bluuebunny/crossref_metadata_2025 huggingface dataset:
Hyper-excretion of Human Immunodeficiency Virus Type 1 RNA in Saliva
Authors: Shugars D.C. , Patton L.L. , Freel S.A. , Gray L.R. , Vollmer R.T. , Eron J.J. , Fiscus S.A.
Published: January 2009

Anatomical compartments (e.g., the reproductive tract) are reservoirs of human immunodeficiency virus type-1 (HIV-1) and potential sites of residual infection in patients receiving anti-retroviral therapy (ART). Viral hyper-excretion relative to blood is a hallmark of reservoirs. To determine whether hyper-excretion can occur in the oral cavity, we compared viral loads in blood plasma and saliva of 67 adults. Salivary viral hyper-excretion was defined as a four-fold or higher viral load in saliva than in plasma. HIV-1 RNA was detected in 79% of plasma samples, in 44% of unfiltered saliva samples, in 16% of filtered saliva samples, and in 59% of saliva-derived cell pellets. Compared with non-hyper-excretors (n = 62), hyper-excretors (n = 5) had elevated levels of viral RNA in unfiltered saliva and saliva-derived cells, HIV-associated periodontal disease, gingival inflammation, and no combination ART. Morphological characterization of cell pellets identified lymphocytes as a likely HIV-1 source. These collective findings are consistent with an oral HIV-1 reservoir in selected individuals.
A Re-analysis of a Caries Clinical Trial by Survival Analysis
Authors: Hannigan A. , O'Mullane D.M. , Barry D. , Schafer F. , Roberts A.J.
Published: January 2009

The decline in caries prevalence, the increases in the level of fluoride exposure, and the lack of placebo control subjects have complicated caries clinical trials in recent times. There has been a substantial increase in the numbers of subjects required for the detection of statistically significant differences between dental products, and hence, the cost of these trials has grown enormously. This study uses a new statistical approach to the analysis of the data from these trials with the ultimate aim of providing a more sensitive method of analysis. The new approach uses survival analysis, where the outcome measure is the survival time of an individual tooth surface. It exploits recent developments in the analysis of clustered survival data where survival times within the same cluster or subject are correlated. To illustrate, the new method of analysis was used for the North Wales, UK, caries clinical trial. It is concluded that survival analysis uses most of the data available in a caries clinical trial, an outcome measure that is easily understood and may lead to a more sensitive method of analysis.
Intermittent Force in Orthodontic Tooth Movement
Authors: Konoo T. , Kim Y.J. , Gu G.M. , King G.J.
Published: January 2009

A single orthodontic activation lasting one hour can initiate tooth movement. The purpose of this study is to examine tooth movement, osteoclasts, and root resorption in rats following several one-hour activations. Rats (n = 144) were randomly assigned to intermittent (multiple activations of 1 hr/day), continuous, and sham appliances. Twelve rats were killed at 3, 5, 7, and 14 days. Tooth movement, osteoclasts, osteoclast %, and root resorption % were quantified. Continuous force moved molars mesially at days 3 and 14 (p < 0.05), but intermittent and sham did not. Intermittent and continuous force increased osteoclast numbers at days 3, 5, and 7 (p < 0.05). Continuous force increased osteoclast surface on days 3 and 14 (p < 0.05). Continuous force increased root resorption at days 5, 7, and 14 (p < 0.05). These results demonstrate that orthodontic force for one hour in 24 stimulates osteoclasts at compression sites but does not stimulate tooth movement or root resorption.
Evidence for Reactive Nitrogen Species Formation in the Gingivomucosal Tissue
Authors: Lohinai Z. , Stachlewitz R. , Virág L. , Székely A.D. , Haskó G. , Szabó C.
Published: January 2009

An increase in nitric oxide production has been demonstrated in periodontitis. Here we investigated the potential role of nitric-oxide-derived nitrating species (such as peroxynitrite) in a rat model of ligature-induced periodontitis. Formation of 3-nitrotyrosine, the stable product formed from tyrosine reacting with nitric-oxide-derived nitrating species, was detected in the gingivomucosal tissue. 3-Nitrotyrosine immunohistochemical analysis revealed a significant elevation in the number of immunopositive leukocytes, and higher immunoreactivity of the gingival ligaments and epithelium in the ligated than in the contralateral (control) side. On both sides, several 3-nitrotyrosine-positive bands and, on the ligated side, a unique 52-kDa 3-nitrotyrosine-positive band were detected by Western blot. However, in the sterile gingivomucosal tissue of rat pups, no 3-nitrotyrosine or inducible nitric oxide synthase immunoreactivity was found. Analysis of these data suggests that resident bacteria of the gingivomucosal tissue induce an increase in reactive nitrogen species, which is greatly enhanced by plaque formation in periodontitis.
A New Ti-5Ag Alloy for Customized Prostheses by Three-dimensional Printing (3DP™)
Authors: Hong S.-B. , Eliaz N. , Leisk G.G. , Sachs E.M. , Latanision R.M. , Allen S.M.
Published: January 2009

Three important considerations in the fabrication of customized cranio-maxillofacial prostheses are geometric precision, material strength, and biocompatibility. Three-dimensional printing (3DP™) is a rapid part-fabrication process that can produce complex parts with high precision. The aim of this study was to design, synthesize by 3DP™, and characterize a new Ti-5Ag (wt%) alloy. Silver nitrate was found to be an appropriate inorganic binder for the Ti powder-based skeleton, and the optimum sintering parameters for full densification were determined. The hardness of the Ti-5Ag alloy was shown to be much higher than that of a pure titanium sample. Potentiodynamic measurements, carried out in saline solution at body temperature, showed that the Ti-5Ag alloy had good passivation behavior, similar to that of pure titanium. It is concluded that the Ti-Ag system may be suitable for fabrication of customized prostheses by 3DP™.
Cloning and Characterization of the Mouse and Human Enamelin Genes
Authors: Hu J.C.-C. , Zhang C.H. , Yang Y. , Kärrman-MÅrdh C. , Forsman-Semb K. , Simmer J.P.
Published: January 2009

Enamelin is likely to be essential for proper dental enamel formation. It is secreted by ameloblasts throughout the secretory stage and can readily be isolated from the enamel matrix of developing teeth. The gene encoding human enamelin is located on the long arm of chromosome 4, in a region previously linked to an autosomal-dominant form of amelogenesis imperfecta (AI). To gain information on the structure of the enamelin gene and to facilitate the future assessment of the role of enamelin in normal and diseased enamel formation, we have cloned and characterized the mouse and human enamelin genes. Both genes are about 25 kilobases long. The enamelin gene has 10 exons interrupted by 9 introns. Translation initiates in exon 3 and terminates in exon 10. All of the intron/exon junctions within the mouse and human enamelin coding regions are between codons, so there are no partial codons in any exon, and deletion of one or more coding exons by alternative RNA splicing would not shift the downstream reading frame.
Fluoride Release from Glass lonomer Activated with Fluoride Solutions
Authors: Dhondt C.L. , De Maeyer E.A.P. , Verbeeck R.M.H.
Published: January 2009

The mechanism of the fluoride release from glass-ionomer cements (GICs) is not yet completely understood, due to the complexity of these systems. The objective of the present study was to investigate the fluoride and alkali metal ion release from a relatively simple GIC formulation with fluoride- and alkali metal-free glass and activated with a NaF or KF solution. The set formulations were eluted during 168 days in water at 37°C. The cumulative fluoride release was the result of an initial high release that ceased after some time and a prolonged but slow release, both of which increased with increasing fluoride concentrations in the activating solution, independently of the type of alkali metal. Maturation prior to elution decreased the fluoride and slowed the alkali metal release. The release of these ions was not (completely) correlated. The results suggest that the release process is due not only to a loss of relatively loosely bound fluoride in the cement matrix, but also to the release of fluoride which becomes strongly bound during the setting reaction and induces a long-term release.
Low Magnitude of Tensile Strain Inhibits IL-1β-dependent Induction of Pro-inflammatory Cytokines and Induces Synthesis of IL-10 in Human Periodontal Ligament Cells in vitro
Authors: Long P. , Hu J. , Piesco N. , Buckley M. , Agarwal S.
Published: January 2009

Applied mechanical loading induces inflammation in the periodontal ligament (PDL). However, the mechanisms involved in bone deposition at tension sites in an inflammatory environment are not clear. Here, in an in vitro model system, we show that equibiaxial tensile strain of low magnitude (TENS) provokes potent anti-inflammatory signals in PDL cells. TENS inhibits IL-1β-induced synthesis of IL-1β, IL-6, and IL-8 by inhibiting their mRNA expression, and thus significantly suppresses the amplification of IL-1 (3-induced inflammatory responses in PDL cells. Additionally, as an anti-inflammatory signal, TENS induces IL-10 synthesis in the presence and absence of IL-1β. These observations are the first to demonstrate that TENS antagonizes IL-1β actions on PDL cells by (i) inhibiting IL-1β-induced transcriptional regulation of proinflammatory cytokines, and (ii) inducing synthesis of IL-10, which may post-transcriptionally suppress the synthesis of proinflammatory cytokines.
Coronal and Root Caries in Southern Chinese Adults
Authors: Lin H.C. , Wong M.C.M. , Zhang H.G. , Lo E.C.M. , Schwarz E.
Published: January 2009

Southern China is the most prosperous part of China, but information useful for oral care planning is very limited. A large-scale epidemiological survey was conducted in 1996-97. The objectives of this report were to describe the coronal and root caries of the adult Southern Chinese and to analyze the influence of selected demographic and socio-economic factors on the disease pattern. A total sample of 1573 35- to 44-year-olds and 1515 65- to 74-year-olds from 8 urban and 8 rural survey sites in Guangdong Province participated in an oral health interview and underwent clinical examination. World Health Organization examination procedures and diagnostic criteria were used. The weighted mean DMFT scores of the middle-aged and the elderly subjects were 4.8 and 16.1, respectively. People living in rural areas had a higher DMFT score than those living in urban areas (4.9 vs. 4.3 in the 35- to 44-year-olds and 16.5 vs. 14.7 in the 65- to 74-year-olds). In both age groups, MT was the major component of the DMFT score. Analysis of covariance showed that women and those who were economically less well off had higher DMFT scores in both age groups. The weighted prevalence rates of decayed/filled roots were 12% and 37%, with a mean of 0.2 and 0.7 teeth affected, in the middle-aged and the elderly, respectively. In conclusion, socio-economic factors had a considerable effect on the dental caries status of adults in Southern China.
Oral Mucosal Lesions in Adult Chinese
Authors: Lin H.C. , Corbet E.F. , Lo E.C.M.
Published: January 2009

The objectives of this analysis were to determine the prevalence of oral mucosal lesions (OML) among adults in Southern China and to determine possible associations between OML and reported tobacco-smoking and alcohol-drinking habits. The sample consisted of 1573 35- to 44-year-old and 1515 65- to 74-year-old Chinese from both urban and rural areas of Guangdong Province. The subjects were interviewed by trained interviewers and underwent a clinical examination of the oral mucosa performed according to WHO guidelines. A specially prepared color atlas of OML was used for lesion recognition and confirmation during the survey. Among the 35- to 44-year-old subjects, the overall prevalence of OML was found to be 13% in urban men, 6% in urban women, 15% in rural men, and 4% in rural women. The corresponding figures for the 65- to 74-year-olds were 22%, 12%, 26%, and 19%. Tongue lesions and white lesions were relatively common, but denture-related lesions were not. No malignancies or erythroplakia was observed. Age and gender were found to relate to the occurrence of OML. In elderly men, smoking was significantly (p < 0.05) associated with some white lesions and tongue lesions, and alcohol drinking was also associated with some white lesions. In conclusion, tongue lesions and white lesions were relatively common in men, but pre-cancerous lesions were not prevalent.
Sustained Microglial Immunoreactivity in the Caudal Spinal Trigeminal Nucleus after Formalin Injection
Authors: Yeo J.-F. , Liu H.P. , Leong S.-K.
Published: January 2009

Recent studies indicate that glia may be involved in altered nociceptive processing after a peripheral inflammatory lesion produced by injection of inflammatory reagents such as formalin and zymosan. Most of these studies, however, confined their observations to a period shortly after the injections. This study investigated the immunohistochemical responses of microglia in the caudal part of the spinal trigeminal nucleus for up to 60 days after subcutaneous injection of formalin into the lateral faces of Wistar rats. The results showed obvious up-regulation of microglial markers such as OX-18, OX-42 and OX-6 up to 21 days after formalin injection. These were somewhat reduced at 30 days after injection. Electron microscope investigation revealed no evidence of significant phagocytosis of degenerative neuronal elements by microglia in the nucleus at the time-that is, 7 days after formalin injection, when microglial activation was at its peak. Significantly, however, the period of microglial activation corresponded closely to that showing enhanced nociceptive behavior after perioral formalin injection (Cadet et al., 1995). This study indicates a microglial role in the genesis of enhanced nociceptive behavior.
Primary and Secondary Induction of Apoptosis in Odontoblasts after Cavity Preparation of Rat Molars
Authors: Kitamura C. , Kimura K. , Nakayama T. , Toyoshima K. , Terashita M.
Published: January 2009

The death regulation of damaged pulp cells after cavity preparation is not well-known. In this study, we examined whether apoptosis is associated with the death regulation of damaged pulp cells. In normal rat molars, terminal deoxynucleotidyl transferase-mediated labeling (TUNEL)-positive cells were not observed. Just after surgery, odontoblasts under cavities were TUNEL-positive, and these signals disappeared in six hours. One day after surgery, we found the reappearance of TUNEL-positive cells in the subodontoblastic region under cavities, and positive signals disappeared in four days. Ultrastructure of TUNEL-positive cells showed characteristics typical of apoptotic cells. Phagocytosis of apoptotic cells by scavenger cells was also observed. By immunohistochemistry, we also found Bcl-2-positive odontoblasts one day after surgery. These results suggest that two waves of apoptosis are induced in odontoblasts after cavity preparation, and that apoptotic cells must be eliminated before the initiation of reparative dentinogenesis.
The Effects of MMP Inhibitors on Human Salivary MMP Activity and Caries Progression in Rats
Authors: Sulkala M. , Wahlgren J. , Larmas M. , Sorsa T. , Teronen O. , Salo T. , Tjäderhane L.
Published: January 2009

Previous studies suggest that salivary and pulp-derived host enzymes, matrix metalloproteinases (MMPs), may be involved in dentin caries pathogenesis. To study the inhibition of acid-activated human salivary MMPs by non-antimicrobial chemically modified tetracyclines (CMTs), we used a functional activity assay with 125I-labeled gelatin as a substrate. To address the role of MMPs in the progression of fissure caries in vivo, we administered the MMP inhibitors CMT-3 and zoledronate to young rats per os for 7 weeks, 5 days a week. Caries lesions were visualized by Schiff reagent in sagittally sectioned mandibular molars. Marked reduction in gelatinolytic activity of human salivary MMPs was observed with CMT-3. CMT-3 and zoledronate, both alone and in combination, also reduced dentin caries progression in the rats. These results suggest that MMPs have an important role in dentin caries pathogenesis, and that MMP inhibitors may prove to be useful in the prevention of caries progression.
Influence of Pulse-Delay Curing on Softening of Polymer Structures
Authors: Asmussen E. , Peutzfeld A.
Published: January 2009

Resin composites may be polymerized according to one of several light-curing modes. These modes include variations in intensity of the curing lights and time delay before final cure. The so-called pulse-delay method has earlier been found to reduce the formation of gaps due to polymerization contraction, without mechanical properties of the resin composite being compromised. It was hypothesized that the slow pre-cure of this method would give rise to a different polymer structure than results when the polymer is cured in one step at high intensity. It was found that although the quantity of remaining double bonds was unaffected, the pulse-delay technique led to polymers of increased susceptibility to softening in ethanol. The softness increased with the intensity of the pre-cure and with the waiting time before final cure. The increased softening may be interpreted as the manifestation of a polymer structure having fewer crosslinks.
Early-onset Periodontitis in Morocco is Associated with the Highly Leukotoxic Clone of Actinobacillus actinomycetemcomitans
Authors: Haubek D. , Ennibi O.-K. , Poulsen K. , Poulsen S. , Benzarti N. , Kilian M.
Published: January 2009

A particular clone (JP2) of Actinobacillus actinomycetemcomitans with increased leukotoxin production has been isolated from individuals with early-onset periodontitis (EOP). The aim of this study was to determine the frequency of carriers of this clone and its association with EOP in Moroccan schoolchildren. Of 217 plaque samples, 131 (60.4%) were culture-positive for A. actinomycetemcomitans. A total of 19 of these isolates had a 530-bp deletion in the leukotoxin promoter region characteristic of the JP2 clone. A strong association between the presence of A. actinomycetemcomitans with the 530-bp deletion and EOP was found (adjusted OR = 29.4; 95% CI = 8.3 - 104.4; p < 0.0005), while no association could be demonstrated between the presence of A. actinomycetemcomitans without the deletion and EOP (adjusted OR = 1.3; 95% CI = 0.5 - 2.9; p = 0.750). The study demonstrates that the endemic presence, in a human population, of the highly leukotoxic JP2 clone may result in an unusually high prevalence of EOP.
The Effects of Duration and Intensity of Stimulation on Total Protein and Mucin Concentrations in Resting and Stimulated Whole Saliva
Authors: Payment S.A. , Liu B. , Soares R.V. , Offner G.D. , Oppenheim F.G. , Troxler R.F.
Published: January 2009

The present investigation has characterized the influence of the duration and intensity of stimulation on the secretion pattern of total protein and salivary mucins MG1 and MG2 in whole saliva. Resting and stimulated whole saliva was collected from six healthy subjects on 2 consecutive days. Whole saliva was collected for 2 five-minute intervals under resting conditions followed by collection under masticatory stimulation induced by the chewing of parafilm (1 g) at 10 or 60 strokes/min for 15 min. Flow rates were different under the 2 levels of stimulation. The concentration of total protein was different in resting and stimulated whole saliva but was not affected by the duration or intensity of stimulation. Analysis of mucin concentrations determined by capture ELISAs revealed that the pattern of MG1 secretion was similar to that of total protein. The pattern of MG2 secretion was unique in that no differences were observed in the concentration of this mucin under resting and stimulated conditions. This study shows that the pattern of protein secretion in whole saliva does not reflect the combined pattern observed for protein secretion in parotid and submandibular/sublingual glands, and that the secretion patterns of MG1 and MG2 in whole saliva are quite different from one another.
Elevated Systemic Concentrations of Soluble ICAM-1 (sICAM) are Not Reflected in the Gingival Crevicular Fluid of Smokers with Periodontitis
Authors: Fraser H.S. , Palmer R.M. , Wilson R.F. , Coward P.Y. , Scott D.A.
Published: January 2009

Raised serum levels of soluble intercellular adhesion molecule-1 (sICAM-1) in smokers could have immunomodulatory effects in periodontitis. The aim of this study was to compare serum and gingival crevicular fluid (GCF) concentrations of sICAM-1 in smokers and non-smokers with periodontal disease. sICAM-1 in serum and GCF collected from age- and gender-matched smokers (n = 14) and non-smokers (n = 14) with periodontitis were measured by ELISA. Mean serum sICAM-1 concentrations were significantly elevated in smokers (331 ng mL-1), compared with non-smokers (238 ng mL-1, p = 0.008). However, the concentration of sICAM-1 in the GCF was significantly lower in the smokers (83 ng mL -1), compared with non-smokers (212 ng mL-1, p = 0.013). The difference between concentrations of sICAM-1 in GCF and serum was significant only in smokers (p < 0.001). Since GCF is a serum-derived tissue exudate, these results suggest that, in smokers, circulating sICAM-1 molecules are affected either in their passage from the periodontal microvasculature or within the periodontal tissues.
Relationship between Tooth Loss and Electrocardiographic Abnormalities in Octogenarians
Authors: Takata Y. , Ansai T. , Matsumura K. , Awano S. , Hamasaki T. , Sonoki K. , Kusaba A. , Akifusa S. , Takehara T.
Published: January 2009

Recent reports have suggested that periodontal disease is a risk factor for coronary heart disease (CHD). However, little is known about the relationship between periodontal disease and CHD in the very elderly. Therefore, we evaluated the association between tooth loss and abnormal ECG findings in octogenarians. Of the 1282 octogenarians in Fukuoka Prefecture, Japan, 697 participated. Oral examinations-including a tooth count and an assessment of the Community Periodontal Index-and a 12-lead ECG were performed. Logistic regression analysis revealed that individuals with < 20 teeth had increased prevalence of ST segment depression, and T-wave abnormalities, after we adjusted for gender, smoking, serum cholesterol and glucose, blood pressure, and body mass index. Compared with individuals with ≥ 20 teeth, edentulous individuals had an increased prevalence of T-wave abnormalities and arrhythmias after adjustment for coronary risk factors. We conclude that tooth loss may be an independent predictor of abnormal ECG findings in octogenarians.
Expression of Bone Matrix Protein mRNAs by Primary and Cloned Cultures of the Regenerative Phenotype of Human Periodontal Fibroblasts
Authors: Ivanovski S. , Haase H.R. , Bartold P.M.
Published: January 2009

The successful regeneration of periodontal tissues is dependent, in part, on the ability of cells to reconstitute the mineralized tissues of cementum and bone. The aim of the present study was to characterize regeneration-associated cells in terms of their ability to express mineralized tissue macromolecules. Following guided tissue regeneration, cell cultures were established from regenerating tissue, periodontal ligament, and gingiva. Additionally, these cells were transfected, and single-cell-derived clones were established. Following treatment with platelet-derived growth factor-BB and insulin-derived growth factor-1, the presence of mRNA for alkaline phosphatase, osteocalcin, bone sialoprotein, osteopontin, and bone morphogenetic proteins-2 and -4 was assessed. The three cell types expressed similar mRNA levels for alkaline phosphatase, bone morphogenetic protein-2, and bone morphogenetic protein-4, whereas the expression of osteopontin, osteocalcin, and bone sialoprotein was greater in the periodontal ligament and regenerating tissue fibroblasts compared with the gingival fibroblasts. The two growth factors did not affect the expression of any of the genes. This study has identified markers that correlate with the known ability of periodontal ligament and regenerating tissue-derived fibroblasts to facilitate regeneration of the mineralized tissues of the periodontium.
CONCISE REVIEW Biological: Periodontal Inflammation and Insulin Resistance— Lessons from Obesity
Authors: Nishimura F. , Murayama Y.
Published: January 2009

Recent attention has been focused on our understanding of the negative influences of oral chronic inflammation on systemic health. Successful periodontal treatment appears to have beneficial effects on the metabolic control of type 2 diabetes. Although type 2 diabetes is a multiple-risk-factor syndrome, lowered insulin sensitivity, called insulin resistance, is essential in developing the disease. Pro-inflammatory cytokine, tumor necrosis factor-a (TNF-a), produced from adipose tissues in obese subjects, is known to play a predominant role in inducing insulin resistance. Therefore, it can be hypothesized that anti-infectious periodontal treatment may improve metabolic control of diabetes via improved insulin sensitivity by reducing peripheral TNF-a concentration. In this review, we summarize the nature of insulin resistance and discuss the mechanisms by which insulin sensitivity is influenced by chronic inflammation, such as in periodontal disease.
Cell-surface Proteoglycan Expression by Lymphocytes from Peripheral Blood and Gingiva in Health and Periodontal Disease
Authors: Manakil J.F. , Sugerman P.B. , Li H. , Seymour G.J. , Bartold P.M.
Published: January 2009

Cell-surface proteoglycans are involved in lymphocyte migration and activation. This study investigated the expression of syndecan-1, syndecan-4, and glypican in peripheral blood lymphocytes and by lymphocytes in variously inflamed periodontal tissues. Gingival specimens from healthy, gingivitis, or chronic periodontitis sites were stained by means of antibodies against B- and T-lymphocytes and also syndecan-1, syndecan-4, and glypican. Syndecan-1 expression by peripheral blood mononuclear cells (PBMC) from healthy, gingivitis, and chronic periodontitis subjects was assessed by flow cytometry. Syndecan-1 was expressed by B-cells/plasma cells but not T-cells in both gingivitis and chronic periodontitis lesions. Both B-cells/plasma cells and T-cells in gingivitis and chronic periodontitis expressed syndecan-4. Glypican was expressed only by macrophages. Stimulation of PBMC with mitogens and growth factors modulated syndecan-1 expression in both the T- and B-cells. Thus, cell-surface proteoglycan expression by lymphocytes in periodontal inflammation is cell-type-specific and may be modulated by inflammation.
Autoantibodies to Human α6 Integrin in Patients with Oral Pemphigoid
Authors: Bhol K.C. , Goss L. , Kumari S. , Colon J.E. , Ahmed A.R.
Published: January 2009

Mucous membrane pemphigoid or cicatricial pemphigoid is a mucocutaneous blistering disease characterized by autoantibodies to different molecules in the basement membrane zone. Our objectives were to identify the target antigen recognized by sera from 20 untreated patients with pemphigoid disease limited to the oral cavity, and to determine the pathogenicity of autoantibodies in oral pemphigoid, with an organ culture model. We conducted indirect immunofluorescence, immunoblot, and immunoprecipitation assays, with accompanying absorption experiments, using normal human skin, conjunctiva and gingiva, bovine gingiva and a tumor cell line, which were reacted with sera from patients with oral pemphigoid, anti-α6 antibody, and control sera. Sera of oral pemphigoid patients selectively and specifically bound to human a6 integrin, a 120-kDa protein present in gingiva and the tumor cell line. Oral pemphigoid sera and anti-a6 antibody produced separation of epithelium from basement membrane (blister formation) of normal human buccal mucosa, after 48 hours, in organ culture.
The Novel Gene Locus for Agenesis of Permanent Teeth (He-Zhao deficiency) Maps to Chromosome 10q11.2
Authors: Liu W. , Wang H. , Zhao S. , Zhao W. , Bai S. , Zhao Y. , Xu S. , Wu C. , Huang W. , Chen Z. , Feng G. , He L.
Published: January 2009

He-Zhao deficiency has been recently characterized with a distinct form of agenesis of permanent teeth that is different from other previously reported disorders of tooth agenesis. This inherited abnormality suggests that some gene(s) associated with the development of permanent teeth may mutate. In this study, we map the gene locus to chromosome 10q11.2. The DNA pooling method combined with two-point and multi-point linkage analysis has been successfully applied. The maximum LOD (Zmax) scores for two-point and multi-point analyses are 13.29 (on marker D10S196) at recombination fraction (θ) = 0 and 18.09 (between markers D10S1772 and D10S1766), respectively. Haplotype analysis confined the locus within an interval of 5.5 cM flanked by markers D10S604 and D10S568. This study has demonstrated a novel gene locus responsible for He-Zhao deficiency and provides a good likelihood for the discovery of one of the genes determining permanent tooth formation and development.
Enamel Demineralization in situ with Various Frequencies of Carbohydrate Consumption with and without Fluoride Toothpaste
Authors: Duggal M.S. , Toumba K.J. , Amaechi B.T. , Kowash M.B. , Higham S.M.
Published: January 2009

There is little information in the literature on the relationship among the frequency of carbohydrate consumption, the use of fluoride toothpaste, and enamel demineralization. The aim of this investigation was to compare the extent of demineralization of enamel slabs in situ, with a sugar-based solution, consumed in constant amounts but with various frequencies in subjects both with and without the use of fluoride (F) toothpaste. Eight subjects wore removable mandibular appliances carrying an enamel slab cut from white-spot lesions. The subjects were required to drink 500 mL of a 120-gm/L sugar solution either once, 3, 5, 7, or 10 times/day for 30 sec on each occasion, for a period of 5 days while brushing their teeth twice daily with either a F (1450 ppm NaF) or a F-free toothpaste. Mineral analysis revealed that when the subjects used a F toothpaste, net demineralization was evident only with the seven- and 10-times/day regime (ns). When F-free toothpaste was used, statistically significant demineralization was observed when the frequency exceeded 3 times/day. This study demonstrates the importance of F-containing toothpaste in enamel re-/demineralization by varying the frequency of carbohydrate challenge in situ.
Effect of After-meal Sucrose-free Gum-chewing on Clinical Caries
Authors: Szöke J. , Bánóczy J. , Proskin H.M.
Published: January 2009

Previous in situ and in vitro studies have demonstrated that the chewing of sucrose-free gum after eating reduces the development of dental caries. To investigate the extrapolation of these findings to the clinical setting, we conducted a two-year study on 547 schoolchildren in Budapest, Hungary. Subjects in the "Gum" group were instructed to chew one stick of a commercially available sorbitol-sweetened chewing gum for 20 minutes after meals, three times daily. The "Control" group was not provided with chewing gum. After two years, the "Gum" group exhibited a 38.7% reduction in incremental caries, excluding white spots, compared with the "Control" group. Including white spots, a corresponding 33.1% reduction was indicated. These results clearly suggest that even in a moderate caries population practicing normal oral hygiene, including the use of fluoride dentifrices, an after-meal gum-chewing regimen can significantly reduce the rate of caries development.
Effects of Post-natal Serotonin Levels on Craniofacial Complex
Authors: Byrd K.E. , Sheskin T.A.
Published: January 2009

Although the role of serotonin (5-hydroxytryptamine or 5-HT) in pre-natal craniofacial growth and development has been studied, no research has been done on the effects of serotonin on post-natal craniofacial growth and development. The following experimental question was tested: What effect does increasing in vivo serotonin levels adjacent to trigeminal motoneurons have on post-natal craniofacial structures in young, actively growing rats? Forty male Sprague-Dawley rats were divided into 4 experimental groups (10% serotonin microspheres, 15% serotonin microspheres, blank microspheres, sham surgeries) and underwent stereotactic neurosurgery at post-natal day 35; 5 rats of each group were killed at 14 and 21 post-surgical days for data collection. Statistical analyses by mixed-model, 4 x 2 repeated-measures ANOVA, and post hoc Fisher LSD tests revealed significant (P ≤ 0.05, 0.01) differences between groups and sides for muscle weight, cranial dimension, and TMJ dimension data. Data described here indicate that significant alterations of post-natal craniofacial structures can be caused by altered in vivo levels of serotonin adjacent to trigeminal motoneurons.
Qualitative Light and Electron Microscope Study of Glutamate Receptors in the Caudal Spinal Trigeminal Nucleus of the Rat
Authors: Tang F.R. , Yeo J.F. , Leong S.K.
Published: January 2009

Though ionotropic and metabotropic glutamate receptors have recently been recognized to play important roles in the transmission of orofacial nociceptive impulses, their detailed distribution in the spinal trigeminal nucleus has not been systematically investigated. There is also controversy regarding the electron microscope localization of metabotropic receptors. We therefore undertook this investigation to address the above-mentioned issues in the caudal part of the spinal trigeminal nucleus, using light and electron microscope immunocytochemistry, to provide baseline information for the development of agonists and antagonists of these receptors in the clinical treatment of orofacial pain. The results showed some moderately to strongly stained glutamate receptor 1 neurons, and many strongly stained glutamate receptor 2/3 neurons in lamina II of the nucleus, suggesting that the latter may play an important role in orofacial pain processing, with the former playing a minor role. The metabotropic glutamate receptor 1 immunoreactive product was localized mostly in dendrites, while most of the metabotropic glutamate receptors 2/3 immunoreactive product was deposited in axon terminals containing synaptic vesicles of different shapes, suggesting that glutamate receptors 2/3 may control the release of both excitatory and inhibitory neurotransmitters.
Mechanical Properties of Glass-only Porcelains Prepared by the Use of Two Feldspathic Frits with Different Thermal Properties
Authors: Kon M. , O'Brien W.J. , Rasmussen S.T. , Asaoka K.
Published: January 2009

Low- and non-leucite-containing commercial porcelains with low firing temperatures have become popular. However, improving the strength of glass porcelains is difficult. The purpose of this study was to determine if dispersed glass particles could be used as a reinforcing agent for an all-glass porcelain. We produced 3 feldspathic glasses (high-fusing, medium-fusing, low-fusing) by melting powders consisting of potassium-feldspar and 0, 5, or 20mass% Na2O, respectively. For high-fusing, medium-fusing, and low-fusing feldspathic glasses, the deformation temperatures were 945°C, 647°C, and 518°C, and the thermal expansion coefficient values were 8.6 x 10-6/°C, 10.3 x 10-6/°C, and 13.4 x 10 -6/°C between 25°C and the glass-transition temperature, respectively. The high-fusing-glass (or medium-fusing-glass) powders were mixed with low-fusing-glass powders before being fired into test specimens. The mean flexural strength and fracture toughness (KIC) of 3 single-glass porcelains ranged from 57 to 63 MPa and from 0.68 to 0.73 MPa·m1/2, respectively, presenting no significant differences in one-way ANOVA. However, the flexural strength of 50% high-fusing-glass + 50% low-fusing-glass porcelain was 114 MPa (p < 0.05) and KIC was 1.2 MPa·m1/2 (p < 0.05). Microcracks were observed with a back-scattered scanning electron microscope and were associated with the high- (or medium-) fusing glass particles, suggesting residual stress in the low-fusing-glass matrix due to a coefficient of thermal expansion mismatch between the dispersed glass particles and the matrix glass. The dispersing glass particles appeared to act as a reinforcing agent for strengthening a glassy porcelain.
X-ray Diffraction Study of Acid-degradable Glasses
Authors: De Maeyer E.A.P. , Verbeeck R.M.H.
Published: January 2009

The composition of the degradable glasses used in commercial dental glass-ionomer cements determines their leaching behavior and hence the properties of the cement. The objective of the present study was to assess if the composition and leaching in acetic acid solutions are reflected in the x-ray diffraction characteristics of these glasses. The position (26) of the maximum of the first sharp diffraction peak shifts to higher diffraction angles with increasing number and ionic radius of mono- and bivalent cations in the glass. Upon acid-leaching, these ions are preferentially leached out, so that (26) decreases. These results can be related to the decreasing Si-Si distance in the glass network with increasing modifier radius.
Effects of Mechanical Force on Primary Human Fibroblasts Derived from the Gingiva and the Periodontal Ligament
Authors: Theilig C. , Bernd A. , Leyhausen G. , Kaufmann R. , Geurtsen W.
Published: January 2009

Previous experiments have shown that mechanical stress may alter the interactions between cells and extracellular matrix (ECM). The purpose of our study was to investigate the effects of mechanical load on metabolism and ECM expression of primary human periodontal cells. The influence of gravitational force on proliferation, lactate dehydrogenase (LDH) release, and tenascin expression of gingival (HGF) and periodontal ligament fibroblasts (HPDL), as well as their adhesion to various extracellular matrix (ECM) components, was determined. Cells were centrifuged in microplates or flat tubes for 16 hrs at 217 g. Neither an enhanced release of LDH nor an alteration of cell proliferation could be detected after centrifugation. However, the attachment of loaded gingival and periodontal ligament fibroblasts to all tested ECM components significantly decreased in comparison with controls (Wilcoxon-Mann-Whitney test; HGF, p < 0.05; HPDL, p < 0.01). Tenascin expression of mechanically stressed fibroblasts significantly increased in comparison with controls (p < 0.01).
Low Metacarpal Bone Density, Tooth Loss, and Periodontal Disease in Japanese Women
Authors: Inagaki K. , Kurosu Y. , Kamiya T. , Kondo F. , Yoshinari N. , Noguchi T. , Krall E.A. , Garcia R.I.
Published: January 2009

The relationship between periodontitis and systemic bone mineral density in Japanese women is undetermined. We tested the hypothesis that periodontitis was more frequent in women with low metacarpal bone mineral density (m-BMD). Subjects were 190 Japanese women (89 premenopausal, 101 post-menopausal). Periodontal status was evaluated according to the Community Periodontal Index of Treatment Need (CPITN). M-BMD was measured by computed x-ray densitometry. The proportion of subjects with periodontitis (CPITN ≥ 3) increased as m-BMD decreased in pre-menopausal (18.2%, 36.9%, and 66.6% in the normal, borderline, and very low m-BMD groups, p < 0.02) and post-menopausal women (41.5%, 54.8%, 60%, and 68.4% in the normal, borderline, low, and very low m-BMD groups, p < 0.05). Among post-menopausal women, those with very low m-BMD had fewer teeth present than women with normal m-BMD (19.9 ± 7.2 vs. 25.1 ± 4.1, p < 0.01). These results indicate that m-BMD loss is associated with periodontitis in Japanese women, and with tooth loss after menopause.
The Predominant Aciduric Microflora of Root-caries Lesions
Authors: Brailsford S.R. , Shah B. , Simons D. , Gilbert S. , Clark D. , Ines I. , Adams S.E. , Allison C. , Beighton D.
Published: January 2009

The etiology of root caries is not fully understood, and although mutans streptococci, lactobacilli, and A. naeslundii have been implicated in its initiation and progression, this study was designed to determine the potential role of other microbial species and the nature of predominant aciduric microflora in the root caries process. We isolated the predominant aciduric microflora from root-caries lesions (n = 14) and sound root surfaces in subjects with (n = 13) or without (n = 10) root caries, using both a "most probable numbers" method and conventional plating methods. The predominant aciduric bacteria from root lesions were lactobacilli and A. israelii, while from sound root surfaces in subjects with root caries, A. gerencseriae comprised over 60% of aciduric isolates. Mutans streptococci were not among the aciduric isolates. Subjects without root caries harbored fewer bacteria, and S. anginosus (pH 4.8) and S. oralis (pH 5.2) were the predominant aciduric bacteria. The microbial etiology of root caries is more complex than was previously appreciated, and factors underlying the microbial succession occurring during the disease process are not known. Taxa with previously unrecognized aciduric characteristics have been isolated routinely, and the role of these organisms in the root caries process requires further investigation.
Activation of the Bulbospinal Serotonergic System during Experimental Tooth Movement in the Rat
Authors: Yamashiro T. , Fukunaga T. , Kabuto H. , Ogawa N. , Takano-Yamamoto T.
Published: January 2009

Experimental tooth movement is known to induce characteristic delayed and continuous nociception. Nociceptive somatic stimuli activate endogenous pain control systems such as descending monoaminergic pathways, which modulate the transmission of ascending sensory messages. To test the hypothesis that bulbospinal serotonergic pathways modulate subchronic nociception, we assayed the medulla at the level of the subnucleus caudalis and peri-aqueductal grey by high-performance liquid chromatography with electrochemical detection for the serotonin (5-hydroxytryptamine, 5-HT) and its metabolite (5-hydroxyindoleacetic acid, 5-HIAA) 24 hrs after the onset of experimental tooth movement. Experimental tooth movement significantly increased 5-HT and 5-HIAA levels, and 5-HIAA/5-HT, an index of serotonin turnover, in the medulla, and 5-HIAA level and 5-HIAA/5-HT in the peri-aqueductal grey, indicating that nociception induced by experimental tooth movement activates the bulbospinal serotonergic pathway.
Influences of Ovariectomy on Experimental Tooth Movement in the Rat
Authors: Yamashiro T. , Takano-Yamamoto T.
Published: January 2009

Estrogen withdrawal, which is important in the pathogenesis of post-menopausal osteoporosis, accelerates bone metabolism with a negative calcium balance. Therefore, it is hypothesized that estrogen deficiency could affect the rate of experimental tooth movement and alveolar bone remodeling. Six-week-old rats received a bilateral ovariectomy (OVX) or sham operation. Fourteen days later, rats were subjected to lateral tooth movement in the upper molar with nickel-titanium wire of 10 g of force. OVX significantly increased the rate of experimental tooth movement from 12 days after experimental tooth movement (p < 0.001). Eighteen days after the start of tooth movement, bone histomorphometry demonstrated that OVX significantly elevated the osteoblast surface, osteoclast surface, and number of osteoclasts (p < 0.05) in the alveolar bone. These findings indicated that estrogen deficiency caused significantly rapid orthodontic tooth movement, and that the acceleration of tooth movement could be due to the further activation of alveolar bone turnover.
Purification of Kinase Activity from Primate Parotid Glands
Authors: Lamkin M.S. , Lindhe P.
Published: January 2009

Salivary secretions contain phosphoproteins that contain phosphorylation sites composed of serine residues in acidic environments. The hypothesis of this study is that a protein kinase responsible for phosphorylating these proteins is similar to kinases that phosphorylate proteins in other glandular secretions. Homogenates and subfractions from macaque parotid glands were able to phosphorylate synthetic peptide substrates containing each of the phosphorylation sites in acidic proline-rich proteins, statherin, and histatin 1. Activity was purified from Golgi membranes to greater than 220-fold by extraction with Triton X-100 and affinity chromatography with the use of immobilized ATP. The enzyme preferred substrates containing serine residues in a specific acidic environment, particularly those containing the Ser-Xaa-acidic sequence, preferred ATP over GTP, and was sensitive to high concentrations of heparin. These characteristics are similar to those reported for Golgi casein kinase, which phosphorylates casein in vivo. Based on these observations, the parotid gland kinase may be related to other Golgi-localized serine kinases.
Cloning, Characterization, and Tissue Expression Pattern of Mouse Nma/BAMBI During Odontogenesis
Authors: Knight C. , Simmons D. , Gu T.T. , Gluhak-Heinrich J. , Pavlin D. , Zeichner-David M. , MacDougall M.
Published: January 2009

Degenerate oligonucleotides to consensus serine kinase functional domains previously identified a novel, partial rabbit tooth cDNA (Zeichner-David et al., 1992) that was used in this study to identify a full-length mouse clone. A 1390-base-pair cDNA clone was isolated encoding a putative 260-amino-acid open reading frame containing a hydrophobic 25-amino-acid potential transmembrane domain. This clone shares some homology with the TGF-β type I receptor family, but lacks the intracellular kinase domain. DNA database analysis revealed that this clone has 86% identity to a newly isolated human gene termed non-metastatic gene A and 80% identity to a Xenopus cDNA clone termed BMP and activin membrane bound inhibitor. Here we report the mouse Nma/BAMBI cDNA sequence, the tissue expression pattern, and confirmed expression in dental cell lines. This study demonstrates that Nma/BAMBI is a highly conserved protein across species and is expressed at high levels during odontogenesis.
The Three-dimensional Active Envelope of Jaw Border Movement and its Determinants
Authors: Koolstra J.H. , Naeije M. , Van Eijden T.M.G.J.
Published: January 2009

The sagittal and frontal active envelope of border movement is applied regularly as a clinical tool in functional examinations of the human masticatory system. In contrast, the three-dimensional movement area has hardly been examined. Furthermore, the determinants of this area are not established unambiguously. In the present study, the three-dimensional envelope of incisor movement was predicted with a three-dimensional mathematical model of the human masticatory system, which included the morphology of the system and the fine architecture of its muscles. With this model, the influence of the temporomandibular ligaments and the passive muscle tensions on the envelope were estimated. The predicted three-dimensional active envelope of border movements was limited in horizontal directions, predominantly by the temporomandibular ligaments. The passive tensions of the masticatory muscles influenced, although marginally, its vertical extension. It appeared unlikely that, in a normal situation, active muscle tensions (casu quo muscle reflexes) contribute to the shape of the envelope.