bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors related to missed and cancelled dental appointments among adolescents in Norway
Authors: Skaret Erik , Raadal Magne , Kvale Gerd , Berg Einar
Published: March 2003

The aim of this study was to explore possible explanatory factors related to high frequency of missed/cancelled dental appointments during the age group 12–18 yr. A total of 754 20 yr olds completed a questionnaire including variables measuring demographics, occupation (school/job), attendance pattern, attitudes to dentists, opinion about importance of dental treatment, and the psychometric scales Dental Fear Scale (DFS), Dental Beliefs Survey (DBS) and Geer Fear Scale (GFS). Based on written consents, the following data were recorded from their dental records: the total number of scheduled appointments, the number of missed and cancelled appointments and the individual caries experience of those in the age group 12–18 yr. A total of 124 subjects who had missed/cancelled 20% or more of their dental appointments during this age were defined as a target group. A stepwise regression model indicated that the likelihood of being included in the target group increased by a factor of 6.0 if the subject had forgotten dental appointments during the last 5 yr, by a factor of 3.5 for working or without specified occupation (as opposed to attending school), by a factor of 2.7 for negative beliefs of dentists, and by a factor of 2.1 for high caries experience.
Enamel demineralization under driving forces found in dental plaque fluid
Authors: Zhang Y. P. , Kent R. L. , Margolis H. C.
Published: March 2003

The present study was carried out to examine the kinetics of enamel demineralization in vitro under driving forces for demineralization (i.e., the degree of saturation with respect to enamel, DSEn) similar to those found in dental plaque fluid. Thin sections of human enamel were exposed at 25°C to lactic acid solutions with DSEn values (DSEn=[(Ca2+)5(OH−)(PO43−;)3/KEn]1/9; KEn=5.5×10−55) ranging from 0.28 to 0.79. Lesion development was monitored by quantitative microradiography. Enamel mineral loss in solutions with DSEn values of 0.28, 0.32 and 0.36 was first detected after 3, 3, and 7 wk of continuous exposure, respectively. Consistent with previous findings, subsurface demineralization was observed and rates of mineral loss increased significantly with decreasing DSEn values. However, no mineral loss was observed in sections of enamel exposed to solutions with DSEn values of 0.41 and 0.79, even after 11 months. These results suggest that (outer) enamel mineral behaves as a mineral phase that is less soluble than that dictated by the solubility product constant (KEn) used in this study. Furthermore, these results indicate that the kinetics and general features of the demineralization process are maintained over a wide range of DSEn values, including conditions that better reflect those found in the oral cavity. These findings are particularly relevant to the assessment of the cariogenic potential of dental plaque fluids.
An 8‐year evaluation of sintered ceramic and glass ceramic inlays processed by the Cerec CAD/CAM system
Authors: Pallesen Ulla , Van Dijken Jan W. V.
Published: March 2003

The purpose of this study was to evaluate Cerec CAD/;CAM inlays processed of two industrially made machinable ceramics during an 8‐yr follow‐up period. Each of 16 patients received two similar ceramic inlays. Half the number of the inlays were made of a feldspathic (Vita Mark II) and the other of a glass ceramic (Dicor MGC) block. The inlays were luted with a dual resin composite and evaluated clinically using modified USPHS criteria at baseline, 8 months, 2, 3, 5, 6 and 8 yr, and indirectly using models. At baseline, 84% of the inlays were estimated as optimal and 16% as acceptable. Postoperative sensitivity was reported by one patient for 8 months. Of the 32 inlays evaluated during the 8 yr, 3 failed due to fracture of the material. No secondary caries was found adjacent to the inlays. No significant differences in the clinical performance were found between inlays made of the two ceramics. It can be concluded that the CAD/CAM inlays processed of the two ceramics functioned well during the 8‐yr follow‐up period.
In vitro synchronization of embryonic mouse incisor preodontoblasts and preameloblasts: repercussions on terminal differentiation
Authors: Schmitt Régine , Ruch Jean‐Victor
Published: March 2003

Preodontoblasts divide asynchronously and their terminal differentiation occurs gradually. Experimental data suggested that the expression of competence by preodontoblasts to respond to specific epigenetic signals, triggering their overt differentiation, requires a minimal number of cell cycles. The intrinsic timing mechanism could imply division counting and preodontoblasts of juxtaposed cell generations might sequentially withdraw from the last physiological cycle. To test such an hypothesis, embryonic mouse lower incisors were cultured in vitro and treated sequentially with nocodazole in order to induce a transitory synchronization of the dividing preodontoblasts and preameloblasts. This synchronization led to a disorganization of the physiological gradual terminal differentiation of the odontoblasts, giving rise to three distinct domains comprising respectively: 1) odontoblasts with altered polarization and predentin secretion; 2) odontoblasts demonstrating equivalent polarization and predentin deposition; and 3) preodontoblasts‐odontoblasts involved in gradual terminal differentiation. These results strongly suggest that the gradient of odontoblast functional differentiation results from sequential withdrawal from asynchronous cell cycles of competent cells able to overtly differentiate.
Substitutes for methylene chloride as dental softening agent
Authors: Asmussen Erik , Peutzfeldt Anne
Published: March 2003

Methylene chloride is used as softening agent for guttapercha and as adhesion promotor for polymethylmethacrylate (PMMA). However, methylene chloride has been found to be carcinogenic. It was the aim of the present work to search for harmless substitutes for methylene chloride in these situations. A number of possible candidates with structural similarities to guttapercha or PMMA were selected. The efficacy in softening of guttapercha of these compounds was measured by the depth of penetration of a needle under the load of 2 N. The effect of the compounds on the adhesion between PMMA and an acrylic rebasing material was measured in shear. It was found that a number of alkenes or dialkenes of moderate molecular weight (1,3‐pentadiene, cyclopentene, isoprene, 2‐methyl‐2‐butene, and 1,5‐hexadiene) were as effective as methylene chloride as softening agent for guttapercha. As adhesion promotor in bonding to PMMA, it was found that low molecular weight methyl esters (methyl formate and methyl acetate) were as effective as methylene chloride. Because of the variation in polarity, the calculated solubility parameter was not a reliable predictor of softening efficacy of the investigated compounds.
Craniofacial morphology, dental occlusion, tooth eruption, and dental maturity in boys of short stature with or without growth hormone deficiency
Authors: Kjellberg Heidrun , Beiring Martin , Wikland Kerstin Albertsson
Published: March 2003

The aim of this project was to study the craniofacial morphology, dental occlusion, dental maturation and tooth eruption in short‐statured boys with growth hormone secretion ranging from low to high. The measurements from lateral and postero‐anterior cephalograms, orthopantomograms and plaster models were used. Almost all linear measurements of the facial structures were significantly smaller. A disproportionate growth in the cranial base structures as well as in the jaws resulted in facial retrognathia, a proportionately smaller posterior than anterior facial height, and a steep vertical inclination of the mandible. Dental crowding was more common and the overbite was small. Dental maturity and tooth eruption were delayed 1.2 and 1.3 yr, respectively. No significant differences between the idiopathic short‐statured and the growth hormone‐deficient group in any of the above‐mentioned variables were found. It can be concluded that although most of the cephalometric variables measured differed significantly from the average, the facial appearance of the boys is not conspicuous and is of minor clinical importance. However, the short‐statured boys might be in greater need of orthodontic treatment due to the higher percentage of dental crowding.
A comparison of the erosive potential of different beverages in primary and permanent teeth using an in vitro model
Authors: Lussi A. , Kohler N. , Zero D. , Schaffner M. , Megert B.
Published: March 2003

The aim of this study was to compare the erosive potential of different beverages and foodstuffs in primary and permanent teeth. Sixty primary and 60 permanent human teeth were immersed for 3 min in the solution under study (5 teeth per treatment group). Surface microhardness was measured before and after exposure. Initial (baseline) surface microhardness was lower for primary teeth than for permanent teeth. In both primary and permanent teeth, Sprite showed the highest decrease in surface microhardness, whereas yogurt showed an increase in surface microhardness in the primary teeth. Overall decrease was 27.2±17.5 KHN (mean±SD) for primary and 25.9±15.6 KHN for permanent teeth. The comparison of the erosive susceptibility in this in vitro model showed that primary teeth were not more susceptible to erosion compared to permanent teeth.
A comparative study of sialic acid‐rich proteins in rat bone and dentin
Authors: Qin Chunlin , Brunn Jan C. , Jones Jarrod , George Anne , Ramachandran Amsaveni , Gorski Jeffrey P. , Butler William T.
Published: March 2003

Four sialic acid‐rich (SA‐rich) proteins found in bone and dentin, osteopontin (OPN), bone sialoprotein (BSP), bone acidic glycoprotein‐75 (BAG‐75), and dentin matrix protein 1 (DMP1), share some common features. We used SDS‐PAGE and Western immunoblots to analyze and compare SA‐rich proteins in bone and dentin extracts from rats with a single chromatographic procedure. OPN was detected in dentin extracts, with a relative level less than one‐seventieth of that in bone. Both bone and dentin BSP demonstrated an extremely broad distribution pattern, probably due to a high degree of heterogeneity in post‐translational modifications. BAG‐75 in both bone and dentin was detected as an 83 kDa band, dramatically distinct from that of DMP1. Using a polyclonal antibody raised against a purified bone 57 kDa protein (a portion of DMP1), we detected 150 kDa protein bands in bone fraction; the same bands were recognized by anti‐recombinant rat DMP1 antibody. Bands from dentin migrating at about 150 kDa in earlier fractions and progressing to 200 kDa in later fractions showed a clear immunoreactivity to the anti‐57 kDa antibody. We conclude that the majority of DMP1 in rat bone is processed into fragments, whereas that in dentin remains intact.
Caries in populations – a theoretical, causal approach
Authors: Holst Dorthe , Schuller Annemarie A. , Aleksejuniené Jolanta , Eriksen Harald M.
Published: March 2003

The focus of this paper is caries in populations. Caries is assessed as a phenomenon and as it occurs in populations. It is observed that in recent literature the notion of causation of caries is restricted to the biological process on the tooth surface. This may be sufficient to explain caries as a phenomenon, but it is argued that a biological causation is insufficient in order to understand caries and its variation in populations. The understanding of the determinants of a population's oral health has been seriously impeded by the absence of a theoretical framework. A framework would be useful to the extent that it would bridge relevant categories for portraying complex causal patterns of caries in populations. An approach to a framework has therefore been outlined, and the idea of such a framework has been confronted with three critical comments. The framework is as yet pragmatic, incomplete, uncertain and fragmented. Yet, even such an approach may invite greater precision in epidemiological concepts about causes of caries than presently prevails. The framework directs attention to health effects of collective phenomena that cannot be reduced to individual attributes. The image proposed in this paper is intended to spur discussion about important aspects of the epidemiology of caries in populations.
Adhesive bonding of titanium nitride‐plated stainless steel for magnetic attachments
Authors: Taira Yohsuke , Hai Kan‐ichi , Matsumura Hideo , Atsuta Mitsuru
Published: March 2003

The purpose of this study was to evaluate adhesive bonding of resin to titanium nitride ion‐plated stainless steel in order for magnetic attachments to survive in the oral environment. Two primers, Cesead II Opaque Primer (CPII) and Metal Primer II (MPII), and one bonding agent, Super‐Bond C&B (SB), were used. The surfaces of stainless steel disks were ground and then plated with titanium nitride. After the primer and SB resin were applied, a self‐curing resin was bonded to the metal surfaces. Shear bond strengths were determined after 24 h of water storage and after 2,000 thermocycles. Titanium nitride ion‐plated stainless steel showed bond strength comparable to the non‐plated material. After thermocycling, all specimens of the group no primer/no SB were debonded. The bond strengths of groups CPII/no SB, MPII/no SB and no primer/SB were significantly lower bond strengths than groups CPII/SB and MPII/SB. An appropriate combination of primer and bonding agent should be selected when bonding a magnetic attachment to the denture base.
Protease inhibitors, the responsible components for the serum‐dependent enhancement of Actinobacillus actinomycetemcomitans leukotoxicity
Authors: Johansson A. , Claesson R. , Belibasakis G. , Makoveichuk E. , Hänström L. , Olivecrona G. , Sandström G. , Kalfas S.
Published: March 2003

Serum enhances the leukotoxic activity of Actinobacillus actinomycetemcomitans against human polymorphonuclear leukocytes (PMNL) by a mechanism that still is unknown. Early attempts to identify the serum components responsible for this enhancement gave no conclusive results, but indicated that the lipoprotein‐containing fraction of the serum was involved in the interaction. This study aimed to clarify the role of serum lipoproteins in the leukotoxin interaction, and to identify other serum components involved. The main hypothesis examined was that the leukotoxicity enhancement might depend on serum protease inhibitors that block proteolytic cleavage of leukotoxin by enzymes released from the leukocytes. PMNL were isolated from human peripheral blood and incubated with purified leukotoxin in the presence of serum or purified serum components or lipoprotein‐deficient serum. Leukotoxin was also incubated with purified elastase and cathepsin G or with enzyme mixtures from degranulated PMNL. The leukotoxic activity in these mixtures was determined as the extracellular release of lactate dehydrogenase from PMNL. Cleavage of the toxin was showed by gel electrophoresis and Western blot. Morphological changes in PMNL from the above mixtures were examined by electron microscopy. Enzymes from degranulated PMNL cleaved leukotoxin to non‐cytotoxic fragments. Elastase and cathepsin G were mainly responsible for the cleavage. Inhibition of leukotoxin degradation was found in the presence of whole serum or of the serum protease inhibitors α2‐macroglobulin and α1‐proteinase inhibitor. Under these conditions enhanced PMNL lysis was also observed. A similar enhancement of PMNL lysis was found when PMNL degranulation was blocked by EDTA. On the other hand, lipoprotein‐deficient serum had no influence on the leukotoxic activity. The results indicate that the increased leukotoxicity of A. actinomycetemcomitans observed in the presence of human serum is caused by the serum protease inhibitors that counteract proteolytic degradation of leukotoxin. The degradation is caused by enzymes from degranulated PMNL triggered by leukotoxin.
Influence of selected components on crosslink density in polymer structures
Authors: Asmussen Erik , Peutzfeldt Anne
Published: March 2003

Bifunctional methacrylates polymerize to form crosslinked polymer structures which may be characterized by the quantity of remaining double bonds and by the crosslink density. This study investigated the influence of composition variation on the crosslink density of model methacrylate polymers. It was hypothesized that addition of a monofunctional monomer would reduce crosslink density and that compositions giving rise to many centers of polymer growth would result in increased crosslink density. Unfilled resins with varying content of BisGMA, TEGDMA, a monofunctional monomer, camphoroquinone, and amine were polymerized by visible light irradiation. After polymerization, the quantity of remaining double bonds and the Wallace hardness were determined. Polymer softening upon storage in ethanol was taken as a measure of the crosslink density. After ethanol storage, the relationship between hardness number and amount of monofunctional monomer showed a minimum. At same quantity of remaining double bonds, a high content of camphoroquinone compared to amine resulted in reduced softening in ethanol. Composition influenced not only remaining double bonds but also the crosslink density of the resulting polymer structures.
The value of salivary bacterial counts as a supplement to past caries experience as caries predictor in children
Authors: Van Palenstein Helderman Wim H. , Mikx Frans H M , Van'T Hof Martin A. , Truin Gerrit J , Kalsbeek Huib
Published: March 2003

This study aimed to determine whether salivary mutans streptococci and lactobacilli counts could add any value to a combination of caries experience variables that was recently presented for the prediction of caries. Sixty‐nine children at the age of 7.5 yr participated in this longitudinal study. Microbiological data were obtained at the ages of 7.5, 9.5 and 11.5 yr and caries data at the ages of 7.5, 9.5, 11.5, 13.5 and 15.5 yr. Spearman's correlation coefficients were computed, and forward multiple regression analyses were carried out using bacterial counts and caries experience parameters as explanatory variables and caries increment as a dependent variable. The explained variance (adjusted R2 value) was the measure used to assess the additional value of bacterial counts to the caries predictive potential of the combined parameters of the past caries experience. Correlation coefficients between bacterial counts and 4‐yr caries increment were from 0.22 up to 0.54. In all cases, the simultaneous streptococcus mutans‐lactobacilli counts showed a statistically non‐significant additional adjusted R2 value of <0.06. The results do not lend support to the concept that these salivary bacterial counts are useful additional caries predictors for the mixed dentition, when a combination of caries experience parameters is used.
Inositol hexasulphate, a casein kinase inhibitor, alters the distribution of dentin matrix protein 1 in cultured embryonic mouse tooth germs
Authors: Septier D. , Torres‐Quintana M.‐A. , Menashi S. , George A. , Goldberg M.
Published: March 2003

Immunohistochemical studies using a polyclonal antibody, raised against the recombinant form of dentin matrix protein 1 (DMP1), show that DMP1 was detected mainly in odontoblasts in cultured mouse embryonic tooth germs. However, in restricted areas, DMP1 staining was also observed in secretory ameloblasts, in the stratum intermedium and stellate reticulum, but only when the odontoblasts located in front of them were unstained. When the embryonic tooth germs were cultured in the presence of inositol hexasulfate, a casein kinase I and II inhibitor, staining of odontoblasts was weak or nil, whereas, in contrast, ameloblasts and enamel organ were strongly immunolabelled, suggesting an enhanced translocation of DMP1 after secretion to the secretory ameloblasts and/or stratum intermedium and stellate reticulum. Moreover, DMP1 was shown to be a good substrate for gelatinase A (MMP‐2), but not to gelatinase B (MMP‐ 9). We hypothesized that DMP1 – or the sub‐fractions cleaved by the MMP – could behave as diffusible signaling molecule (s) rather than as a true dentin extracellular matrix component.
Influence of periodontal receptors on the jaw‐jerk reflex amplitude in man
Authors: Lobbezoo Frank , Verheij Johannes G.C. , Naeije Machiel
Published: March 2003

To study the role of periodontal mechanoreceptors in the modulation of the human jaw‐jerk reflex, 60 reflexes were elicited in each of six healthy individuals under three different conditions: (a) with unilateral tooth support on the ipsilateral side; (b) with support on the contralateral side; and (c) with support and local anesthesia of the periodontal tissues on the ipsilateral side. During all conditions, background muscle activity and mandibular displacement were kept as constant as possible. Using on‐surface EMG and the amplitude of the first peak of the biphasic jaw‐jerk potential as the outcome variable, a condition‐dependent reflex amplitude was found for the visually controlled right anterior temporalis muscle. Specifically, the ‘ipsilateral support plus anesthesia’ condition yielded higher amplitudes than the ‘ipsilateral support’ condition. Highest amplitudes were found for the ‘contralateral support’ condition. It was concluded that periodontal mechanoreceptors on the ipsilateral side have an inhibitory effect on the jaw‐jerk reflex amplitude in the anterior temporalis muscle.
Influence of restraint stress on ligature‐induced periodontitis in rats
Authors: Gašperšič Rok , Štiblar‐Martinčič Draga , Skalerič Uroš
Published: March 2003

The influence of stress on periodontal breakdown in Wistar rats was analyzed during experimental periodontitis, induced by placing silk ligatures around the maxillary right second molar teeth. The rats were divided into three groups with 10 animals in each; the first group was exposed to restraint stress for 12 h d−1 for a period of 4 wk; the second group was exposed to restraint stress for 2.5 h d−1 for a period of 4 wk; the third group served as a control group. Ligation for 4 wk resulted in an accelerated periodontal degradation, whereas the restraint stress by itself had no significant effect. Combined stress and ligation resulted in a significantly higher attachment loss and alveolar bone resorption than either treatment alone, while no differences were seen between the two stress regimens. After 4 wk, a reduced body weight was found in both restrained groups of rats and a reduced weight of the thymus in the rats restrained for 12 h d−1, while no changes were observed in the weight or composition of the suprarenal glands. We conclude that stress alone does not result in periodontal disease but may modulate the pathophysiological processes of already present periodontal inflammation, resulting in accelerated degradation of periodontal tissues.
Detection of marginal defects of composite restorations with conventional and digital radiographs
Authors: Haak Rainer , Wicht Michael J. , Hellmich Martin , Noack Michael J.
Published: March 2003

The purpose of this study was to determine the validity of detecting approximal imperfections of composite fillings using three intraoral radiographic systems in vitro. Class II composite resin restorations (108) with three radiopacities (264, 306, 443% Al 99.5) of which 27 had marginal openings or overhangs, respectively, were conventionally (Ektaspeed plus) and digitally (Dexis, Digora) radiographed. Images were assessed by 10 observers for the presence of marginal gaps and overhangs, as well as for their need of restorative treatment according to a five‐point confidence rating scale. The validity of the observations were expressed as areas under receiver operating characteristic (ROC) curves (Aroc). Repeated measures analysis of variance revealed significant effects of ‘radiographic system’ and ‘diagnostic purpose’. Marginal overhangs (Aroc = 0.90) were significantly easier to diagnose than openings (Aroc = 0.63). Marginal gaps were better detected on conventional and Dexis radiographs than on Digora images. the range of sensitivities and specificities of the treatment decision was 0.53–0.56 and 0.87–0.88, respectively. It was concluded that the validity of detecting marginal defects of composite resin restorations based on radiographs was only slightly affected by the radiographic system being used. The diagnosis of marginal gaps frequently resulted in false‐positive and false‐negative decisions.
Toothbrushing affects the protein composition of whole saliva
Authors: Hoek G. Henk , Brand Henk S. , Veerman Enno C. I. , Nieuw Amerongen Arie V.
Published: March 2003

Saliva is increasingly used for diagnostic purposes, but little is known about the potential effect of toothbrushing on the composition of saliva. Therefore, saliva collected before and 0, 15, 30 and 45 min after toothbrushing according to the Bass method was analysed for relevant protein composition. The flow rate initially increased (+15%) after toothbrushing, followed by a decrease after 15 min (−15%). The concentration of salivary immunoglobulin A (S‐IgA) decreased (−40%) whereas the albumin concentration increased (+400%) within 20 min. Flow rate and S‐IgA concentration returned to baseline values within 30 min. The albumin concentration, however, was still increased after 45 min. No significant increases were observed in the concentrations of total protein and amylase. Our results show that toothbrushing has a significant effect on the protein composition of saliva, by contamination with serum constituents. This should be taken into account when saliva is used for diagnostic purposes.
On the role of MT1‐MMP, a matrix metalloproteinase essential to collagen remodeling, in murine molar eruption and root growth
Authors: Beertsen Wouter , Holmbeck Kenn , Niehof Anneke , Bianco Paolo , Chrysovergis Kaliiopi , Birkedal‐Hansen Henning , Everts Vincent
Published: March 2003

Although the connective tissues of the periodontium are subject to a high turnover rate, no conclusive evidence has yet emerged that periodontal collagen turnover is essential for the eruption of teeth or for root elongation. These processes were studied in mice deficient in MT1‐MMP, a membrane type matrix metalloproteinase essential for remodeling of soft tissue–hard tissue interfaces. Mandibular first molars of deficient mice and their wild‐type littermates were subjected to stereological analysis in order to assess root length, eruption and the volume density of phagocytosed collagen in periodontal ligament fibroblasts. The data showed that both eruption and root elongation were severely inhibited in animals lacking the enzyme. We also found, in periodontal ligament fibroblasts from MT1‐MMP‐deficient mice, a massive age‐related accumulation (up to 60‐fold over controls) of collagen fibril‐containing phagosomes. Phagolysosomes, which represent the next downstream step in collagen fibril degradation by the lysosomal pathway, did not accumulate. These observations indicate that MT1‐MMP plays a central role in periodontal remodeling. The stunted root growth and the failure to erupt indicate the important role of the enzyme in tooth development.
Might Wasp Venom Desensitization Induced Th2 to Th1 Shift Cause Pregnancy Failure?
Authors: MARKERT UDO R. , ARCK PETRA C. , PEIKER GERTRUD , MOCK BETTINA A.
Published: March 2003

The case of a 28‐year‐old woman under wasp venom desensitization having a premature birth in her 24th week of pregnancy 16 days after the last injection is described. To test the hypothesis that a special profile of immune cells in the decidua may trigger abortions, placental and decidual tissue sections were stained with antibodies against T cells (CD3), cytotoxic cells (CD8), natural killer cells (CD56), and mast cells, and an in‐situ‐hybridization was performed for tumor necrosis factor‐α (TNF‐α). CD56+ Natural killer cells were the dominating population. In earlier analyses of healthy first trimester decidua the percentage of NK cells and T cells was in a similar range, but the CD8:CD3 ratio was only 2.2% in contrast to 27% in the present case. Mast cells, which are known to be able to secrete abortogenic TNF‐α, were only detectable in the decidua (10 cells/mm2) and decidua sections were TNF‐α positive. Since SIT induces a shift of the interleukin and functional profile from a Th2 type towards a Th1 type, and pregnancy is dependent on a Th2 pronounced profile, SIT may trigger abortions or immature births. This is supported by the present results and might have happened in this case.
The Same Immunoregulatory Molecules Contribute to Successful Pregnancy and Transplantation
Authors: GORCZYNSKI REGINALD M. , HADIDI SIMA , YU GARY , CLARK DAVID A.
Published: March 2003

PROBLEM: At least two dendritic cell‐associated molecules have been shown to contribute to the successful outcome of organ and tissue allografts in mice, namely CD200 and MD‐1. CD200 is up‐regulated in rodent transplantation models where successful inhibition of rejection is accomplished, and is believed to signal immunosuppression following engagement of a receptor, CD200R, on macrophages and/or γδ T‐cell receptor (γδ TCR+cells MD‐1 is implicated in controlling expression of costimulatory molecules including CD80/CD86 which induce an immunorejection response, and thus inhibition of MD‐1 expression also facilitates increased graft survival MD‐1 also stabilizes expression of CD14, part of the receptor complex for LPS. As well as the inhibition of rejection which follows blockade of MD‐1 expression and/or augmentation of CD200 expression, an altered polarization in cytokine production is seen, with increased expression of interleukin‐4 (IL‐4), IL‐10 and transforming growth factor‐β (TGF‐β), and decreased IL‐2, interferon‐γ (IFN‐γ) and tumor nerosis factor‐α (TNF‐α). Successful pregnancy in allopregnant mice also depends upon control of graft rejection mechanisms. Proinflammatory T‐helper 1 (Th1) cytokines (TNF‐α + IFN‐γ + IL‐1) have been shown to cause spontaneous abortion in mice by activating a novel prothrombinase, fibrinogen‐like peptide (fibroleukin) fgl2, which may promote fibrin deposition in the graft rejection process; expression of IL‐10, TGF‐β, and progesterone‐induced blocking factor (PIBF) in contrast leads to lowering of abortion rates. Interestingly, the spontaneous abortion rates in abortion‐prone CBA × DBA/2 matings and in the low abortion rate CBA × BALB/c matings were lower than the frequency of implantation sites showing fibrinhi+ fgl2 (mRNA)hi, implying regulation of the pro‐abortion consequences of fgl2 expression.

METHODS: We have investigated, byin situhybridization, CD200, MD‐1 and fgl2 expression in implantation sites in different strains of mice, and studied the effects of anti‐MD‐1, anti‐CD200 and CD200Fc immunoadhesin on fetal and allograft survival. The role of indoleamine dioxygenase (IDO) was evaluated.

RESULTS: CD200 mRNA expression occurred in the same sites as fgl2 mRNA. Anti‐CD200 antibody raised the abortion rate to predicted levels, and infusion of a CD200 immunoadhesin reduced the abortion rate, as did an anti‐MD‐1 antibody. The latter also improved organ and tissue graft survival. Suppression by antigen‐presenting macrophages triggered by CD200 is dependent upon intact IDO activity.

CONCLUSION: Regulation of CD200 and MD‐1 expression may control both pregnancy and allograft survival.
Natural Killer Cell Receptor Expression by Human First Trimester Decidual Granular Leukocytes and T‐Lymphocytes
Authors: LEWIS BARRY J. , CROKER SIMON , NEWTON DARREN J. , LENNON GREIG P. , JOHNSON PETER M. , CHRISTMAS STEPHEN E.
Published: March 2003

PROBLEM: Detailed analysis of the expression of natural killer (NK) cell activatory and inhibitory receptors by human decidual leukocyte subpopulations has not been undertaken.

METHOD OF STUDY: Expression of the natural cytotoxicity receptors NKp30, NKp44 and NKp46 by decidual leukocytes were studied by reverse transcriptase polymerase chain reaction. Expression of the killer cell Ig‐like receptors CD158a and CD158b on decidual T cells were studied by flow cytometry.

RESULTS: First trimester decidual leukocytes expressed mRNA for the NKp30 and NKp46 receptors but expression of NKp44, a marker of activated NK cells, was not detected. A mean of 11.8 and 15.8% of decidual T cells expressed CD158a or 158b, respectively, while only around 1% of peripheral blood T cells were CD158a+ or CD158b+.

CONCLUSIONS: Like peripheral blood NK cells, decidual NK cells express the natural cytotoxicity receptors NKp30 and NKp46 but the significance of this will not become apparent until ligands for these molecules have been identified. Only a minority of decidual T cells express CD158, indicating that this is not a mechanism for inhibition of cytotoxicity mediated by all decidual T cells.
The Role of Pro‐ and Anti‐apoptotic Molecular Interactions in Embryonic Maldevelopment
Authors: TODER V. , CARP H. , FEIN A. , TORCHINSKY A.
Published: March 2003

Toder V, Carp H, Fein A, Torchinsky A. The role of pro‐ and anti‐apoptotic molecular interactions in embryonic maldevelopment. AJRI 2002; 48:235–244 © Blackwell Munksgaard, 2002

PROBLEM: Pregnancy loss and the occurrence of inborn structural anomalies are often preceded by excessive apoptosis in targeted embryonic and extraembryonic tissues. Apoptogenic stimuli activate both death and survival, signaling cascades consisting of molecules acting as activators and effectors, or negative regulators of apoptosis. The interplay between these cascades determines whether the cell which is exposed to an apoptogenic stimulus dies or survives. This review summarizes the functioning of pro‐ and anti‐apoptotic molecules in embryos responding to various teratogens. The effect of potentiation of the maternal immune system on these molecules is also discussed.

METHODS OF STUDY: The data on the functioning of various pro‐ and anti‐apoptotic molecules in embryos exposed to various developmental toxicants, and embryos developing in a diabetic environment are reviewed. Techniques such as the TUNEL method, DNA fragmentation assay, electromobility shift assay (EMSA), fluorometric assay, immunohistochemistry, Western blot, In situ hybridization, have been used in our studies to detect apoptosis, and evaluate the functioning of molecules such as TNFα, caspases, NF‐κB and IκB, p53, and bcl‐2 in different embryonic and extraembryonic tissues.

RESULTS: Our and other data summarized in this review have demonstrated that the doses of developmental toxicants required to induce pregnancy loss and gross structural anomalies induce excessive apoptosis shortly after treatment. Depending on the intensity and type of targeted tissues, this apoptosis was accompanied by alterations in the activity of the molecules which act as activators and effectors (e.g. caspase 3, caspase 8, caspase 2, p53) or negative regulators (bcl‐2, NF‐κB) of apoptosis. Maternal immunopotentiation, which decreases the level of induced and spontaneous pregnancy loss and the incidence and severity of teratogen‐induced structural anomalies has been shown to modulate the expression of these molecules both in embryonic tissues and at the feto‐maternal interface.

CONCLUSIONS: The data presented in this review suggest that molecules such as TNFα, caspase 3, caspase 8, NF‐κB, p53 and bcl‐2, which are involved in the regulation of apoptosis, may also be involved in determining the sensitivity of the embryo to developmental toxicants. Maternal immunopotentiation may modulate the functioning of these molecules.
Characterization of Proteins from Boar Prostate
Authors: MAŇÁSKOVÁ PAVLA , RYŠLAVÁ HELENA , TICHÁ MARIE , JONÁKOVÁ VĚRA
Published: March 2003

Maňásková P, Ryšlavá H, Tichá M, Jonáková V. Characterization of proteins from boar prostate. AJRI 2002; 48:283–290 © Blackwell Munksgaard, 2002

PROBLEM: Most components of seminal plasma are secreted by accessory sexual glands: seminal vesicle, prostate gland and bulbourethral gland. The portion of proteins secreted by prostate gland differs in various species. Characterization of boar prostate proteins is the subject of this communication.

METHODS OF STUDY: Proteins of boar prostate gland were separated by affinity chromatography on heparin‐polyacrylamide to non‐heparin‐binding (H−) and heparin‐binding (H+) fractions. The H− and H+ fractions were subjected to reverse phase high performance liquid chromatography (RP HPLC) and their elution profiles were compared with those of the H− and H+ fractions of boar seminal plasma. The isolated proteins were characterized by sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE), immunodetection, N‐terminal amino acid sequencing and mass spectrometry (MALDI).

RESULTS: The following proteins of boar prostate secretion were identified: β‐microseminoprotein, serotransferrin, serum albumin, myoglobin and PSP I and PSP II spermadhesins.

CONCLUSION: Presented results demonstrate composition of the main proteins of boar prostate secretion. β‐Microseminoprotein was found to be a major protein of prostate secretion. PSP I and PSP II, major proteins of the H− fraction of boar seminal plasma, were found in boar prostate secretion in lower amounts. The major proteins of the H+ fraction of boar seminal plasma (AQN, AWN) were not detected in prostate secretion.
Induction of Transferrin Secretion in Murine Sertoli Cells by FSH and IL‐1: The Possibility of Different Mechanism(s) of Regulation
Authors: HULEIHEL MAHMOUD , ZEYSE DANIEL , LUNENFELD EITAN , ZEYSE MELANIE , MAZOR MOSHE
Published: March 2003

In the present study we examined the capacity of interleukin‐1 (IL‐1) α, β, interleukin‐1 receptor antagonist (IL‐1ra) and follicle stimulating hormone (FSH) to induce transferrin secretion by Sertoli cells under in vitro conditions. Primary Sertoli cell (SC) cultures from immature mice secreted constitutively transferrin. Stimulation of these cultures with IL‐1α, IL‐1β significantly increas\d their capacity to secrete transferrin. Addition of IL‐1ra to unstimulated SC cultures did not affect their capacity to secrete transferrin. Stimulation of SC cultures with a combination of both IL‐1α and FSH or IL‐1β and FSH showed additive effect between IL‐1 and FSH in their capacity to induce transferrin secretion by these cells. However, stimulation of Sertoli cells with a combination of both IL‐1ra and FSH did not affect their capacity to secrete transferrin compared with FSH‐stimulated cultures.

Our results may suggest the involvement of testicular paracrine/autocrine factors (IL‐1) and endocrine (FSH) factors in the regulation of transferrin secretion by SC. This capacity seems to be differently regulated by these factors.

Thus, IL‐1α and β may directly affect physiological functions of the testis; which may suggest their involvement in the regulation of spermatogenesis and spermiogenesis processes and male fertility.
Evaluation of the Trifecta obturating technique
Authors: Al‐Dewani N. , Hayes S. J. , Dummer P. M. H.
Published: March 2003

Abstract – The aim of this project was to evaluate and compare the radiographic quality and sealability of root fillings in extracted human teeth using lateral condensation of gutta‐percha or the Trifecta obturating system. One hundred freshly extracted human mature, single‐rooted teeth were divided into four identical groups of 25 teeth on the basis of root canal shape. The root canals of two groups were prepared in such a way as to produce a relatively parallel canal shape with little or no flare towards the coronal orifice. The root canals of the other two groups were prepared in such a way as to produce a canal shape that was deliberately more flared to ensure that they were wider at the orifice than at the endpoint of the preparation. All root canals were flushed with 17% EDTA solution and 2.5% NaOCl to remove the dentinal smear layer. The canals of one flared and one parallel group were obturated using cold lateral condensation and the canals of the other two groups were obturated using the Trifecta system. The sealability of each technique was assessed by a dye penetration method. The radiographic quality of obturation was determined for each canal using a 4‐point scale. Canals filled with thermoplasticised gutta‐percha had significantly less apical dye penetration than those obturated by lateral condensation (P<0.001). Lateral condensation achieved significantly better scores for radiographic quality than thermoplasticised gutta‐percha from both the bucco‐lingual (P<0.001) and the mesio‐distal views (P<0.001). Root canals obturated using the Trifecta technique showed significantly more apical extrusion of sealer than those obturated by lateral condensation (P<0.001). Under laboratory conditions the Trifecta technique had better sealability but poorer radiographic quality than lateral condensation.
Crown dilaceration of a first premolar caused by extraction of its deciduous predecessor: a case report
Authors: Matsuoka T. , Sobue S. , Ooshima T.
Published: March 2003

Abstract – This report describes a rare case of crown dilaceration of the mandibular first premolar caused by trauma during extraction of the precedent primary first molar. The mandibular first primary molar had been extracted at the age of 4 years 7 months. Compared to the pre‐operative radiograph, the post‐operative film showed that the direction of the first premolar tooth germ had changed, suggesting that crown dilaceration had been induced by the surgical procedures during tooth extraction. From radiographic examinations, the premolar was considered to have erupted spontaneously.
An in vitro investigation into the cutting action of ultrasonic radicular access preparation instruments
Authors: Waplington M. , Lumley P. J. , Blunt L.
Published: March 2003

Abstract – The aim of this study was to investigate the dentine cutting action of a CT4 and SJ4 radicular preparation inserts (Excellence in Endodontics/Analytic Technology, Orange, CA, USA) used in a Piezon Master 400 ultrasonic handpiece (Electro Medical Systems SA, Nyon, Switzerland). Calibration of the ultrasonic inserts was carried out at minimum, medium and maximum power settings using light microscopic measurement of the tip displacement amplitudes (×120 mag). Polished dentine samples were instrumented, at monitored loads, at the three chosen power settings, to produce uniform dentine cuts. The resultant dentine debris was collected for SEM analysis, and comparison with that produced by rotary instruments. The depth of dentine cut was measured at ×30 magnification. Fracture of the SJ4 insert was noted at medium power setting. Results revealed a significant increase in both displacement amplitude and depth of dentine cut with power setting (ANOVA P<0.001). Dentine chip size increased with power, and differed in structure and appearance from those produced by rotary instruments. In conclusion, ultrasonic cutting is influenced significantly by power setting, and dentine chip formation is fundamentally different to rotary instrumentation.
The influence of sample dimensions on hydroxyl ion release from calcium hydroxide products
Authors: Murray P. E. , Lumley P. J. , Smith A. J. , Ross H. F.
Published: March 2003

Abstract – The purpose of this study was to compare the rate of hydroxyl ion release from commercially available setting and non‐setting calcium hydroxide products. The rate of hydroxyl ion release is important, as this has been suggested to be the main factor in the therapeutic activity of these products. In total, hydroxyl ion release was measured from 1104 samples of Dycal, Life, Calasept and Hypocal in solution using in vitro titration. The rate of hydroxyl ion release was measured for up to 14 days, using two sizes of sample surface area. The dimensions of the exposed sample surface area was found to be an important physical constraint to the hydroxyl ion release from non‐setting calcium hydroxide products, whereas this was not found to be the case with setting products. The range in hydroxide activity between products was found to be 298%. In rank order of hydroxide ion release, from the most to the least active was: Hypocal, Calasept, Life and Dycal. The differences in the rate of hydroxyl ion release from these products may have some implications for their clinical applications. It is suggested that in cases where the oral healing responses have been poorer than expected, the size and seal of prepared cavities could have negatively influenced the therapeutic release of hydroxyl ions from non‐setting calcium hydroxide products.
The effect of zinc oxide‐eugenol on the shear bond strength of a commonly used bonding system
Authors: Leirskar J. , Nordbø H.
Published: March 2003

Abstract – It has been claimed that eugenol has a detrimental effect on resin composites and dentin bonding systems. The aim of the present study was to examine whether zinc oxide‐eugenol (ZOE) cement would reduce the efficacy of a bonding system. Human third molars were selected for the study, and cylindrical posts of a resin composite (Z100) were bonded vertically to a standardized flat dentinal surface, prepared on the buccal surface of the teeth and treated with Scotchbond Multi‐Purpose. The tooth surfaces involved were either freshly cut, or had been exposed to ZOE cement for 6 days, with and without a subsequent thorough cleansing with ethanol. The bond strength in shear was measured after 24 hours. The results showed that ZOE cement had no negative effect on the bond strength of the resin composite (Z100) to dentin when this bonding system was used. The mean shear bond value for the specimens covered with ZOE cement for 6 days was 28.1 MPa. For specimens covered with ZOE cement and cleansed with 96% ethanol, the mean shear bond value was 23.5 MPa. The corresponding value for the controls was 19.0 MPa. These findings suggested that eugenol‐containing temporary filling materials may be used safely prior to inserting resin based restorative materials, when Scotchbond Multi‐Purpose is employed as the bonding agent.
Efficacy of laser Doppler flowmetry for the diagnosis of revascularization of reimplanted immature dog teeth
Authors: Yanpiset Kallaya , Vongsavan Noppakun , Sigurdsson Asgeir , Trope Martin
Published: March 2003

Abstract – This study was performed to assess if laser Doppler flowmetry (LDF) is an improved method for the detection of revascularization of replanted teeth. Teeth were extracted and reimplanted under different experimental conditions. LDF readings were taken before extraction and weekly for 3 months. In control teeth, LDF baseline readings were taken and then repeated after the apical blood vessels were cut surgically. At the end of 3 months it was determined radiographically and histologically whether revascularization had occurred, i.e. vitality had returned. Results: LDF readings correctly predicted the pulp status (vital vs. non‐vital) in 83.7% of the readings. 73.9% (17 of 23) were correct for the vital teeth and 95% (19 of 20) were correct for the non‐vital teeth. Fisher’s exact test (2‐tail) indicated that there was no significant association between the efficacy of LDF and tooth type (P=0.166), although P2 was the least accurate tooth tested. Wilcoxon’s matched‐pair signed rank test demonstrated that in the revascularized (vital) teeth, the flux value between the baseline and week 2 dropped significantly (P=0.0001), increased significantly from week 2 to week 4 (P=0.0001) and then decreased steadily until week 12. However, at week 12 the flux was still significantly higher than at week 2 (P=0.010). In the teeth that failed to revascularize, the flux value dropped significantly by weeks 1 and 2 (P=0.004 and P=0.0001, respectively). Flux values did not increase from week 2. A Fast Fourier Transform (FFT) analysis confirmed a pulse of dominant frequency of 2 Hz in the teeth that returned to vitality and the lack thereof in those that stayed non‐vital. One tooth in which the flux value evaluation indicated a non‐vital tooth but the radiographic/histologic findings showed vital (false negative) possessed a pulse of dominant frequency and proved by this method to have successfully revascularized.