bluuebunny/crossref_metadata_2025 huggingface dataset:
Matrix and Mineral Changes in Developing Enamel
Authors: Robinson C. , Briggs H.D. , Atkinson P.J. , Weatherell J.A.
Published: November 2010

An investigation of the changes taking place in the enamel and the enamel organ during enamel development has been carried out by analyzing small samples of tissue dissected from developing incisors of rat and bovine incisors. Observations showed that the synthesis of the enamel matrix and its subsequent loss were associated chiefly with a change in the major matrix components. This consisted of a selective loss of amelogenin components prior to secondary mineralization. Before this loss, some increase in the proportion of smaller molecular weight components suggested the possibility of limited breakdown. Even at the earliest stages examined, significant concentration of mineral ions was present. This increased steeply after most of the organic matrix had been removed. The Ca/P ratio of this mineral was constant throughout development. The concentration of minor inorganic ions (F, Mg and CO3) decreased as the tissue developed and a tendency was observed for certain ions (F, 32PO4) to penetrate and concentrate in the enamel, apparently as a consequence of the lost matrix being replaced by water, just prior to the steep increase in mineral content of the tissue.
Patterns of Enamel Maturation
Authors: Glick P.L.
Published: November 2010

Investigations of the maturation pattern of rat incisor enamel by quantitative electron microscopy and electron-probe microanalysis indicate that mineralization of rat enamel can be regarded, as in humans, as a regular and progressive process pattern of enamel matrix formation. The species variations that have been proposed in the pattern of enamel mineralization can be related to differences in both the rate of formation of the enamel matrix and in the total thickness of the enamel produced. Neither the microradiographic appearance of developing enamel, nor the solubility and staining characteristics of the organic matrix accurately reflects the mineral concentration gradients established during the mineralization process as indicated from electron microprobe analysis.
Enamel Crystal Chemistry-Where Do We Go From Here?
Authors: Ingram G.S.
Published: November 2010

This section of the meeting has been devoted to enamel crystal chemistry and its behavior during formation and demineralization. In dealing with calcified tissues of any type we are looking at a crystalline formation with the most diverse range of properties which one could choose for its purpose. The size, shape, and intercrystalline binding give mechanical strength, cutting ability, and flexibility where necessary.
Matrix - Mineral Relationships in Enamel Tissues
Authors: Fearnhead R.W.
Published: November 2010

A personal view of vertebrate enamels and their matrix-mineral relationships is given by first considering enamel types and speculating on the nature, distribution, formation and role of enamel protein. Not all the work consulted is mentioned in the text. The additional works are, however, included in the list of references.
Matrix-Mineral Relationships-A. Morphologist's Viewpoint
Authors: Nylen M.U.
Published: November 2010

The literature on the ultrastructural morphology of the enamel matrix and its relationship to the crystals is reviewed. Two morphological entities of the matrix are discussed: One is the so-called stippled material which may be the initial cell product; the other, variously described as fibrillar, lamellar, tubular or helical, is thought by many to play a crucial role in nucleation and orientation of the crystals. A number of observations, however, suggest that the latter structures form secondarily to the crystals and that in reality they represent organic material adsorbed to the crystal surface and maintained as independent structures upon removal of the mineral. The need for additional studies is stressed including systematic studies of interactions between constituents of the organic matrix and the apatite crystals.
Enamel Matrix and Crystals — Chicken and Eggs?
Authors: Leach S.A.
Published: November 2010

This discussion is presented as an attempt to interrelate the matrix and mineral in terms of our existing knowledge as presented at this Symposium, and to relate it, where possible, to what is being accomplished in allied disciplines and research areas elsewhere. The present author is fully aware of the difficulties involved in this task and of his own inadequacies in attempting to perform it. As a general rule, with perhaps the morphologists being the exception to it, the matrix and crystal components have been investigated independently of each other. This, of course, is quite justifiable, as the presence of one can often interfere with the investigation of the other, and each needs to be examined initially in as pure a state as possible.
Axial Stiffness of Retention Pins in Human Dentin
Authors: Dhuru V.B. , McLachlan K. , Kasloff Z.
Published: November 2010

Axial deflections of pins, anchored in specimens of human dentin by five different procedures, were measured by a specially constructed apparatus to an accuracy of 0.1 μ. Axial stiffness values calculated from these measurements were found to be significantly different for different methods of anchorage. Cemented pins displayed the lowest axial stiffness when compared with friction-locked and self-threading pins.
A Photoelastic Study of Stress Concentrations Produced by Retention Pins in Amalgam Restorations
Authors: Dhuru V.B. , Mclachlan K. , Kasloff Z.
Published: November 2010

Photoelastic models of pin-amalgam restorations were constructed to simulate different pin-dentinamalgam relationships. The stress-raising effect of a pin is influenced by the axial stiffness of the pin and its capability of bonding with the amalgam. The stress produced by a very stiff non-bonded pin could cause failure of the restoration.
The Hydration of Dental Cements
Authors: Wilson Alan D. , Paddon John M. , Crisp Stephen
Published: November 2010

A study was made of the hydration of dental cements, water being classified as "non-evaporable" and "evaporable". The ratio of these two types of water was found to vary greatly among different cement types, being lesser in zinc oxide and ionic polymer cements and greater in ion-leachable glass and phosphoric acid cements. The cement with the least "non-evaporable" water, i.e., showing least hydration (the zinc polycarboxylate cement), had the lowest strength and modulus and the greatest deformation at failure. A linear relationship was found to exist between strength and the degree of hydration of dental cements. All the cements were found to become more highly hydrated and stronger as they aged.
The Structure of a Glass-Io nomer Cement and its Relationship to the Setting Process
Authors: Barry Thomas I. , Clinton Desmond J. , Wilson Alan D.
Published: November 2010

The G-200 glass of the glass-ionomer cement has two phases: a continuous calcium aluminosilicate matrix and partly crystalline calcium fluoride-rich droplets, the nature of which depend on the thermal history of the glass. The setting process of the cement takes place when the glass is mixed with poly(acrylic acid). It has two overlapping stages corresponding to the rapid leaching of calcium ions from the uncrystalline part of the droplets, followed by the slower release of aluminum (and some calcium) from the main glass phase. These processes are affected by the microstructure and microcomposition of the glass.
Localized Fluoride Release from Fluorine-carrying Polyphosphonates
Authors: Anbar M. , Farley E.P. , Denson D.D. , Maloney K.R.
Published: November 2010

Fluoride release from fluorine-carrying copolymers of vinylphosphonate induced by calcium apatite and tooth enamel has been investigated. Fluoride ions were determined potentiometrically in the study of calcium hydroxyapatite, and Auger spectroscopy was used to study the fluoride release to enamel. The adsorbed copolymer of vinylphosphonic acid and vinylphosphonyl thiofluoride was shown to release fluoride to calcium hydroxyapatite and to enamel. The oxygen analog has shown a similar behavior with calcium hydroxyapatite, but not with tooth enamel. The results suggest a potential application of such copolymers as caries preventive agents which combine the effects of polyphosphonates and of fluoride ions.
Trend Analysis of Jaw Jerk Action Potential-Amplitude Data
Authors: Widmalm Sven-Erik , Gill Harry , Widmalm Sven
Published: November 2010

The amplitude of the jaw jerk action potential (MSP) is a parameter with potential diagnostic value. It has apparently a large and irregular variation which has not yet been subjected to a thorough analysis. It is important to know if samples of MSP contain trends. The occurrence of trends indicates that the average value is influenced in a principally different way by changes in the number of observations per sample than if trends do not occur. If, for instance, there is a positive linear trend in the data, this means that the average value is larger if the number of observations is large and smaller if the number of observations is small. Samples of MSPs therefore were recorded, using surface EMG electrodes in the masseter and the anterior temporal muscles of young and elderly subjects, and subjected to trend analysis. Trends of the 14th grade occurred in 51% of the samples. Both positive and negative linear trends were found and had about the same frequency. The trend components were, however, randomly distributed. Comparisons between groups may therefore be made without the claim of trend-free samples. This significantly facilitates the use of the parameter MSP-amplitude, since it is difficult to obtain samples which have a normal and identical distribution.
Predictability of Treatment Outcome in Patients with Myofascial Pain-Dysfunction (MPD) Syndrome
Authors: Millstein-Prentky Shana , Olson Ronald E.
Published: November 2010

Responses to the Minnesota Multiphasic Personality Inventory (MMPI) were used to develop a 29-item scale designed to predict the treatment outcome of 135 patients with Myofascial Pain-Dysfunction (MPD) Syndrome. The results suggested that a single scale to predict treatment outcome would be ineffective due to the absence of consistent personality differences in MPD patients.
Cell-to-Cell Communication of Osteoblasts
Authors: Jeansonne B.G. , Feagin F.F. , McMinn R.W. , Shoemaker R.L. , Rehm W.S.
Published: November 2010

Osteoblasts were investigated by two methods, electrical conductance and dye injection. Current injection into one cell caused a change in the recorded transmembrane potential of a second cell, indicating high conductance pathways between the two cells. Dyes injected into a single osteoblast were transmitted to numerous surrounding cells.
The Growth of Hydroxyapatite from Solution. A New Constant Composition Method
Authors: Amjad Z. , Koutsoukos P. , Tomson M.B. , Nancollas G.H.
Published: November 2010

A new constant solution composition method is described for the study of calcium phosphate mineralization. It enables large quantities of stoichiometric hydroxyapatite to be formed by direct precipitation from solution at 37°C and pH = 7.40.
Dental Resins with Reduced Shrinkage During Hardening
Authors: Thompson Van P. , Williams Earl F. , Bailey William J.
Published: November 2010

Unsaturated spiro-orthocarbonates are monomers that expand on polymerization and will co-polymerize with conventional BIS-GMA based resins. This combination has good physical properties and bonding to enamel with some polymerization expansion evident at 50 C. Dispersion of the carbonate in microcrystalline form in liquid monomer appears to be a method to allow its reaction in the initial polymerization.
The Chloride Corrosion Behavior of Silver-base Casting Alloys
Authors: Sarkar N.K. , Fuys R.A. , Stanford J.W.
Published: November 2010

The chloride corrosion behavior of five silver-palladium dental casting alloys was investigated in a 1% NaCl solution through the use of electrochemical hysteresis technique. The corrosion mechanism has been interpreted in terms of the microstructure of these alloys and their possible electrochemical reactions.
The Nature of Covalent Complexes of Phosphoproteins with Collagen in the Bovine Dentin Matrix
Authors: Curley-Joseph Jean , Veis Arthur
Published: November 2010

The bovine dentin matrix still contains some non-collagenous proteins after thorough extraction and decalcification. These have been obtained following digestion of the matrix by cyanogen bromide. Peptides containing non-collagenous portions were isolated by chromatography on diethylaminoethyl cellulose columns and fractionated on hydroxyapatite columns. Several fractions were obtained. The principal component was a complex between a highly-phosphorylated serine-aspartic acid-rich protein and a collagen peptide. These collagenous and non-collagenous moieties could not be separated from each other even under highly dissociative solvent conditions. After digestion with collagenase, the resulting phosphoprotein fraction still contained a few residues of hydroxyproline and hydroxylysine, and an enhanced content of pro-line, compared to the equivalent directly extractable phosphophoryn of the matrix. These data were interpreted as indicating that the phosphophoryn which is not extractable in 0.5M ethylenediaminetetraacetic acid is in fact covalently bound to some specific section of the matrix collagen. The covalent modification of the collagen matrix with highly acidic phosphoproteins may have an important role in the mineralization process.
Polyamine Metabolism in Isoproterenol-stimulated Mouse Salivary Glands
Authors: Nelson Norman F. , Brown K. Birgitta , Douthit Douglas D. , Ghatan Sina , Brown David G.
Published: November 2010

Isoproterenol (0.3 μmole/gm body weight) was injected intraperitoneally every 24 h for three days. The synthesis of deoxyribonucleic acid, the concentration of putrescine, spermidine and spermine and the activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase were measured in parotid and submandibular glands at 4 to 8 h after each injection. The parotid glands responded with peaks of DNA synthesis at 24 and 72 h and peaks of putrescine content and decarboxylase activities 8 to 12 h after each injection. Spermidine increased steadily in the parotid, whereas there was little change in the spermine concentration throughout the 72 h. Polyamine metabolism showed much less response in the submandibular gland, and little or no increase in spermidine or spermine levels or in DNA synthesis was observed.
In vitro Collagen Synthesis of Tooth Germs from Newborn Rats with Protein-Energy Malnutrition
Authors: Nakamoto Tetsuo , Mallek Henry M. , Miller Sanford A.
Published: November 2010

Mineralization and matrix formation are closely related processes in the growth and development of both incisor and molar tooth germs. Addition of ascorbic acid does not affect in vitro collagen synthesis of tooth germs from protein-energy malnourished rats.
Palate Morphology and Fetal Movements in Mice After DPH
Authors: Walker Brlce E.
Published: November 2010

Effects of DPH on fetal development were studied using a dose which produced 65% cleft palate in the CD-1 strain. Generalized developmental re tardation and diminution of fatal muscular movements occurred at the early fetal stage. Intermediate stages of palate closure persisted to term, indicating interference with palatine shelf rotation.
Effects of Stannous Fluoride and Tiodonium Chloride on Dental Plaque in Rats
Authors: Shern R.J. , Couet K.M.
Published: November 2010

Rats with six-day-old plaque were treated twice daily with mouthrinses containing either tiodonium chloride, stannous fluoride or a placebo. Although the results for tiodonium chloride were unremarkable, stannous fluoride mouthrinses proved to be significantly effective in removing dental plaque and in restricting the ability of plaque to lower the pH of sugar solutions.
Ready-to-eat Cereals and Dental Caries in Children: A Three-year Study
Authors: Wilson Charles J.
Published: November 2010

In a three-year study of 145 adolescent males in a boarding school in Wisconsin, there were no statistically significant differences in dental caries experience between a group consuming phosphates added to pre-sweetened and non-presweetened ready-to-eat cereals, and the control group, or between cereal eaters and non-cereal eaters.
The Influence of Functional Use of Endosseous Dental Implants on the Tissue-implant Interface. II. Clinical Aspects
Authors: Brunski John B. , Moccia Aquilante F. , Pollack Solomon R. , Korostoff Edward , Trachtenberg Don I.
Published: November 2010

Functional and non-functional endosseous dental implants were clinically compared in beagle mandibles for up to one year post-operatively. Differing biomechanical conditions led to clinical differences between functional and non-functional implants. Typical clinical tests, however, did not always reveal detailed histological differences between implant-tissue interfaces of functional and non-functional implants.
A New Composite Restorative Based on a Hydrophobic Matrix
Authors: Douglas W.H. , Craig R.G. , Chen C.J.
Published: November 2010

A hydrophobic restorative composite based on a fluorocarbon analog of an alkyl methacrylate and a bisphenol adduct was formulated into a one-paste system, which polymerized in the presence of blue light. Physical, mechanical, and water-related properties were determined. High contact angles and low water sorption were shown by the experimental composite. Capillary penetration of oral fluids around restorations, therefore, could be prevented in the presence of this highly hydrophobic surface. The physical and mechanical properties of the experimental composite were either comparable to or somewhat less favorable than commercial Bis-GMA composites.
Microstructures in Non-precious Alloys Near the Porcelain-Metal Interaction Zone
Authors: Ringle Robert D. , Fairhurst Carl W. , Anusavice Kenneth J.
Published: November 2010

The chemistry of microstructures near the interfacial reaction zones of four non-precious alloys and two different brands of dental porcelain has been analyzed. It was found that most non-precious dental alloys contain second phases which can alter elemental concentration profiles. Recommendations for assessing interfacial reaction zone chemistry in dental non-precious alloys are offered.
Viscosity of Dental Porcelain as a Function of Temperature
Authors: Bertolotti R.L. , Shelby J.E.
Published: November 2010

A method for viscosity measurement is described and representative data are given for opaque, gingival, and incisal porcelains. The significance of viscosity in annealing and in stress development due to thermal expansion mismatch is discussed. Thermal history of the porcelain is shown to be important only over a relatively small temperature interval in affecting residual stresses.
Antibodies to Tooth Allografts in H-2 Matched Mice
Authors: Riviere George R. , Tarbox Georgene S.
Published: November 2010

Teeth were transplanted among mice which represented the best match possible between unrelated humans. Sera were examined for their ability to kill donor cells with the help of complement, to trigger complement-independent, cell-mediated cytolysis, and to agglutinate RBC. All responses were weak, but rejection correlated best with antibody-dependent cytolysis.
A Further Assessment of Predictors of the Child's Behavior in Dental Treatment
Authors: Klorman Rafael , Michael Robin , Hilpert Pamela L. , Sveen Odd B.
Published: November 2010

The child's disruptiveness during dental treatment was related modestly to his age as well as his state, trait, and dental anxiety. In three samples comprising 132 experienced and 49 inexperienced pedodontic patients, the child's behavior during treatment could not be predicted from any aspect of maternal anxiety - trait, state, or dental. Previous conceptions of maternal influence on the child's dental anxiety should be re-evaluated.
EMG Silent Periods in Immediate Complete Denture Patients: A Longitudinal Study
Authors: Mccall W.D. , Tallgren Antje , Ash M.M.
Published: November 2010

Jaw muscle silent periods in response to chin taps were recorded from immediate complete denture patients before extraction of a residual anterior dentition, after insertion of the dentures, and three and six months after insertion. After three months' use of the dentures, the mean EMG silent period duration was significantly increased compared to the pre-extraction stage.
Design of Studies to Evaluate Plaque Control Agents
Authors: Fischman Stuart L.
Published: November 2010

The importance of plaque in the etiology of periodontal diseases is reviewed. A survey is also presented of the various indices for scoring plaque in clinical trials. Variations in the clinical design, type of population studied, and difficulty in scoring gingival plaque are reviewed. A survey is presented of some recent published studies of plaque-inhibiting agents.
Zinc Oxide Eugenol Cements. V. Instrumental Studies of the Catalysis and Acceleration of the Setting Reaction
Authors: Crisp Stephen , Ambersley Michael , Wilson Alan D.
Published: November 2010

Zinc oxide eugenol (ZOE) cements were prepared by mixing powders of widely differing reactivity with a variety of liquid formulations. The course of the setting reaction was followed by penetrometer, rheological and electrical techniques. Small amounts of water, organic acids, and the reactivity of the zinc oxide all have a profound influence on the setting characteristics of cement pastes.
Translucency of Dental Porcelains
Authors: Brodbelt R.H.W. , O'Brien W.J. , Fan P.L.
Published: November 2010

The translucency of comparable shades of five dental porcelains was determined. Both direct transmittance and total transmittance were measured at wavelengths of 400 - 700 nm. For 1 mm of porcelain, the values for direct transmittance were low and averaged 0.13 percent, whereas the values for total transmittance averaged 26.8 percent. Transmittance increased with increasing incident wavelength. These results indicated a high degree of light scattering.
Experimentally Induced Alterations in Periapical Tissues of the Cat
Authors: Torabinejad Mahmoud , Kiger Robert D.
Published: November 2010

Ten cats were immunized with subcutaneous injections of keyhole limpet hemocyanin (KLH). After it was determined that the experimental animals had developed circulating antibodies to KLH, challenge doses of KLH were administered via the root canal system. The radiographic and histologic findings suggest that antigen-antibody complex reactions can occur in periapical tissues of teeth, and that they can play a role in the pathogenesis of periapical lesions. In contrast, no radiographic and histologic changes were noted in non-immunized cats.
Microscopic Study of Smooth Silver-plated Retention Pins in Amalgam
Authors: Galindo Y. , McLachlan K. , Kasloff Z.
Published: November 2010

A silver-plating technique was developed in an effort to produce good mechanical bonding characteristics between stainless steelpins and amalgam. Metallographic microscope and scanning electron microscope (SEM) studies were made to assess the presence, or otherwise, of such a bond between (a) the silver layer plating and the surface of the stainless steel pins, and (b) and silver plating and the amalgam. Unplated stainless steel and sterling silver pins were used as a control and as a comparison, respectively. A "rubbing" technique of condensation was devised to closely adapt amalgam to the pins. It is concluded that there is strong evidence for the existence of a good bond between the plated pins and amalgam. The mechanical performance of the bond is discussed elsewhere. 1.
Characterization of Autonomic Receptors in Isolated Human Parotid Acinar Cells
Authors: Mangos John A.
Published: November 2010

Isolated human parotid acinar cells have been used for the in vitro characterization of the muscarinic cholinergic and alpha- and beta-adrenergic receptors of these cells. The agonist-antagonist interactions at the receptor level were studied, and the role of the receptor-activated cellular systems in the process of secretion was characterized.
Characterization of the Rupture Properties of Denture Soft Lining Materials
Authors: Wright P.S.
Published: November 2010

Rupture properties of soft lining materials are characterized by their resistance to tearing. The energy necessary for their rupture depends upon rate of deformation, temperature, and conditions of storage or use. After storage in water for six months, some silicone rubber materials are no stronger than irreversible hydrocolloid materials.
Jaw Muscle Silent Periods: The Effect of Acrylic Splints
Authors: Moini M.R. , McCall W.D. , Mohl N.D.
Published: November 2010

Jaw muscle silent periods were recorded in response to a chin tap during maximal clench in asymptomatic subjects. The insertion of a palatal splint did not change the silent period duration. However, an occlusal splint, or part of it, caused a significant increase in the duration of the silent period.
Statistical Relationship of Morsal to Bucco-lingual, Approximal and Sulcal Caries in Rats
Authors: Rinehimer L.A. , Tanzer J.M.
Published: November 2010

The correlation of morsal with sulcal, bucco-lingual and approximal caries scores of rats was compared. The morsal with bucco-lingual plus approximal correlation was significantly better than the morsal with sulcal correlation. When reporting rat caries, sulcal scores should be reported alone; morsal scores should be grouped with bucco-lingual and approximal to demonstrate total smooth surface lesions.
Mucopolysaccharidase Activity and Glycosaminoglycan Content in Traumatized Resorbing Deciduous Teeth
Authors: Alexander Stanley A. , Swerdloff Mark
Published: November 2010

The periodontal ligaments from traumatized deciduous teeth, while undergoing rapid resorption, were analyzed biochemically for mucopolysaccharidase activity and for total glycosaminoglycan content of dentin and cementum. Enzyme activity was present only in resorbing teeth. A concomitant 65 percent decrease in glycosaminoglycans from these teeth occurred as well.
Composition and Metabolic Activity of Dental Plaque From Healthy Young and Elderly Individuals
Authors: Holm-Pedersen Poul , Folke Lars E.A. , Gawronski Thomas H.
Published: November 2010

The composition and biochemical activities of 4-and 9-day-old plaque were studied in young and elderly subjects. Plaque accumulation tended to be greater in the older group. Levan hydrolase activity and the total number of recoverable, viable microorganisms were higher in plaque from younger subjects. Results suggest that the microbial composition of plaque is qualitatively different in younger and elderly subjects.
Systemic Absorption of Fluoride from Alginate Impression Material in Humans
Authors: Whitford Gary M. , Ekstrand Jan
Published: November 2010

Thirty minutes after routine alginate impressions in five adult subjects, plasma fluoride levels increased by an average of 2.6 times over control values. Urinary fluoride excretion rates increased approximately 2.9 times during the first two hours after the impressions. Average whole saliva fluoride levels at 15 minutes were over 100 times the average control concentration. When small amounts of alginate were deliberately ingested, plasma fluoride levels and urinary excretion rates increased sharply.
Sn4(OH)6Cl2 and SnO Corrosion Products of Amalgams
Authors: Marshall Sally J. , Marshall Grayson W.
Published: November 2010

Although the corrosion characteristics of dental amalgam have been of considerable interest to dental researchers, it has been difficult to identify the products which form in vivo. This report demonstrates that Sn4(OH)6Cl 2 and SnO are formed in vivo and in vitro. The Sn-Cl product is the predominant phase formed by corrosion-induced changes of the Sn8Hg phase of amalgam. It is present in conventional and, in smaller amounts, Cu-rich amalgam restorations.
Castability of Low Gold Content Alloys
Authors: Howard William S. , Newman Sheldon M. , Nunez Loys J.
Published: November 2010

A test pattern composed of 14 gauge sprue wax and various gauges of nylon lines was constructed, and used to differentiate the castability of several alloys. The castability of seven commercial low gold content alloys for porcelain fused to metal restorations was compared. Five commercial low gold content yellow alloys for full cast restorations were compared to each other and to a Type III certified control.
Effects of Fluoride in Remineralized Human Surface Enamel on Dissolution Resistance
Authors: Feagin F. , Sierra O. , Thiradilok S. , Jeansonne B.
Published: November 2010

Remineralized surfaces of human tooth enamel were dissolved at constant rates in 10 mM acetic acid at pH 4.0, and in 10 mM EDTA at pH 7.4 in a system that prevented redistribution of dissolved F. Surfaces remineralized 25 hours in 0.4 mM NaF (8 ppm F -) dissolved slower in acid or in EDTA than those remineralized in the absence of F-. The F- in three-hour remineralized surfaces had no effect on rates of mineral dissolution. Resistance to EDTA, as well as acid of 25-hour remineralized surfaces, indicates the occurrence of a maturation process, which may involve F- exchange for OH- ions in newly formed crystals. The results indicated that F- may slow caries by its action on remineralization if given sufficient time for this maturation.
Fluoride Concentration in Enamel Treated with 50% Phosphoric Acid and NaF with Subsequent Decalcification in "Acid-gel"
Authors: Bohrer J. , Gedalia I.
Published: November 2010

Acid conditioning of enamel surface does not predispose to an increased caries challenge in vitro.
An Explanation for the Water Distribution in A Hygroscopic Expansion Technique
Authors: Consani Simonides , Ruhnke Luiz Antonio
Published: November 2010

The water distribution in a controlled water addition technique was investigated using a Liquid Scintillation Counter. The mix water arrangement varied in different sections of the investment mass. The water distribution seemed to be the result of the influence of added water and a sprue base.
Basic Biological Sciences
Authors: Brownell Anna G. , Rovero Linda J.
Published: November 2010

Developing enamel organ epithelium was cultured in the presence and absence of non-viable dental papilla mesenchyme cells. Epithelial cell proliferation was enhanced by 75% when cultivated on the mesenchyme cell substratum. The addition of epidermal growth factor (EGF) to enamel organ epithelium cultured on this substratum resulted in a synergistic enhancement of DNA synthesis.
Estimation of Radiation Dose from Porcelain Teeth Containing Uranium Compound
Authors: Sairenji E. , Moriwaki K. , Shimizu M. , Noguchi K.
Published: November 2010

Uranium concentrations of porcelain teeth were determined using the fission track method. The uranium contents of each brand range 0.33-10 ppm,* 0.69-81 ppm,§ 2.5-14 ppm, † and 11-205 ppm, # respectively. In addition, corresponding dose equivalents to the oral mucosa were calculated.
Apparent Viscosities of Setting Elastomers
Authors: Vermilyea Stanley G. , Huget Eugene F. , De Simon Laszlo B.
Published: November 2010

The flow behavior of five elastomeric impression materials was determined by extrusion viscometry. Initial viscosity ranged from 400 to 5,100 poise at a shear rate of 2.2 reciprocal seconds. All of the elastomers showed initial non-Newtonian behavior and increased viscosity with time.
Linear Dimensional Changes in Elastic Impression Materials
Authors: Marcinak C.F. , Young F.A. , Draughn R.A. , Flemming W.R.
Published: November 2010

Four classes of elastomeric impression materials (polysulfide, polyether, silicone, and agar-agar) were evaluated on the basis of linear dimensional stability as a function of time between taking and pouring an impression of mounted teeth. Four polysulfide materials produced dies which were larger than the teeth and generally increased in size with impression storage time. One silicone material produced dies slightly smaller than the teeth, and the dies from another silicone were dramatically smaller with increasing storage times. A polyether material produced slightly smaller dies for up to four hours' storage time, then increasingly larger dies up to 24 h. The dies from a reversible hydrocolloid were larger than the teeth for storage times up to 30 min, and then decreased rapidly at longer times.
Basic Biological Sciences
Authors: White Wesley D. , Nancollas George H.
Published: November 2010

A rotating disc method has been used to study simulated white spot formation at a bovine enamel surface in the presence of 1-hydroxy-1-ethane-1, 1-diphosphonic acid (HEDP) at PH = 5.0. The reaction appears to be accompanied by the slow precipitation of a CaHEDP phase within the pores of the "intact" layer.
Materials Science
Authors: Johnston W.M. , O'Brien W.J.
Published: November 2010

The widespread use of porcelain in restorative dentistry is generally due to its esthetic appearance even though it is brittle. The transverse strength, or modulus rupture, averages around 108 MPa (16,000 psi) for aluminous porcelain and 88 MPa (13,000 psi) for feldspathic porcelain.1 The tensile strength, as determined by diametral compression, is approximately 29 MPa (4,200 psi) for opaque feldspathic porcelain and 40 MPa (5,800 psi) for gingival feldspathic porcelain.2 The compressive strength is reported to be 340 MPa (50,000 psi) for a feldspathic porcelain.3 These mechanical strength properties of dental porcelain confine its use to low stress-bearing restorations or to those restorations with a metal substrate.
Reactions of Powdered Human Enamel and Fluoride Solutions with and without Intermediate CaHPO4 • 2H20 Formation
Authors: Chow L.C. , Guo M.K. , Hsieh C.C. , Hong Y.C.
Published: November 2010

Powdered human enamel treated for three minutes each with a CaHPO4·2H2O forming solution and a fluoride solution, and then suspended in "synthetic saliva" for 72 hours acquired a large amount of apatitic fluoride. This apatitic fluoride appears to form after the fluoride treatment.
The Vascular Pattern in the Papillary Region of Rat Incisor and Molar Tooth Enamel Organ
Authors: Skobe Ziedonis
Published: November 2010

Scanning electron microscopy of the enamel organ of rat incisor and molar teeth in the maturation stage of amelogenesis revealed two vascularization patterns of the papillary layer. In one pattern, the anastomosing capillaries formed loops of varying sizes around spherical or somewhat oblong papillae. In the second pattern, the capillaries were parallel to each other embedded in furrows between long ridges of papillary cells. It is postulated that each of these two patterns may be associated with a specific stage in the process of enamel maturation.
Clinical Science
Authors: Dipaola Camille , Mandel Irwin D.
Published: November 2010

The enzyme-linked immunosorbent assay (ELISA) was found to be a reliable and accurate method for quantitating lactoferrin in parotid fluid. In saliva from normal glands, the concentration was usually below 1 mg% and was always higher in unstimulated than in stimulated secretion.
Spectral Studies of New Luminophors for Dental Porcelain
Authors: Peplinski D.R. , Wozniak W.T. , Moser J.B.
Published: November 2010

Luminescence spectra of several non-radioactive luminophors that may be suitable for dental porcelain have been obtained. It was found that porcelain composition and maturation temperature have large effects on excitation and emission spectra. Most of the luminophors had excitation maxima lower in wavelength than have been observed for natural teeth.
Assessment of Variables in Clinical Studies of Amalgam Restorations
Authors: Mjor Ivar A. , Espevik Svein
Published: November 2010

Marginal degradation of two amalgams with different creep properties was studied as a function of clinical variables. The amalgam with the highest creep values showed the most marked marginal degradation, irrespective of operator, doubling of the trituration time, and the use of contralateral, opposing, or unrelated teeth for comparison.
Clinical Science
Authors: Laikko I. , Larmas M.
Published: November 2010

The changes of acid and alkaline phosphatase activities were quantitatively analyzed in different layers of dentine in developing and intact states of human teeth. The peripulpal areas revealed the highest activities. In the mineralizing apical area the alkaline phosphatase activity was ten times higher than that in fully-formed teeth.
Nocturnal Masseter Muscle Activity and Urinary Catecholamine Levels in Bruxers
Authors: Clark G.T. , Rugh J.D. , Handelman S.L.
Published: November 2010

Nocturnal electromyographic recordings of masseter muscle activity were performed on 20 bruxist and ten control subjects. Each subject collected two 24-hour urine samples. An analysis of urinary catecholamine content was performed. A positive relationship was found between increased epinephrine contentand high levels of nocturnal masseter muscle activity.
Cariogenicity of Mutants of Streptococcus mutans
Authors: Mao Michael W.H. , Rosen Sam
Published: November 2010

In this study, we induced a number of mutants of S. mutans differing in their abilities to synthesize glucan and produce acid. When tested for cariogenicity in gnotobiotic rats, "high pH" mutants caused less caries, but could not supplant a cariogenic parent strain.
Inhibition of Streptococcus mutans by Human Plaque Flora
Authors: Deyloff John L. , Sanders Christine C.
Published: November 2010

The ability of human oral bacteria to inhibit Streptococcus mutans was studied under a variety of in vitro conditions using an agar overlay assay. Extensive inherent variability in microbial antagonism by certain organisms was demonstrated. Antagonistic activity was also significantly influenced by changes in the assay conditions.
The Expression of the Epithelial Blood-group Substances: Normal and Malignant Tissues
Authors: George D.I. , Hanks C.T. , Lopatin D.E.
Published: November 2010

The blood-group isoantigens are macromolecules localized to the plasma membranes of certain epithelial tissues.2,11-15 These substances are not detectable on the epithelium once it has undergone malignant transformation.2,9,13 Results of this investigation have demonstrated that the loss of detectability of the blood-group isoantigens does not appear to be related to a "masking" effect by an increase in surface sialic acid. Using fluorescein-labeled lectins specific for sugar subunits which are components of the blood-group oligosaccharide chain, it was found that the malignant cells and cells of the para basal layer of normal oral epithelium had high levels of N-acetyl-D-glucosamine (GlcNAC), the subterminal sugar residue of the blood-group chain. The basal cells of normal epithelium and a minority of the malignant cells demonstrated levels of D-galactose-N-acetyl-D-galactosamine, which are the most proximal blood-group sugar subunits, as well as subunits of other membrane antigens.

Our results indicate that malignant cells seem to be capable of synthesizing the blood-group oligosaccharide chains to the same level as the normal cells of the para basal layer of stratified squamous epithelium. This level is just subjacent to the terminal D-galactose residue of the blood-group precursor chain. Increased or decreased differentiation characteristics of squamous cell carcinomas did not alter the level of blood-group synthesis. However, there may be a correlation between the level of synthesis of these antigens and the ability of the cells to demonstrate motility and to proliferate.
Repeat Measurements Analysis of Dental Data
Authors: Wallenstein S. , Fleiss J.L. , Kingman A.
Published: November 2010

The statistical analysis of trials in which individuals are evaluated repeatedly at several time points is examined. For the case in which correlations between observations follow a specified pattern, a conservative F test is applied to test for the effects of time and for the interaction between time and treatment groups.
Basic Biological Sciences
Authors: Balekjian Aram Y. , Turner D.W. , Cotton W.R. , Guidry M.S.
Published: November 2010

Synthetic culture medium containing potato starch and 1 gm% sucrose, with and without human parotid saliva, were pre-incubated. Filtrates from these mixtures were then incubated with Streptococcus mutans. S. mutans colonization on glass rods was suppressed in the cultures using filtrates from saliva and starch interaction. No inhibition was noted in filtrates pre-treated with parotid saliva in the absence of starch. The results suggest that the hydrolysis of starch by saliva yields by-products which inhibit in vitro S. mutans colonization.
Clinical Science
Authors: Van Houte J. , Aasenden R. , Peebles T.C.
Published: November 2010

Lactobacilli were isolated from about 50% of plaques from sound tooth surfaces of human subjects who had ingested fluoride (F) supplements since their births or subjects with negligible systemic fluoride exposure. In about 10% of these plaques, the proportions were 1% or higher of the total flora. Lactobacilli were not always isolated from caries-associated plaques. The mean salivary lactobacillus count of the F-supplement group was comparable to that generally reported for other groups of caries-active subjects with varying caries experience. The findings are discussed in relation to the role of lactobacilli in caries initiation and the anti-caries effect of fluoride supplementation.
Materials Science
Authors: Jedrychowski Joseph R. , Caputo Angelo A. , Prola Jeff
Published: November 2010

The effects of ferric chloride mordant solution, two cleansing solutions, and three chemical adhesion promoters were examined on resin-dentin adhesion. Adhesion was increased with the use of ferric chloride solution. An NPG-GMA or butyl acrylate-acrylic acid copolymer type of adhesion promoter also increased resistance to shear separation.
Kinetics of Cell Proliferation and Migration Associated with Orthodontically-induced Osteogenesis
Authors: EugeneRoberts W. , Chase Donald C.
Published: November 2010

Cell kinetics of rat molar periodontal ligament (PDL) during orthodontically-induced osteogenesis revealed: 1) primary growth fraction of 59%, 2) proliferating cells from throughout the PDL migrate toward the bone surface, 3) preosteoblasts, capable of forming osteoblasts without synthesizing DNA, are present in the PDL, 4) osteoblasts are derived from local PDL cells, and 5) cell death is a characteristic feature of the osteogenic response.
Rapid Quantitative Determination of the Effect of Antiplaque Agents and Antisera on the Growth, Acid Production, and Adherence of Streptococcus mutans
Authors: Ciardi J.E. , Rosenthal A.B. , Bowen W.H.
Published: November 2010

A rapid quantitative in vitro assay measured the effects of antiplaque agents and antiserum on growth and sucrose-mediated adherence of radiolabeled S. mutans 6715. Acid production was measured by change in pH. In this assay the primary effect of chlorhexidine and fluoride was bacteriostasis and inhibition of acid production, respectively; the primary effect of dextran, dextranase, and specific antiserum was inhibition of sucrose-mediated adherence.
The Effect of Daily Mouthrinsing with Stannous Fluoride on Dental Plaque and Gingivitis — Four-month Results
Authors: Leverett Dennis H. , McHugh William D. , Jensen Øivind E.
Published: November 2010

This clinical trial of a daily 0.1% SnF2 mouthrinse involved over 400 children, from 12 to 15 years of age. With 0.05% NaF as the active control, rinsing was conducted daily for four mo after baseline examinations. Four-month examinations showed significantly lower Plaque Index scores for the SnF2 group. Gingival Index scores for the SnF2 group were lower, but the difference did not reach statistical significance.
Fracture Toughness of Human Enamel
Authors: Hassan R. , Caputo A.A. , Bunshah R.F.
Published: November 2010

A microindentation technique was employed to estimate the fracture toughness of human enamel. A pattern of increasing fracture toughness values existed from incisal to cervical in incisor enamel. Statistical analysis indicated that the molar enamel was more brittle than either the canine or incisor enamel. It was observed that the cracks emanating from the comers of an indentation propagated preferentially, with the weakest path of fracture usually extending along the cervical-incisal axis.
Thiocyanate as a Cofactor in Myeloperoxidase Activity Against Streptococcus mutans
Authors: Kersten Henk W. , Moorer Wilfred R. , Wever Ron
Published: November 2010

Inhibition of glycolysis of some oral bacteria was established in vitro by an antibacterial system, consisting of myeloperoxidase, H202, and a cofactor. When thiocyanate was used in physiological concentration as a cofactor, the system acted (at low pH) bactericidally on Streptococcus mutans, as indicated by the determination of viable counts. However, at neutral pH, the glycolysis of Streptococcus mutans was inhibited, while its viability remained unaffected. The possible role of such a pH-dependent antibacterial system in the oral cavity is discussed.
Magnesium Inhibition of Apatite Nucleation by Proteolipid
Authors: Ennever J. , Vogel J.J.
Published: November 2010

The effect of magnesium on apatite nucleation by Bacterionema matruchotii proteolipid was determined. The ion, in metastable calcium phosphate solution at a concentration that did not reduce proteolipid calcium binding, prevented apatite crystallization. The data were compared with those involving magnesium and homogenous nucleation of apatite in vitro.
Adhesive Bonding of Various Materials to Hard Tooth Tissues: XXIII. Isotonic Monomer Formulations
Authors: Bowen R.L.
Published: November 2010

With regard to adhesion to dentin by chemical mechanisms, the vitality of odontoblasts and contiguous pulpal cells might require that materials influencing the dentinal tubules be maintained within certain limits of osmotic pressure. Resins for use in adhesive formulations can be made isotonic with vital tissues by adjusting the proportions of hydrophilic monomers and the water contents of the formulations.
Frictional Behavior and Surface Failure of Acrylic Denture Teeth
Authors: Raptis C.N. , Powers J.M. , Fan P.L.
Published: November 2010

The wear characteristics of acrylic denture teeth were investigated under single- and double-pass sliding. The response of acrylic teeth to sliding was that of a relatively ductile material. The wear characteristics were affected similarly by environments of water and saliva. The "enamel" surfaces showed more resistance to penetration and were less susceptible to surface damage than the "dentin" surfaces. The effect of the second pass was to increase track width and cause a more severe mode of surface failure.
Basic Biological Sciences
Authors: Fitzgerald Robert J. , Adams Beatrice O. , Fitzgerald Dorothea B. , Knox Kenneth W.
Published: November 2010

Thirty-two strains of Lactobacilli, comprising eight species and obtained from human dental plaque or other sources, were tested for cariogenic potential in gnotobiotic Sprague-Dawley rats receiving modified cariogenic Diet 2000. Seventeen of these strains were moderately to highly cariogenic, and only one, a strain of Lactobacillus lactis, was scored as non-cariogenic. The molar fissures were the predominant site of caries attack. Primary lesions of the smooth surfaces were infrequently seen, although these surfaces were often secondarily involved by the extension of fissure lesions. The preferential location of caries in the sheltered fissure sites was attributed to their inability to form adherent plaque deposits on the smooth surfaces of the teeth. Caries production by a strain of L. salivarius was equally severe on sucrose- or glucose-containing versions of Diet 2000, but glucose was less supportive of caries development than sucrose for a strain of L. fermentum. It is concluded that a wide variety of lactobacilli may be cariogenic under favorable environmental conditions.