bluuebunny/crossref_metadata_2025 huggingface dataset:
Stimulation of in vitro Growth of Treponema denticola by Extracellular Growth Factors Produced by Porphyromonas gingivalis
Authors: Nilius A.M. , Spencer S.C. , Simonson L.G.
Published: November 2010

Cell-free culture filtrates of Porphyromonas gingivalis grown in Wilkins-Chalgren broth stimulated the growth of six strains of Treponema denticola in 1186 broth when compared with the effect of uninoculated WC. The pH of the 1186 broth was not altered by the addition of either culture filtrate or WC, and all media were fully reduced prior to inoculation with T. denticola. Growth was also stimulated by factors precipitated from the culture filtrate with 90% (NH4)2SO4, 50% cold ethanol, or 50% cold acetone, and by factors retained after dialysis of the culture filtrate through a membrane with a molecular weight cut-off of 50 kDa. Growth factor activity was eliminated by heating of the culture filtrate at 55°C for 4 h. An ether extract of the culture filtrate containing acetic, butyric, isobutyric, isovaleric, propionic, and phenylacetic acids did not stimulate growth. Since subgingival plaque from periodontal pockets colonized with T. denticola also contains P. gingivalis, certain extracellular proteins with molecular weights greater than 50 kDa produced by P. gingivalis may act as growth factors for T. denticola in the microenvironment of the periodontal pocket.
Detection of Porphyromonas gingivalis in Oral Plaque Samples by Use of the Polymerase Chain Reaction
Authors: Watanabe K. , Frommel T.O.
Published: November 2010

Periodontitis is believed to be caused by bacteria which inhabit periodontal pockets. The identification of these periodontal pathogens by currently available methods requires considerable time and expertise. In this study, we have used a polymerase chain reaction (PCR) assay that is quick, relatively simple, and can detect low numbers of a putative periodontal pathogen. Primers specific for the fimbrial gene of Porphyromonas gingivalis were selected from the published sequence and used for amplification of a 131-basepair sequence of genomic DNA. The PCR detected as few as 100 P. gingivalis cells obtained from pure cultures. Three other bacteria (Actinobacillus actinomycetemcomitans, Prevotella intermedia, and Capnocytophaga gingivalis) that are also putative periodontal pathogens yielded no PCR product at any of the cell concentrations used. This assay was also used for detection of P. gingivalis in subgingival plaque. Five of 13 subgingival bacterial plaque samples obtained from four advanced adult periodontitis patients and two samples from a prepubescent child with advanced periodontitis contained P. gingivalis. The protocol developed is relatively simple and can be completed within four hours of the time of sample acquisition.
Characterization of Actinomyces with Genomic DNA Fingerprints and rRNA Gene Probes
Authors: Bowden G. , Johnson J. , Schachtele C.
Published: November 2010

Cellular DNA from 25 Actinomyces naeslundii and Actinomyces viscosus strains belonging to the 7 taxonomic clusters of Fillery et al. (1978) and several unclustered strains was obtained by enzymatic and N-lauroylsarcosine/ guanidine isothiocyanate treatment of whole cells, followed by extraction of the nucleic acid. The DNA samples were digested with restriction endonucleases Bam HI or Pvu MII, and agarose gel electrophoresis was used to obtain DNA fingerprints. The DNA fragments were subjected to Southern blot hybridization with a digoxigenin-labeled cDNA probe transcribed from Escherichia coli 16S and 23S rRNA. The patterns of bands from genomic (DNA fingerprints) and rDNA fingerprints (ribotypes) were used for comparison between the taxonomic cluster strains and strains within clusters. Representative strains from each taxonomic cluster provided different BamHI DNA fingerprints and ribotype patterns with 3 to 9 distinct bands. Some strains within a cluster showed identical ribotype patterns with both endonucleases (A. naeslundii B120 and A. naeslundii B102 from cluster 3), while others showed the same pattern with BamHI but a different pattern with PvuII (A. naeslundii ATCC 12104 and 398A from cluster 5). A. viscosus ATCC 15987 (cluster 7) and its parent strain T6 yielded identical fingerprint and ribotype patterns. The genomic diversity revealed by DNA fingerprinting and ribotyping demonstrates that these techniques, which do not require phenotypic expression, are suited for study of the oral ecology of the Actinomyces, and for epidemiological tracking of specific Actinomyces strains associated with caries lesions and sites of periodontal destruction.
In vitro Demineralization by Strains of Actinomyces viscosus and Streptococcus sobrinus of Sound and Demineralized Root Surfaces
Authors: Firestone A.R. , Feagin F.F. , Heaven T.J. , Sheetz J. , Denys F.
Published: November 2010

Root sections were inoculated with one of two strains of Actinomyces viscosus or a strain of Streptococcus sobrinus and then incubated for 9 days in Trypticase soy broth (TSB) containing 0.25% glucose or TSB supplemented with 0.25% sucrose (TSB + S). Lesion progression was measured from microradiographs. One section from each group was examined with a transmission electron microscope. Lesion progression was associated with a fall in the pH of the medium. However, lesion progression was not correlated with the mean 48-hour pH of the medium. In both TSB and TSB + S, lesion progression withA. viscosus was significantly greater than in the S. sobrinus group. However, the mean 48-hour pH value in TSB + S was lower than that in the S. sobrinus group. Plaque formation in TSB was, subjectively, least in the S. sobrinus group. Examination of transmission electron micrographs revealed bacteria penetrating the surfaces of the sections and extending into the lesion in the A. viscosus groups but not in the S. sobrinus group. This in vitro bacterial plaque model of root caries may be suitable for investigations of the bacterial etiology of root-surface caries and the virulence factors associated with pathogenicity.
Long-term Effects of Meridol® and Chlorhexidine Mouthrinses on Plaque, Gingivitis, Staining, and Bacterial Vitality
Authors: Brecx M. , Macdonald L.L. , Legary K. , Cheang M. , Forgay M.G.E.
Published: November 2010

The aim of the present study was to compare the effect on plaque growth and gingival response of Meridol®, an amine/stannous fluoride solution, during a three-month investigation, with those of a placebo preparation as a negative control and a chlorhexidine solution as a positive control, in a double-blind study. After having their teeth professionally cleaned, 36 volunteers continued their usual oral hygiene for a period of two weeks. Their teeth were then polished again (month 0) after which they rinsed twice daily (morning and evening) with one of the three mouthrinses in addition to their habitual toothcleaning. After three months of rinsing, plaque indices remained lowest in the chlorhexidine group, although the subjects using Meridol ®had indices significantly lower than those of individuals rinsing with the placebo solution. The gingival index scores in the Meridol® group were higher than in the chlorhexidine group and lower than in the placebo group. The plaque vitality scores showed a bactericidal effect in vivo with chlorhexidine and Meridol® during the entire experiment. The use of Meridol® resulted in more toothstaining than with the placebo, but significantly less than with chlorhexidine. This study demonstrated that Meridol® reduced plaque accumulation, retarded gingivitis development, possessed a definite bactericidal action, and produced only slight toothstaining.
Nucleolar Organizer Regions as Markers of Incipient Cellular Alterations in Squamous Epithelium
Authors: Schwint A.E. , Gomez E. , Itoiz M.E. , Cabrini R.L.
Published: November 2010

Transcriptionally active nucleolar organizer regions identified by silver staining (AgNOR) vary in number with cellular activity and/or malignant transformation and have been used as a diagnostic tool. A morphometric study of AgNORs was performed in an experimental model of irradiated squamous epithelium (Wistar rat sole skin) 4, 8, and 14 hours and 1, 2, 5, and 7 days post-irradiation with 50 Gy of x-rays. A statistically significant and progressive rise in AgNOR average volume of up to 238% and reduction in AgNOR number/nucleus of up to 40% were detected as a function of post-irradiation time. A statistically significant 46% increase in AgNOR volume was detected as early as 8 h post-irradiation, when no histological changes were observable in routine preparations. These results suggest that AgNORs may be useful as a quantitative marker of incipient changes in cellular activity and caution against the indiscriminate use of AgNORs in the follow-up of lesions which may have been exposed to radiotherapy. Furthermore, this study suggests the possibility of using AgNORs as a sensitive biological dosimeter in cases of uncontrolled exposure to radiation.
Coping with Oral Surgery by Self-efficacy Enhancement and Perceptions of Control
Authors: Litt M.D. , Nye C. , Shafer D.
Published: November 2010

Recent work has suggested that patients' coping could be improved in stressful dental situations if perceptions of self-efficacy and control could be enhanced. To test this hypothesis, 70 first-time third-molar extraction patients were randomly assigned to one of four surgery preparation conditions: standard preparation, oral premedication, relaxation, and a relaxation + efficacy-enhancing feedback condition in which subjects were given false galvanic skin response (GSR) biofeedback leading them to believe that they were highly skilled at relaxing. Analyses indicated that: (1) all treatments were seen as equally credible (controlling for placebo effects); (2) a priori contrasts showed that both the relaxation-only treatment and the relaxation + efficacy-enhancement treatment were superior to the premedication and standard preparations in raising coping self-efficacy; (3) regardless of treatment condition, increase in reported coping self-efficacy was significantly correlated with pre-operative anxiety, with self-reported peri-operative distress, and with behavioral ratings of peri-operative distress; and (4) the relaxation treatments resulted in lower pre-operative anxiety than the other interventions, and linear contrasts showed significant trends in which the relaxation + efficacy-enhancing condition was superior to the relaxation-only condition, which was in turn superior to the medication condition and the standard preparation in reducing both pre-operative anxiety and behavioral ratings of peri-operative distress. It was concluded that thoughts related to self-confidence and control can be manipulated, and that these thoughts can in part determine how well a person copes in stressful dental situations.
Perceptions of Dental Fluorosis
Authors: Riordan P.J.
Published: November 2010

Mild dental fluorosis has long been accepted as a side-effect of water fluoridation and, more recently, has been recognized as a consequence of the use of other fluoride-based caries-preventive strategies. Traditionally, dental health professionals have not seen this as being of public health importance, but members of the public have not been asked their opinion. The purpose of the present study was to gather the opinions of lay groups concerning the appearance of the teeth of children with various degrees of fluorosis. Twenty-eight children, born in 1978, who had earlier participated in a study of fluorosis in Perth (Western Australia), allowed 110 observers to look at their upper central incisors under good viewing conditions. Fluorosis in these teeth ranged from TF score 0 (no fluorosis) to TF score 3. The observers were university students, parents, public servants, or dentists. They responded to statement items about the appearance of the teeth. The results, based on just over 3000 responses, showed that lay and dental observers could distinguish between different fluorosis levels. In response to a statement that the teeth appeared pleasing, a large majority agreed when the TF score was 0, but agreement declined as the TF score increased; when the TF score was 3, most people disagreed. Similarly, observers felt that the appearance would increasingly embarrass the child as the TF score increased. Observers, except the dentists, tended to feel that higher TF scores indicated neglect on the part of the child. Most observer groups felt that fluorosis would be no greater an esthetic problem for girls than for boys, but for more severe fluorosis, the dentists saw the appearance as being a greater problem for girls. The dentists responded that most fluorosis did not require any treatment, but when the TF score was 3, a majority of them felt that esthetic treatment would be warranted. The results suggest that, for these observers, fluorosis score TF = 2 or greater was easily noticed, and when the TF score was 3, fluorosis aroused concern in most observers. Recent epidemiological studies reported TF scores of 2 or more in 11.3% of 12-year-olds and 17.5% of 7-year-olds in Perth. Strategies to reduce the prevalence of fluorosis with TF score 2 and avoid fluorosis with TF score 3-including reduction of toothpaste ingestion, removal of fluoride from infant formulae, and avoidance of inappropriate supplement use-should be devised and implemented.
Operatory Ventilation and Scavenger Evacuation Rate Influence on Ambient Nitrous Oxide Levels
Authors: Borganelli G.N. , Primosch R.E. , Henry R.J.
Published: November 2010

Investigations have shown that greater than Federally-recommended levels of ambient nitrous oxide often exist in the dental workplace. The purposes of this investigation were to examine the influences of (1) operatory ventilation rate and (2) scavenger evacuation rate on ambient nitrous oxide concentrations within a closed dental operatory. This laboratory investigation utilized a scavenging nasal mask assembly (Porter/Brown) to deliver 40% nitrous oxide in oxygen, at a total flow rate of 5 L/min, to a mannequin positioned supinely in a dental chair. Eight experimental groups were assigned based on combinations of operatory air exchange rates (0, 5, 10, or 15 room air changes per hour) and scavenger evacuation rates (18.8 L/min and 21.4 L/min). Ambient nitrous oxide levels were monitored at four locations (0, 15.3, 30.7, and 61.4 cm) from the nasal mask by means of an infrared spectrophotometer (Miran 1B). The operatory air exchange rate was measured with a flow hood (Short Ridge) and manipulated to one of the desired ventilation rates. Time-weighted average (TWA) concentrations of ambient nitrous oxide (ppm) were continuously recorded at 15-second intervals with a microprocessor (DL332F Datalogger) connected directly to a microcomputer. The results demonstrated that significantly reduced (p < 0.05) ambient nitrous oxide levels were achieved with increasing room air exchange rates and the high scavenger evacuation rate. It was concluded that operatory ventilation and scavenger evacuation rates were significant control measures available for reduction of ambient nitrous oxide to Federally recommended levels.
Influence of Carbonate on Sintering of Apatites
Authors: Koda Y. DOI. T. , Wakamatsu N. , Goto T. , Kamemizu H. , Moriwaki Y. , Adachi M. , Suwa Y.
Published: November 2010

Sintering of carbonate apatite, prepared at 100°C and pH 9.0 for 3 days, was studied by thermal analysis, x-ray diffraction, and infrared spectroscopy. The sintering temperature, at which the linear thermal shrinkage of isostatically compacted specimens increased sharply, decreased in proportion to the amount of carbonate initially present in the apatite. For example, specimens with over 8 wt% carbonate could be sintered at a temperature (650°C) which was nearly 400°C lower than that needed for sintering a specimen with no carbonate. Amounts of carbonate lost at the end of sintering, estimated chemically and by infra-red specroscopy, were approximately equal to sample weight losses estimated thermogravimetrically
An in vivo Study of the Influence of the Surface Roughness of Implants on the Microbiology of Supra- and Subgingival Plaque
Authors: Quirynen M. , Van Der Mei H.C. , Bollen C.M.L. , Schotte A. , Marechal M. , Doornbusch G.I. , Naert I. , Busscher H.J. , Van Steenberghe D.
Published: November 2010

In nine patients with fixed prostheses supported by endosseous titanium implants, 2 titanium abutments (trans-mucosal part of the implant) were replaced by either an unused standard abutment or a roughened titanium abutment. After 3 months of habitual oral hygiene, plaque samples were taken for differential phase-contrast microscopy, DNA probe analysis, and culturing.

Supragingivally, rough abutments harbored significantly fewer coccoid micro-organisms (64 us. 81%), which is indicative of a more mature plaque. Subgingivally, the observations depended on the sampling procedure. For plaque collected with paper points, only minor qualitative and quantitative differences between both substrata could be registered. However, when the microbiota adhering to the abutment were considered, rough surfaces harbored 25 times more bacteria, with a slightly lower density of coccoid organisms. The presence and density of periodontal pathogens subgingivally were, however, more related to the patient's dental status than to the surface characteristics of the abutments. These results justify the search for optimal surface smoothness for all intra-oral and intra-sulcular hard surfaces for reduction of bacterial colonization and of periodontal pathogens.
Protein Analysis of Human von Ebner Saliva and a Method for its Collection from the Foliate Papillae
Authors: Spielman A.I. , D'Abundo S. , Field R.B. , Schmale H.
Published: November 2010

The lingual serous glands of von Ebner are located close to the foliate and circumvallate papillae. Saliva secreted by these glands provides the immediate environment of the taste buds, and it has been hypothesized that it modulates taste perception. The purpose of this study was to develop a technique for collection of unstimulated and stimulated saliva from human von Ebner glands. Saliva was collected under resting conditions and after application of various gustatory stimuli (sweet, sour, salt, and bitter) by insertion of periostrips into the folds of the foliate papillae of healthy human volunteers. Stimulated saliva was also collected in glass microcapillaries or micropipettes. The flow-rates of unstimulated von Ebner saliva were 2.3 ± 0.6 (S.E.) μL/min and 4.5 ± 1.2 (S.E.) μL/min with 1% citric acid stimulation. The protein content was 2.5 ± 0.5 (S.E.) mg/mL. The SDS gel electrophoretic profile of von Ebner saliva revealed two protein bands of Mr 18,000 that were identified on Western blots as von Ebner gland (VEG) proteins. Although lingual lipase activity was detected at very low levels by enzyme assay, this protein was not detected on Western blots. This collection technique should prove useful for analysis of specific functions associated with secretion from von Ebner glands.
Effect of Centrifugal Force on Growth of Mouse Osteoblastic MC3T3-E1 Cells in vitro
Authors: Inoue H. , Nakamura O. , Duan Y. , Hiraki Y. , Sakuda M.
Published: November 2010

The effect of biomechanical force on growth of skeletal tissue was studied in monolayer cultures of mouse osteoblastic MC3T3-E1 cells which were centrifuged at 320 g for 15 min to 72 h in a CO2 incubator. Centrifugation of the cells for 30 min in low concentrations (0.3 or 1%) of fetal bovine serum (FBS) caused a two-fold increase of [3H]thymidine incorporation at 20 h from the start of centrifugation. However, centrifugation under 10% FBS caused no increase in [3H]thymidine incorporation into DNA. Under 0.3% FBS, [3H]thymidine incorporation increased in a manner dependent on the period of centrifugation and reached a maximum when the cells were centrifuged for 3 h. Stimulation of DNA synthesis by centrifugation was abolished in the presence of H-7, an inhibitor of protein kinase C. Moreover, conditioned medium collected from the centrifuged cultures increased [3H]thymidine incorporation by two-fold over the basal when added to a quiescent culture of MC3T3-E1 cells. These results suggest that centrifugal force stimulates growth of osteoblastic cells through autocrine secretion of some diffusible growth-promoting activity. On the other hand, centrifugation of the cells inhibited induction by FBS of alkaline phosphatase activity and calcium-uptake, two indices of the differentiated phenotype of osteoblasts.
Adsorption of Low-molecular-weight Sodium Polyacrylate on Hydroxyapatite
Authors: Misra D.N.
Published: November 2010

Adsorption of low-molecular-weight sodium polyacrylate from aqueous solution onto synthetic hydroxyapatite was studied at room temperature so that the mechanism of adhesion of polyacrylate cements to tooth mineral could be elucidated. The adsorption isotherm of sodium polyacrylate was Langmuirian in shape and was thus qualitatively different from that of polyacrylic acid (Misra, 1991), which exhibited an adsorption maximum. The self-association of the molecules that probably causes the maximum to occur with polyacrylic acid was effectively absent for the relatively well-ionized, electrostatically repelling polyacrylate ions ofthe salt. With the adsorption of acrylate ions, the concentration of phosphate ions increased monotonically, while the concentration of calcium ions showed a minimum. The adsorption of sodium polycrylate was irreversible, as it was for polyacrylic acid.
Chemical Characterization of the Resin-Dentin Interface by Micro-Raman Spectroscopy
Authors: Van Meerbeek B. , Mohrbacher H. , Celis J.P. , Roos J.R. , Braem M. , Lambrechts P. , Vanherle G.
Published: November 2010

The chemical nature of the interface between dentin and adhesive resin materials was characterized by micro-Raman spectroscopy. The resulting chemical profiles were correlated with photomicrographs obtained by SEM after an argon-ion-beam etching treatment of the sample surface. Two commercially available dentin adhesive systems, of which one was also applied with a different conditioning agent, were investigated. Raman spectra, which were recorded along line scans across the interface with a step increment of 1 μm, revealed that resin effectively penetrated 4 to 6 μm deep into the superficially decalcified dentin zone. Across the interface, a gradual transition from resin to dentin over the interdiffusion zone with a mixed contribution of both substances was noticed. Finally, resin appeared to penetrate to the entire decalcification depth of dentin regardless of the aggressiveness of the conditioning procedure.
Assessment by Nano-indentation of the Hardness and Elasticity of the Resin-Dentin Bonding Area
Authors: Van Meerbeek B. , Willems G. , Celis J.P. , Roos J.R. , Braem M. , Lambrechts P. , Vanherle G.
Published: November 2010

The hardness and Young's modulus of the successive layers across a resin-dentin bonding area were determined by nano-indentation for four commercially-available dentin adhesive systems, of which two were also applied with a different conditioning agent. With a computer-controlled nano-indentation technique, minute triangular indentations were made within a small area of a few micrometers' diameter at a load of a few milli-Newtons. The load and displacement of the indenter were continuously monitored during the loading-unloading sequence, so hardness and Young's modulus could be computed as a function of the indenter geometry and the applied load.

The hardness of the resin-dentin interdiffusion zone was significantly lower than that of unaltered dentin. A gradient of moduli of elasticity was observed from the rather stiff dentin over a more elastic resin-dentin interdiffusion zone and adhesive resin layer to the restorative composite. That gradient was more substantial in those systems that produced relatively thick adhesive resin layers or supplementally provided a filled low-viscosity resin as an intermediate layer between the adhesive resin and the bulk restorative composite. Such an elastic bonding area might have a strain capacity sufficient to relieve stresses between the shrinking composite restoration and the rigid dentin substrate, thereby improving the conservation of the dentin bond and, as a consequence, the marginal integrity and retention of the restoration.
Involvement of the Central Nervous System in the Salivary Secretion Induced by Pilocarpine in Rats
Authors: Renzi A. , Colombari E. , Mattos T.R. , Silveira J.E.N. , Saad W.A. , Camargo L.A.A. , De Luca L.A. , Derobio J.G. , Menani J.V.
Published: November 2010

The effect in rats of an anteroventral third ventricle (AV3V) electrolytic lesion on salivary secretion induced by intraperitoneal (i.p.) or intracerebroventricular (i.c.v.) injection of a cholinergic agonist (pilocarpine) was investigated. Sham- or AV3V-lesioned rats anesthetized with urethane and with a stainless steel cannula implanted into the lateral ventricle (LV) were used. The amount of salivary secretion was studied over a seven-minute period after i.c.v. or i.p. injection of pilocarpine. In sham-operated rats, i.p. injection of pilocarpine (1 mg/kg b.w.) (after 6 h, 2, 7, and 15 days) produced salivary secretion (486 ± 21, 778 ± 85, 630 ± 50, and 560 ± 55 mg/7 min, respectively). This effect was reduced 6 h, 2, and 7 days after an AV3V lesion (142 ± 22, 113 ± 32, and 290 ± 62 mg/7 min, respectively), but not 15 days after an AV3V lesion (516 ± 19 mg/7 min). I.c.v. injection of pilocarpine (120 μg in 1 μL), in sham-operated rats after 6 h, 2, 7, and 15 days also produced salivary secretion (443 ± 20, 417 ± 81, 496 ± 14, and 427 ± 47 mg/7 min, respectively). The effects of i.c.v. pilocarpine were also reduced 6 h, 2, and 7 days after an AV3V lesion (143 ± 19, 273 ± 14, and 322 ± 17 mg/7 min, respectively), but not after 15 days (450 ± 28 mg/7 min). The results demonstrate that the central nervous system, and particularly the AV3V region, is important for the effect of pilocarpine on salivary secretion in rats. Moreover, they suggest that activation of central pathways may play an important part in the salivary secretion to peripheral pilocarpine in rats.
Motor Unit Territories and Fiber Types in Rabbit Masseter Muscle
Authors: Weijs W.A. , Jüch P.J.W. , Kwa S.H.S. , Korfage J.A.M.
Published: November 2010

The myosin heavy chain (MHC) content and spatial distribution of the fibers of 11 motor units (MUs) of the rabbit masseter muscle were determined. The fibers of single MUs were visualized in whole-muscle serial sections by a negative periodic acid/Schiff reaction for glycogen after they had been depleted of glycogen by extracellular stimulation of their motoneuron in the trigeminal motor nucleus. The MHC isoforms present in the fibers were characterized by monoclonal antibodies. Individual fibers appeared to contain from one to three MHC isoforms. In six cases, all fibers of a motor unit had an identical MHC content; in five cases, different fiber types were found in a single unit. The fiber number per MU varied between 40 and 424, the territory size between 1.1 and 11.0 mm2 (of a total muscle cross-section of 200 mm2), and fiber density between 6 and 17 MU fibers per 100 muscle fibers. In the multipennate masseter, the fibers were usually restricted to a single anatomical compartment. In comparison with leg muscles, the fibers of the masseter motor units, although similar in number, were restricted to relatively smaller subvolumes of the muscle and thus reached higher densities in their territories. The small territories are the anatomical substrate for the observed heterogeneity of motor behavior. Since the different anatomical compartments of the masseter differ with respect to their biomechanical capabilities, this makes this muscle multifunctional in the exertion of complex motor tasks.
Sternocleidomastoid Muscle Inhibition Induced by Trigeminal Stimulation
Authors: Browne P.A. , Clark G.T. , Yang Q. , Nakano M.
Published: November 2010

Among numerous reports of anatomical and functional coupling between the trigeminal and cervical systems is the demonstration that the sternocleidomastoid (SCM) muscles may become activated along with the masseter muscles during forceful abrupt biting maneuvers. Whether the co-activated SCM is also inhibited by stimuli that produce masseter inhibition is not known. This study evaluated the SCM for the presence of inhibition during mechanically-elicited (chin or forehead tap) and electrically-elicited (anterior maxillary gingiva stimulation) inhibition of the masseter muscle in ten healthy men. Surface EMG data were recorded bilaterally from the masseter and SCM muscles. The data for each muscle were converted to ratios of the pre-stimulus maximum voluntary contraction activity for each subject and averaged across subjects. Means of these percentages were determined at several defined pre- and post-stimulus intervals. The results indicate that masseter inhibition was clearly elicited by the electrical and both forms of mechanical stimulation. SCM co-inhibition could be evoked by electrical and chin tap stimulation but not by forehead tap. The responses to these stimuli varied among subjects, from trial to trial, and within subjects depending on the experimental condition. The fact that it was possible for this co-inhibition to be evoked is presented as further indication of the functional coupling of the trigeminal and cervical systems.
Maxillary Anterior Caries Associated with Increased Caries Risk in Other Primary Teeth
Authors: O'Sullivan D.M. , Tinanoff N.
Published: November 2010

It has been suggested that children with caries of maxillary anterior primary teeth may have increased caries incidence in other teeth. This study aimed to quantify the extent of posterior dental caries in those children who initially presented with maxillary anterior caries compared with that of those who did not. Data were collected for 217 Head Start children participating in a one-year study to determine caries risk factors. Tooth surfaces were recorded as carious, restored, or extracted (missing due to caries). Caries was then categorized into the following pattern(s): maxillary anterior (MA), pit/fissure (PF), posterior proximal (PP), and posterior buccal/lingual smooth surface (BL). Compared with children who did not initially present with the maxillary anterior pattern, those with the maxillary anterior pattern had 2.5 times (p < 0.01) the mean number of posterior decayed, missing, and filled surfaces (dmfs) and approximately 3 times the prevalence (p < 0.01) of the PP and BL patterns. The positive predictive value of the MA pattern was 86.8% for children who developed the PF pattern, and the negative predictive values were greater than 91% for children who did not develop the PP and BL patterns. The prevalence of maxillary anterior caries among children in this study is associated with a significantly greater caries incidence in posterior teeth.
Dentin Caries Recording with Schiff's Reagent, Fluorescence, and Back-scattered Electron Image
Authors: Hietala E.-L. , Tjaderhane L. , Larmas M.
Published: November 2010

After being weaned, the Wistar rats (12) were fed on a sucrose diet for five weeks to induce dental caries. Tetracycline was injected intraperitoneally into 7 of them to label the mineralizing dentin front. Five rats without tetracycline injection were used to verify spontaneous fluorescence. The evidently carious area under one prominent fissure from each mandibular molar hemisected sagittally in the midline was photographed under ultraviolet light so that autofluorescence would be revealed. The jaws were then stained with Schiff's reagent and photographed under normal light and again under ultraviolet light. The areas of all the lesions were quantified planimetrically as they appeared on the photographs. The mineral contents of the areas were verified with the back-scattered electron images. The caries lesions revealed with Schiff's reagent also exhibited a change in the color of the dentin fluorescence regardless of the tetracycline labeling. The areas of these lesions followed the shapes of the lesions stained by Schiff's reagent but they were greater. Staining with Schiff's reagent was repeatable after the specimen was washed with ethanol for a few weeks. The loss of minerals was seen in the areas stained with Schiff's reaction but was also related to the change in dentin fluorescence, which seems to be a more sensitive indicator of the caries progression than Schiff's reagent, especially in the early phase of the carious process.
Radiographic Secondary Caries Prevalence in Teeth with Clinically Defective Restorations
Authors: Hewlett E.R. , Atchison K.A. , White S.C. , Flack V.
Published: November 2010

Decisions to replace existing restorations are often based on clinical findings of margin discrepancies and other restoration defects. Previous studies have suggested that such findings do not correlate well with the actual presence of secondary caries, and that treatment should be deferred until caries is clinically or radiographically evident. The purpose of this study was to assess the frequency with which clinically defective restorations are associated with radiographic secondary caries. As part of a study to assess the efficacy of guidelines for the ordering of dental radiographs, 6285 restored teeth in 490 subjects were examined clinically and radiographically by three calibrated investigators. Specific criteria were used to determine whether restorations were intact or defective. Of the total, 822 teeth (13%) were judged to have clinically defective restorations. Of these, 113 teeth (14%) had radiographic secondary caries. Of the 5463 teeth with intact restorations, 5% had radiographic secondary caries. We found that the likelihood of radiographic secondary caries was nearly three-fold higher for defective restorations than for intact restorations. The large percentage (86%) of defective restorations with no radiographic secondary caries suggests, however, that replacement of all defective restorations due to risk of secondary caries may constitute overtreatment. The use of defective restoration status and presence of radiographic secondary caries as a combined criterion for replacement may potentially reduce such overtreatment. The prevalence of secondary caries under defective restorations should be determined clinically so that the usefulness of combining the criteria of defective restoration with those of radiographic secondary caries can be evaluated.
Saliva Composition in Indian Children with Chronic Protein-Energy Malnutrition
Authors: Johansson I. , Lenander-Lumikari M. , Saellström A.-K.
Published: November 2010

The composition of paraffin-stimulated and unstimulated whole saliva was compared between two groups of 8-12-year-old Indian children—one group with severe to moderate chronic protein-energy malnutrition (PEM group) and an age- and sex-matched control group with normal protein status or mild PEM. The classification of PEM was based on anthropometric measurements compared with Indian standards. Stimulated saliva was analyzed for the following variables : electrolytes (Na+, K+, Ca2+, Cl, and PO 43-), total protein, hexosamines, fucose, sialic acid, and amylase. Unstimulated saliva samples were analyzed for total protein, salivary and myeloperoxidase, thiocyanate, lactoferrin, lysozyme, a bacteria-agglutinating protein (BAGP), total IgG, total IgA, and specific anti- S. mutans IgA. The results show that the PEM group had a reduced secretion rate of stimulated but not unstimulated saliva. Further, the Ca2+ and Cl- concentrations in stimulated saliva were significantly lower in the PEM group compared with the control group, but the other electrolyte levels were similar. No differences were found in total protein concentration or glycoprotein bound carbohydrates in stimulated saliva between the two groups, but the quantity of total protein secreted per min was reduced by 20% in the PEM group. Significantly lower levels of lactoferrin, BAGP, and anti- S. mutans IgA were found in unstimulated saliva from children in the PEM group, but significantly higher levels of total IgG. We conclude that children with severe or moderate PEM, who have reduced secretion rate, buffer capacity, lower Ca2+, and protein secretion in stimulated saliva, also have impaired immunological and agglutinating defense factors in unstimulated saliva.
Effects on Whole Saliva of Chewing Gums Containing Calcium Phosphates
Authors: Chow L.C. , Takagi S. , Shern R.J. , Chow T.H. , Takagi K.K. , Sieck B.A.
Published: November 2010

To evaluate chewing gums as a vehicle to increase salivary mineral saturation levels and enhance salivation, monocalcium phosphate monohydrate (MCPM) and an equimolar mixture of tetracalcium phosphate (TTCP) with dicalcium phosphate anhydrous (DCPA) were chosen as experimental chewing gum additives. Each of eight subjects chewed a commercial sugarless bubble gum (control) for 16 min or the same gum to which 5 wt% of MCPM or the TTCP-DCPA mixture had been added. The saliva samples collected every 2 min were analyzed for weight, pH, and total calcium (Ca) and phosphate (P) concentrations. Both experimental gums were found to increase significantly the Ca and P concentrations of saliva during the 16-minute period even more than with a previously evaluated gum that contained dicalcium phosphate dihydrate. The degree of saturation of tooth mineral was significantly increased by both experimental gums, with the greater increase being produced by the TTCP-DCPA gum. The MCPM gum produced a significantly greater saliva flow and a lower salivary pH than did the control and TTCP-DCPA gums. The results suggest that the experimental gums may be useful for promoting remineralization in general and for inducing salivation in xerostomic patients.
Effects of the β-adrenoceptor Antagonists Atenolol and Propranolol on Human Parotid and Submandibular-Sublingual Salivary Secretion
Authors: Nederf ors T. , Ericsson T. , Twetman S. , Dahlof C.
Published: November 2010

The aim of the study was to evaluate the effects of a β1-selective (atenolol 50 mg q.d.) and a non-selective (propranolol 80 mg b.i.d.) p-adrenoceptor antagonist on human stimulated parotid and submandibular-sublingual (SM-SL) gland secretion. A randomized double-blind, placebo-controlled cross-over ("Latin square") design was used in 19 healthy male volunteers. Stimulated parotid and SM-SL saliva were sampled immediately before and 7 days after the start of each treatment period. Stimulation of salivary secretion was achieved by use of a 3% citric acid solution. Plasma concentrations of propranolol and atenolol were determined from blood samples. The salivary secretion of both glands was assessed for flow rate, amylase, lysozyme, and salivary peroxidase activity and for concentrations of total protein, hexosamine, sialic acid, Ca2+, Cl-, K+, Mg2+, Na +, and PO43-. In both parotid and SM-SL secretions, the total protein and phosphate concentrations and amylase activity were significantly decreased during the two active treatment periods. In SM-SL gland secretion, there were significant changes in potassium and calcium concentrations during active treatment as compared with baseline, with potassium showing a decreased and calcium an increased concentration. During atenolol treatment, salivary peroxidase activity decreased significantly in SM-SL secretion. In parotid secretion, the hexosamine/total protein ratio decreased and the sialic acid/hexosamine ratio increased during atenolol treatment, which may indicate an effect on protein synthesis. No significant effects on salivary secretion rates were disclosed.
An Analysis of Socio-Cultural and Economic Changes in Migrant Agricultural Labourers in Punjab
Authors: Verma Anil , Singh Gian , Singh Balwinder
Published: November 2010

This article examines the key issues relating to the socio-cultural and economic changes witnessed by the migrant agricultural labourers working in the farm sector of Punjab. A large number of labourers from the poor states of Bihar, Uttar Pradesh, Jharkhand, West Bengal and neighbouring country of Nepal have been migrating to Punjab ever since the advent of the green revolution in the agricultural sector of Punjab. The empirical findings of the study confirm that migration is an important source of survival for these poor people across the country but while working in the fields of Punjab the majority of them lose their social and cultural identity.
From the Field to the Factory
Authors: Kumar Ajit
Published: November 2010

Occupational mobility has been a major way of escaping distress for the rural poor in India. Traditionally, when the economy was based on agriculture the institution of family and the caste system would restrict the choices available to the rural poor, but with growing industrialisation new factors have come into play. Educational attainments and the politico-legal framework of labour recruitment are now superimposed on the traditional structures of caste and family in the process of occupational mobility. These new factors have cut across caste boundaries and widened the choices available to the rural poor, yet it does not substantially alter the traditional patterns of dominance. In this study four factors stand out in enabling the process of occupational mobility. First, of prime importance is schooling. Second is the support received from the family. Third is the economic condition of the household. It is not the poorest from the rural community who are able to make the transition. Lastly there is a manifest political dimension to this process.
Supplementary Nutrition to Women and Children
Authors: Ratnawali
Published: November 2010

This article reports findings from a survey of anganwadis, undertaken in the tribal region of Gujarat. It was found that services were poorer in the more backward and distant hilly areas than in the plain areas of the region. The coverage of population by anganwadis was not uniform and was disproportionately divided even within the same village. At places they were serving a larger section of population than was specified by the norm. The scattered habitation in the tribal village leaves many households unattended as anganwadis were located at a considerable distance and it was difficult for women and children to cover the long distance for availing food. Hence just one fourth of the targeted population were beneficiaries of the food supplied by anganwadis. Poor infrastructure, inadequate effort and negligence by AWWs and low awareness among people were some of the concerns that accounted for the poor functioning of anganawdis. Food was cooked in excess of the expected numbers of beneficiaries, which is a cause for concern. Apart from recommending measures for improving the service delivery, the study also advocates strong participation of people to make the programme a success.
Improving Construct Measurement In Management Research: Comments and a Quantitative Approach for Assessing the Theoretical Content Adequacy of Paper-and-Pencil Survey-Type Instruments
Authors: Schriesheim Chester A. , Powers Kathleen J. , Scandura Terri A. , Gardiner Claudia C. , Lankau Melenie J.
Published: November 2010

A cursory review of the measurement practices found in four diverse management journals is briefly reported, suggesting that the current authors’ concerns about serious measurement deficiencies in at least some subdomains of the field may not be groundless. Then, it is suggested that the demonstration of instrument content adequacy be demanded as an initial step toward construct validation by all studies which use new, modified, or previously unexamined measures. Although adequate content is a necessary pre-condition for instrument validity, there are no well-established quantitative methods for examining content adequacy. Consequently, the main focus of this article is to propose a new approach for the quantitative assessment of content adequacy and to illustrate this approach by evaluating a commonly-used job satisfaction scale. Problems in and suggestions for the use of this method a represented, along with implications and potential new applications of the method for management research.
The MBA as Careerist: An Analysis of Early-Career Job Change
Authors: Dougherty Thomas W. , Dreher George F. , Whitely William
Published: November 2010

This study examined the job changes of 680 early-career business school graduates. Although a number of anecdotal articles characterize MBAs as overly “careerist” and oriented toward job-hopping, little empirical research has focused on this issue. The research included a direct comparison of job-hopping behavior of MBAs with bachelor S degree graduates, taking into account a number of control variables, including demographic and economic variables. Results indicated that MBAs changed jobs less frequently than bachelor 5 degree graduates, even when a variety of other factors were controlled.
Individualism and the Modern Corporation: Implications for Innovation and Entrepreneurship
Authors: Morris Michael H. , Avila Ramon A. , Allen Jeffrey
Published: November 2010

The extent to which entrepreneurship in established firms is the result of a more individualistic versus collectivistic culture is explored. Hypotheses are tested in which it is proposed that a curvilinear relationship exists between individualism-collectivism and corporate entrepreneurship. Findings are reported from a survey completed separately by three functional area managers in each of eighty-four industrial firms. The results support the hypotheses, such that entrepreneurship is highest under conditions of balanced individualism-collectivism, and declines in highly individualistic and more collectivistic environments.
Computer-facilitated Qualitative Data Analysis: Potential Contributions to Management Research
Authors: Wolfe Richard A. , Gephart Robert P. , Johnson Thomas E.
Published: November 2010

The development of software programs designed to facilitate qualitative data analysis has proltferated recently. Despite their potential to contribute much to management research, very little concerning the use of such programs has appeared in the management literature. The purpose of this paper is to review the current state of computer-facilitated qualitative data analysis [CQDA] in order to contribute to its effective use by management researchers. In an effort to achieve this purpose we discuss why CQDA programs are proliferating, describe the potential of such programs to contribute to management research, address program capabilities and features, describe CQDA applications in management research, and review issues researchers should be aware of in considering the use of C&DA.
An Empirical Assessment of the Multidimensionality of Union Participation
Authors: Cohen Aaron
Published: November 2010

The purpose of this article is to explore empirically some similarities and differences among six forms of union participation: union commitment, participation in decision making, participation in union activities, attitudinal militancy, serving in elected offices and the propensity to strike. The study examines five models of union participation: the social background model, the work dissatisfaction model, the economic model, the structural model, and the socialization model. The research sample consisted of 603 employees from white collar occupations, members of local unions in Israel. The findings demonstrate that the forms of union participation are independent constructs. They also show that different theoretical explanations apply to different forms of participation. The conclusions indicate that a fundamental direction for future research should be to develop and test hypotheses that refer to specific forms of union participation.