bluuebunny/crossref_metadata_2025 huggingface dataset:
Microcapsules on Streptococcus mutans Serotypes by Electron Microscopy
Authors: Grenier Ella M. , Gray R.H. , Loesche W.J. , Eveland W.C.
Published: November 2010

Extracellular microcapsules have been demonstrated on cells of most serotypes of Streptococcus mutans by electron microscopy, using bacterial strains of the various serotypes and peroxidase labeled or unlabeled immune serum. A correlation was noted between the amount of capsular substance on the strains of S mutans examined and degree of antigenicity as expressed by the indirect fluorescent antibody (FA) title. A serotype d strain was shown to lose both antigenicity as determined by the FA reaction and capsular material as seen by electron microscopy with repeated in vitro passage. When 10% unheated rabbit serum was added to the medium, antigenicity and capsular material were restored.
Noncollagenous Proteins of a Rat Dentin Matrix Possessing Bone Morphogenetic Activity
Authors: Butler William T. , Mikulski Andrezej , Urist Marshall R. , Bridges G. , Uyeno S.
Published: November 2010

An insoluble preparation of rat dentin matrix was shown to possess bone morphogenetic protein (BMP) activity, i.e. the capacity to induce the formation of cartilage and bone when implanted intramuscularly. Since BMP activity was previously attributed to noncollagenous proteins (NCP) of bone and dentin, the nature of NCP of the rat dentin was examined. After treatment of the matrix with purified bacterial collagenase, three NCP were solubilized concomitantly with digestion of the dentin collagen to smaller peptides. The three proteins were separated by anion-exchange chromatography on DEAE-cellulose. Two of the NCP were rich in aspartate, glutamate, glycine, serine, and alanine, and thus displayed compositions similar to acidic proteins of other connective tissues. The third NCP was shown by amino acid composition to be the aspartate, serine-rich phosphoprotein, which occurs mostly in a soluble form in rat dentin. This observation supports the view that a portion of dentin phosphoprotein is firmly bound.
Stimulation of Bone Formation and Bone Resorption by Fluoride in Thyroparathyroidectomized Rats
Authors: Liu Chung-Ching , Baylink David J.
Published: November 2010

In TPTX as well as sham-operated rats, F increased periosteal bone formation, decreased endosteal bone formation and endosteal osteoid maturation rate, and increased endosteal bone resorption. Serum iPTH was not affected by F treatment. Thus, the effects of F on bone are not mediated by PTH.
In Vitro Study of Cellular Influence on 45Ca Uptake in Developing Rat Enamel
Authors: Bawden James W. , Wennberg Alf
Published: November 2010

An in vitro method was used to study the influence of enamel organ cellular activity on the uptake of 45Ca in the developing enamel of rat molars. Heat killing, inhibition with DNP, or stripping of the enamel organ from the tooth had no apparent effect on 45Ca uptake patterns in maturing enamel. However, uptake in newly secreted enamel matrix was increased.
Purification and Partial Characterization of Deoxyribonuclease I from Bovine Parotid Gland
Authors: Lundblad Roger L. , Hoffman Steve , Noyes Claudia M. , Kingdon Henry S.
Published: November 2010

Deoxyribonuclease I has been purified from bovine parotid gland. The purification procedure utilizes an acid extraction of minced parotid gland, salt fractionation, gel filtration, and ion-exchange chromatography. The last step, chromatography on Sulfopropyl-Sephadex, resolves the enzymatic activity into several fractions. The major fraction, designated DNase A, was subjected to further investigation. This enzyme has, as expected, an alkaline pH optimum and an obligate requirement for divalent cations. The presence of calcium chloride protects DNase A from inactivation by proteolytic enzymes. Despite the previously described immunologic dissimilarity, there appears to be a large amount of homology between the parotid and pancreatic DNase's.
Detection of Functional Complement Components in Gingival Crevicular Fluid from Humans with Periodontal Disease
Authors: Courts Frank J. , Boackle Robert J. , Fudenberg H. Hugh , Silverman Myron S.
Published: November 2010

Crevicular fluid was collected from patients with periodontitis and tested for the presence of a functional complement system. The effect of dental plaque on the first complement component (C1) was studied. Results indicated functional C1 and functional whole complement activities in gingival crevicular fluid are rapidly inactivated by dental plaque and possibly other host factors.
In Vitro Metabolism of 4-Androstene-3,17-Dione by Human Submaxillary Gland Homogenates
Authors: Coffey James C. , Crutchfield William C.
Published: November 2010

Tritiated 4-androstene-3,17-dione was incubated with human submaxillary gland homoaenates. In 180-minute incubations, human submaxillary gland converted 4-androstene-3, 17-dione predominately to testosterone and to a lesser extent, 5α-androstane-3α,17β-diol and androsterone.
Research and Development Contracting at the National Institute of Dental Research
Authors: Goggins John F.
Published: November 2010

Government contracting for biomedical research and development is a cooperative venture of high public visibility. It must be soundly conceived, openly instituted, and skillfully managed. Because of the cooperative nature of contract activities, it is important for the scientific community to understand the contract mechanism and the concepts upon which its use is based. Therefore, these concepts are described and how this mechanism serves as an aid in accomplishing the mission of the National Institute of Dental Research is discussed.
Synchronized Crystal Dissolution Behavior for Tooth Enamel and Synthetic (NBS) Hydroxyapatite
Authors: Fawzi M.B. , Sonobe T. , Higuchi W.I. , Hefferren J.J.
Published: November 2010

The synchronized crystal dissolution hypothesis previously proposed to explain the unusual dissolution behavior of human dental enamel and hydroxyapatite in partially saturated acidic media has been critically examined with dissolution-dialysis transport experiments. The findings are in accord with the hypothesis. A model based upon a variable effective solubility for the hydroxyapatite crystal is proposed.
Marginal Failure of Amalgam Class II Restoration
Authors: Dérand T.
Published: November 2010

Analysis of stresses in a bicuspid with an amalgam Class II restoration was carried out with the finite element method. When stresses were known, creep in the margin of the restoration was calculated. If the buccal cusp was loaded, the maximum compressive stresses were found in the buccal part of the restoration.
Enamel Hypoplasia in Relation to Caries in Guatemalan Children
Authors: Infante Peter F. , Gillespie George M.
Published: November 2010

Guatemalan children with anterior linear enamel hypoplasia (LEH) had a significantly greater caries experience in posterior dentition than their peers who did not have anterior LEH. The findings suggest that the synergistic mechanism of undernutrition and infection, which may underlie the occurrence of anterior LEH, may also predispose clinically normal appearing deciduous molars to an excessive caries attack equal to that observed in the grossly hypoplastic anterior teeth. The nutritional implications merit further investigation.
Morphology and Incidence of Torus Palatinus and Mandibularis in Brazilian Indians
Authors: Mema Bernaba Jorge
Published: November 2010

The incidence and morphology of torus platinus and mandibularis was verified in 200 Indians, residents of two Brazilian Indian Reserves in São Paulo State, Brazil. A low incidence of both types of exostoses was observed, with torus palatinus occurring more frequently than mandibularis. These structures did not occur in individuals less than 10 years of age. Flattened torus palatinus predominated in relation to the other forms.
Quantitative Study of Enamel Dissolution Under Conditions of Controlled Hydrodynamics
Authors: White Wesley , Nancollas George H.
Published: November 2010

A rotating disk method has been used to study the dissolution of bovine enamel. A diffusion model adequately describes the reaction for a wide range of conditions, and the rate is also hydrogen ion dependent. The solubility product of bovine enamel, 5.9 ± 1.8 × 10-59 moles9 1-9 at 25 C is derived by a method that minimizes the possibility of phase changes.
Snack Food Intake of Adolescents and Caries Development
Authors: Clancy Katherine L. , Bibby Basil G. , Goldberg Hyman J.V. , Ripa Louis W. , Barenie James
Published: November 2010

The relationship between the frequency of eating various snack foods, socioeconomic variables, and an increment in caries was studied in 143 adolescents. There were negative correlations between DMFT increments and the frequency of apples, fruit juice, and sugarless gum intake, and a positive association of DMFT increments with chocolate candy intake and spending money.
Electroless and Chemical Metal Deposition on Human Tooth Enamel
Authors: O'Keefe Thomas J. , Christie Richard D.
Published: November 2010

The feasibility of depositing a thin metal film onto tooth enamel has been demonstrated. The process employs chemical solutions containing ions of the metal to be deposited and suitable reducing agent solutions. The deposits are quite adherent and exhibit the normal properties of the bulk metal.
Sorption of Water by Filled-Resin Composites
Authors: Misra D.N. , Bowen R.L.
Published: November 2010

Water-sorption studies discriminate between passive (those containing Sn, Nb, and Ti) and reactive (those containing Zn and an alloy of CoCrMo) metal-resin composites. The reactive ones form hydrated oxides or hydroxides or both, in accord with a parabolic rate law. The nature of the chemical reaction is elucidated in two instances by analysis of the resultant gases.
Influence of Certain Manipulative Variables on the Static Creep of Amalgam
Authors: Osborne John W. , Phillips Ralph W. , Norman Richard D. , Swartz Marjorie L.
Published: November 2010

The effects of trituration time on the creep of eight commercial dental amalgams was determined. The data show that trituration time does influence the creep of amalgam, but its magnitude varies from one alloy to another. The condensing procedure also influences creep.
The Mechanism of Tensile Failure in a Nickel-Base Casting Alloy
Authors: Lewis Arthur J.
Published: November 2010

Standard tensile specimens were cast from a nickel-base partial denture casting alloy and subsequently fractured in a tensile stress testing machine. Fracture sites were subjected to scanning electron microscopy in order to determine the exact mechanism by which failure had occurred. A metallographic examination of prepared specimens was used to demonstrate the distribution of phases within the alloy.
The Young Child's Response to Repeated Dental Procedures
Authors: Venham L. , Quatrocelli S.
Published: November 2010

Children's responses to dental procedures which were repeated over a series of six visits were studied. Response to a mirror and explorer examination at the beginning of each visit deteriorated initially and then improved over the last three visits. Responses to the four injections were increasingly negative. The response to cavity preparation did not change significantly during the four treatment visits. The results suggest dental experience resulted in desensitization to nonstressful procedures and sensitization to stressful procedures.
Inhaled Nitrous Oxide and Cathepsin D Activity in the Lung
Authors: Ramazzotto Louis J. , Carlin Ronald , Engstrom Robert
Published: November 2010

Acute exposures of lungs to nitrous oxide in anesthetic concentration results in an initial lowered free activity of cathepsin D. Chronic exposures with either continuous or interrupted anesthetic exposure increases the free activity of this enzyme.
Evaluation of Intracytoplasmic Particles in Histiocytes after Endodontic Therapy with a Hydr ophilic Plastic
Authors: Kronman J.H. , Goldman M. , Lin P.S. , Goldman L.B. , Kliment C.
Published: November 2010

The presence of granules within the cytoplasm of periapical tissue histiocytes had been observed in teeth which had a root canal over-filled with a hydrophilic plastic polymer. SEM examinations revealed these granules to be barium sulfate, which was added to the polymer for radiopacity. X-ray spectra revealed strong calcium peaks in bone adjacent to the histiocytes, which showed strong barium peaks. In addition, between the histiocytes and the bone a greater concentration of calcium was seen. Because the histiocytes and not the plastic polymer contained barium sulfate, the evidence for this material's biocompatibility is greatly enhanced.
Late Elongation of the Cranial Base
Authors: Roche Alex F. , Lewis Arthur B. , Wainer Howard , Mccartin Robert
Published: November 2010

A single logistic curve was fitted to serial data for three cranial base lengths (S-N, Ba-N, and Ba-S) in 33 boys and 26 girls. Elongation during pubescence plus adolescence is greater in boys than girls for each length. The maximum rate of pubescent elongation occurs earliest in Ba-N. There are no consistent sex differences in the maximum rates of elongation but they occur considerably earlier in girls. Similarly, girls reach 95% of their adult lengths at younger ages than boys.
Cydophosphamide-Induced Abnormalities in the Incisors of the Rat
Authors: Lee Vahlsing H. , Kim Sun-Kee , Feringa Earl R.
Published: November 2010

A single injection of 75 mg/kg cyclophosphamide caused gross dental abnormalities in rats. Broken, malformed, overgrown, and "extra" incisors developed several weeks after drug treatment. Radioautographic investigations show no unusual features in the morphology or labeling with H3-thymidine in the odontogenic cells. The results suggest that the cytotoxic effect of the drug is a temporary one which induces a residual alteration of tooth growth.
Effectiveness of Glutaraldehyde as a Chemosterilizer Used in a Wrapping Technique on Simulated Metal Instruments
Authors: Christensen Rella P.
Published: November 2010

Chemosterilization utilizing glutaraldehyde-moistened gauze as a wrap on simulated metal instruments was evaluated. Non-sporeforming test organisms were killed within five minutes. Two sporeforming test organisms were killed in six hours. The sporicidal effect obtained would indicate that glutaraldehyde used in a wrap technique could sterilize objects.
The Role of Calcitonin in the Calcification of Dental Matrix
Authors: Kline L.W. , Thomas N.R.
Published: November 2010

Chronic calcitonin (CT) deficiency was shown to have several effects on the incisors of young growing rats. The incisors had a significantly wider predentin layer, interglobular dentin, and frequent pulpal exposures at the incisal edge. It was concluded that CT plays a role in the normal calcification of dentin matrix.
Manual and Oral Sensation in Patients with Cushing's Syndrome
Authors: Catalanotto Frank A. , Henkin Robert I.
Published: November 2010

Thresholds for light touch detection and two-point discrimination on the hand and in the mouth, and oral and manual stereognosis ability were measured in patients with untreated Cushing's syndrome and normal volunteers. Results indicated that patients with Cushing's syndrome displayed decreased two-point discrimination on the tongue and palate and decreased oral stereognosis.
The Effect of Acid Etching on Enamel, Dentin, and the Inner Surface of the Resin Restoration : A Scanning Electron Microscopic Investigation
Authors: Brännström Martin , Nordenvall Karl Johan
Published: November 2010

Buceal cavities were prepared in vivo on 22 contralateral tooth pairs. The cavities and the surrounding enamel were either etched or cleaned, with a surface-active solzition (the control). The cavities were filled with Concise Enamel Bond and composite or left unrestored. The teeth were extracted, imanertiately after treatment. Treated surfaces or the inner surface of the restorations were studied in the scanning electron microscope (SEM). An "in-pair" evaluation of the results of 320 photographs was done.

The etched axial wall had a smooth surface with widened and patent denlinal tubule apertures. The corresponding inner resin surfaces were irregular, sporadically showing tags of varying length corresponding to the denlinal tubules and alternating with pits of varying size. Etching for 15 seconds or two minutes gave no apparent difference in appearance of enamel, denlin, and inner surface of the restoration.
In Situ Replication Techniques: I. Preliminary Screening and the Negative Replication Technique
Authors: Kusy R.P. , Leinfelder K.F.
Published: November 2010

Fourteen commercially available elastomeric materials were investigated for their suitability as in vivo replication media. After a preliminary screening on an annotated specimen, three materials were chosen for further study. Of all materials evaluated, Xantopren Blue and Silene silicone impression materials provided the best results in vivo. This study demonstrates that a high resolution (ca 1 micron) negative replication technique may prove useful for the clinical evaluation of single-surface phenomena.
A Laboratory Evaluation of the Effect of Two Surface-Wetting Treatments on Soft Denture Liners
Authors: Louka Amazis N. , Gesser Hymie D. , Kasloff Zack
Published: November 2010

The wettability of acrylic and silicone soft denture-liners was improved by two methods of surface treatment. They consisted of formation of a thin film of silica from the application of silicon tetrachloride, and by cross-linking the surface molecules and bombarding with hydroxyl free radicals. Softness and water sorption were monitored throughout the study.
A Microbiological Study of Normal Flora of Macropod Dental Plaque
Authors: Beighton David , Miller William A.
Published: November 2010

The percentage bacterial composition of dental plaques from 12 macropods was determined. The major group of organisms was gram-positive filamentous and pleomorphic rods whose median representation was 92.2%. These were mainly Actinomyces viscosus (median value 62.5%) and Bacterionema matruchotii (median value 23.2%). Streptococci were poorly represented (median value 4.2%) as were anaerobic gram-negative organisms. Aerobic gram-negative bacteria were identified as neisseriae and Moraxella sp. The macropod plaque flora was compared with that of human beings and rodents and the differences discussed in relation to dietary differences and the early externalization of the marsupial young.
The Strengthening of Aluminous Porcelain with Bonded Platinum Foils
Authors: Sced I.R. , McLean J.W. , Hotz P.
Published: November 2010

Results are presented to demonstrate the effect of bonding thin platinum foils to aluminous dental porcelain. The increased strength is explained in terms of a reduction in surface and subsurface pores in the porcelain brought about by improved wetting.
The Effect of Added Particles on the Properties of Ag3 Sn-Additive Amalgams
Authors: Reisbick M.H.
Published: November 2010

Physical and chemical properties of amalgam alloys containing varying amounts of copper were evaluated. Evidence presented refutes the theory of Physical strengthening due to the addition of silver-copper by its eutectic. Results suggest that reactive copper could be more advantageously added to the system by using fewer copper additive particles; these particles may need to have a greater copper content that those used in Dispersalloy.
Basic Biological Sciences
Authors: Schoenfeld Charles M. , Lauten Schlager Eugene P. , Moore B. Keith , Rechtient James J.
Published: November 2010

A computer program was formulated and veri fied experimentally to predict the optical den sity on an image receptor for any given set of radiographic variables including tube kilovoltage, milliamperage, and wave form; x-ray beam filtration; nature of filters and absorbers, and type of x-ray film.
Dental and Skeletal Ages in Hypopituitary Patients
Authors: Edler R.J.
Published: November 2010

As controversy persists as to the true relationship of skeletal to dental age in normal patients, so differing statements have been made regarding these factors in patients with hormonal disorders. This study is an attempt to examine and compare these physiological ages in a small group of children with hypopituitarism.
The Morphologic Relationship Between Dental Resins and Etched Dentin
Authors: Gwinnett A. John
Published: November 2010

The interface between different resins and dentin etched with orthophosphoric acid indicated that tubules and their lateral extensions were occupied by resin. The extent and depth of penetration were influenced by the drying procedure. Penetration was approximately 0.2 mm after drying according to clinical protocol, and approximately 2.0 mm after drying dentin for 24 hours.
The Effects of Inorganic Ions Situated at the Enamel Surface on the Adsorption and Activity of Acid Phosphatase
Authors: Johnson Arthur R.
Published: November 2010

Ionically pretreated, pellicle-free enamel was reacted with acid phosphatase. Compared to control enamel, calcium, zinc, and phosphate increased initial phosphatase adsorption; magnesium and fluoride had little effect. Calcium-and zinc-treated enamels enhanced enzymic activity ; other ions depressed it. Results suggest phosphatases to be unimportant to the carious process.
The Effect of Adsorption on the Acid Production of Caries and Noncaries-Producing Streptococci
Authors: Berry Charles W. , Henry Clay A.
Published: November 2010

Eighteen different Streptococcus strains including S mutans, sanguis, mitis, salivarius, bovis, and 2F2, were assayed for their relative adsorption to synthetic hydroxyapatite and for quantities of lactic acid produced while in the adsorbed state. The results indicated that all S mutans and some S sanguis have an enhanced metabolic activity while adsorbed to hydroxapatite as compared to control suspensions without hydroxyapatite.
Association Between HLA-Antigens and Periodontal Disease
Authors: Reinholdt Jesper , Bay Inger , Svejgaard Arne
Published: November 2010

Patients with periodontitis juvenilis and patients with periodontitis were tissue typed. In the juvenile group, frequencies of tissue type specificities HLA-A9, HLA-A28, and HLA-BW15 were significantly increased as compared to the findings in the general population. In the periodontitis groups, no significant tissue type deviations were found.
The Merkel Cell in Oral Human Mucosa
Authors: Fortman Gene J. , Winkelmann R.K.
Published: November 2010

A study of the mucosal Merkel cells from 10 patients showed that the cell contained an intranuclear rodlet, clear cell qualities, fine desmosomes, characteristic membrane-bound Merkel granules, and cellular "horns" and had a close relationship to terminal axons. The Merkel cell is an intraepithelial cell with features of neurons and of amine-storage cells.
Sealant Effectiveness for Children Receiving a Combination of Preventive Methods in a Fluoridated Community: Two-Year Results
Authors: Bagramian Robert A. , Graves Richard C. , Srivastava Sujan
Published: November 2010

A series of preventive methods in combination have been used to reduce dental caries in children including dental health education, prophylaxes, pit and fissure sealants, topical application of fluoride and restorative care. Prophylaxes, sealant, and fluoride procedures are repeated every six months. Two-year results show reductions of occlusal caries increments of 74.3% for first graders and 77.1% for sixth graders. Sealant loss, as defined in this study, varied from 33% to 90% with the highest loss occurring in the newly erupted permanent molars during the first six months of the project. These high sealant loss rates are thought to be related to the age of the population which was designed to include children at the ages of peak eruption of permanent molar teeth (ages six and twelve). These teeth were often only minimally erupted and maintaining the dry field required for sealant retention was extremely difficult. However, in spite of these high rates of sealant loss, caries reduction on occlusal surfaces was highly significant in comparison to that of children who did not receive sealants.
Cytochemical and Autoradiographic Study of Nuclei in Zinc-Deficient Rat Buccal Epithelium
Authors: Chen Sow-Yeh
Published: November 2010

Ammoniacal silver stain showed that there was a decrease in nucleohistones in zinc-deficient rat buccal hyperplastic epithelaum as compared to control. Autoradiographic study showed that there was decreased incorporation of 3H-arginine and3 H-lysine in the hyperplastic epithelium.
Alkylamine Salts and Amides: In Vitro Inhibition of S mutans 6715
Authors: Warner Victor D. , Sane Jayant N. , Warner Ann M. , Mirth Dale B. , Turesky Samuel , Soloway Barbara
Published: November 2010

Our studies with the salts and amides of alkylamines have shown that the undecylenate salts have significant in vitro activity against S mutans No. 6715, suggesting that these agents are worthy of additional evaluation. The attempt to increase activity by combining undecylenic acid with the alkylamines was not successful; however, better attachment to tooth surfaces and/or retention during washing did occur. Our results suggest that the free amino group of alkylamines and the free acid group of undecylenic acid are required for these two classes of agents to demonstrate antibacterial activity.
Study on the Biosynthesis of Bovine Enamel Protein In Vitro
Authors: Shimokawa H. , Sasaki S.
Published: November 2010

Biosynthesis of enamel protein was investigated by incubating bovine tooth germs with 3H-proline containing medium. The radioactivity was incorporated into two protein fractions: one had a molecular weight of about 25,000, being secreted from the ame.'oblast to the enamel matrix, another having a higher molecular weight was supposed to be a cell associated protein.
Rate of Stannous Fluoride Reaction with Hydroxyapatite
Authors: Nelson Kenneth G.
Published: November 2010

Solutions of stannous fluoride are reacted with hydroxyapatite and the progress of the reaction is monitored by calcium analysis. The formation of Sn3F3PO4 proceeds faster with an increase in SnF2 concentration and can be further increased by adding Sn++ to the stannous fluoride solution.
Corrosion and Creep of Dental Amalgam
Authors: Gjerdet Nils R. , Espevik Svein
Published: November 2010

The influence of stress on corrosion was investigated by a potentiostatic technique. Amalgrams with low creep, both with and without γ2-phase, revealed small increases in current with stress application while alloys with high creep exhibited large increases in current. Rupture of protective oxide due to increased strain for high creep alloys may explain the phenomenon.
Thermal Analysis of Dental Impression Waxes
Authors: Powers John M. , Craig Robert G.
Published: November 2010

Ten dental impression waxes were characterized by penetration and differential thermal analysis. Penetration and initial transition temperatures were directly correlated. Penetration at 37 C ranged from 2.5 to 22% for bite waxes and was 100% for corrective waxes. Distortion of an impression wax may occur upon removal from the mouth.
Dentin Permeability: Determinants of Hydraulic Conductance
Authors: Reeder O.W. , Walton R.E. , Livingston M.J. , Pashley D.H.
Published: November 2010

A technique is described which permits measurement of the ease with which fluid permeates dentin. This value, the hydraulic conductance of dentin, increased as surface area increases and/or as dentin thickness decreases. It increased 32-fold when dentin was acid etched due to removal of surface debris occluding the tubules.
Incidence of Torsiversion in Mandibular Third Molars
Authors: Neiburger E.J.
Published: November 2010

Two percent of 826 adults examined during routine dental check-up visits show torsiversion in their mandibular third molars. The degree of rotation ranges from 20° to 60° with the predominant position at 30° buccal. This condition is quite rare and appears to be genetically directed at the infracrypt level of development.
Topography and Distribution of Trace Surface Metals (Sn, In) on Alloys for Porcelain-Metal Restoration: Influence of Surface Treatments
Authors: Stewart G.P. , Maroso D. , Schmidt J.R.
Published: November 2010

Gold alloys were given five different conditioning treatments prior to porcelain firing. The alloys were examined with a scanning electron microscope and energy dispersive X-ray analyzer. Only two of the alloys had tin and indium present; these were concentrated in particles partially fused to the alloy's surface.
Influence of the Pulpal Route on Uptake of 45Ca in Enamel and Dentin of Developing Rat Molars
Authors: Wennberg Alf , Bawden James W.
Published: November 2010

45 Ca uptake in developing enamel and dentin was studied by autoradiography. The findings indicate that the pulpal route does not supply significant amounts of calcium to the rapidly mineralizing enamel. Disruption of the odontoblastic layer did not seem to result in altered penetration of calcium into the dentin in a manner similar to that described for disruption of the matrix secreting cell layer of enamel and of bone.
Sources of Variability in Rat Caries Studies: Microbial Infection and Caging Procedure
Authors: Schuster G.S. , Navia J.M. , Amsbaugh S. , Larson R.H.
Published: November 2010

Two sources of variability in rat caries experiments have been investigated: infection with two S mutans strains and two types of caging. Results indicated that strain 6715 was more virulent than was strain 10449 when 24-day-old rats were orally infected with the organzsm under standardized conditions. Caging of rats (2 per cage) in stainless steel, raised bottom cages resulted in higher level of caries than in plastic tubs (3 per cage) with hardwood bedding. Infection and caging conditions are two of the factors which may contribute to variability in caries pattern and severity in experimental rats.
Compounds which Affect the Adherence of Streptococcus sanguis and Streptococcus mutans to Hydroxyapatite
Authors: Liljemark W.F. , Schauer S.V. , Bloomquist C.G.
Published: November 2010

Several compounds were evaluated in an in vitro assay system for their ability to block the adherence of Streptococcus sanguis to saliva-coated hydroxyapatite and Streptococcus mutans to dextran-coated hydroxyapatite. Fatty acids, ranging from C-12 to C-20, the enzyme amylase, chlorhexidine, human sera, and several serum proteins blocked S sanguis adherence to saliva-coated hydroxyapatite. Chlorhexidine blocked S mutans adherence to dextran-coated hydroxyapatite, but human sera and serum proteins did not. The effects of these compounds on the adherence of these organisms to hydroxyapatite may help in the development of specific plaque control methods for use in human populations.
The Cranial Base in Fetal Macaca nemestrina: A Quantitative Analysis of Size and Shape
Authors: Lestrel Pete E. , Moore Robert N.
Published: November 2010

The applicability of Fourier analysis to quantitate the midsagittal cranial base has been demonstrated utilizing fetal Macaca nemestrina. This methodology accurately measures the irregular form of the endocranial profile, minimizes the effects of size, and maximizes shape differences. This method provides a quantitative dimension to the descrzptive analysis of shape change previously observed with a combined histologic and cephalometric analysis.
Effects of Craniofacial Structures on Mouse Palatal Closure In Vitro
Authors: Brinkley L. , Basehoar G. , Avery J.
Published: November 2010

Heads of Swiss-Webster mouse fetuses of four ages spanning days 12-13 of gestation, were partially dissected by removing the brain (B), tongue (T) and mandible (M) alone or in combination (BT, BM, BTM). Preparations were suspended in a gassed, circulating culture system such that palatal closure must take place against gravity. Closure occurred earlier than in vivo and required the posterior half of the mandible be intact and the tongue removed.
An Epidemiologic Study of the Relationship between Various States of Occlusion and the Pathological Conditions of Dental Caries and Periodontal Disease
Authors: Katz Ralph V.
Published: November 2010

This study explored relationships between dental caries and periodontal disease and either (1) any of 8 existing orthodontic indices or (2) any of 41 individual cephalometric measures. The 486 subjects examined revealed no clinically significant associations between any of the disease measures and either the indices or the cephalometric measurements.
Effect of 4.5-Year Use of Xylitol and Sorbitol on Plaque
Authors: Mäkinen Kauko K. , Virtanen Kauko K.
Published: November 2010

The pH values of xylitol-containing plaque suspensions of persons who habitually used xylitol and sorbitol during 3.2 to 4.5 years did not significantly differ from those observed with suspensions containing no added carbohydrates. Sorbitol produced in 22-hour incubations pH values as low as 3.9 to 5.5. The activity of plaque xylitol dehydrogenase was almost nil, whereas sorbitol dehydrogenase activity was higher. The nonacidogenic nature of xylitol in relation to plaque did not change in prolonged use of xylitol.
Enamel Dissolution by Various Food Acidulants in a Sorbitol Candy
Authors: Kleber Carl J. , Putt Mark S. , Muhler Joseph C.
Published: November 2010

The carboxylic acids used as food acidulants were evaluated for their effect on enamel dissolution in vitro. In water, the potential of the food acids to demineralize enamel was directly proportional to their acidity. However, in a sorbitol candy, the amount of enamel dissolution was correlated with the potential of the acids to chelate calcium.
Dentinoenamel Junction Area in Primary Teeth Affected by Morquio's Syndrome
Authors: Lustmann J.
Published: November 2010

Separation of dentin from enamel in the dentinoenamel junction area was achieved in primary teeth affected by Morquio's syndrome. Enamel and dentin junctional surfaces were examined by means of scanning electron microscope. These two tissues were found to be separated by a layer of amorphous material. Recurrent treatment of the amorphous layer with NaOCl caused its gradual removal, exposing the rod tips on the enamel side and tubules on the dentin side. It is reasonable to suppose from this finding that the amorphous layer is rich in organic matrix. It is suggested that this amorphous layer is analogous to the enamel-dentin membrane, that in this syndrome is only partially calcified.
BASIC BIOLOGICAL SCIENCES Confirmation that Neither Phenotype Nor Hydroxylation of Collagen Is Altered In Overgrown Gingiva From Diphenylhydantoin-Treated Patients
Authors: Schneir M. , Ogata S. , Fine A.
Published: November 2010

Collagens, solubilized by pepsin-digestion of diphenylhydantoin-induced overgrown gingiva, appeared similar to collagens solubilized from inflamed gingiva with regard to: ratio of type I to type III collagen, ratio of α1 to α2 of type I collagen, and degree of hydroxylation of type I collagen.
Mineral and Collagen Fiber Orientation in Human Secondary Osteons
Authors: Frasca Peter , Harper Richard A. , Katz J. Lawrence
Published: November 2010

Scanning electron microscopy and x-ray micro-diffraction studies were conducted on single isolated osteons appearing "bright," "dark" and "intermediate" under crossed polaroids and the orientations of collagen fibers and crystallites within them determined.
Micromorphologic Features of Cervical Erosion After Acid Conditioning and Its Relation with Composite Resin
Authors: Gwinnett A. John , Jendresen Malcolm D.
Published: November 2010

The dentin surface in cervical erosion appears relatively smooth with evidence of intratubular deposits. After acid conditioning, the tubules are made patent though some still contain relatively less soluble intratubular contents. Resin applied to acid-conditioned, eroded dentin penetrated approximately 30 micrometers compared to more than 100 micrometers into the tubules of similarly treated normal dentin.
Adhesive Bonding of Various Materials to Hard Tooth Tissues. XIV. Enamel Mordant Selection Assisted by ESCA (XPS)
Authors: Bowen R.L.
Published: November 2010

Surface analysis by XPS (X-ray photoelectron spectroscopy), also called ESCA (electron spectroscopy for chemical analysis), indicates that only certain cations are appreciably sorbed by enamel from an acid etching solution containing phosphoric acid and equimolar concentrations of candidate mordant salts.
The Influence of Fluoride on Apatite Formation from Unstable Supersaturated Solutions at pH 7.4
Authors: Eanes E.D. , Meyer J.L.
Published: November 2010

The present study was undertaken to examine the effect of fluoride on the formation of apatite in aqueous calcium phosphate suspensions prepared by spontaneous precipitation at pH 7.4. The most notable finding was that fluoride greatly curtailed or eliminated the appearance of octacalcium phosphate-like precursor phases in these preparations.
Replantation of Mature Teeth Without Endodontics in Monkeys
Authors: Nasjleti Carlos E. , Caffesse Raul G. , Castflli Walter A.
Published: November 2010

The purpose of this study was to evaluate the histologic response after replantation of mature, developed teeth without endodontic treatment in monkeys. To serve as experimental controls, the other replanted teeth received endodontic treatment. No significant differences were noted in the rate and quality of periodontal tissues healing between the endodontically and the nonendodontically treated teeth in monkeys sacrificed at 5, 7, and 14 days, and at 1, 2, and 3 months after replantation. However, specimens obtained at 4, 6, 9, and 12 months showed that teeth replanted without endodontics developed periapical complications, whereas endodontically treated teeth did not.
Sintered Hydroxyapatite Ceramic for Wear Studies
Authors: Rootare Hillar M. , Powers John M. , Craig Robert G.
Published: November 2010

A sintered hydroxyapatite (HAP) ceramic for use in wear studies was prepared from a commerical tricalcium phosphate. The sintered HAP had physical properties close to those of human enamel. The coefficient of friction and wear of the sintered HAP ceramic as characterized by tangential force, track width, and surface failure data, approximated those of human enamel.
The Metal Oxide/Eugenol Cements. I. The Chelating Power of the Eugenol Type Molecule
Authors: Douglas W.H.
Published: November 2010

The chelating power of the orthomethoxy phenolic (guaiacyl) group is fundamental to the accepted setting reaction of the metal oxide/eugenol cements. In this report, the chelating power is quantitatively described by the sequence of β2 for the chelates of the relevant metal ions.
A Micropuncture Study of the Handling of Calcium by the Rat Parotid
Authors: Mangos John A. , Garrish M.T. , Wells R. , Farnham W. , Bouchlas G.
Published: November 2010

The handling of Ca by the rat parotid gland was investigated using micropuncture, microperfusion, and microanalytical techniques. Concentrations of Ca were measured in salivary fluid from intercalated, lobular and main ducts, and net transductal fluxes of Ca and water were calculated during stimulation of secretion with acetylcholine, pilocarpine, and DLisoproterenol.
Inhibition and Killing of Oral Bacteria by Silver Ions Generated with Low Intensity Direct Current
Authors: Thibodeau E.A. , Handelman S.L. , Marquis R.E.
Published: November 2010

Silver cations generated by passing low intensity direct current through pure silver electrodes were found to be sufficiently antibacterial to cause sterilization of samples of infected dentin. The optimal procedure involved a 5 μA current applied for 20 minutes with the anode then left in contact with the sample. Minimal inhibitory concentrations of electrically generated silver ions for representative oral bacteria were essentially equal to those for silver ions added as nitrate or fluoride salts, and medium constituents, including sodium thioglycolate, antagonized antibacterial action. A major advantage to the use of the electrode method is that it allows for continuous, focal application of antibacterial silver cations.
The Reaction of Stannous Fluoride and Hydroxyapatite
Authors: Babcock F. David , King Jeana C. , Jordan Truman H.
Published: November 2010

Systematic investigation of the chemical reaction of a slurry of SnF2, Ca10(OH)2(PO 4)6, and H2O shows that products other than CaF2 are determined by the relative concentrations of the reactants. In addition to Sn2OHPO4, and Sn3F3PO 4, a previously unreported compound, Ca(SnF3)2, has been observed as a product of the reaction.
Purification and Some Properties of a-L-Fucosidase Isolated from Streptococcus sanguis
Authors: Shizukuishi S. , Taniguchi T. , Shibata S. , Nakamura R. , Tsunemitsu A. , Uesugi Y.
Published: November 2010

α-L-Fucosidase acting on naturally occurring substrates was highly purified from the growth culture of Streptococcus sanguis ATCC 10557. The molecular weight of the enzyme was approximately 120,000 and the optimal pH was at 5.5. The purified enzyme showed specificity toward the linkage of α-(1→2) fucosides in oligosaccharides and glycoproteins. The enzyme released L-fucose from glycoprotein in human parotid saliva.
Effect of Salivary Pellicle Formation Time on In Vitro Attachment and Demineralization by Streptococcus mutans
Authors: Zahradnik R.T. , Propas D. , Moreno E.C.
Published: November 2010

Enamel subsurface demineralization induced by Streptococcus mutans was significantly reduced by seven-day saliva pre-treatments conducive to the formation of enamel pellicles. A two-hour saliva pre-treatment was ineffective. Results suggest that the protection provided by long-term pellicles may relate to changes in ionic transport rates rather than cell attachment.
Clinical Performance and Physical Properties of Twelve Amalgam Alloys
Authors: Osborne J.W. , Gale E.N. , Chew C.L. , Rhodes B.F. , Phillips R.W.
Published: November 2010

An assessment of the marginal failure rate of 1,041 restorations of twelve alloys was made at one year. In addition, physical property tests were conducted. A correlation was found between the clinical performance and creep (.79), flow (.62) and 24-hour compressive strength (.60).
Tooth Allografts Fail to Stimulate Immunologic Memory in Mice
Authors: Moore Larry J.
Published: November 2010

Tooth transplants should not preclude future transplants in the recipient. In this study teeth failed to stimulate immunologic memory in weakly disparate mice. The teeth did carry transplantation antigens and were rejected after second-set skin grafts. The teeth probably enhanced their own survival through some immunoregulatory mechanism.
LETS Protein in Normal and Pathological Human Oral Epithelium
Authors: Zetter B.R. , Daniels T.E. , Quadra-White C. , Greenspan J.S.
Published: November 2010

The distribution of LETS protein in human oral mucosa was studied by indirect immunofluorescence. Normal epithelium showed surface staining. Intracellular staining occurred in epithelial cell cytoplasm in lichen planus and pemphigoid. Surface staining was absent in discoid lupus erythematosus. In pemphigus, intercellular staining was seen near areas of acantholysis.
A White Band and a Transparent Zone Observed at an Interface Between a Polymerizing Polyfunctional Monomer and a Poly(Methyl Methacrylate) Rod, I
Authors: Hikage Sakari , Tanaka Takuo , Atsuta Mitsuru , Uchiyama Yoichi , Nakabayashi Nobuo , Masuhara Echi
Published: November 2010

Macro- and microscopic studies were made of an interfacial microstructure which developed between a bifunctional monomer and a PMMA rod (or beads) during polymerization. The microstructure consisted of a white band and a blue transparent zone.
The Role of Cutaneous Receptors in the Menton Tap Silent Period
Authors: Bailey J.O. , Mccall W.D. , Mansour N.N. , Ash M.M.
Published: November 2010

The neuromuscular mechanisms of the electromyographic silent period are poorly understood but clinically significant. Our purpose was to isolate the contribution of cutaneous afferents from the chin to the latency and the duration of the EMG silent period. Under the conditions of our experiment, the afferents of the mental nerve have no observable influence on the latency or the duration of the silent period educed by a menton tap.
Partial Amino Acid Sequences of Two Proteins in Developing Porcine Enamel
Authors: Fukae M. , Ijiri H. , Tanabe T. , Shimizu M.
Published: November 2010

The enamel proteins prepared from porcine enamel samples at an early stage of development are separated at least 4 fractions by Sephadex G-100 gel filtration at pH 10.8. The main components of secondary and fourthly-eluted fraction were further purified by ion exchange chromatography. The results of sequence analyses of these proteins by sequential Edman degradation and by hydrolysis with carboxypeptidase Y showed that the partial amino acid sequences of these proteins were iden tical.
Thermal Expansion of Composite Resins and Sealants
Authors: Powers J.M. , Hostetler R.W. , Dennison J.B.
Published: November 2010

Linear thermal coefficients of expansion (α) of seven commercial composite resins and four pit and fissure sealants were determined between 0 and 60°C on a thermomechanical analyzer. The thermal expansion curves obtained were nonlinear. Values of α ranged from 26.5 to 39.6 × 10-6 °/C for the composite and from 70.9 to 93.7 x 10-6/°C for the sealants.
Uptake of Radioactive Calcium by Hard Tissue Cells
Authors: Sayegh F.S. , Porter K. , Sun G.
Published: November 2010

45Ca was injected into prenatal mice to study the calcium uptake by tooth germ cells. Both dental papillae, containing the odontoblasts, and the enamel organs were found to actively metabolize the labeled calcium. The maximum specific radioactivity occurred at 15 minutes after injection. The subcellular organelles (e.g. mitochondria) of the papillae were more active in metabolizing the labeled calcium whereas a large portion of the radioactivity of the enamel organ was found in a fraction containing the pre-calcified material. In fetal tooth germs, the rate of incorporation of labeled calcium into the pre-calcified material was slower than in the postnatal tooth germs since a large portion of the radioactivity remained in the soluble fraction.
The A and B Blood Group Substances on Odontogenic Epithelium
Authors: Wright John M.
Published: November 2010

The presence of glycoprotein-associated blood group substances on various types of odontogenic epithelium has been demonstrated through enzyme histochemistry. The sporadic nature of their appearance would preclude speculation about these substances and the development of odontogenic neoplasms.
The Effect of Vitamin A on Hamster Cheek Pouch Mucosa in Organ Culture
Authors: Mock D. , Main J.H.P.
Published: November 2010

Vitamin A was added to the medium of neonatal hamster cheek pouch mucosa maintained in organ culture. The epithelium of the treated explants showed a reduction in keratinization and down-growth into the underlying connective tissue. The cytological and morphological changes in the epithelium were consistent with glandular metaplasia.
Ameloblasts: Secretory and Resorptive Functions
Authors: Smith C.E.
Published: November 2010

The sequence of steps which an ameloblast passes through in forming enamel appears remarkably similar in amphibian and man. Despite considerable improvements in understanding the early events in the life cycle that lead to the intracellular synthesis and secretion of enamel matrix by the cell, little is known about the cell's functional role at later stages of the life cycle when the extracellular enamel matrix undergoes classical maturation in becoming fully mineralized.
Proteolytic Enzyme in Porcine Immature Enamel
Authors: Shimizu M. , Tanabe T. , Fukae M.
Published: November 2010

A proteolytic enzyme cleaving the main component of enamel proteins obtained from immature enamel has been purified from a soluble extract of porcine immature enamel. It is optimally active around pH 6 against enamel protein. It is completely inhibited by phenylmethylsulfonyl fluoride and diisopropyl phosphofluoridate, and partially by benzamidine. EDTA does not affect its activity. The enzyme seems to sever initially enamel protein into two segments, one containing lysine, arginine and tyrosine and the other being free from these amino acids.