
Association between Serum Albumin and Root Caries in Community-dwelling Older Adults
Authors: Yoshihara A. , Hanada N. , Miyazaki H.
Published: January 2009

Recently, associations between dental diseases and the general health condition have been reported. The purpose of this study was to evaluate, by serum albumin concentrations, the relationship between the general health condition and root caries. We randomly selected 763 individuals (600 70-year-olds and 163 80-year-olds) living in Niigata City, Japan. The variables body composition, blood measurements, daily nutrient intakes, and root caries were measured. The relationship between root caries and serum albumin concentration was evaluated. The differences in serum albumin concentrations between subjects with untreated root caries (DT = 0 and DT > 3) were 75.56 mg/dL in 70-year-olds and 202.97 mg/dL in 80-year-olds (p < 0.05, ANOVA). The findings of the present study indicated that a relationship between root caries and serum albumin concentration in these elderly subjects is highly possible.
Increased Preventive Practices Lead to Greater Tooth Retention
Authors: Kressin N.R. , Boehmer U. , Nunn M.E. , Spiro A.
Published: January 2009

Prior research has rarely examined the impact of ADA-recommended preventive practices on tooth retention. We hypothesized that better oral hygiene leads to increased tooth retention. We examined the association of cross-sectional and long-term assessments of preventive practices, as well as various combinations of hygiene practices, with tooth retention. Among 736 male participants in the VA Dental Longitudinal Study, we utilized cross-sectional and longitudinal self-reports of toothbrushing, dental floss use, annual prophylaxis, and combinations of such behaviors, and examined their association with clinically assessed numbers of teeth. Baseline and long-term hygiene behaviors (except brushing) were associated with an increased baseline number of teeth and decreased subsequent tooth loss. Use of multiple hygiene behaviors was associated with greater tooth retention, cross-sectionally and longitudinally. Adherence to ADA recommendations for preventive care leads to better oral health, and consistently practicing preventive behaviors over the long term confers greater benefits than doing so over the short term.
Dynamic Shear Properties of the Temporomandibular Joint Disc
Authors: Tanaka E. , Hanaoka K. , van Eijden T. , Tanaka M. , Watanabe M. , Nishi M. , Kawai N. , Murata H. , Hamada T. , Tanne K.
Published: January 2009

Shear stress might be an important factor associated with fatigue failure and damage of the temporomandibular joint disc. Little information, however, is available on the dynamic behavior of the disc in shear. Since the disc is an anisotropic and viscoelastic structure, in the present study the dependency of the dynamic shear behavior on the direction and frequency of loading was examined. Ten porcine discs were used for dynamic shear tests. Shear stress was applied in both anteroposterior (A-P test) and mediolateral (M-L test) directions. The dynamic moduli increased as the loading frequency increased. The dynamic elasticity was significantly larger in the A-P test than in the M-L test, although the dynamic viscosity was similar in both tests. The present results suggest that non-linearities, compression/shear coupling, and intrinsic viscoelasticity affect the shear material behavior of the disc, which might have important implications for the transmission of load in the temporomandibular joint.
Neurotoxicity of Dental Amalgam is Mediated by Zinc
Authors: Lobner D , Asrari M
Published: January 2009

The use of dental amalgam is controversial largely because it contains mercury. We tested whether amalgam caused toxicity in neuronal cultures and whether that toxicity was caused by mercury. In this study, we used cortical cell cultures to show for the first time that amalgam causes nerve cell toxicity in culture. However, the toxicity was not blocked by the mercury chelator, 2,3-dimercaptopropane-1-sulphonate (DMPS), but was blocked by the metal chelator, calcium disodium ethylenediaminetetraacetate (CaEDTA). DMPS was an effective mercury chelator in this system, since it blocked mercury toxicity. Of the components that comprise amalgam (mercury, zinc, tin, copper, and silver), only zinc neurotoxicity was blocked by CaEDTA. These results indicate that amalgam is toxic to nerve cells in culture by releasing zinc. While zinc is known to be neurotoxic, ingestion of zinc is not a major concern because zinc levels in the body are tightly regulated.
Evidence that Experimentally Induced Sleep Bruxism is a Consequence of Transient Arousal
Authors: Kato T. , Montplaisir J.Y. , Guitard F. , Sessle B.J. , Lund J.P. , Lavigne G.J.
Published: January 2009

Spontaneous rhythmic masticatory muscle activity (RMMA) during sleep occurs more frequently following spontaneous transient micro-arousal in patients with sleep bruxism (SB) and normal controls. Here, we tested the hypothesis that an experimental arousal would be followed by an increase in RMMA. We identified RMMA on polygraphic recordings taken before and after sensory stimulation to induce experimental arousal in eight SB patients and eight matched normal subjects. The rate of experimental arousal and the level of resting electromyographic activity in masseter and suprahyoid muscles during sleep did not differ between the groups. In both, muscle tone and heart rate increased during the experimental arousal. Although post-arousal RMMA occurred in all SB patients, it was seen in only one normal subject. Moreover, tooth-grinding occurred during 71% of the evoked RMMA in SB patients. These results support the hypothesis that SB is an exaggerated form of oromotor activity associated with sleep micro-arousal.
β2-Adrenoceptor Regulation of CGRP Release from Capsaicin-sensitive Neurons
Authors: Bowles W.R. , Flores C.M. , Jackson D.L. , Hargreaves K.M.
Published: January 2009

Previous studies have suggested that neurotransmitter substances from the sympatho-adrenomedullary system regulate pulpal blood flow (PBF), in part, by the inhibition of vasoactive neuropeptide release from pulpal sensory neurons. However, no study has evaluated the role of β-adrenoceptors. We evaluated the hypothesis that activation of β-adrenoceptors inhibits immunoreactive calcitonin gene-related peptide (iCGRP) release from capsaicin-sensitive nociceptive neurons via in vitro superfusion of bovine dental pulp. Either norepinephrine or epinephrine inhibited capsaicin-evoked iCGRP. The norepinephrine effect was blocked by the selective β2-adrenoceptor antagonist, ICI 118,551, but not by pre-treatment with the selective β1-adrenoceptor antagonist, atenolol. In addition, application of albuterol, a selective β2-adrenoceptor agonist, significantly blocked capsaicin-evoked release of iCGRP. Collectively, these studies demonstrate that activation of β2-adrenoceptors in dental pulp significantly reduces exocytosis of neuropeptides from capsaicin-sensitive nociceptors. This effect may have physiologic significance in regulating PBF. Moreover, since capsaicin selectively activates nociceptors, β2-adrenoceptor agonists may have clinical utility as peripherally acting therapeutics for dental pain and inflammation.
New Animal Model for Studying Mastication in Oral Motor Disorders
Authors: Okayasu I. , Yamada Y. , Kohno S. , Yoshida N.
Published: January 2009

To identify the basic parameters of oral behavior in mice, we recorded the three-dimensional jaw movement trajectories and masseter and digastric muscle activities in freely behaving mice eating foods of various textures. Results showed that: (1) there are characteristic jaw movement patterns for food intake and mastication; (2) the pattern in a chewing cycle may be divided into opening, closing, and protruding (power) strokes; and (3) food texture affects basic patterns of jaw movement, muscle activities, and chewing rhythms. The oral motor behavior of mice appears identical to those of other experimental animals, so mice are appropriate animal models for the study of mastication.
New Bacterial Species Associated with Chronic Periodontitis
Authors: Kumar P.S. , Griffen A.L. , Barton J.A. , Paster B.J. , Moeschberger M.L. , Leys E.J.
Published: January 2009

Recent investigations of the human subgingival oral flora based on ribosomal 16S cloning and sequencing have shown many of the bacterial species present to be novel species or phylotypes. The purpose of the present investigation was to identify potential periodontal pathogens among these newly identified species and phylotypes. Species-specific ribosomal 16S primers for PCR amplification were developed for detection of new species. Associations with chronic periodontitis were observed for several new species or phylotypes, including uncultivated clones D084 and BH017 from the Deferribacteres phylum, AU126 from the Bacteroidetes phylum, Megasphaera clone BB166, clone X112 from the OP11 phylum, and clone I025 from the TM7 phylum, and the named species Eubacterium saphenum, Porphyromonas endodontalis, Prevotella denticola, and Cryptobacterium curtum. Species or phylotypes more prevalent in periodontal health included two uncultivated phylotypes, clone W090 from the Deferribacteres phylum and clone BU063 from the Bacteroidetes, and named species Atopobium rimae and Atopobium parvulum.
Bias Induced by Self-reported Smoking on Periodontitis-Systemic Disease Associations
Authors: Spiekerman C.F. , Hujoel P.P. , DeRouen T.A.
Published: January 2009

Non-causal associations between periodontitis and systemic diseases may be spuriously induced by smoking because of its strong relationship to both. The goal of this study was to evaluate whether adjustment for self-reported smoking removes tobacco-related confounding and eliminated such spurious confounding. Using NHANES III data, we evaluated associations between attachment loss and serum cotinine after adjustment by self-reported number of cigarettes smoked. Cotinine, a metabolite of nicotine, should not be related to attachment loss, if self-reported smoking captures the effect of tobacco on attachment levels. Adjustment for self-reported cigarette smoking did not completely remove the correlation between attachment loss and serum-cotinine level (r = 0.075, n= 1507, p = 0.003). Simulation studies indicated similar results for time-to-event data. These findings demonstrate the difficulty in distinguishing the effects of periodontitis from those of smoking with respect to a smoking-related outcome. Future studies should report results of analyses on separate subcohorts of never-smokers and smokers.
Molar Intercuspal Dimensions: Genetic Input to Phenotypic Variation
Authors: Townsend G. , Richards L. , Hughes T.
Published: January 2009

Molecular studies indicate that epigenetic events are important in determining how the internal enamel epithelium folds during odontogenesis. Since this process of folding leads to the subsequent arrangement of cusps on molar teeth, we hypothesized that intercuspal distances of human molar teeth would display greater phenotypic variation but lower heritabilities than overall crown diameters. Intercuspal distances and maximum crown diameters were recorded from digitized images of dental casts in 100 monozygotic and 74 dizygotic twin pairs. Intercuspal distances displayed less sexual dimorphism in mean values but greater relative variability and fluctuating asymmetry than overall crown measures. Correlations between intercuspal distances and overall crown measures were low. Models incorporating only environmental effects accounted for observed variation in several intercuspal measures. For those intercuspal variables displaying significant additive genetic variance, estimates of heritability ranged from 43 to 79%, whereas those for overall crown size were higher generally, ranging from 60 to 82%. Our finding of high phenotypic variation in intercuspal distances with only moderate genetic contribution is consistent with substantial epigenetic influence on the progressive folding of the internal enamel epithelium, following formation of the primary and secondary enamel knots.
Genetic Predisposition to External Apical Root Resorption in Orthodontic Patients: Linkage of Chromosome-18 Marker
Authors: Al-Qawasmi R.A. , Hartsfield J.K. , Everett E.T. , Flury L. , Liu L. , Foroud T.M. , Macri J.V. , Roberts W.E.
Published: January 2009

External apical root resorption (EARR) is a common orthodontic treatment sequela. Previous studies implicate a substantial genetic component for EARR. Using a candidate gene approach, we investigated possible linkage of EARR associated with orthodontic treatment with the TNSALP, TNF α , and TNFRSF11A gene loci. The sample was comprised of 38 American Caucasian families with a total of 79 siblings who completed comprehensive orthodontic treatment. EARR was assessed by means of pre- and post-treatment radiographs. Buccal swab cells were collected for extraction and analysis of DNA. No evidence of linkage was found with EARR and the TNF α and TNSALP genes. Non-parametric sibling pair linkage analysis identified evidence of linkage (LOD = 2.5; p = 0.02) of EARR affecting the maxillary central incisor with the microsatellite marker D18S64 (tightly linked to TNFRSF11A). This indicates that the TNFRSF11A locus, or another tightly linked gene, is associated with EARR.
Biocompatibility of Hydroxylated Metabolites of BISGMA and BFDGE
Authors: Kostoryz E.L. , Eick J.D. , Glaros A.G. , Judy B.M. , Welshons W.V. , Burmaster S. , Yourtee D.M.
Published: January 2009

Unpolymerized dental monomers can leach out into the oral biophase and are bioavailable for metabolism. We hypothesize that metabolites would be less toxic than parent monomers. We first identified the formation of metabolites from bisphenol F diglycidyl ether (BFDGE) and Bisphenol A glycidyl methacrylate (BISGMA) after their exposure to liver S9 fractions. Then, the metabolites and parent compounds were subjected to in vitro cytotoxicity, mutagenicity, and estrogenicity studies. Bisphenol A bis(2,3-dihydroxypropyl) ether and bisphenol F bis(2,3-dihydroxypropyl) ether were the hydroxylated metabolites of BISGMA and BFDGE, respectively. Cytotoxicity against L929 cells showed that the metabolites were significantly ( p < 0.05) less cytotoxic than the parent monomers. Only BFDGE was mutagenic in the Ames assay with strain TA100 of Salmonella typhimurium. Parent and metabolite compounds did not stimulate estrogen-dependent MCF-7 cell proliferation above solvent controls. These results indicated that the hydroxylated metabolites were non-mutagenic, non-estrogenic, and less cytotoxic than their parent monomers.
Nature of Neck Motor Unit Activities Evoked by Different Trigeminal Inputs in Rats
Authors: Zeredo J.L. , Toda K. , Soma K.
Published: January 2009

Recent reports have suggested functional interactions between the masticatory and head motor systems. However, the neurophysiological mechanisms behind these phenomena have not been thoroughly investigated. In this study, the motor unit activity was recorded bilaterally from the dorsal neck splenius muscles (SPL) while the cell bodies of trigeminal afferent fibers were stimulated at either the trigeminal mesencephalic nucleus (Me5) or the Gasserian ganglion (5Gn) in 13 barbiturate-anesthetized Wistar rats. After Me5 electrical stimulation, SPL motor unit responses were recorded ipsilaterally (n = 24), with an onset latency distribution between 1.3 and 1.8 ms. After 5Gn stimulation, SPL responses were recorded bilaterally from 18 single units, with latencies ranging from 2.2 to 2.4 ms. Our results suggest that there are at least two distinct pathways from the trigeminal afferents to the neck muscles, with significant functional differences.
Accuracy of a System for Creating 3D Computer Models of Dental Arches
Authors: DeLong R. , Heinzen M. , Hodges J.S. , Ko C.-C. , Douglas W.H.
Published: January 2009

Three-dimensional imaging of dental tissues will have a major impact in dentistry if the images are accurate. The purpose of this study was to measure the accuracy and precision of a system for creating three-dimensional images of dental arches. Using vinyl polysiloxane impression materials and improved dental stone, we made 10 stone casts of a "dental" standard with known dimensions. The impressions and casts were scanned by means of a Comet 100 optical scanner. Custom software created three-dimensional images (computer models) from the scanned data. Accuracy was defined as the average of the absolute differences between the computer models and the standard. Precision was the standard deviation of accuracy over 10 repeated measures. Software processing improved the accuracy of the scanner data. Accuracy ± precision for the casts and impressions was 0.024 ± 0.002 mm and 0.013 ± 0.003 mm, respectively. The system produced computer models with sufficient accuracy for clinical application.
Lipoteichoic Acid Up-regulates VEGF Expression in Macrophages and Pulp Cells
Authors: Telles P.D.S. , Hanks C.T. , Machado M.A.A.M. , Nör J.E.
Published: January 2009

Vascular endothelial growth factor (VEGF) is a potent inducer of angiogenesis, vascular permeability, and edema. Up-regulation of VEGF expression in the dental pulp may result in increased intra-pulpal pressure, and contribute to pain and irreversible tissue damage. Lipoteichoic acid (LTA) is an amphiphilic molecule from Gram-positive bacteria that has been associated with the pathogenesis of pulpitis. To investigate if LTA regulates expression of VEGF, we exposed mouse odontoblast-like cells (MDPC-23), undifferentiated pulp cells (OD-21), fibroblasts, or macrophages to streptococcal LTA, and evaluated VEGF expression by ELISA and RT-PCR. LTA induced up to a nine-fold increase in VEGF protein expression in macrophages, a 2.4-fold increase in MDPC-23, and a 1.6-fold increase in OD-21 as compared with controls. In contrast, LTA did not induce VEGF expression in fibroblasts. VEGF mRNA expression remained constant upon exposure to LTA, which suggests that VEGF regulation in these cells is primarily post-transcriptional. This work constitutes the first demonstration that lipoteichoic acid is sufficient to induce expression of a pro-angiogenic factor.
Myosin Heavy-chain Isoform Composition of Human Single Jaw-muscle Fibers
Authors: Korfage J.A.M. , Van Eijden T.M.G.J.
Published: January 2009

Diversity in muscle contractile properties is based on the variability of contractile properties of single muscle fibers which in turn is related to the presence of different myosin heavy-chain (MyHC) isoforms. Human jaw muscles are featured by many hybrid fibers expressing more than one MyHC isoform. The purpose of this study was to determine the proportion of each isoform within these fibers for evaluation of the fiber’s capacity of producing a large diversity in contractile properties. Electrophoretic separation of MyHC isoforms was performed on 218 single fibers of the temporalis and digastric muscles. Of these fibers, 100 were classified as hybrid fibers. Most hybrid fibers co-expressed MyHC-IIA and -IIX (n = 62); a smaller number co-expressed MyHC-I and -IIA (n = 14), MyHC-I and -IIX (n = 12), and MyHC-I, -IIA, and -IIX (n = 12). The proportions of the individual MyHC isoforms in the hybrid fibers varied highly, suggesting a large range of contractile properties among these fibers.
Analysis of Multiple 2x2 Tables with Site-specific Periodontal Data
Authors: Panageas K.S. , Begg M.D. , Grbic J.T. , Lamster I.B.
Published: January 2009

Periodontal data typically consist of observations made at multiple sites within each patient. Observations within a patient tend to be positively correlated; hence, standard statistical techniques that assume independence are invalid. Regression techniques for correlated data have been proposed; communicating results from these models, however, is difficult, due to their inherent complexity. Simpler statistical approaches have also been proposed, but many of these methods can be applied only when covariates are specific to the subject, and do not vary from site to site within a subject. In this paper, we present two methods for the analysis of multiple 2x2 tables containing site-specific periodontal data. The methods presented are modifications of the well-known Mantel-Haenszel methods. We illustrate these methods using a subset of data from a clinical trial examining the effects of scaling and root planing on levels of interleukin-1β.
Cot/Tpl2 is Essential for RANKL Induction by Lipid A in Osteoblasts
Authors: Kikuchi T. , Yoshikai Y. , Miyoshi J. , Katsuki M. , Musikacharoen T. , Mitani A. , Tanaka S. , Noguchi T. , Matsuguchi T.
Published: January 2009

Lipopolysaccharide (LPS) is a pathogenic factor that increases bone resorption in periodontal diseases. LPS treatment of osteoblasts was shown to induce the receptor activator of NF-κB ligand (RANKL), an essential secretory or membrane-bound factor for osteoclast function, in a manner dependent on extracellular signal-regulated kinase (ERK) activation. However, the mechanisms regulating this process remained unknown. Here, we show that RANKL mRNA induction and ERK activation, when treated with synthetic lipid A (an active center of LPS), were markedly reduced in mouse osteoblasts lacking Cot/Tpl2, which was recently recognized as an essential kinase for the induction of TNF-α by LPS in macrophages. In contrast, c-Jun N-terminal kinase (JNK), p38 kinase, Raf-1, and NF-κB were normally activated in cot/tpl2-/- osteoblasts. These findings indicate that Cot/Tpl2 is essential for LPS-induced ERK activation and RANKL induction in osteoblasts.
Bone with a Vascular Flap Induced from Fat Tissue with the Use of rhBMP-2 in Rats
Authors: Hosoya M. , Maruoka Y. , Oda M. , Asahina I. , Ichinose S. , Omura K.
Published: January 2009

Here we report that successful bone formation with a vascular flap inside a cylindrical mold was induced from fat tissue with the use of recombinant human bone morphogenetic protein-2 in rats. Fat tissue connected to blood vessels was prepared to fit into the mold and implanted intramuscularly into the hind leg in Wistar rats. RhBMP-2 (20 μg) was applied in a collagen sheet previously placed on the inside surface of the mold. Bone formation was confirmed radiologically and morphologically at 2, 4, and 8 weeks after the surgery. In the control group without rhBMP-2 or the group with ligation of the blood vessels before the implantation, bone formation was not observed. Our success in bone formation having a definite size, shape, and blood supply may lead to a therapeutic approach to effective bone reconstitution. The present study is the first report on bone induction from fat tissue by rhBMP-2 in vivo.
Effects of HEMA/Solvent Combinations on Bond Strength to Dentin
Authors: Carvalho R.M. , Mendonça J.S. , Santiago S.L. , Silveira R.R. , Garcia F.C.P. , Tay F.R. , Pashley D.H.
Published: January 2009

Re-expansion of dried demineralized dentin is required to optimize resin adhesion. This study tested the hypothesis that bond strengths to dentin depend upon the ability of experimental HEMA(2-hydroxy-ethyl-methacrylate)/solvent primers to re-expand the matrix. Dentin surfaces were acid-etched with 37% phosphoric acid for 20 sec, air-dried for 30 sec, primed with either 35/65% (v/v) HEMA/water, HEMA/methanol, HEMA/ethanol, or HEMA/propanol for 60 sec, and bonded with 4-META-TBBO(4-methacryloyloxyethyl trimellitate anhydride-tri- n-butyl borane) adhesive. After storage in water for 1 day at 37°C, the samples were prepared for microtensile bond strength testing. We used transmission electron microscopy to measure the width of interfibrillar spaces in the hybrid layers. The HEMA/ethanol primer and the HEMA/propanol primer produced the highest and the lowest bond strengths, respectively (p < 0.05). Bond strengths were directly correlated with the width of the interfibrillar spaces (p < 0.05). Bond strengths are related to the ability of the primer to maintain the re-expansion of collapsed demineralized dentin matrix.
Single-nucleotide Polymorphism in the CD14 Promoter and Periodontal Disease Expression in a Japanese Population
Authors: Yamazaki K. , Ueki-Maruyama K. , Oda T. , Tabeta K. , Shimada Y. , Tai H. , Nakajima T. , Yoshie H. , Herawati D. , Seymour G.J.
Published: January 2009

It has been reported that there is a relationship between a single-nucleotide polymorphism (SNP) in the promoter region of the CD14 gene at position -159 (C→T) and infectious diseases. The aim of the present study was to test the hypthesis that expression of this SNP correlates with periodontal disease in a Japanese population. The CD14 genotype was determined in 163 subjects with periodontitis and in 104 age- and gender-matched control subjects without periodontitis. The genotype distribution and allele frequency within the periodontitis patients were not significantly different from those of control subjects. There was, however, a significant difference in the genotype distribution between young patients (< 35 yrs) and older patients (≥ 35 yrs). These findings suggest that CD14 -159C/T polymorphism is not related to the development of periodontitis in a Japanese population, but that, within the periodontitis subjects, expression of the SNP may be related to early disease activity.
Differential Injury Responses in Oral Mucosal and Cutaneous Wounds
Authors: Szpaderska A.M. , Zuckerman J.D. , DiPietro L.A.
Published: January 2009

Oral mucosa heals faster than does skin, yet few studies have compared the repair at oral mucosal and cutaneous sites. To determine whether the privileged healing of oral injuries involves a differential inflammatory phase, we compared the inflammatory cell infiltrate and cytokine production in wounds of equivalent size in oral mucosa and skin. Significantly lower levels of macrophage, neutrophil, and T-cell infiltration were observed in oral vs. dermal wounds. RT-PCR analysis of inflammatory cytokine production demonstrated that oral wounds contained significantly less IL-6 and KC than did skin wounds. Similarly, the level of the pro-fibrotic cytokine TGF-b1 was lower in mucosal than in skin wounds. No significant differences between skin and mucosal wounds were observed for the expression of the anti-inflammatory cytokine IL-10 and the TGF-β1 modulators, fibromodulin and LTBP-1. These findings demonstrate that diminished inflammation is a key feature of the privileged repair of oral mucosa.
Accelerated Alveolar Bone Loss in Mice Lacking Interleukin-10
Authors: Al-Rasheed A. , Scheerens H. , Rennick D.M. , Fletcher H.M. , Tatakis D.N.
Published: January 2009

Interleukin-10 regulates pro-inflammatory cytokines, including those implicated in alveolar bone resorption. We hypothesized that lack of interleukin-10 leads to increased alveolar bone resorption. Male interleukin-10(−/−) mice, on 129/SvEv and C57BL/6J background, were compared with age-, sex-, and strain-matched interleukin-10(+/+) controls for alveolar bone loss. Immunoblotting was used for analysis of serum reactivity against bacteria associated with colitis and periodontitis. Interleukin-10(−/−) mice had significantly greater alveolar bone loss than interleukin-10(+/+) mice (p = 0.006). The 30–40% greater alveolar bone loss in interleukin-10(−/−) mice was evident in both strains, with C57BL/6J interleukin-10(−/−) mice exhibiting the most bone loss. Immunoblotting revealed distinct interleukin-10(−/−) serum reactivity against Bacteroides vulgatus, B. fragilis, Prevotella intermedia, and, to a lesser extent, against B. forsythus. The results of the present study suggest that lack of interleukin-10 leads to accelerated alveolar bone loss.
Novel OK-432-conjugated Tumor Vaccines Induce Tumor-specific Immunity against Murine Tongue Cancer
Authors: Li X. , Bukawa H. , Hirota M. , Tsuyuki Y. , Omura S. , Fujita K.
Published: January 2009

Priming with tumor antigens is one of the most important strategies in cancer immunotherapy. To enhance tumor antigenicity, OK-432, a streptococcal preparation, was coupled to squamous cell carcinoma (KLN-205) by means of a 0.2% glutaraldehyde method. The purpose of this study was to investigate whether OK-432-conjugated tumor vaccines could induce tumor-specific immunity. Our originally developed mouse tongue cancer model was used throughout this work for the analysis of antitumor effects. Prepared OK-432-conjugated KLN-205 vaccines were immunized 3 times to DBA/2 mice. The results showed that the KLN-205 vaccines induced cytolytic activity and strongly suppressed both KLN-205 tumor incidence and growth, and survival of the mice was improved. Moreover, the histological results showed that a greater number of lymphocytes had infiltrated around tumor cells by 24 hours after tumor inoculation in the vaccine group. These results suggest that immunizations with KLN-205 vaccines increase the antitumor effects against tongue cancer.
Gene Profiling in Human Periodontal Ligament Fibroblasts by Subtractive Hybridization
Authors: Yamamoto T. , Myokai F. , Nishimura F. , Ohira T. , Shiomi N. , Yamashiro K. , Arai H. , Murayama Y. , Takashiba S.
Published: January 2009

Genes expressed by human periodontal ligament fibroblasts (HPFs) are likely to be associated with specific functions of the ligament. The aim of this study is to profile genes expressed highly by HPFs. A library (6 × 103 pfu) was constructed, followed by subtraction of HPF cDNAs with human gingival fibroblast (HGF) cDNAs. Reverse-dot hybridization revealed that 33 clones expressed higher levels of specific mRNAs in HPFs than in HGFs. These were mRNAs for known genes, including several associated with maturation and differentiation of cells. None had been reported in PFs. One clone, PDL-29, identified as a COX assembly factor, showed much stronger mRNA expression in HPFs than in HGFs in culture. In rat periodontium, however, PDL-29 mRNA expression was similar in PFs and GFs. These results suggest that HPFs express many previously unreported genes associated with maturation and differentiation, but expression can differ in vitro and in vivo.
Evidence of a Substantial Genetic Basis for IgG2 Levels in Families with Aggressive Periodontitis
Authors: Diehl S.R. , Wu T. , Burmeister J.A. , Califano J.V. , Brooks C.N. , Tew J.G. , Schenkein H.A.
Published: January 2009

IgG2 is elevated in localized but not in generalized aggressive periodontitis (AgP). Exposure to pathogenic bacteria is essential for disease. Immune responses are dominated by IgG2 reactive with bacterial surface carbohydrates. We used variance component analyses to assess IgG2 heritability and determine whether genes that influence IgG2 are the same genes that influence disease susceptibility. We studied 17 Caucasian and 43 African American families with two or more localized or generalized AgP-affected members (274 subjects with IgG2 measurements). Only 16% of the variance in IgG2 was attributable to age, race, and smoking. Even with the addition of localized AgP, the model still explained only 19% of IgG2 variance. By contrast, heritability of IgG2 levels was estimated to be 38% and highly significant (P = 0.0006), demonstrating a substantial genetic basis. Bi-trait variance component analyses of IgG2 and quantitative measures of AgP indicate that different genes appear to control IgG2 levels and disease susceptibility.
Alteration in Salivary Function in Early HIV Infection
Authors: Lin A.L. , Johnson D.A. , Stephan K.T. , Yeh C.-K.
Published: January 2009

The etiology of salivary gland hypofunction in HIV(+) patients is unclear. This study was designed to determine the effect of early-stage HIV(+) infection (CD4+ > 200 cells/μL; n = 139) on salivary gland function and the relationship of this dysfunction to the taking of xerostomic medications. Salivary flow rates and the content of electrolytes and antimicrobial proteins in stimulated parotid and submandibular/sublingual saliva were determined. Compared with healthy controls (n = 50), the HIV(+) group showed significant reductions in flow rates of unstimulated whole (35%), stimulated parotid (47%), unstimulated submandibular/sublingual (23%), and stimulated submandibular/sublingual (39%) saliva. The flow rates for the HIV(+) patients taking xerostomic medications did not differ from those of patients who did not. Concentrations of some salivary gland components were altered in the HIV(+) group. Analysis of these data suggests that salivary gland function is adversely affected early in HIV infection and that these changes do not appear to be compounded by the taking of xerostomic medications.