bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitation of Human Salivary Acidic Proline-rich Proteins in Oral Diseases
Authors: Mandel I.D. , Bennick A.
Published: November 2010

Acidic proline-rich proteins (APRP) were quantitated immunochemically in salivary secretions from groups of: caries-resistant (CR) and caries-susceptible (CS) subjects; heavy- and light-calculus-formers; and patients with Sjögren's Syndrome, drug-induced xerostomia, and recurrent parotitis. In all groups except the parotitis patients, there were comparable levels of APRP, about 40-50 mg%, with similar values in parotid and submandibular saliva. In chronic recurrent parotitis, the values were somewhat higher (about 60 mg%). There were no differences in the proportion of APRP-A to C in a subset of CR and CS. Taken as a whole, the data support the view that the secretion of APRP is stable and that caries status and propensity to calculus formation are not associated with abnormal levels of these phosphoproteins.
Clinical Science Human Factors in the Measurement of the Masseteric Silent Period
Authors: Lavigne G. , Frysinger R. , Lund J.P.
Published: November 2010

Human variability in the measurement of the masseteric silent period (SP) was quantified. There were significant differences among (1) observer groups (technicians and dental students), (2) individual observers, (3) repeated measures of the same SP, and (4) trials. No significant observer bias was found. SP's were significantly longer at an inter-incisal distance of 10 mm (48.8 ± 5.4 ms) than at 14 or 19 mm (44. 7 ± 9.8 ms, 44.5 ± 6.5 ms).
Estimates of the Gain in Power Utilizing Transformations of DMFS Scores
Authors: Smith M.R. , Rule J.T.
Published: November 2010

More than 100,000 clinical caries trials were simulated utilizing the negative binomial distribution on a UNIVAC 1100 computer. In each trial, the raw data and logarithmic transformed data were analyzed using a standard t test analysis. The results were summarized as estimates of the power functions for each case. In almost all cases, the transformed data gave greater power than did the untransformed data. In several common situations, the differences were dramatic.
Progesterone Metabolism in the Murine Submandibular Salivary Gland
Authors: Ferguson M.M. , Bannon A.M.
Published: November 2010

Homogenates of submandibular salivary glands from female mice were incubated with progesterone. This resulted in the formation of 20α-hydroxy-progesterone, thus indicating the presence of the enzyme, 20α-hydroxysteroid dehydrogenase.
Production of Histolytic Enzymes by a Combination of Oral Bacteria with Known Pathogenicity
Authors: Dahlén G. , Wikström M. , Möller Å.
Published: November 2010

Eight oral bacterial strains, isolated from an infected root canal, have been investigated for their capacity to produce histolytic enzymes. The determination was performed using methods espoused by two different principles. Eleven out of 12 enzymes examined were demonstrated in the "eight-strain collection". In no single bacterial strain were all enzymes revealed. It was suggested that the pathogenicity of the bacterial strains, singly or in combination, was not solely dependent on the production of these enzymes. The histolytic enzymes may have a potentiating role on other pathogenic factors in infectious diseases.
Taste Thresholds, Taste Preferences, and Dental Caries in 15-year-olds
Authors: Nilsson B. , Holm A.-K.
Published: November 2010

In two groups of 15-year-olds — 50 with a high and 50 with a low caries experience — recognition thresholds were determined for sweet, salty, sour, and bitter tastes and preferences for sweet taste, using a full-mouth technique. No statistically significant difference in thresholds could be found between the groups. No correlation between threshold values and preferences for sucrose could be established.
The Influence of Drawing Parameters on the Mechanical Properties of Two Beta-titanium Alloys
Authors: Shastry C.V. , Goldberg A.J.
Published: November 2010

The total cold reduction and reduction per pass used during the drawing of fine wires affected the mechanical properties of two beta-titanium alloys. Both Ti-11.5Mo-6Zr-4.5Sn and Ti-13V-llCr-3Al showed increased yield strengths and low moduli of elasticity, which resulted in wires appropriate for orthodontic application.
Plasma Beta-Endorphin-like Immunoreactivity, Pain and Anxiety Following Administration of Placebo in Oral Surgery Patients
Authors: Hargreaves K.M. , Dionne R.A. , Mueller G.P.
Published: November 2010

Plasma beta-endorphin was measured in patients undergoing a stressful procedure, the removal of impacted third molars. In patients reporting little pain, endorphin levels increased significantly during surgery, whereas patients reporting pain and anxiety showed little increase in endorphin levels.
Acid Sensitivity of Glycolysis in Normal and Proton-permeable Cells of Streptococcus mutans GS-5
Authors: Thibodeau E.A. , Marquis R.E.
Published: November 2010

Gramicidin, an ionophoric antibiotic which enhances proton permeability of cell membranes, was found to increase the acid sensitivity of glycolysis by intact cells of Streptococcus mutans GS-5, to inhibit uptake of 2-deoxyglucose at pH values of 5.5 or less, and to cause a decrease in the intracellular levels of early intermediates of glycolysis. The inhibitory effects of the antibiotic on glycolysis at low pH values were related to inhibition of sugar uptake via the phosphotransferase system.
Basic Biological Sciences
Authors: Calhoon D.A. , Mayberry W.R. , Slots J.
Published: November 2010

We compared the cellular fatty acid and protein content of 43 strains of oral fusobacteria isolated from patients with chronic gingivitis, acute necrotizing ulcerative gingivitis, and juvenile and adult periodontitis, as well as from the stump-tailed macaque, to that of eight reference strains of oral and non-oral Fusobacterium species. A gas-liquid chromatographic examination of trimethylsilyl derivatives of the fatty acid methyl esters revealed n14:0, 3-OH-14:0, n16:0, 16 :1, 3-OH-16:0, n18:0, and 18:1 in each of the 51 study strains, and a variable occurrence of 14 other fatty acids. The n16:0 to 3-OH-16:0 ratio distinguished between Fusobacterium nucleatum and the non-oral species Fusobacterium varium, Fuso bacterium necrophorum, Fusobacterium russii, Fusobacterium necrogenes, Fusobacterium mortiferum, and Fusobacterium naviforme. The soluble protein content, as determined by polyacrylamide gel electrophoresis, varied considerably among the oral fusobacterial strains studied, and underscored the heterogenous nature of these organisms. "Fingerprinting" of oral fusobacteria may be readily accomplished by polypeptide analysis.
The Composition of Recrystallized Bone Mineral
Authors: Biltz R.M. , Pellegrino E.D.
Published: November 2010

Bone mineral and synthetic calcium-deficient carbonate apatite (CDCA), when defined in terms of their respective thermal stabilities and ignition products, are homologous. When heated to 550°, they may have a structure similar to that of the mineral dahllite. When heated to temperatures >550°, CDCA (like bone mineral) loses its structural CO3 and is recrystallized to whitlockite and/or OH-apatite, depending on its stoichiometry.
Materials Science
Authors: Johnson D.L. , Rinne V.W. , Bleich L.L.
Published: November 2010

Based on polarization measurements, high Au alloys are highly corrosion-resistant and exhibit the lowest corrosion rates; intermediate Au, Ag, and Pd alloys with Cu are passive but exhibit higher corrosion rates. Twenty weight percent (w/o) In-Ag alloys exhibit active corrosion behavior at potentials only 100 m V noble to the corrosion potential.
High-temperature Behavior of a Pd-Ag Alloy for Porcelain
Authors: Mackert J.R. , Ringle R.D. , Fairhurst C.W.
Published: November 2010

The mechanism of formation of nodular material on the surface of a Pd-Ag-based alloy for porcelain during pre-porcelainization heat treatment was investigated using scanning electron microscopy, x-ray diffraction, quantitative metallography, and Auger electron spectroscopy. The nodules were found to form by a Nabarro-Herring creep mechanism driven by the internal oxidation of tin and indium. Implications of this process with regard to porcelain bonding and discoloration are discussed.
The Effect of Polyvalent Metal Ion Mordanting on Caries-like Lesion Progression in Enamel
Authors: Clarkson B.H. , Wefel J.S. , Miller I.
Published: November 2010

The ability of metal ion mordanting followed by APF application to inhibit the progression of caries-like lesions was compared with APF treatment alone. The progression of the lesion was investigated in vitro using an acidified gel system, and the lesions were compared using polarized light microscopy. Both ferric and zirconyl pre-treatments, but not titanium, were shown to inhibit lesion progression to a greater extent than did APF. This inhibition was thought to be due to the presence of an amorphous-type coating similar to those produced on sound enamel by metal ion mordanting.
Extensive Degradation of Recently Synthesized Collagen in Gingiva of Normal and Streptozotocin-induced Diabetic Rats
Authors: Schneir M.L. , Ramamurthy N.S. , Golub L.M.
Published: November 2010

The degradation of recently synthesized collagen (probably procollagen) in rat incisor gingiva was three times greater than that in skin. Concomitantly, the formation of undegraded (intact) collagen molecules in gingiva was slower than that in skin. This high basal rate of degradation in gingiva was just slightly increased in streptozotocin-induced diabetic rats, whereas the low basal rate in skin was dramatically increased by the diabetic state.

The degradation of recently synthesized collagen was measured by the relative amounts(%) of [3H]hydroxyproline-containing material in the TCA-soluble fraction of a tissue, compared with the total amount (TCA-soluble + TCA-insoluble) of [3H]hydroxyproline-containing material. Separation of the TCA fractions allowed the formation of collagen degradation products (TCA-soluble) to be viewed separately from the formation of undegraded collagen molecules (TCA-insoluble).

The [3H]hydroxyproline-containing material in the TCA-soluble fraction was greatest in amount and in specific activity, 30 min after [ 3H] proline injection, supporting the origin of this material as being procollagen. At this time period, the relative amounts of TCA-soluble [ 3H] hydroxyproline-containing material were 40.3% (gingiva) and 12.7% (skin). For diabetic rats, the values were 55% and 48.8%, respectively.

For the [3H] hydroxyproline-containing material in the TCA-insoluble fraction, at 30 min, the specific activity of [3H] hydroxyproline was 4.3 for gingiva and 7.4 for skin. At all other time periods, the values were also greater for skin than for gingiva, making it unlikely that the formation of intact collagen molecules occurred faster in gingiva than in skin.

Overall, the prevailing concept of rapid collagen turnover in oral tissues seems applicable to procollagen, but not to collagen of rat incisor gingiva.
Streptococcus mutans and Caries Prevalence in Lisu and Karen of Northern Thailand
Authors: Reichart P. , Gehring F.
Published: November 2010

The prevalence of dental caries was studied in 139 Lisu and 167 Karen using the DMF-T index. Oral habits were recorded, including the chewing of betel nut. Samples of drinking water and betel constituents were collected and assayed for fluoride concentrations. Plaque material from 100 randomly selected individuals from each village was examined qualitatively for S. mutans. The DMF-T index scores for both tribal groups were low (0.00 - 1.00), and there was no significant difference in caries prevalence between betel chewers and non-chewers. Fluoride concentrations of the water samples were comparably low (0.02 - 0.29 ppm F). 30% of 200 plaque samples were positive for S. mutans, mostly of Biotype I.
Crystallographic Structure of Enamel Surfaces Treated with Topical Fluoride Agents: TEM and XRD Considerations
Authors: Nelson D.G.A. , Jongebloed W.L. , Arends J.
Published: November 2010

The crystallographic structure of surface coatings produced by three topical fluoride agents deposited by a single application on intact human enamel surfaces was investigated by light- and dark-field transmission electron microscopy, as well as by electron and x-ray diffraction. The agents studied were an acidic silane fluoride lacquer, a neutral NaF lacquer, and an APF gel. The smallest coherently diffracting particles were CaF2 microcrystallites 4-15 nm in diameter. Large apatite-like crystals, approximately I μm in length, were also observed in the outer surface coating produced by the silane fluoride lacquer.
Clinical Science Nitrous Oxide Analgesia: A Psychophysical Evaluation Using Verbal Descriptor Scaling
Authors: Heft M.W. , Gracely R.H. , Dubner R.
Published: November 2010

The effect of 33% nitrous oxide/67% oxygen was compared with 100% oxygen and air on verbal reports of either sensory intensity or unpleasantness of sensations associated with painful electrical tooth pulp stimulation. Forty-eight subjects used words describing the sensory intensity (i.e., weak, mild, strong) or degree of unpleasantness (i.e., annoying, unpleasant, distressing) to assess the sensations produced by a broad range of tooth pulp stimuli. Within the experimental session, a given subject assessed the painful sensations under all three treatments delivered through a nasal inhaler in a double-blind manner. The incorporation of within-subject placebo (nasal inhaler + air) and active placebo (nasal inhaler + oxygen) controls allowed for rigorous assessment of the components of nitrous oxide analgesia. The results of this study suggest that 33% nitrous oxide analgesia reduces the intensity but not the unpleasantness of painful tooth pulp sensations. Further, 100% oxygen provides no analgesic effect.
Enamel Fluoride Uptake and Acid Resistance in Subjects with High and Low Experimental Cariogenicity
Authors: Ostrom C.A. , Koulourides T. , Retief D.H. , Bradley E.L.
Published: November 2010

The response of bovine enamel to intra-oral cariogenic environments was studied in human volunteers. Enamel slabs were mounted in dentures and treated with either 10% sucrose or 10% sucrose plus 20 ppm fluoride mouthrinses for one minute five times daily. After one week, these enamel slabs were studied for change in surface hardness and for the degree of fluoride incorporation, or for their resistance to acid acquired by the intra-oral exposure. Among the eight subjects, those with the highest experimental cariogenicity exhibited the highest benefit of enamel from the fluoride in terms of fluoride incorporation and in their resistance to the subsequent acid test. The results suggest that cariogenic activity and fluoride will synergistically improve the tooth resistance to subsequent attack, apparently through mineral exchange that favors the formation of acid-resistant minerals with high fluoride content within enamel lesions.
Materials Science Cements Containing Syringic Acid Esters- o-Ethoxybenzoic Acid and Zinc Oxide
Authors: Brauer G.M. , Stansbury J.W.
Published: November 2010

Fissure caries is reduced when syringic acid is incorporated into a cariogenic diet of rats. It was therefore of interest to synthesize n-hexyl and 2-ethylhexyl syringate and to evaluate the properties of cements with these compounds as ingredients. Liquids containing the esters dissolved in o-ethoxybenzoic acid (EBA) - when mixed with powders made up from zinc oxide, aluminum oxide, and hydrogenated rosin - hardened in from four to nine min.

Properties of the cements were determined, when possible, according to ANSI/ADA specification tests. Depending on the powder-liquid ratio employed, we obtained compositions with varying physical properties desirable for different dental applications.

The syringate cements, compared with the commonly used ZOE materials, have improved compressive and tensile strength, lower water solubility, do not inhibit polymerization, and are compatible with acrylic monomers. These cements pass, and mostly greatly exceed, the requirements for ZOE-type restorative materials. They also bond significantly to resins, composites, and non-precious metals. The bond strength is somewhat less than that of n-hexyl vanillate-EBA cement, but greatly exceeds the adhesion to various substrates of ZOE luting agents.

Cements containing n -hexyl syringate were somewhat brittle. Best results were obtained with liquid compositions containing 5% 2-ethylhexyl syringate, 7% n -hexyl vanillate, and 88% EBA, which yielded non-brittle materials. These cements, because of the syringate ingredient, may possess caries-reducing properties. Thus, perhaps in conjunction with fluoride additives, they would be useful as insulating bases, pulp capping agents, root canal sealers, soft tissue packs, or intermediate restoratives.
Class 2 Composite Restorations: Prevention in vitro of Contraction Gaps
Authors: Jørgensen K.D. , Hisamitsu H.
Published: November 2010

The present in vitro study has shown that it is possible to prevent marginal contraction gaps at composite restorations in the proximal section of Class 2 cavities by use of a condensable composite and adequate condensers. An explanation of condensation to eliminate the wall-to-wall polymerization contraction is suggested, and a possible complete Class 2 composite technique is outlined, The subject studied is only one of several problems that must be analyzed before acceptance of composite resins as Class 2 restoratives can be made possible.Received for publication June 30, 1983 Accepted for publication October 17, 1983
The Structure of a Commercial Dental Ag-Pd-Cu-Au Casting Alloy
Authors: Niemi L. , Her H.
Published: November 2010

The structure of a commercial dental Ag-Pd-Cu-Au casting alloy has been studied by microprobe and X-ray diffraction analyses after various heat treatments. The composition of phases in equilibrium was established. After being annealed at 400°C, 500°C, and 600°C for seven wk, the alloy consisted of three phases: a Cu- and Pd-rich fcc phase (α1) with a = 0.372nm, a Ag-rich matrix (α 2) with a = 0.399nm, and an ordered CsCl-type bcc PdCu phase with a = 0.296nm. The PdCu phase was not observed above 600°C, and the proportion of the α1 phase decreased sharply above 700°C. After being annealed at 900°C, the alloy matrix was partly decomposed at the Cu-enriched grain boundaries. The decomposed areas grew into the grain interior during subsequent precipitation hardening. No segregation of Au was detected after casting, and the element was evenly distributed throughout the alloy structure after all heat treatments.
Long-term F Release from Glass Ionomer Cements
Authors: Swartz M.L. , Phillips R.W. , Clark H.E.
Published: November 2010

Fluoride release from three commercial glass ionomer filling cements and three glass ionomer luting cements was measured in the laboratory over a 12-month period. Fluoride release from these glass ionomer cements was compared with that released from a silicate, silicophosphate, and a fluoride-containing polycarboxylate cement. The fluoride released from the glass ionomer cements throughout the one-year period was similar, both in quantity and pattern, to that released by the silicate cement. The silicophosphate cement tended to release fluoride in somewhat lesser amounts, while the amount of fluoride released by the polycarboxylate was negligible after the first few days.

Analysis of these data indicates that these glass ionomer cements probably possess anticariogenic properties similar to those of silicate cement.
Microheterogeneity of Rat Parotid Gland Proteins After Chronic Treatment with Isoproterenol
Authors: Mednieks M.I. , Hand A.R.
Published: November 2010

Two ultrasensitive methods were employed to determine the effect of repeated in vivo stimulation with isoproterenol on the protein composition of parotid acinar cells. Silver staining showed electrophoretic banding pattern changes in a wide range of cellular proteins during and after multiple injections of the β-adrenergic agonist. Photo-affinity labeling with [32P]-N3-cyclic AMP showed the disappearance and eventual return (after discontinuation of the injections) of the cellular cyclic AMP-binding proteins as measurable cellular components. These findings indicate that major translation-associated changes may occur in target cell protein composition both during and after hormonal stimulation.
Inhibition of Seeded Growth of Enamel Apatite Crystals by Amelogenin and Enamelin Proteins in vitro
Authors: Doi Y. , Eanes E.D. , Shimokawa H. , Termine J.D.
Published: November 2010

The effect of enamel matrix proteins on the seeded growth of enamel apatite crystals was studied in stable supersaturated solutions at pH 7.4 and 37°C. Of the two major protein classes in the enamel matrix, the enamelins were considerably more effective than the amelogenins in retarding seeded growth. However, the amelogenin species that did show significant inhibitory activity are those known to be lost first from the enamel matrix during the rapid mineralization stage of enamel maturation.
Microbial Ecology Adherent Interactions Which May Affect Microbial Ecology in the Mouth
Authors: Gibbons R.J.
Published: November 2010

Bacteria attach to teeth and oral mucosal surfaces in a surprisingly selective manner, and attachment appears to be the first step in the colonization process. Attachment is thought to involve lectin-like and/or hydrophobic ligands, called adhesins, often present in bacterial surface appendages which interact with receptors on oral tissues. A variety of factors can influence bacterial attachment, and therefore have the potential to affect host-parasite interactions in the mouth. Factors discussed include salivary components, dietary lectins, and sublethal concentrations of antibiotics.
A Conceptual Model for the Co-existence of Streptococcus Spp. and Actinomyces Spp. in Dental Plaque
Authors: Van der Hoeven J.S. , De Jong M.H. , Rogers A.H. , Camp P.J.M.
Published: November 2010

One of the most important questions in ecology is how to explain the co-existence of the variety of physiologically related organisms in the same habitat. A model is presented for the co-existence of Streptococcus species and Actinomyces species in dental plaque. The hypothesis is that these organisms co-exist because they simultaneously utilize several carbon and energy substrates. The hypothesis follows from the observation that the growth yield of oral streptococci and actinomyces in saliva is limited by carbohydrate. Preliminary experiments were undertaken to test the hypothesis using mixed chemostat cultures and gnotobiotic rats.

Competition between S. mutans K1R and A. viscosus Ut2 in mixed chemostat cultures on glucose and asparagine was hampered by the early appearance of high-glucose-affinity variants of A. viscosus. From the physiological characteristics of S. sanguis and S. milleri, it might be predicted that simultaneous utilization of carbohydrate and arginine would enable these organisms to co-exist with S. mutans in an ecosystem.

To test this mechanism under natural conditions, germ-free rats were inoculated with a combination of S. mutans K1R and S. sanguis P4A7 or the combination S. mutans K1R and S. milleri B448. The rats were fed on three different diets: (1) 58% cornstarch ; (2) 48% cornstarch and 10% sucrose; and (3) 53% cornstarch and 5% arginine.

The results of this experiment demonstrated that dietary arginine caused a significant decrease of the ratios K1R/P4A7 and K1R/B448 in dental plaque. Thus, arginine stimulated S. sanguis and S. milleri, whereas sucrose promoted S. mutans. It can be concluded that bacterial substrate is a major ecological factor for dental plaque. This factor can potentially be studied in mixed-chemostat cultures and in gnotobiotic rats.
The Function and Distribution of Different Fimbriae on Strains of Actinomyces viscosus and Actinomyces naeslundii
Authors: Cisar J.O. , Sandberg A.L. , Mergenhagen S.E.
Published: November 2010

Actinomyces viscosus and Actinomyces naeslundii differ in their abilities to colonize tooth and epithelial surfaces. These differences appear to be associated with the distribution of different fimbriae on the two species and with the distinct adherence-related functions of these structures.
Relationship of Bioenergetic Processes to the Pathogenic Properties of Oral Bacteria
Authors: Marsh P.D. , Keevil C.W. , Ellwood D.C.
Published: November 2010

The energized membrane has been shown to affect properties (sugar transport, acid production, intracellular polysaccharide formation, and glycosyltransferase secretion) related to the pathogenicity of oral bacteria. The activity of the energized membrane was susceptible to modulation by environmental conditions likely to be encountered by bacteria in dental plaque.
Microbial Pathogenicity in Oral Soft Tissue Diseases
Authors: Greenspan J.S. , Shillitoe E.J.
Published: November 2010

Recent work implicating microbial factors in the pathogenesis of several oral soft tissue diseases is discussed. These conditions include recurrent aphthous ulceration, oral cancer, Sjogren's syndrome, and the oral lesions of AIDS (the acquired immune deficiency syndrome). This paper reviews some recent work on these topics, with emphasis on investigations in our laboratory.
The Control of Morphogenesis in Candida albicans
Authors: Shepherd M.G. , Sullivan P.A.
Published: November 2010

Morphogenesis (germ-tube formation) in Candida albicans was induced gratuitously by N-acetylhexosamine derivatives (N-acetylglucosamine covalently linked to agarose, N-acetylmannosamine, hyaluronic acid, colloidal chitin, and mucin). These compounds were not taken up by the yeast cells and did not support growth. 2-Deoxyglucose was a potent inhibitor of germ-tube formation (50 μM), but did not affect the yeast growth yield at a concentration of 2.5 mM. 2-Deoxyglucose covalently linked to agarose did not affect germ-tube formation, and the inhibition by free 2-deoxyglucose was overcome by the addition of glucose to the germ-tube-forming cells. Glucose competitively inhibited 2-deoxyglucose uptake (Ki = 0.14 mM), and these data indicate that 2-deoxyglucose acted intracellularly.
Host Response in Experimental Periodontal Disease
Authors: Taubman M.A. , Yoshie H. , Ebersole J.L. , Smith D.J. , Olson C.L.
Published: November 2010

Experiments were performed to determine the role of the immune response in rat periodontal disease. Germ-free rats were fed defined antigen-free liquid diets or a diet containing ovalbumin(OVA) as a prototype antigen. The OVA-fed rats demonstrated increased gingival lymphocytes (mainly T at early times), OVA-sensitized spleen cells, and increased periodontal bone loss. In further studies, rats pre-sensitized with OVA, and receiving OVA in the diet, showed elevated IgG antibody, sensitized spleen cells, and elevated periodontal bone loss scores. The concept that bone loss was due to mixed hypersensitivity reaction is consistent with the periodontal pathology. The effects of pre-immunization with A. actinomycetemcomitans (Aa ) on periodontal bone loss in Actinobacillus (Aa ) - infected rats was examined. Delayed hypersensitivity (DTH) was present in immunized rats throughout the experimental period. Sham-immunized rats showed DTH after 30 days of infection. In addition, immunized rats showed elevated bone loss scores. These experiments support the contention that a combination of hypersensitivity reactions (i.e., mixed hypersensitivity to Aa) could give rise to the periodontal pathology observed.

Congenitally athymic rats (nude) were shown to have more periodontal bone loss than did normal littermates. However, bone loss in thymus-cell reconstituted nude rats was not different from that in control rats. Normal rats receiving Aa-sensitized T lymphocytes prior to infection with Aa demonstrated increased DTH and periodontal bone loss. These studies support the concept that T-cell functions and thymic regulation of immune responses can exert protective and/or destructive effects in periodontal disease. In order to modify disease, it will be necessary to enhance the protective aspects of the immune response and to minimize the detrimental aspects.
Collagen and Prostaglandin Synthesis in Force-stressed Periodontal Ligament in vitro
Authors: Duncan G.W. , Yen E.H.K. , Pritchard E.T. , Suga D.M.
Published: November 2010

.4 periodontal organ culture system capable of receiving orthodontic type forces was developed. Histalogical, radioautographical, collagen, and prostaglandin synthetic data demonstrated the vitality of the organ over a 24-hour period of culture. Significant increases in the proportion of type III collagen synthesized during periods of active stress were found, but no alterations in relative levels of prostaglandins synthesized during periods of force application were discernible.
Clinical Assessment of New I.V. Sedation Agents and Techniques
Authors: Peterson L.J.
Published: November 2010

The purpose of this paper has been to describe the information that must be gathered before a new drug can be used effectively and safely for I.V. sedation. A new drug, midazolam, has been used as an illustrative example.
Experimental Osteo-fluorosis in the Domestic Pig: A Histomorphometric Study of Vertebral Trabecular Bone
Authors: Kragstrup J. , Richards A. , Fejerskov O.
Published: November 2010

The experiment aimed at describing effects of fluoride on structure and remodeling of vertebral trabecular bone in pigs. Eight animals receiving a supplement of 2 mg F /kg b. w. per day from age eight to 14 mo were compared with eight controls. Plasma fluoride increased from 0.7 ± 0.1 μM/1 to 12.7 ± 2.0 μM/1 in pigs receiving fluoride. At slaughter, the concentration of fluoride in dry fat-free bone was 149.3 ± 10.5 mM/kg for fluorotic animals and 9.5 ± 0.9 mM/kg for controls. Morphologic changes were assessed in un-decalcified specimens of the fourth lumbar vertebra by quantitative histology using fluorochromes as intra-vital tissue time markers. The volume of trabecular bone tissue (bone + marrow) was unchanged in fluorotic animals, but the volume density of bone was increased by 17%. Surface densities of cancellous bone were almost unchanged, whereas the thickness of trabeculae increased in fluorosis. Fluoride enhanced remodeling of trabecular surfaces: The fraction of surface occupied by resorption lacunae increased 40%, and the formative surface approximately 30%. No changes were demonstrated at surface points undergoing formation: Osteoid thickness, calcification rate, lamellar thickness, and completed wall thickness were normal. It is concluded that the observed findings cannot be explained by fluoride-induced changes in a single cell. Fluoride appears to affect all cells involved in remodeling by direct or indirect mechanisms.
Lipid Peroxidation as a Possible Cause of Benzoyl Peroxide Toxicity in Rabbit Dental Pulp—A Microsomal Lipid Peroxidation in vitro
Authors: Terakado M. , Yamazaki M. , Tsujimoto Y. , Kawashima T. , Nagashima K. , Ogawa J. , Fujita Y. , Sugiya H. , Sakai T. , Furuyama S.
Published: November 2010

The toxicity of composite resin on rabbit dental pulp was investigated biochemically. A microsomal fraction of rabbit dental pulp was incubated with each of the components of composite resins, and the formation of peroxide was determined by the thiobarbituric acid reaction. Benzoyl peroxide (BPO), the most widely used catalyst, was the most effective on peroxidation, but monomers were not. Cations such as Cu2+ or Fe2+ were required for acceleration of this reaction. Authentic polyunsaturated fatty acids and phospholipids were extensively converted into their peroxides by BPO, but amino acids and carbohydrates were not. Among the active oxygens, hydroxyl radicals were thought to be responsible for BPO-dependent peroxidation. The results presented in this paper indicate that the lipid portion of the cells may be attacked by hydroxyl radicals produced by BPO and copper or iron. Therefore, BPO is considered to be the major factor responsible for the toxicity of composite resins.
Automated Immunofluorescent Speciation of Oral Bacteria Using Flow Cytometry
Authors: Barnett J.M. , Cuchens M.A. , Buchanan W.
Published: November 2010

Mixtures containing two bacterial species were analyzed using flow cytometric techniques. Light scattering characteristics of Streptococcus mutans and Actinomyces viscosus show unique profiles for pure cultures. However, the light scatter analysis of a mixture containing these two species demonstrates overlapping near the origin. Thus, light scatter analysis was not sufficient to speciate bacteria with different morphologies. Labeling of samples with species-specific immunofluorescent antibodies permitted speciation of mixtures. As the percentage of the bacterium to which the antibody is directed increased in a two-component mixture, fluorescent flow cytometric analysis showed a corresponding increase in the percentage of cells displaying fluorescent labeling. These methods could permit the rapid identification of bacteria from oral sites without culturing.
Fluoride Uptake by Partially-decalcified Enamel: A Study of Possible Involvement of Acid Phosphate Ions
Authors: Moore A.J.
Published: November 2010

Ionic fluoride and HPO 2-4 concentrations were determined in partially-decalcified enamels before and after exposure to NaF or MFP toothpastes, to determine whether fluoride uptake could be attributed to reactions with HPO2- 4. Acid phosphate concentrations did not alter upon exposure to fluoride, even though large uptake of fluoride did occur. Infra-red spectroscopy showed HPO2-4 in artificially decalcified enamel to be adsorbed rather than present as a discrete secondary orthophosphate.
Clinical Science Cusp Reinforcement by the Acid-etch Technique
Authors: Morin D. , DeLong R. , Douglas W.H.
Published: November 2010

Strain gauges were mounted on 12 maxillary pre-molars which were subjected to a sequence of restorative procedures for MOD preparations. An occlusal stress was applied using servohydraulics, and the cuspal flexure was assessed using a strain gauge. Two bonded and three non-bonded restorative procedures were tested for each tooth. The two bonded conditions showed significantly higher cuspal reinforcement when compared with the MOD preparation and the non-bonded restorative procedures.

The non-bonded restorations showed some intragroup differences, with one non-bonded composite showing useful cuspal reinforcement. However, this was much less than that afforded by the bonded technique.

The deformation of the cusp under occlusal force in restorations bonded by the acid-etch technique showed much less hysteresis when compared with non-bonded restorations.
Basic Biological Sciences Regulation of Tight Junctional Permeability in the Rat Parotid Gland by Autonomic Agonists
Authors: Mazariegos M.R. , Hand A.R.
Published: November 2010

The permeability of tight junctions in the rat parotid gland to the ultrastructural tracer myoglobin (m.w. 17,800) was investigated after in vivo stimulation by autonomic drugs. At various times after administration of β-adrenergic (isoproterenol), α-adrenergic (methoxamine), or cholinergic (methacholine) agonists, the parotid duct was cannulated, and a solution of myoglobin was allowed to flow by gravity (16 mm Hg) into the gland for one hr. In resting glands, cytochemical reaction product for myoglobin was localized in the luminal space of acini and ducts. The tracer was also localized to the luminal space after stimulation with methacholine and methoxamine. In contrast, one to four hr after isoproterenol stimulation, reaction product was present in the intercellular and interstitial spaces of the gland. At later times after stimulation (from six to 24 hr), the tracer was again restricted to the luminal space of the acini and ducts. These results indicate that isoproterenol stimulation causes a transient increase in tight junctional permeability, whereas stimulation with methoxamine or methacholine does not change junctional permeability to myoglobin.
Effects of Fluoride, Lithium, and Strontium on Intracellular Polysaccharide Accumulation in S. mutans and A. viscosus
Authors: Wegman M.R. , Eisenberg A.D. , Curzon M.E.J. , Handelman S.L.
Published: November 2010

Fluoride (5 mg/l) consistently depressed the accumulation of intracellular iodophilic polysaccharides (IPS) in Streptococcus mutans strains BHT, FA-1, and GS-5 by over 90% and in Actinomyces viscosus strain RC-45 by over 50%. There was little further reduction in IPS content when fluoride was increased from 5 to 100 mg/l. Lithium (0 to 1 mg/l) neither enhanced nor inhibited IPS accumulation, nor did it modify the inhibitory effects of fluoride in three of the four strains tested. Strontium (0 to 100 mg/l) did not alter IPS accumulation in S. mutans GS-5 but decreased accumulation (<10%) in S. mutans FA-1 and BHT and significantly enhanced IPS accumulation in A. viscosus RC-45. Analysis of variance indicated no statistically significant interactions between fluoride and strontium, fluoride and lithium, or strontium and lithium.
Acceleration of Remineralization in vitro by Sodium Monofluorophosphate and Sodium Fluoride
Authors: Mellberg J.R. , Mallon D.E.
Published: November 2010

Sixteen groups of artificial caries lesions were treated with from 75-900 ppm F from MFP, NaF, combinations of the two, or water for five min twice daily for ten days. Between treatments, the lesions were placed in a remineralizing solution at 37°C. Quantitative microradiography of the treated lesions vs. matched untreated lesions showed significant remineralization of the surface layer and lesion body of all groups, including the water-treated control group. Fluoride treatments improved remineralization. Increasing the concentration of NaF had only a small effect on remineralization, but MFP was more effective at higher concentrations.

Evaluation of MFP/NaF mixtures showed that greatest remineralization was obtained from a 75/225 ppm F ratio of NaF/ MFP. This combination of F- and PO3F= was more effective than a fluoride concentration of 300 ppm F from either agent alone.
A Model for Producing Caries-like Lesions in Enamel and Dentin Using Oral Bacteria in vitro
Authors: Clarkson B.H. , Wefel J.S. , Miller I.
Published: November 2010

Subsurface enamel lesions and root surface caries-like lesions were consistently produced in vitro using Streptococcus mutans FA1 cultured in thioglycollate broth containing 3.5% w/v dextrose and 2% w/v gelatin. When viewed in polarized light and after imbibition in water, the enamel lesions had a negatively birefringent surface zone and positively birefringent body of the lesion. Those lesions produced after six weeks, after imbibition in quinoline, exhibited a dark zone. The root surface caries-like lesions exhibited a lessradiolucent surface zone above a heavily demineralized body of the lesion. However, no reactionary dentin was seen in the in vitro lesions.
Caries Prevention in Rats by Fluoride Varnish Treatment Combined with Addition of Fluoride to Dietary Sugar
Authors: Seppa L. , Luoma H. , Koskinen M. , Syrjanen S.
Published: November 2010

Osborne-Mendel rats were fed a cariogenic diet containing 43% sucrose for 48 days. The control group received no additional treatment. The teeth of the second group received topical treatment with a sodium fluoride varnish which was applied twice onto newly-erupted molars. The third group received topical treatment with the sodium fluoride varnish combined with a NaF + Mg addition to the diet. In both treatment groups, caries was significantly reduced as compared with caries in the control group. Combined treatment was significantly more effective than was the varnish alone. In spite of the high fluoride concentration in the varnish, no changes in the oral mucosa were found at the end of the study.
Fluoride in Deciduous Teeth from an Anti-caries Clinical Study
Authors: Sakkab N.Y. , Cilley W.A. , Haberman J.P.
Published: November 2010

The fluoride content of both sound and white-spot enamel was determined in deciduous teeth collected from an anti-caries clinical trial which compared a 0.243% NaF dentifrice, a 0.4% SnF2 dentifrice, and a placebo. A microdrill enamel biopsy technique was developed for the analysis of white spots. No correlations were found between caries increment scores and the fluoride content of sound enamel. The enamel in white spots from users of the 0.243% NaF dentifrice had a mean fluoride content higher than that from users of the 0.4% SnF2 dentifrice. There was a negative correlation between fluoride found in white-spot enamel and caries increment scores. It is hypothesized that fluoride affects the caries rate by its control over the rate of remineralization in previously demineralized areas.
Effects of Backing Reflectance and Mold Size on Polymerization of Photo-activated Composite Resin
Authors: Fan P.L. , Stanford C.M. , Stanford W.B. , Leung R. , Stanford J.W.
Published: November 2010

The in vitro depth of cure of a visible-light-activated microfilled composite, as influenced by backing reflectance and mold size, was investigated using microhardness measurements. More extensive polymerization was obtained with higher values of backing reflectance. Mold size larger than the cross-sectional area of the photo-activating beam also increased the degree of polymerization. Backing reflectance and mold size are influential factors and need to be defined in depth-of cure evaluations if in vitro measurements are to be valid predictors of clinical performance.
Extensibility Characteristics of Human Cheek-Visco-elastic Properties
Authors: Ho T.P. , Weinstein S. , Bowley W.W.
Published: November 2010

Using a hydraulic bellows system mounted on a maxillary partial denture, continuous force-displacement data were taken in an edentulous area in the maxillary bicuspid-molar region on ten adults. Both loading and unloading force-displacement curves showed three segments. Two visco-elastic properties - hysteresis and relaxation - were consistently evident. The maximum difference in force-magnitude of the hysteresis loop was 1.02 g. A pre-conditioning phenomenon of the cheek tissue, evidenced by a reduction of the area of the hysteresis loop, was observed in a series of repeated runs.

The significance of the study was that: (1) in some individuals, the cheek could be displaced, by expansion of the molars, up to 1 mm into a second stable position; and (2) the relaxation phenomenon suggests a limited adjustive capacity in cheek stiffness.
Comparison of Artificial White Spots by Microradiography and Polarized Light Microscopy
Authors: Wefel J.S. , Harless J.D.
Published: November 2010

This work compared lesions produced by three artificial caries systems with natural white spot lesions using both polarized light microscopy and microradiography. The three systems employed were the acidified gelatin gel, diphosphonate surface dissolution inhibitor, and a partially saturated buffer system. When we compared the natural white spot lesions with the artificial caries-like lesions, we found that the acidified gel system reproduced the classical histological zones most frequently. All systems showed a radiopaque surface layer overlying a radiolucent body of the lesion. This radiopaque layer could not be equated with the negatively birefringent surface zone seen in polarized light.
Effect of Splint Placement on Black-pigmented Bacteroides and Spirochetes in the Dental Plaque of Beagle Dogs
Authors: Mikx F.H.M. , Ngassapa D.N.B. , Reijntjens F.M.J. , Maltha J.C.
Published: November 2010

The gingival microbiota in beagle dogs was investigated during a period of 42 days after the placement of continuous wire and arch bar splints. The splints were found to induce an increase in helicoidal-shaped micro-organisms and black-pigmented Bacteroides. Two different asaccharolytic Bacteroides types were isolated and tentatively identified as B. gingivalis and B. asaccharolyticus. In addition, B. intermedius- like organisms were isolated. The last two species were observed only after splint placement. The local accumulation of helicoidal-shaped micro-organisms in the epithelial tissue rather than in the micro-ulcerations was regarded as an indication of an active role for these spirochetes in the disease process. The observed shift toward tissue-invading and potentially pathogenic micro-organisms after splinting stresses the need for antimicrobial measures during splint placement in order to minimize periodontal destruction.
Influence of Silane Treatment and Filler Fraction on Thermal Expansion of Composite Resins
Authors: Soderholm K.-J.M.
Published: November 2010

The coefficient of thermal expansion of experimental composite materials containing either silane-treated or untreated fillers in a triethylene glycol dimethacrylate (TEGDMA) matrix was investigated. The results show that an inverse linear relationship existed between volume fraction filler and coefficient of thermal expansion. No differences were seen between silane-treated and untreated composites, while it was found that repeated heating (aging) caused the thermal expansion to decrease for all material combinations.

Reduction in the coefficient of thermal expansion with increased filler fraction of unbonded filler indicates that the polymerization shrinkage of the matrix induces hoop stresses around the fillers.

By use of a simplified theoretical model (Appendix), these stresses could be estimated. These estimates revealed that the induced stresses were remarkably high, and that increased filler fraction increased the tensile stress level surrounding the filler particles. Since these tensile stresses could facilitate crazing and crack growth in the matrix, these estimates may explain why filled resins containing low fractions of microfilled particles seem to possess remarkably good clinical wear resistance when compared with composites containing higher filler concentrations, at least during the first years in service.
Effect of Metal Design on Marginal Distortion of Metal-Ceramic Crowns
Authors: DeHoff P.H. , Anusavice K.J.
Published: November 2010

An analysis of residual stress and marginal distortion due to thermal contraction mismatch between metal and ceramic is presented for metal-ceramic crowns. Using dilatometric data, finite element stress analyses were performed on pre-molar crowns designed with chamfer-knife edge, chamfer with collar, shoulder with collar, and shoulder-bevel with collar geometries and a maxillary central incisor crown with a chamfer-knife edge geometry. Calculations were made using combinations of a Ni-Cr alloy or a Au-Pd alloy with each of three porcelain products. Calculated marginal distortions due to crown design and metal-porcelain thermal contraction incompatibility were found to be well below experimental values found in the literature. For the cases studied, the calculated marginal distortions due to metal-porcelain thermal contraction mismatch depend primarily on the metal-porcelain combination and are insensitive to the coping design. However, this study excluded copings which have been extensively ground to thicknesses of 0.1 mm or less, and such copings may be more susceptible to localized or generalized distortion.