bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Solvent Extracts of Rice Bran and Free-fatty Acids Upon Plaque and Acid Formation
Authors: Katz S. , Williams K.A.
Published: November 2010

Marked inhibition of S. mutans plaque and acid formation was observed when solvent extracts of rice bran or several fatty acids were added to the culture medium. It is proposed that the effects observed with bran extracts are due to their fatty acid content. It would appear that the growth of, and acid formation by, microorganisms frequently mentioned in relation to dental caries can be controlled by a mixture of two or more fatty acids.
Fatty Acid Composition in Phenol Extracts from Actinomyces Species
Authors: Wada H. , Kurihara H. , Okada H.
Published: November 2010

Fatty acid composition in phenol extracts of some strains of Actinomycetaceae was investigated by the combined system of gas chromatography and mass spectrometry (GC-MS). A variety of fatty acids was detected in these extracts, including branched and straight-chain acids.
Chronic Candidiasis of the Rat Tongue: A Possible Model for Human Median Rhomboid Glossitis
Authors: Allen C.M. , Blozis G.G. , Rosen S. , Bright J.S.
Published: November 2010

Ten female Sprague-Dawley rats were inoculated orally with a suspension of viable Candida albicans. Lesions were induced on the posterior midline dorsum of the tongue in seven of ten animals. The clinical and histologic appearance of these lesions was similar to human median rhomboid glossitis.
Clinical Science
Authors: Stinson M.W. , Levine M.J. , Cavese J.M. , Prakobphol A. , Murray P.A. , Tabak L.A. , Reddy M.S.
Published: November 2010

This study demonstrated that human submandibular-sublingual saliva (HSMSL) provided a better substrate than did whole saliva or parotid saliva for the binding of Streptococcus sanguis in a glass adherence assay. Additional evidence indicated that the lower molecular weight salivary mucin in HSMSL was involved in these interactions. Mucin's sialic acid residues were found to play a major role in mediating the binding of certain strains of Streptococcus sanguis.
Effect of Soluble Calcium on Fluoride Uptake By Enamel From Sodium Monofluorophosphate
Authors: Mellberg J.R. , Chomicki W.G.
Published: November 2010

The fluoride uptake by sound, acid-etched and artificial white spot lesions treated with sodium monofluorophosphate in dentifrice slurries, abrasive slurries, or calcium chloride solutions was determined. Fluoride uptake by sound enamel decreased in the presence of soluble calcium; however, uptake by etched and white spot enamel was greatly enhanced. The optimum Ca:MFP molar ratio was 0.5. Because fluorine-containing dentifrices probably inhibit dental caries by interaction with white spots or at the initial stage of acid-attack, the soluble calcium contained in saliva or a dentifrice might enhance the anti-caries effect of monofluorophosphate.
Electronic and Clinical Comparison of Pulp Testers
Authors: Kleier D.J. , Sexton J.R. , Averbach R.E.
Published: November 2010

Electronic and clinical comparisons of three commercially available pulp testers were investigated using oscilloscopes and a clinical trial. The three devices varied in wave-form characteristics and showed statistically significant differences in patient responses.
The Effect of Composition on the Erosion Properties of Calcium Hydroxide Cements
Authors: Prosser H.J. , Groffman D.M. , Wilson A.D.
Published: November 2010

Calcium hydroxide - alkyl salicylate cements are based on bidentate chelate structures. All of the cements are hydrolytically unstable. The release of calcium, hydroxide, and salicylate ions into aqueous solution depends on the nature of the plasticizer.
Pseudocholinesterase Activity and Its Origin in Human Oral Fluid
Authors: Ryhanen R. , Narhi M. , Puhakainen E. , Hanninen O. , Kontturi-Narhi V.
Published: November 2010

Pseudocholinesterase (PCE) activity in oral fluid of 31 male and 24 female subjects was determined using butyrylthiocholine iodide as substrate. Males had approximately twice as much salivary PCE activity as did females [4.8 ± 2.4 (S.D.) U/1 and 2.2 ± 1.5 (S.D.) U/1, respectively]. The activity was not much affected by salivary flow rate, although in men it was a little higher in stimulated than in unstimulated saliva. Salivary PCE activity showed diurnal variation. Accordingly, activities were about three times greater at four a.m. than at four p.m. Parotid PCE activity correlated with that of whole saliva in both men and women. PCE activity in crevicular fluid (four subjects) was 120 ± 48 (S.D.) U/1. An elevation of PCE activity in oral fluid was found after experimental induction of gingival inflammation. However, the mean PCE activity of patients with clinical gingivitis was not significantly higher than that of healthy subjects, although some exceptionally high values were found. Sonicated samples of plaque did not contain any PCE activity. No correlation existed between PCE activities in saliva and serum.
Association of Lipids with Proteins and Glycoproteins in Human Saliva
Authors: Slomiany B.L. , Witas H. , Murty V.L.N. , Slomiany A. , Mandel I.D.
Published: November 2010

The distribution of lipids in the fractions of parotid and submandibular saliva following Bio-Gel A-50 column chromatography was measured. Over 50% of the total lipids of submandibular saliva was found in the fraction which contained mainly the high-molecular-weight glycoprotein. This fraction also contained most of the glycolipids, free fatty acids, phospholipids, and cholesterol. In the parotid saliva, the fraction containing the basic glycoprotein (the major glycoprotein fraction of parotid saliva) contained 35% of the total saliva lipids and was enriched in phospholipids ana cholesterol esters.
Changes in the Microstructures of Silver-Tin and Admixed High-copper Amalgams During Creep
Authors: Okabe T. , Butts M.B. , Mitchell R.J.
Published: November 2010

The microstructures of an Ag-Sn amalgam and an admixed high-copper amalgam have been observed during compressive creep tests. Sliding of γ1 grains has been observed. The sliding rate is much lower in the γ2-free high-copper amalgam than in the γ2-containing Ag-Sn amalgam.
Quantitative Changes in Amylase Activity in the Salivary Glands, Pancreas, Saliva, and Serum after Administration of Isoproterenol, Pilocarpine, and Acetylcholine
Authors: Ikeno T. , Nasu J. , Kuzuya H.
Published: November 2010

Amylase activity in various tissues - i.e., submandibular/sublingual and parotid glands, the pancreas, saliva, and serum — in rats was measured after injection of isoproterenol, pilocarpine, and acetylcholine. All agents reduced amylase activity in the parotid gland and increased the enzyme activity in the submandibular/sublingual glands, in saliva and serum.
Target Cells for 1,25-Dihydroxyvitamin D3 in Developing Rat Incisor Teeth
Authors: Kim Y.S. , Stumpf W.E. , Clark S.A. , Sar M. , DeLuca H.F.
Published: November 2010

The concentration of radioactivity is observed in the nuclei of pulpal cells of maxillary and mandibular incisors of 20-day-old fetal rats, following injection of [3H]-1,25 (OH) 2 vitamin D3. Cells in the odontoblast and ameloblast layers are essentially free of nuclear labeling. The radioactively labeled pulpal cells exist throughout the length of the incisors with the exception of the progenitor areas. The results indicate the presence of receptors for 1,25 (OH)2 vitamin D3 in pulpal cells, and suggest the effects of the hormone on these cells.
Synergistic Inhibitory Effect of Zinc and Hexetidine on in vitro Growth and Acid Production of Streptococcus mutans
Authors: Moermann J.E. , Muehlemann H.R.
Published: November 2010

The combined effect of Zn and hexetidine on Streptococcus mutans OMZ 176 growth and acid production was investigated in vitro. Since the minimum inhibitory and bactericidal concentration of zinc and hexetidine in combination was significantly, lower than when applied separately, a synergistic antimicrobial action was evident.
In vitro Caries-like Lesion Formation in F-containing Tooth Enamel
Authors: LeGeros R.Z. , Silverstone L.M. , Daculsi G. , Kerebel L.M.
Published: November 2010

In vitro caries-like lesion formation in F-containing tooth enamel (shark) showed a lower depth of penetration compared to that in human enamel (42 vs. 100%). After longer periods of exposure, the depth of penetration in shark enamel is only 33% relative to that in human enamel. The extent of dissolution in acetate buffer for powdered human enamel and for synthetic F-free calcium-carbonated-apatites was greater than for powdered shark enamel and for synthetic F-containing apatites.

These results suggest that the cariostatic action of fluoride may be explained in terms of a combination of two effects: (a) the stabilizing effect against acid dissolution (caries) when fluoride is incorporated in the tooth mineral (apatite), and (b) a greater degree of remineralization (repair) in the presence of F solution.
Effect of Zinc Citrate on Fluoride Uptake by Artificial Caries Lesions
Authors: Mellberg J.R. , Chomicki W.G.
Published: November 2010

Artificial caries lesions were treated three times with dentifrice slurries or aqueous solutions of sodium monofluorophosphate with and without zinc citrate. Analysis of the treated lesions showed that the presence of zinc citrate reduced fluoride uptake by 60%. Very high levels of zinc were found at the lesion surface, suggesting that zinc precipitates prevented diffusion of fluoride into the lesion.
Microbeam X-ray Diffraction Analysis of Dental Calculus
Authors: Kani T. , Kani M. , Moriwaki Y. , Doi Y.
Published: November 2010

The crystalline components of human dental calculus were investigated using microbeam x-ray diffraction analysis. Hydroxyapatite and octacalcium phosphate were most frequently found in that portion having porous and zonal structure. In the portion of the homogeneous illustration showing high calcification, whitlockite is a main component. Brushite was unexpectedly rare, and no calcite was detected in any portion of human dental calculus. The mechanism of the formation of dental calculus being considered in this paper is that octacalcium phosphate or brushite is formed during the initial stage of calcification of dental plaque, and is gradually hydrolyzed and transformed into hydroxyapatite and/or whitlockite.
Prevention of Dental Caries in Hamsters by an Endo-1,3-α-D-Glucanase
Authors: Simonson L.G. , Lamberts B.L. , Reiher D.A. , Walter R.G.
Published: November 2010

An endo-1,3-α-D-glucanase was evaluated for its dental caries-preventive efficacy in male Syrian hamsters. The enzyme significantly reduced both total caries and carious area scores.
The Ultrastructure of Dentinal Tubules from Erupted Human Premolar Teeth
Authors: Thomas H.F. , Payne R.C.
Published: November 2010

Different regions of crown dentin from erupted human premolars were examined ultrastructurally to determine the contents of the dentinal tubules. Odontoblast processes were limited to inner dentin, and nerve fibers were not observed in any tubules examined.
Fluoride Uptake by Artificial Caries Lesions from Fluoride Dentifrices in vivo
Authors: Mellberg J.R. , Chomicki W.G.
Published: November 2010

Artificial caries lesions were implanted in removable dentures and were brushed for two wk or two mo with several fluoride-containing dentifrices. An analysis of thin layers of enamel removed from the lesions showed that more fluoride was deposited after two mo of brushing, and that fluoride deposition from the sodium monofluorophosphate was similar to deposition from the sodium fluoride dentifrice.
Effects of Porcelain/Alloy Interfacial Diffusion Zones on Thermo-mechanical Strain
Authors: Tesk J.A. , Hinman R.W. , Widera G.E.O. , Holmes A.D. , Cassel J.M.
Published: November 2010

Chemical bonding between dental porcelains and alloys results from interdiffusion of porcelain and metal ions. An interfacial diffusion zone is created which, most likely, has properties different from those of bulk materials. The changed interface might affect experimental measurements of thermo-mechanical strain. To determine the magnitude and conditions under which this would occur, the interface was modeled as the intermediate layer of a three-layered porcelain-veneered split-metal ring. Layer thicknesses and coefficients of thermal expansion were varied, and the effects on gap change after cooling through 500°C were calculated. Results are presented in a series of 14 Figs., ten curves each, which depict not only interfacial effects, but are extended for use in interpretation of the effects of properties of opaques and glazes as well. Under most conditions, the interface will not affect experimental measurements; some special exceptions are noted.
Basic Biological Sciences Relationships Among the Oral Fusobacteria Assessed by DNA-DNA Hybridization
Authors: Potts T.V. , Holdeman L.V. , Slots J.
Published: November 2010

DNA was purified from 16 strains of Fusobacterium nucleatum and from five strains representing other Fusobacterium species. The relationships among fusobacteria were examined by DNA-DNA hybridization and by determining the guanine plus cytosine content of the DNA. F. nucleatum was found to comprise a heterogenous group of organisms related to Fusobacterium periodonticum and Fusobacterium simiae, but unrelated to any of the other species of Fusobacterium tested.
Carbonic Anhydrase in Developing Hamster Molars
Authors: Dogterom A.A. , Bronckers A.L.J.J.
Published: November 2010

Carbonic anhydrase (CA) activity decreased slightly in hamster molars from one to four d after birth. It was inhibited by low concentrations of acetazolamide. Histochemically, the stratum inter-medium and stellate reticulum showed an intense staining for CA, whereas ameloblasts increased and odontoblasts decreased their CA activity with age.
Nuclear Magnetic Resonance Spectroscopic Studies of the Interaction of Phospholipids with Stabilizing Lysosome Agents
Authors: Fujisawa S. , Kadoma Y. , Masuhara E.
Published: November 2010

The interaction between phospholipids and stabilizing lysosome agents such as acetylsalicylic acid (ASA), colchicine (CC), prednisolone (PD), etc., was studied using NMR spectroscopy. The peak intensity of protons arising from these compounds was reduced in liposomes containing lecithin and various agents with a molar ratio of 1:1 in D2O. The reduced percentage of protons in the agents differed due to their molecular structures: ASA was about 20%, CC about 30%, and PD about 100%.
The Presence of Fucosyltransferases with Different Substrate Specificity in Human Parotid Saliva
Authors: Tamagawa H. , Inoshita E. , Shibata S. , Shizukuishi S. , Tsunemitsu A.
Published: November 2010

Using glycoproteins and milk oligosaccharides as substrate acceptors, we demonstrated at leaet two fucosyltransferases in human parotid saliva. One enzyme transferred L-fucose from GDP-fucose to the C-3 position of N-acetylglucosamine or glucose residue of oligosaccharide chains, and the other transferred to the C-4 position of N-acetylglucosamine residue of oligosaccharide chains.
Fluoride Uptake and Retention in vitro Following Topical Fluoride Applications
Authors: Wei S.H.Y. , Connor C.W.
Published: November 2010

Fluoride uptake and retention on maxillary and mandibular incisors were compared using a conventional APF gel, a thixotropic gel, and a new pluronic-based fluoride gel. Based on the results of in vivo acid-etch biopsies, significant fluoride uptake was obtained with each of the three agents. The highly viscous pluronic gel may provide an alternative to conventional topical fluoride gels for subjects - e.g., handicapped persons - with whom a tray system is not feasible.
The Flexure Modulus of Elasticity of Orthodontic Wires
Authors: Goldberg A.J. , Morton J. , Burstone C.J.
Published: November 2010

The flexure moduli of elasticity of solid and multi-stranded orthodontic wires were determined. Results for the solid wires approximated their tensile values, but the differences were statistically significant for the stainless steel, chromium-cobalt-nickel, and nickel-titanium alloys. The flexure moduli of the multi-stranded wires ranged from 0.89 to 5.11 x 106 psi, and were dependent on the direction of activation.
Basic Biological Sciences
Authors: Slomiany B.L. , Murty V.L.N. , Aono M. , Sarosiek J. , Slomiany A. , Mandel I.D.
Published: November 2010

The matrix of supragingival calculus constitutes 15.7% of the calculus dry weight and contains 54.9% protein and 10.2% lipids. Of the total lipids, 61.8% are represented by neutral lipids, 28% by glycolipids, and 10.2% by phospholipids. The neutral lipids exhibit a high content of free fatty acids (63.9%) and triglycerides (15.8%). The glycolipids are comprised of simple glycosphingolipids (17.2%), mainly lactosyl- and glucosylceramides, and of neutral and sulfated glyceroglucolipids (82.8%). The phospholipids contain large quantities of phosphatidylethanolamine (34.2%) and diphosphatidylglycerol (25.5%). Comparison with salivary and submandibular stone lipids indicates that both saliva and bacteria contribute to the lipid content of supragingival calculus.
Lipid Composition of Human Parotid Salivary Gland Stones
Authors: Slomiany B.L. , Murty V.L.N. , Aono M. , Slomiany A. , Mandel I.D.
Published: November 2010

The parotid gland stone matrix constitutes 20.2% of the stone dry weight and contains 8.5% of lipids. Of the total lipids, 74% are represented by neutral lipids, 17% by glycolipids, and 9% by phospholipids. The neutral lipids exhibit a high content of free fatty acids (52.7%) and cholesteryl esters (31.1%). The glycolipids are composed of simple glycosphingolipids (7.1%), and of neutral and sulfated glyceroglucolipids (92.9%). Phosphatidylethanolamine and diphosphatidylglycerol are the principal constituents of the phospholipid fraction.
Juvenile Periodontitis as a Model for Neutrophil Function: Reduced Binding of the Complement Chemotactic Fragment, C5a
Authors: Van Dyke T.E. , Levine M.J. , Tabak L.A. , Genco R.J.
Published: November 2010

The binding of the chemotactic complement fragment, C5a, to peripheral blood neutrophils of Localized Juvenile Periodontitis (LJP) patients and normal controls was quantitated using iodinated human C5a and a rapid centrifugation assay. There was a significant reduction in the number of binding sites per cell on neutrophils from the patient group, whereas the binding affinity remained the same as control values.
The Role of Cyclic AMP, Calcium, and Prostaglandins in the Induction of Osteoclastic Bone Resorption Associated with Experimental Tooth Movement
Authors: Yamasaki K.
Published: November 2010

Administration of imidazole and verapamil inhibited the appearance of osteoclasts and bone resorption induced by experimental tooth movement in rats. On the other hand, administration of theophylline and ouabain enhanced the appearance of osteoclasts. A mixed solution of DB cyclic AMP and A-23187 injected in gingiva near the orthodontically-treated teeth caused enhancement of the appearance of osteoclasts and bone resorption.
Enamel Demineralization Tests with Some Standard Foods and Candies
Authors: Bibby B.G. , Mundorff S.A. , Huang C.T.
Published: November 2010

To indicate the cariogenic potential of some standard foods and confections, their ability to demineralize powdered enamel or enamel sections was tested by incubation with mouth organisms in saliva or plaque. With a few exceptions, the amounts of demineralization produced by the tested substrates in either a closed or flowing system fell within relatively narrow ranges.
Biologic Evaluation of a Silver-Copper-Germanium Dental Casting Alloy and a Gold-Germanium Coating Alloy
Authors: Townsend J.D. , Hamilton A.I. , Sbordone L.
Published: November 2010

An Ag-Cu-Ge alloy and an Au-Ge alloy were evaluated for their hemolytic effect on rabbit blood, cytotoxicity to α-L fibrosarcoma cells, and allergenic effect on guinea pigs. Neither alloy evoked a significant hemolytic response; cytotoxicity, and that of pure germanium, was no greater than that of ZOE cement; and, on the basis of the guinea pig response, the potential human allergenic response was considered to be Grade I (weak) and Grade II (mild), respectively.
Microbiologic Effects of SnF2 and NaF Mouthrinses in Subjects with High Caries Activity: Results after One Year
Authors: Tinanoff N. , Klock B. , Camosci D.A. , Manwell M.A.
Published: November 2010

Twenty-two adults, considered to have high caries activity, rinsed for one yr with either SnF2 or acidulated NaF mouthrinses. Total colony-forming units and numbers of S. mutans and lactobacilli were estimated from saliva samples. Large reductions were found in the number of recoverable S. mutans in subjects rinsing with SnF2 but not in the NaF group.
Materials Science Measurement of of Amalgam Mixes to Condensation
Authors: Ogura H. , Hadavi F. , Asgar K.
Published: November 2010

A method was designed to evaluate the resistance of amalgam mixes to condensation forces. For the purpose of classification with respect to the plasticity of amalgam, the optimum test conditon was to apply 40 or 50 lb of static load at 30 sec after trituration.
Material Science Plastic Deformation of Orthodontic Wires
Authors: Goldberg A.J. , Burstone C.J. , Koenig H.A.
Published: November 2010

Theoretical predictions of the bending moments in the region of plastic behavior were accurate for beta titanium and stainless steel, but were consistently low in the far-elastic region for the three alloys studied.
Dentin Permeability: Effects of Temperature on Hydraulic Conductance
Authors: Pashley D.H. , Thompson S.M. , Stewart F.P.
Published: November 2010

The rates of fluid movement across dentin discs, in vitro, were measured at 10, 20, 30, 40, and 50°C in unetched and acid-etched dentin. Increasing the temperature 40° (i.e., from 10 to 50°C) resulted in a 1.8-fold increase in fluid flow in unetched dentin, which was of a magnitude similar to the decrease in viscosity that occurred over the same temperature range. In acid-etched dentin, the 40°C temperature change produced more than a four-fold increase in fluid conductance, more than double that which could be accounted for by changes in viscosity. Analysis of the data suggests that this additional increment in hydraulic conductance is due to thermal expansion-induced increases in tubular diameter.
Fusobacterium periodonticum, A New Species from the Human Oral Cavity
Authors: Slots J. , Potts T.V. , Mashimo P.A.
Published: November 2010

Isolates of Fusobacterium that differ from type strains of various fusobacterial species with respect to DNA sequence, cellular fatty acid composition, and biochemical activity, were obtained from periodontitis lesions in patient with insulin-dependent diabetes mellitus. These isolates have the following distinguishing characteristics: 28% guanine + cytosine content; 40% or less DNA homology with type strains of representative fusobacterial species; cell size, 0.5 — 1 x 4 -100 μm; absence of motility; ability to ferment glucose, fructose, and galactose, but not 25 other carbohydrates; ability to produce, indole; ability to hydrolyze hippurate but not esculin; sensitivity to bile; ability to produce little or no gas; ability to utilize threonine but not lactate. We propose that the organisms be classified as a distinct species of Fusobacterium to be named Fusobacterium periodonticum. The type strain of this new species has been deposited with the American Type Culture Collection under the designation ATCC 33693.
A Microradiographic and Chemical Comparison of in vitro Systems for the Simulation of Incipient Caries in Abraded Bovine Enamel
Authors: Pearce E.I.F.
Published: November 2010

An acetate buffer system, supersaturated with fluorapatite but not with hydroxyapatite, produced lesions in abraded bovine enamel which resembled human enamel caries lesions, both morphologically and in their F distribution. A gelatin-lactate system gave similar results when unpurified gelatin was used. Systems containing deionized gelatin, diphosphonate, or Ca and phosphate but no F, failed to produce caries-like lesions.
The Effect of Non-steroidal Anti-inflammatory Drugs on the Metabolism of C-Arachidonic Acid by Human Gingival Tissue in vitro
Authors: Elattar T.M.A. , Lin H.S. , Tira D.E.
Published: November 2010

We investigated the effect of non-steroidal anti-inflammatory drugs on prostaglandins (PGs) and 12-hydroxyeicosatetraenoic acid (12-HETE) formation by inflamed human gingival tissues. Gingival tissue homogenates were incubated with14C-arachidonic acid in the presence of indomethacin, piroxicam, or ibuprofen, and the organic solvent extracts were chromatographed on silica gel plates with standards for radiometric assay. There was a significant negative trend between the doses (10-7-10-3M) of each of indomethacin, piroxicam, and ibuprofen, and the amounts of PGF2α, PGE2, PGD2, and 15-keto-PGE2produced. All three drugs have a significant inhibitory effect on PGs and 12-HETE production at 10-3 M when compared with the control. The rank order effectiveness of the drugs, at 10-3 M, on PG inhibition was indomethacin > piroxicam > ibuprofen, and on 12-HETE inhibition was indomethacin > ibuprofen > piroxicam.
Murine Tooth Organ Transplantation after in vitro Culture
Authors: Riviere G.R. , Tarbox G.S. , Bringas P. , Slavkin H.C.
Published: November 2010

Molar tooth organs were transplanted from fetal and neonatal mouse donors as well as from cap-stage molar tooth organs following ten days of in vitro culture. Tooth organs from neonatal donors appeared to develop better than those from fetal donors in syngeneic recipients. Cultured allogeneic molar tooth organs appeared to survive longer than uncultured controls.
Detection of Antigens in Enzymic Lysates of Cell Wall from Streptococcus mutans Strains
Authors: Knox K.W. , Campbell L.K. , Bratthall D.
Published: November 2010

Lysis of cell wall preparations from strains representing serotypes a - g of Streptococcus mutans has provided a convenient and efficient means of obtaining the typing antigens in a soluble undegraded form, and has demonstrated that, in each case, the antigen is a cell wall component in the strict sense of a component joined covalently to peptidoglycan. This influences the choice of extraction procedures.
Acinetobacter Contamination of Laboratory Dental Pumice
Authors: Williams H.N. , Falkler W.A. , Hasler J.F.
Published: November 2010

Micro-organisms of the genus Acinetobacter, implicated as opportunistic pathogens, have been recovered from dentures after laboratory repair. A study was undertaken to determine if Acinetobacter could be isolated from used dental pumice. Cultural studies demonstrated that Acinetobacter calcoaceticus variety lwoffi was present in high numbers in used pumice and was a major gram-negative microbial contaminant.
The Three-point Beam Test for the Evaluation of Dental Porcelain
Authors: Edwards M.R. , Jacobsen P.H. , Williams G.J.
Published: November 2010

The three-point beam test is simple and extremely sensitive to surface conditions. It appears to be ideally suited to the evaluation of dental porcelain, but specimen fabrication is difficult. In this study, specimens of porcelain fired on platinum foil have been constructed using an alumina former. The results showed excellent specimen consistency and reproducibility. Of the surfaces investigated, the use of tin-oxide-coated platinum foil did not result in an increase in transverse strength.
Effect of Processing Temperature on the Properties of a Polyvinyl Chloride Maxillofacial Elastomer
Authors: Yu R. , Koran A. , Powers J.M.
Published: November 2010

Mechanical properties and color of a plasticized polyvinyl chloride (PVC) maxillofacial elastomer were evaluated at processing temperatures from 140 to 190°C. The properties were dependent on processing temperature. Specimens prepared at 170°C had optimum mechanical properties with minimal discoloration.
Modulation of in vitro Human Lymphocyte Responses by an Exopolysaccharide from Capnocytophaga ochracea
Authors: Bolton R.W. , Dyer J.K. , Reinhardt R.A. , Okano D.K.
Published: November 2010

An exopolysaccharide (EP), purified from spent culture fluid previously inoculated with Capnocytophaga ochracea strain 25, suppressed in vitro human peripheral blood lymphocyte responses to the mitogen concanavalin A. EP was suppressive when added to cultures before the mitogen, but enhanced responses when added 24 or 48 hr after the mitogen.
Enhancement of Streptococcus mutans Colonization by Direct Bonded Orthodontic Appliances
Authors: Mattingly J.A. , Sauer G.J. , Yancey J.M. , Arnold R.R.
Published: November 2010

Patients undergoing orthodontic therapy were evaluated for longitudinal changes in relative S. mutans numbers in plaque at discrete sites on the tooth surface associated with direct bond appliances. There was a significant linear increase in the percentage of S. mutans in the total streptococci isolated from the last pre-bracket sample through the last bracket sample.
Enamel Demineralization by Mouthrinses Containing Different Concentrations of Sucrose
Authors: Tehrani A. , Brudevold F. , Attarzadeh F. , Van Houte J. , Russo J.
Published: November 2010

Intra-oral enamel demineralization tests, involving rinsing with sucrose solutions (5, 1, 0.5, or 0.3%) at varying frequencies during a 1.5-hour period, showed that demineralization was a function of the total sugar dose (frequency of rinsing times concentration). Two rinses with a 5% solution caused demineralization, nine rinses were needed in the case of a 0.5% solution, and none occurred after nine rinses with a 0.3% solution. Remineralization was also observed and apparently occurred after exhaustion of the sucrose supply.
Enamel Demineralization Potential of Dietary Carbohydrates
Authors: Brudevold F. , Tehrani A. , Attarzadeh F. , Van Houte J. , Russo J.
Published: November 2010

Mouthrinses with 5% solutions of different sugars were tested for their demineralizing effect on blocks of bovine enamel covered with a layer of S. mutans cells and carried in a palatal prosthesis. The extent of demineralization, as measured by the permeability of the enamel to iodide, was similar for fructose, glucose, and sucrose, less for maltose and lactose, and least for galactose.
Degradation of Luting Cements Measured in vitro and in vivo
Authors: Mesu F.P. , Reedijk T.
Published: November 2010

The degradation of luting cements was quantified when these cements were held as a 20-μ m cement layer. The degradation process, which is mostly a sequence of absorption, disintegration, and solution, was expressed by a time-constant (τ ). By using the same test specimens in vitro as well as in vivo, we determined the correlation of both situations.
Basic Biological Sciences The Effects of Fatty Acids and Their Monoesters on the Metabolic Activity of Dental Plaque
Authors: Hayes M.L.
Published: November 2010

We examined the effects of the saturated series of fatty acids and their esters on plaque bacterial metabolism. Fatty acids with a chain length of 8-15 carbons inhibited Streptococcus mutans and dental plaque in vitro. The glycerol monoesters with a fatty acid chain of 10-14 carbons were inhibitory to a similar extent. The glycolipid (sucrose monolaurate) reduced plaque bacterial glycolysis and sucrose oxidation in a non-competitive manner but stimulated sucrose incorporation at low sucrose concentrations. The relationship between surface activity and inhibition is discussed, since this may help to explain the anti-caries effects of these compounds.
Similarity Between Alkaline Phosphatases from Bovine Dental Pulp and Liver
Authors: Harada M. , Fukasawa K. , Hiraoka B.Y. , Fukasawa K.M.
Published: November 2010

Specific antibody against purified alkaline phosphatase from bovine dental pulp was raised in a rabbit. Immunological analyses by Ouchterlony double-gel diffusion and quantitative immunoprecipitation showed that there was neither a detectable antigenic difference between liver and pulp alkaline phosphatases nor a detectable cross-reaction with the intestinal enzyme.
An Incisor Plaque Model in Rats
Authors: Schemehorn B.R. , McDonald J.L. , Stookey G.K. , Park K.K.
Published: November 2010

An in vivo model for studying plaque accumulation in rats has been described. This model investigates plaque formation on the mandibular incisors in animals which have been found to be rapid plaque-formers during a pre-test period. The accessibility of these tooth surfaces permits the removal of plaque prior to initiation of tests, the use of test groups balanced on the basis of plaque-forming potential, and interitn assessments of plaque formation throughout the test period, In addition, baseline plaque scores of near zero can be attained, thereby permitting investigations of the impact of experimental measures on plaque formation. Moreover, the model permits intermittent plaque assessments throughout the test period, This model was found to have adequate sensitivity to distinguish effects between antimicrobial agents known to differ in their clinical activity and to detect differences between varying concentrations of the same agent.
Streptococcus mutans Levels and Biotypes in Egyptian and Saudi Arabian Students During the First Months of Residency in the United States
Authors: Farghaly M.M. , Eklund S. , Loesche W.J.
Published: November 2010

Several studies indicated that serotype/biotype c strains are the most common on a global basis, but that regional differences may occur relative to other serotype/biotypes. Of particular interest is the observation that individuals residing in the Middle East have higher incidences of serotype e and d strains relative to their levels in American citizens. This could reflect exposure to different Streptococcus mutans serotypes during the period in which the teeth are colonized, or might reflect other factors local to the region, such as diet. The purpose of the present study was to observe Egyptian and Saudi Arabian students during the first four months after their arrival in the United States, in order to determine whether this change in habitat affected the levels and biotypes of S. mutans. The results of this study showed that biotype c strains were the most prevalent in saliva and plaque of these Egyptians and Saudi Arabian students, followed by biotype e and biotype d. There was a drop in the number of S. mutans in the saliva and the proportions of S. mutans in the plaque after two months of residence in the United States, followed by a significant increase after four months of residence. This increase was most noticeable in subjects who had a higher number of decayed surfaces. In these subjects, the percentage of S . mutans in pooled occlusal plaque increased significantly, from 6.1 to 13.2%.
Materials Science Dielectric Properties of Glass Ionomer Cements-Further Studies
Authors: Tay W.M. , Braden M.
Published: November 2010

Two recent proprietary glass ionomer cements showed that in the early stages of set the changes in relative permittivity (dielectric constant) and resistivity were rapid. However, when set, measurements indicated that the cements were highly ionic and polar and behaved similarly to the glass ionomer cements previously reported. 1
The Anti-cariogenic Potential of Xylitol in Comparison with Sodium Fluoride in Rat Caries Experiments
Authors: Havenaar R.
Published: November 2010

Previous rat caries experiments in our laboratory demonstrated an anti-cariogenic and most probably a remineralizing effect of xylitol. The purpose of the present study was to compare the caries-inhibiting property of xylitol and fluoride in drinking water. The study consisted of two experiments with Osborne-Mendel rats, superinfected with S. mutans. In the first experiment, the rats were fed ad libitum a cariogenic diet containing 20% sucrose and 5% glucose (diet SSP 20/5) and tap water containing 0%, 2%, or 4% xylitol. An additional control group was fed diet SSP 20/5 supplemented with 5% xylitol. In the second experiment, the rats were also fed diet SSP 20/5, but received tap water, demineralized water (both containing less than 0.1 ppm F-), or tap water containing 10 and 40 ppm fluoride. Some animals in the 4% xylitol drinking water group showed a mild osmotic diarrhea for the first four days and a retarded increase in body weight of limited duration. S. mutans colonized to a similar level in all groups of both experiments. Fluoride as well as xylitol in the drinking water reduced the fissure caries scores significantly. However, 10 and 40 ppm fluoride had a more pronounced inhibiting effect on the caries experience than did 4% xylitol in the drinking water or 5% xylitol in the diet.
Induction of Immunological Tolerance by Oral Administration of Nickel and Chromium
Authors: Vreeburg K.J.J. , De Groot K. , Von Blomberg M. , Scheper R.J.
Published: November 2010

Oral administration of nickel-chromium to guinea pigs by way of a fixed occlusal splint, or the incorporation of metallic powder or salts into the pelleted food, did not induce hypersensitivity to these metals. In addition, a subsequent attempt to immunize the pre-treated guinea pigs failed in most animals, whereas non-pre-treated guinea pigs became clearly hypersensitive. These results show that oral administration of nickel and chromium induced a state of (partial) tolerance to both metals.
Basic Biological Sciences Reserpinization: Effects on Parotid Gland Function
Authors: Watson E. , Dowd F. , Jacobson K. , Horwitz H.
Published: November 2010

Chronic reserpinization of mice and rabbits affected parotid gland function; cholinergic and β-adrenergic-stimulated amylase release were significantly reduced, and cyclic-AMP and cyclic-GMP levels were significantly elevated above control-stimulated levels. Amylase released by dibutyryl-c-AMP was also reduced, suggesting a defect in stimulus-secretion coupling subsequent to c-AMP formation.
Neutrophil Receptor Modulation in the Pathogenesis of Periodontal Diseases
Authors: Van Dyke T.E.
Published: November 2010

The role of the neutrophil as a primary protective cell in the pathogenesis of periodontal disease has been well established. In this paper, the role of receptor modulation on the neutrophil surface is discussed as a possible mechanism for neutrophil functional abnormalities. Using localized juvenile periodontitis (LJP) as a model, the direct inhibition of neutrophils by bacterial products is discussed as a possible mechanism for local neutrophil dysfunction. In both disease processes, neutrophil receptor modulation plays a central role.
Basic Biological Sciences Saliva Secretion from the Rat Submandibular Gland after Retrograde Infusion of Radiographic Contrast Media
Authors: Qwarnstrom E. , Bodner L. , Baum B. , Hand A. , Omnell K.-A.
Published: November 2010

Rat submandibular saliva was collected at various times after retrograde infusion of water-soluble (Renografin 60%) or lipid-soluble (Lipiodol UF) radiographic contrast medium. Significant alterations in flow rate occurred following heavy parenchymal filling with both types of contrast media. Occasional changes in protein concentration, lactoperoxidase activity, and K+ levels were also noted. These changes were relatively mild and transient, and gland function had generally returned to normal by one wk after infusion. No alterations in glandular function were detected after infusion of contrast medium to a degree (ductal filling) comparable to that usually employed in clinical sialography.
Effect of Inhibition of Net Calcium Uptake on Net Fluoride Uptake in Developing Rat Molars
Authors: Bawden J.W. , Crenshaw M.A.
Published: November 2010

Two methods were used to reduce net calcium uptake by the secretory stage enamel of developing rat molar explants. Neither method had a significant effect on fluoride uptake by the explants. These findings indicate that the mechanisms for uptake in the developing enamel are independent for calcium and fluoride.
Factors Involved in Artificial Caries Induction by Oral Streptococci in Extracted Human Teeth
Authors: Kaufman H.W. , Pollock J.J. , Murphy J. , Lunardi S. , Vlack J.
Published: November 2010

This study assesses the abilities of S. mutans GS5 and BHT and S. sanguis G9B to produce subsurface lesions on smooth surfaces of extracted human teeth and examines factors which might be responsible for any differences encountered. Teeth were incubated in Brain Heart Infusion broth containing 2% sucrose and a pure culture of the organism to be tested, the media being changed each day for eight days. Surface and media pH's were measured. The mineral content of both the surface enamel and the subsurface lesions was determined by contact microradiography. Significantly deeper and more demineralized lesions were produced by GS5 than by either BHT or G9B. GS5 also produced a lower surface and medium pH and a more dense coating on the teeth. Similar results were obtained with GS5 and G9B when the BHI broth was replaced with FMC synthetic media. It is concluded that the system described is suitable for studying cariogenic potential and will be useful in measuring the anticariogenicity of suspected therapeutic agents.
The Initial Gap Around Large Composite Restorations in vitro: The Effect of Etching Enamel Walls
Authors: Brannstrom M. , Torstenson B. , Nordenvall K.-J.
Published: November 2010

Composite resin restorations in cavities are generally associated with the development of a contraction gap during the first minutes after insertion. Enamel-Bond-Concise composite restorations were placed on both approximal sides of extracted pre-molars. The cervical walls of all cavities extended beyond the enamel-cement junction. The enamel walls of one of the cavities in each tooth were acid-etched. The contraction gap was kept air-filled and open at the margin through the use of a special technique. Enamel Bond resin with a fluorescent additive was applied to occlusal and cervical margins of the restorations.

The fluorescent resin was "passively" drawn into the gap. In unetched cavities, resin penetrated both cervical and occlusal gaps and some areas of the gap at the axial wall. In cavities with etched enamel, the penetration occurred only at the cervical wall. The distance of penetration from the cervical margin varied from 1 to 6.5 mm, and the width of the contraction gap filled with the fluorescent resin varied from 3.5 to 16 μm.

Comparison of the width of the gap at the cervical wall in etched and unetched cavities suggested larger gaps for etched cavities. The method used offers a new technique for the measurement of the contraction gaps around composite resin restorations.
The Surface Roughness and Gloss of Composites
Authors: O'Brien W.J. , Johnston W.M. , Fanian F. , Lambert S.
Published: November 2010

The contrast gloss and the average roughness were measured for four commercial composite filling materials. Using a factorial design, each material was subjected to four available finishing methods. A significant difference was found in the contrast gloss among finishing methods, and a significant linear regression is given which relates the inverse of the contrast gloss to the average roughness. Surface gloss is proposed as playing a major role in the esthetic appearance of composite restorations.
Clinical Effectiveness and Untoward Effects of New Agents and Techniques Used in Intravenous Sedation
Authors: Korttila K.
Published: November 2010

An ideal i.v. sedative for dentistry should provide anti-anxiety and analgesic activity, amnesic action, and patient cooperation without depression of the cardiorespiratory system and with rapid recovery. Lorazepam does not provide any advantages over the currently available agents, but midazolam, a new water-soluble benzodiazepine, and later selective benzodiazepine receptor antagonists may play an important role in outpatient sedation.
Effect of Cheese, With and Without Sucrose, on Dental Caries and Recovery of Streptococcus mutans in Rats
Authors: Rosen S. , Min D.B. , Harper D.S. , Harper W.J. , Beck E.X. , Beck F.M.
Published: November 2010

The objective of this study was to determine the effect of aged and young cheddar cheese with and without added sucrose on dental caries and the associated recovery of implanted Streptococcus mutans. Very little caries was observed in rats consuming cheese without sucrose. There was an increase in caries in rats fed cheeses with 20% sucrose, but this increase was not significant. There was significantly greater caries activity in rats fed standard diets containing 20% or 5% sucrose (SLS or MIT 305) than in rats fed cheeses containing 20% sucrose. Rats fed cheese or powdered diets containing sucrose had significantly higher frequency of recovery and higher levels of S. mutans infection than did rats fed cheese containing no sucrose. This study confirms the low cariogenic potential and possible cariostatic activity of cheddar cheese in rats. Since cheddar cheese with sucrose did not significantly interfere with S. mutans implantation, the cariostatic mechanism is apparently unrelated to a direct antimicrobial effect on S. mutans.
Fluoride Levels in Dentin after Iontophoresis of 2% NaF
Authors: Wilson J.M. , Fry B.W. , Walton R.E. , Gangarosa L.P.
Published: November 2010

The fluoride in successive layers of dentin (from 3-6 μm were removed per etch) has been measured following topical or iontophoretic application of 2% aqueous sodium fluoride to coronal exposed dentin of freshly extracted human third molar teeth. The fluoride contents of the topical and iontophoresed first etches were, respectively, 12 and 22-31 times greater than that of control (untreated) teeth. Similarly, the fourth etches were 12 and 50-70 times greater, and the seventh (last sampled) etches were 5 and 28-41 times greater. There was no apparent change in acid solubility of the dentin as its fluoride content varied under the conditions of this study. This is the first report studying the fluoride content of extremely thin layers of dentin successively removed by acid etch and relating topical to iontophoretic uptake.
An in vitro Method for Making Repeated pH Measurements on Human Dental Plaque
Authors: Bibby B.G. , Krobicka A.
Published: November 2010

A combination pH micro-electrode inserted into human plaque centrifuged to the base of a closely-fitting fine-mesh wire "basket" has been used to make continuous recordings of the pH responses produced by exposure to various carbohydrate substrates. The pH depressions given by continued immersion in sugar and starch solutions resemble, both in depth and duration, those obtained by telemetric pH measurements of approximal plaque samples. In contrast, brief exposure to sugar solutions will produce a Stephan type of pH curve.

Measurements of pH can be made using a succession of different substrates if, after each substrate is tested, the electrode-plaque assembly is washed with water and its acidity neutralized in circulating saliva. It is suggested that this in vitro pH method could be used instead of the telemetric measurements of approximal plaque for comparing acid production from foods or for other purposes.
Clinical Science Comparison of Xeroradiographs and Film for Detection of Periapical Lesions
Authors: White S.C. , Hollender L. , Gratt B.M.
Published: November 2010

Xeroradiographs and Kodak Ektaspeed film were compared with Kodak Ultraspeed film for their ability to reveal periapical lesions. Cadaver specimens containing teeth which were normal or demonstrated periapical inflammatory disease were used as the test objects. These specimens were first radiographed using xeroradiographic plates or film. Following radiography, histologic analysis revealed the true presence or absence of disease. Ten oral radiologists scored all xeroradiographic and film images of the specimens for the presence of periapical disease. In general, the observers detected about 70% of the cases with periapical disease, while simultaneously considering about 10 to 15% of the normal surfaces to be abnormal. Receiver-operating-characteristic (ROC) analysis of the radiographic decisions revealed little difference in the diagnostic performance of the observers using the various image receptors, although both types of film and low-contrast xeroradiographs viewed in transmitted light were all more useful than low-contrast xeroradiographs viewed in reflected light. In terms of patient dose, both xeroradiographic images and Ektaspeed film are preferred over Ultraspeed film.