bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Prenatal Exposure to the Dutch Famine on Adult Disease in Later Life: An Overview
Authors: Roseboom Tessa J. , van der Meulen Jan H.P. , Ravelli Anita C.J. , Osmond Clive , Barker David J.P. , Bleker Otto P.
Published: May 2007

People who were small at birth have been shown to have an increased risk of CHD and chronic bronchitis in later life. These findings have led to the fetal origins hypothesis that proposes that the fetus adapts to a limited supply of nutrients, and in doing so it permanently alters its physiology and metabolism, which could increase its risk of disease in later life. The Dutch famine — though a historical disaster — provides a unique opportunity to study effects of undernutrition during gestation in humans. People who had been exposed to famine in late or mid gestation had reduced glucose tolerance. Whereas people exposed to famine in early gestation had a more atherogenic lipid profile, somewhat higher fibrinogen concentrations and reduced plasma concentrations of factor VII, a higher BMI and they appeared to have a higher risk of CHD. Though the latter was based on small numbers, as could be expected from the relatively young age of the cohort. Nevertheless, this is the first evidence in humans that maternal undernutrition during gestation is linked with the risk of CHD in later life. Our findings broadly support the hypothesis that chronic diseases originate through adaptations made by the fetus in response to undernutrition. The long-term effects of intrauterine undernutrition, however, depend upon its timing during gestation and on the tissues and systems undergoing critical periods of development at that time. Furthermore, our findings suggest that maternal malnutrition during gestation may permanently affect adult health without affecting the size of the baby at birth. This gives the fetal origins hypothesis a new dimension. It may imply that adaptations that enable the fetus to continue to grow may nevertheless have adverse consequences for health in later life. CHD may be viewed as the price paid for successful adaptations to an adverse intra-uterine environment. It also implies that the long-term consequences of improved nutrition of pregnant women will be underestimated if these are solely based on the size of the baby at birth. We need to know more about what an adequate diet for pregnant women might be. In general, women are especially receptive to advice about diet and lifestyle before and during a pregnancy. This should be exploited to improve the health of future generations.
Cardiovascular Mortality in Twins and the Fetal Origins Hypothesis
Authors: Christensen Kaare , Wienke Andreas , Skytthe Axel , Holm Niels V. , Vaupel James W. , Yashin Anatoli I.
Published: May 2007

The intrauterine growth patterns for twins are characterized by normal development during the first two trimesters and reduced growth during the third trimester. According to the fetal origins hypothesis this growth pattern is associated with risk factors for cardiovascular morbidity and mortality. We studied cause-specific mortality of 19,986 Danish twin individuals from the birth cohorts 1870–1930 followed from 1952 through 1993. Despite the large sample size and follow-up period we were not able to detect any difference between twins and the general population with regard to all-cause mortality or cardiovascular mortality. Hence, the intrauterine growth retardation experienced by twins does not result in any “fetal programming” of cardiovascular diseases. There is still an important role for twins (and other sibs) to play in the testing of the fetal origins hypothesis, namely in studies of intra-pair differences, which can assess the role of genetic confounding in the association between fetal growth and later health outcome.
Early Changes in Vascular Dynamics in Relation to Twin-Twin Transfusion Syndrome
Authors: Gardiner Helena M.
Published: May 2007

Aclearer understanding of the early determinants of normal and abnormal vascular development is pivotal in order to identify those at increased risk of later vascular disease, and perhaps to prevent it by early intervention. Measurement of pulse wave velocity(PWV) has been used in the postnatal evaluation of the monochorionic(MC) twins. They are genetically identical and those with twin-twin transfusion syndrome(TTTS) provide an ideal natural model in whom to study the influence of differing haemodynamic stresses on the developing vascular tree. We investigated firstly whether surviving twin pairs with TTTS have altered arterial distensibility in childhood by comparing PWV in the radial arteries of surviving MC twin pairs with TTTS and in two control groups, one cohort of MC twins without TTTS and another dichorionic group (DC) Secondly, we tested a cohort of TTTS twin pair survivors treated with laser photocoagulation. The co-twin pairs in the group managed palliatively with amnioreduction showed increased PWV in the donor and reduced PWV in the recipient twins. This was neither seen in the laser-treated, nor in the control groups. Our studies suggest that a period of haemodynamic imbalance gives rise to changes in a muscular conduit artery that persist at least into infancy and it seems that by correcting the abnormal haemodynamics relatively soon after the disease process had begun, the alterations in elasticity are prevented. These studies are the first to demonstrate fetal programming of the vascular bed in humans, and prevention or reversal of this programming by an intervention in mid-gestation.
Comparing Blood Pressure of Twins and Their Singleton Siblings: Being a Twin Does Not Affect Adult Blood Pressure
Authors: de Geus Eco J.C. , Posthuma Danielle , IJzerman Richard G. , Boomsma Dorret I.
Published: May 2007

The hypothesis was tested that monozygotic (MZ) and dizygotic (DZ) twins, with their lower average birth weight, have higher adult blood pressure than their singleton brothers or sisters. From the Netherlands Twin Registry, 261 twin families were recruited from a young adult and an older adult cohort with mean ages of 26.2 and 50.4 respectively. These families yielded 204 MZ twins with 71 singleton siblings and 271 DZ twins with 103 of their singleton siblings. Anti-hypertensive medication use of these 649 participants was assessed twice with a two-year interval. Resting blood pressure was measured thrice during a standardized laboratory protocol. In spite of a significant difference in birth weight (1036 gram), no differences were found in anti-hypertensive medication use at both time points between twins and singletons nor between their resting laboratory diastolic or systolic blood pressure. These results applied to each gender and to both age cohorts. Limiting the analyses to matched twin-sibling pairs of the same families and taking current weight and height into account did not change the results; no evidence was found for a twin-singleton difference. It was concluded that estimates of genetic and environmental contributions to blood pressure deriving from twin studies do not appear to be biased and may be generalized to singletons. Our results suggest that the lower birth weight in twins does not reflect the intrauterine disadvantage described by the Barker hypothesis.
Health of Human and Livestock Conceived by Assisted Reproduction
Authors: Ceelen Manon , Vermeiden Jan P.W.
Published: May 2007

Assisted reproduction is used to resolve infertility problems in human and in breeding programs to generate livestock. Except for gestation length and birth weight, perinatal outcome of children conceived by In Vitro Fertilization is similar to that of spontaneously conceived children. However, large offspring syndrome observed after In Vitro Production in livestock is quite alarming. The distinct parts of assisted reproduction (oocyte maturation, fertilization and culture) have been found to contribute to abnormal fetal growth and development. Genomic imprinting is suggested to be involved in the induction of the aberrant phenotypes observed after assisted reproduction. Furthermore, current knowledge on postnatal health of offspring conceived by assisted reproduction and speculations on potential longterm effects of In Vitro Fertilization will be described.
The Effects of Assisted Reproduction on the Trends and Zygosity of Multiple Births in England and Wales 1974–99
Authors: Platt Mary J. , Marshall Amy , Pharoah Peter O.D.
Published: May 2007

Assisted reproductive techniques have led to an increase in the proportion of maternities that are multiple. Though predominantly dizygotic, they are at greater risk of monozygotic division than those spontaneously conceived. England and Wales data 1974–99 on stillbirths and livebirths were analysed for 4 periods: 1974–80 (pre-assisted reproduction; 1982–8; 1989–91 (pre-redefinition of stillbirth); 1993–9 (post-redefinition of stillbirth). For twin data, Weinberg's rule was applied to estimate the proportions that were mono- (MZ) and dizygotic (DZ). Compared with the period before assisted reproduction, the most recent period shows an increase in twin maternities of 3.81 per 1000 comprised of 3.22 (95% CI 3.10 to 3.33;p< 0.0001) DZ and 0.60 (95% CI 0.51 to 0.68;p< 0.0001) MZ twins. It is estimated that 15.7% of assisted reproduction twins are MZ. Higher order multiple births showed an increase of 3.06 (95% CI 2.85 to 3.29;p< 0.0001) per 10,000 maternities. Stillbirth rates in MZ twins are of the same order of magnitude as those in higher order multiple births but higher than those in DZ twins. The improvement in stillbirth rates over the 26 year study period is of the same order magnitude in singletons, DZ and MZ twins and higher order multiples. Assisted reproduction has led to a significant increase in the proportion of MZ twins. These are at high risk of fetal death and this needs to be considered when local stillbirth and perinatal mortality rates are used in auditing obstetric services.
Feasibility of Using Different Approaches for Recruiting Younger Twins to Establish a Population Based Twin Register in Sri Lanka
Authors: Sumathipala Athula , Siribaddana Sisira H. , De Silva Nimali , Abeysingha Nihal M. R. , Sivayogam Sivagurunathan , Fernando Devaka J. S.
Published: May 2007

Identifying twins for a population-based register can be achieved through birth records or community surveys. We studied the feasibility and effectiveness of different methods of identifying and recruiting twins to establish a population based register. To trace twins a population survey was carried out using an interviewer administered questionnaire. We also inspected the birth registration certificates at a divisional secretariat reported from a specified hospital between the years of 1985–1997 and compared it to the birth register of this same hospital. To recruit twins a random sample of 75 twin pairs (150 twins) identified at the Divisional Secretariat were contacted through the post and 25 twin pairs (50 twins) were personally visited. The prevalence of twins was 6.5 twins per 1000 people in the area surveyed. The twinning rate at the hospital was 18.92 twins per 1000 births. A discrepancy of 38 multiples births between the hospital labour room records and those registered at the DS was noted. The response from the postal invitation for recruitment was 59% and the response from the personal invitation was 68%. (Difference 9.4% 95% CI; 7.06–11.73). Community survey and systematic inspection of birth records either at the hospital or the birth registration office was an effective method to trace twins. Once traced, personal contact was more effective than the postal invitation for recruitment of younger twins. A cost-effective approach would be to use a postal coverage followed by personal contact for non-responders. The alternative method, community coverage, would have financial implications.
Are Twins and Singletons Comparable? A Study of Disease-related and Lifestyle Characteristics in Adult Women
Authors: Andrew Toby , Hart Deborah J. , Snieder Harold , de Lange Marlies , Spector Tim D. , MacGregor Alex J.
Published: May 2007

The classic twin study is sometimes described as “the perfect natural experiment” for the investigation of the aetiology of complex disease, but assumptions of the twin design need to be empirically tested if their results are to be considered unbiased and representative of singleton populations. In this study comparisons of disease and prevalence of lifestyle characteristics have been made between twin participants in the St Thomas' Hospital UK adult twin registry, the largest twin volunteer register in the UK for the study of diseases of ageing, and a parallel population-based study of singleton women. The only differences found were for weight, where monozygotic (MZ) twins were lighter and had a smaller variance than dizygotic (DZ) twins and singletons. For the other variables studied, volunteer twins were not found to differ from age-matched singleton women in distribution or prevalence of: bone mineral density, osteoarthritis, blood pressure, hypertensive drug use, height, history of hysterectomy and ovariectomy, menopausal status and current alcohol and overall tobacco consumption. We conclude that the results of twin studies can be generalised to singleton populations for these measures and disease outcomes.
Processing Asymmetry of Transitions between Order and Disorder in Human Auditory Cortex
Authors: Chait Maria , Poeppel David , de Cheveigné Alain , Simon Jonathan Z.
Published: May 2007

Auditory environments vary as a result of the appearance and disappearance of acoustic sources, as well as fluctuations characteristic of the sources themselves. The appearance of an object is often manifest as a transition in the pattern of ongoing fluctuation, rather than an onset or offset of acoustic power. How does the system detect and process such transitions? Based on magnetoencephalography data, we show that the temporal dynamics and response morphology of the neural temporal-edge detection processes depend in precise ways on the nature of the change. We measure auditory cortical responses to transitions between “disorder,” modeled as a sequence of random frequency tone pips, and “order,” modeled as a constant tone. Such transitions embody key characteristics of natural auditory edges. Early cortical responses (from ∼50 ms post-transition) reveal that order–disorder transitions, and vice versa, are processed by different neural mechanisms. Their dynamics suggest that the auditory cortex optimally adjusts to stimulus statistics, even when this is not required for overt behavior. Furthermore, this response profile bears a striking similarity to that measured from another order–disorder transition, between interaurally correlated and uncorrelated noise, a radically different stimulus. This parallelism suggests the existence of a general mechanism that operates early in the processing stream on the abstract statistics of the auditory input, and is putatively related to the processes of constructing a new representation or detecting a deviation from a previously acquired model of the auditory scene. Together, the data reveal information about the mechanisms with which the brain samples, represents, and detects changes in the environment.
Experience Improves Feature Extraction inDrosophila
Authors: Peng Yueqing , Xi Wang , Zhang Wei , Zhang Ke , Guo Aike
Published: May 2007

Previous exposure to a pattern in the visual scene can enhance subsequent recognition of that pattern in many species from honeybees to humans. However, whether previous experience with a visual feature of an object, such as color or shape, can also facilitate later recognition of that particular feature from multiple visual features is largely unknown. Visual feature extraction is the ability to select the key component from multiple visual features. Using a visual flight simulator, we designed a novel protocol for visual feature extraction to investigate the effects of previous experience on visual reinforcement learning inDrosophila. We found that, after conditioning with a visual feature of objects among combinatorial shape-color features, wild-type flies exhibited poor ability to extract the correct visual feature. However, the ability for visual feature extraction was greatly enhanced in flies trained previously with that visual feature alone. Moreover, we demonstrated that flies might possess the ability to extract the abstract category of “shape” but not a particular shape. Finally, this experience-dependent feature extraction is absent in flies with defective MBs, one of the central brain structures inDrosophila. Our results indicate that previous experience can enhance visual feature extraction inDrosophilaand that MBs are required for this experience-dependent visual cognition.
EphA4 Signaling Regulates Phospholipase Cγ1 Activation, Cofilin Membrane Association, and Dendritic Spine Morphology
Authors: Zhou Lei , Martinez Sarah J. , Haber Michael , Jones Emma V. , Bouvier David , Doucet Guy , Corera Amadou T. , Fon Edward A. , Zisch Andreas H. , Murai Keith K.
Published: May 2007

Specialized postsynaptic structures known as dendritic spines are the primary sites of glutamatergic innervation at synapses of the CNS. Previous studies have shown that spines rapidly remodel their actin cytoskeleton to modify their shape and this has been associated with changes in synaptic physiology. However, the receptors and signaling intermediates that restructure the actin network in spines are only beginning to be identified. We reported previously that the EphA4 receptor tyrosine kinase regulates spine morphology. However, the signaling pathways downstream of EphA4 that induce spine retraction on ephrin ligand binding remain poorly understood. Here, we demonstrate that ephrin stimulation of EphA4 leads to the recruitment and activation of phospholipase Cγ1 (PLCγ1) in heterologous cells and in hippocampal slices. This interaction occurs through an Src homology 2 domain of PLCγ1 and requires the EphA4 juxtamembrane tyrosines. In the brain, PLCγ1 is found in multiple compartments of synaptosomes and is readily found in postsynaptic density fractions. Consistent with this, PLC activity is required for the maintenance of spine morphology and ephrin-induced spine retraction. Remarkably, EphA4 and PLC activity modulate the association of the actin depolymerizing/severing factor cofilin with the plasma membrane. Because cofilin has been implicated previously in the structural plasticity of spines, this signaling may enable cofilin to depolymerize actin filaments and restructure spines at sites of ephrin–EphA4 contact.
Synaptic Ca2+in Darkness Is Lower in Rods than Cones, Causing Slower Tonic Release of Vesicles
Authors: Sheng Zejuan , Choi Sue-Yeon , Dharia Ajay , Li Jian , Sterling Peter , Kramer Richard H.
Published: May 2007

Rod and cone photoreceptors use specialized biochemistry to generate light responses that differ in their sensitivity and kinetics. However, it is unclear whether there are also synaptic differences that affect the transmission of visual information. Here, we report that in the dark, rods tonically release synaptic vesicles at a much slower rate than cones, as measured by the release of the fluorescent vesicle indicator FM1-43. To determine whether slower release results from a lower Ca2+sensitivity or a lower dark concentration of Ca2+, we imaged fluorescent indicators of synaptic vesicle cycling and intraterminal Ca2+. We report that the Ca2+sensitivity of release is indistinguishable in rods and cones, consistent with their possessing similar release machinery. However, the dark intraterminal Ca2+concentration is lower in rods than in cones, as determined by two-photon Ca2+imaging. The lower level of dark Ca2+ensures that rods encode intensity with a slower vesicle release rate that is better matched to the lower information content of dim light.
TRPC3 Channels Are Necessary for Brain-Derived Neurotrophic Factor to Activate a Nonselective Cationic Current and to Induce Dendritic Spine Formation
Authors: Amaral Michelle D. , Pozzo-Miller Lucas
Published: May 2007

Brain-derived neurotrophic factor (BDNF) exerts prominent effects on hippocampal neurons, but the mechanisms that initiate its actions are poorly understood. We report here that BDNF evokes a slowly developing and sustained nonselective cationic current (IBDNF) in CA1 pyramidal neurons. These responses require phospholipase C, IP3receptors, Ca2+stores, and Ca2+influx, suggesting the involvement of transient receptor potential canonical subfamily (TRPC) channels. Indeed,IBDNFis absent after small interfering RNA-mediated TRPC3 knockdown. The sustained kinetics ofIBDNFappears to depend on phosphatidylinositol 3-kinase-mediated TRPC3 membrane insertion, as shown by surface biotinylation assays. Slowly emerging membrane currents after theta burst stimulation are sensitive to the scavenger TrkB–IgG and TRPC inhibitors, suggestingIBDNFactivation by evoked released of endogenous, native BDNF. Last, TRPC3 channels are necessary for BDNF to increase dendritic spine density. Thus, TRPC channels emerge as novel mediators of BDNF-mediated dendritic remodeling through the activation of a slowly developing and sustained membrane depolarization.
Joint universality for sums and products of Dirichlet L-functions
Authors: Sander Jürgen , Steuding Jörn
Published: May 2007

We study analytic properties of certain sums and products of Dirichlet
On the speed of convergence to limit distributions for Hecke L-functions associated with ideal class characters
Authors: Matsumoto Kohji
Published: May 2007

We prove an upper bound estimate of the speed of convergence to limit distributions
Universal Taylor series on non-simply connected domains
Authors: Costakis George , Vlachou Vagia
Published: May 2007

In the present paper, we investigate the existence of universal Taylor series on certain non-simply connected domains. Moreover, we prove that Hadamard-Ostrowski gaps is a generic property in the space of holomorphic functions on a doubly connected domain.
On the zeros of T-universal functions
Authors: Nieß Markus
Published: May 2007

Let {

φ(

In this note we prove the existence of entire T-universal functions that have zeros at certain prescribed points and whose zeros are all known. In addition we will show that such functions may have a regular rate of growth of its zeros.
Uprighting Partially Impacted Permanent Second Molars
Authors: Sawicka Monika , Racka-Pilszak Bogna , Rosnowska-Mazurkiewicz Anna
Published: May 2007

Impaction of the lower second molar is not a common problem, but it is very challenging for both orthodontist and oral surgeon. Treatment options depend on the degree of tooth inclination, the position of the third molars, and the desired type of movement, which may be surgical and/or orthodontic in nature. A good treatment alternative is surgical uncovering with orthodontically-assisted eruption. A case of successful uprighting using a 0.017 × 0.025–inch titanium molybdenum alloy (TMA) tip-back cantilever is presented. Different aspects of uprighting impacted second molars are discussed in light of the literature. The iatrogenic character of lower second molar impaction is emphasized.
Shear Bond Strength Comparison between Two Orthodontic Adhesives and Self-Ligating and Conventional Brackets
Authors: Northrup Rodney G. , Berzins David W. , Bradley Thomas Gerard , Schuckit William
Published: May 2007

Objective: To evaluate and compare the shear bond strengths of two adhesives using two types of brackets: a conventional and a self-ligating bracket system.

Materials and Methods: Sixty extracted human premolars were collected. The premolars were randomly divided into three groups of 20 teeth. All three groups were direct bonded. Groups 1 and 2 used light-cured adhesive and primer (Transbond XT) with a conventional (Orthos) and a self-ligating bracket (Damon 2), respectively. Group 3 used a light-cured primer (Orthosolo) and a light-cured adhesive (Blūgloo) with a self-ligating bracket (Damon 2). The specimens were stored in distilled water at 37°C for 40 ± 2 hours, after which they were debonded and inspected for Adhesive Remnant Index (ARI) scoring.

Results: The mean shear bond strength was 15.2 MPa for group 1, 23.2 MPa for group 2, and 24.8 MPa for group 3. A one-way analysis of variance and post hoc Tukey test showed significant differences in bond strength (P < .001) between group 1 and groups 2 and 3 but no significant difference (P > .05) between groups 2 and 3. A Weibull analysis demonstrated that all three groups provided sufficient bond strength with over 90% survival rate at normal masticatory and orthodontic force levels. A Kruskal-Wallis test showed no significant difference (P > .05) in ARI scores among all three groups.

Conclusions: All three groups demonstrated clinically acceptable bond strength. The Damon 2 self-ligating bracket exhibited satisfactory in vitro bond strength with both adhesive systems used.
Long-Term Stability of Surgical Mandibular Setback
Authors: Cho Heon Jae
Published: May 2007

Objective: To test the relationship between positional changes of the proximal segments during surgery and the positional rebound of the mandible during the postsurgical period of orthodontic treatment.

Materials and Methods: The sample included records for 34 patients who had received sagittal split surgery for the correction of mandibular prognathism. Data were collected from standardized cephalometric radiographs taken immediately prior to surgery (T2), immediately following surgery (T3), and following the completion of orthodontic treatment (T4). Linear and angular changes in the orientation of the posterior border of the ascending ramus between time points T2, T3, and T4 were measured relative to superimposition on the anterior cranial base. In addition, linear changes in the position of pogonion between T3 and T4 were measured.

Results: The magnitude of linear displacement of the posterior border of the proximal segment during surgery (T2 to T3) was statistically significantly correlated (r = .61) with the magnitude of linear displacement of pogonion during the postsurgical phase of orthodontic treatment (T3 to T4). There was a strong relationship between the magnitude of angular (r = .67) displacement of the posterior border of the proximal segments during surgery (T2 to T3) and the magnitude of angular rebound of the posterior border of the proximal segments that occurred during the postsurgical phase of orthodontic treatment (T3 to T4).

Conclusions: When rigid fixation procedures alter the position of the proximal segments during sagittal split osteotomy of the mandible, the proximal segments tend to go back toward their presurgical positions following surgery.
Cytotoxicity of Two Bonding Adhesives Assessed by Three-Dimensional Cell Culture
Authors: Vande Vannet Bart Maurice Rene Antoine , Hanssens Jean Louis
Published: May 2007

Objective: To determine the toxicity of orthodontic adhesives assessed on in vitro three-dimensional reconstructed human oral epithelium (RHOE).

Materials and Methods: Two adhesive primers, Transbond XT (3M, Monrovia, Calif) and Excite (Vivadent, Schaan, Liechtenstein), were tested. After topical exposure, the cell cultures were fixed, cut, and stained for light microscopy (LM) and transmission electron microscopy (TEM). Detection of cytotoxicity by measuring lactate dehydrogenase (LDH) activity was performed. Toxicity was assessed by evaluating the morphological changes with LM and TEM. Copper wires and Triton X-100 served as positive controls, and native cell cultures as negative control.

Results: Morphological evaluation of the native cell cultures revealed no toxic reactions. The LDH assay revealed the following mean values for viability: native cell line (negative control), 1.51; Triton X-100 (positive control), 3.06; Transbond XT polymerized, 1.15; Excite polymerized, 1.11; Transbond XT primer, 2.67; and Excite primer, 0.04. Acute toxicity was observed for Triton X-100 and Transbond XT primer (P < .001). Histological evaluation of the RHOE showed toxicity for both primers and mild changes after topical application of polymerized adhesives. The biocompatibility ranking of the adhesive primers was the same after histological analysis and LDH assay except for Excite™ noncured.

Conclusions: RHOE proved to be a valuable model for topical exposure. The toxicity of both uncured primers was demonstrated.
Effect of Disinfecting Solutions on the Mechanical Properties of Orthodontic Elastomeric Ligatures
Authors: Evangelista Maylani B. , Berzins David W. , Monaghan Peter
Published: May 2007

Objective: To assess the effect extended exposure to disinfectant solutions has on the tensile load at failure and glass transition temperature (Tg) of orthodontic elastomeric ligatures.

Materials and Methods: Elastomeric ligatures from three manufacturers: Rocky Mountain Orthodontics (RMO, Denver, Colo), American Orthodontics (AO, Sheboygan, Wis), and 3M Unitek (3M, Monrovia, Calif) were exposed to two disinfectant solutions, Vital Defense-D and Cidexplus, for up to 28 days. Unexposed ligatures were also tested. Tensile load at failure was determined by stretching the ligatures using a universal testing machine until they fractured. Glass transition temperature was determined using differential scanning calorimetry (DSC).

Results: For tensile load at failure and glass transition temperature of the ligatures, significant differences were observed among the different manufacturers and exposure times. Type of disinfectant solution was a significant factor with Tg, but not with failure load. The 3M ligatures had the highest tensile load at failure and most positive Tg followed by AO and RMO, respectively. Compared to unexposed ligatures, strength significantly decreased after one hour of disinfectant exposure. Glass transition temperature was also significantly affected with extended disinfectant exposure, but the different disinfectants changed Tg in opposite directions.

Conclusion: Exposure of elastomeric ligatures to disinfectant solution for one hour or more decreases their strength.
Alterations of Temporomandibular Disorders before and after Orthognathic Surgery
Authors: Abrahamsson Cecilia , Ekberg Ewa Carin , Henrikson Thor , Bondemark Lars
Published: May 2007

Objective: To answer the question whether orthognathic surgery does affect the prevalence of signs and symptoms of temporomandibular disorders (TMDs).

Materials and Methods: A literature survey in the PubMed and Cochrane Library electronic databases was performed and covered the period from January 1966 to April 2006. The inclusion criteria were controlled, prospective or retrospective studies comparing TMDs before and after orthognathic surgery in patients with malocclusion. There were no language restrictions, and three reviewers selected and extracted the data independently. The quality of the retrieved articles was evaluated by four reviewers.

Results: The search strategy resulted in 467 articles, of which 3 met the inclusion criteria. Because of few studies with unambiguous results and heterogeneity in study design, the scientific evidence was insufficient to evaluate the effects that orthognathic surgery had on TMD. Moreover, the studies had problems with inadequate selection description, confounding factors, and lack of method error analysis.

Conclusion: To obtain reliable scientific evidence, additional well-controlled and well-designed studies are needed to determine how and if orthognathic surgery alters signs and symptoms of TMD.
External Bleaching Effect on the Color and Luminosity of Inactive White-Spot Lesions after Fixed Orthodontic Appliances
Authors: Knösel Michael , Attin Rengin , Becker Klaus , Attin Thomas
Published: May 2007

Objective: To evaluate the effect of external bleaching on the color and luminosity of inactive white-spot lesions (WSLs) present after fixed orthodontic appliance treatment as means for achieving color matching of the WSLs with adjacent tooth surfaces.

Materials and Methods: Ten patients with inactive WSLs after therapy with fixed orthodontic appliances were selected. At baseline, the lightness of maxillary incisors and canines was assessed with a colorimeter. Color determinations were performed in the area of the initial lesions (F1) and at adjacent, sound enamel areas (F2). Then, anterior teeth were bleached once with a bleaching gel for 60 minutes. After a break of 14 days, in-office bleaching was followed by a 2-week home bleaching period with daily home bleaching for 1 hour. After this, color determinations were repeated. Additionally, patients were asked to fill out a questionnaire to provide information about their degree of contentment with the treatment.

Results: The lightness values of both the F1 and F2 regions were significantly higher after bleaching as compared with baseline. F2 L-values increased significantly more as compared with F1, indicating a better color matching of these two areas in comparison with baseline. All patients were satisfied with the outcome of the bleaching therapy.

Conclusion: External bleaching is able to satisfactorily camouflage WSLs visible after therapy with fixed orthodontic appliances.
Perceptions of Orthognathic Surgery Patient's Change in Profile
Authors: Montini Reid W. , McGorray Susan P. , Wheeler Timothy T. , Dolce Calogero
Published: May 2007

Objectives: To compare pairs of silhouettes generated from presurgical and 5-year postsurgical cephalometric radiographs to evaluate whether orthodontists, oral surgeons, and lay persons perceive changes in profile resulting from orthodontics and mandibular advancement surgical treatment.

Materials and Methods: A survey-based method of data collection was used to evaluate 15 pairs of silhouettes. These silhouettes included 1 control pair and 14 surgically treated pairs representing mandibular advancements ranging from 0.11 mm to 10.13 mm. Collected data were analyzed to determine whether changes can be perceived and whether these changes were esthetically pleasing.

Results: The control silhouette pair was identified by 104 of 127 evaluators. For the 14 surgical treated silhouette pairs, the vast majority of evaluators (N = 127; 53 orthodontists, 32 oral surgeons, and 42 lay persons) were able to identify changes in profile and individual features. At least one group of evaluators was able to perceive significant (P < .05) improvement in the visual analog scale (VAS) score for all these silhouette pairs, except for the pair with 10.13 mm of mandibular advancement. This silhouette pair, which represented the largest mandibular advancement, was perceived to have a significant (P < .05) worsening in the VAS score by the lay person group. There were significant differences among the groups of evaluators. Esthetic improvement in profile was perceived for 13 of 14 surgically treated silhouette pairs.

Conclusion: In some cases, orthodontists, oral surgeons, and lay persons perceived changes in profile differently.
Short-term Anteroposterior Treatment Effects of Functional Appliances and Extraoral Traction on Class II Malocclusion
Authors: Antonarakis Gregory Stylianos , Kiliaridis Stavros
Published: May 2007

Objective: To evaluate the anteroposterior short-term skeletal and dental effects on Class II malocclusion in growing patients following treatment with functional appliances (activators or twin block), extraoral traction, or combination appliances (appliances with both functional and extraoral traction components), based on published data.

Materials and Methods: A literature search was carried out identifying a total of nine prospective clinical trials. The data provided in the publications underwent meta-analysis using the random effects model with regard to SNA, SNB, ANB, and overjet.

Results: All appliance groups showed an improvement in sagittal intermaxillary relationships (decrease in ANB) when compared to untreated subjects. Activators and twin block appliances accomplish this mainly by acting on the mandible (increases in SNB) while twin block appliances also seem to act on the maxilla (decrease in SNA). Extraoral traction appliances achieve this by acting on the maxilla (decreases in SNA). Combination appliances mainly act on the mandible (increase in SNB). Activators, twin block, and combination appliances also reveal a decrease in overjet, which is not the case in the singular use of extraoral traction.

Conclusions: Intermaxillary changes being present in all appliance groups, anteroposterior treatment response following the use of functional appliances and/or extraoral traction in growing class II malocclusion patients is most evident in one of the two jaws (mandible for activators and combination appliances and maxilla for extraoral traction) except for the twin block group, which shows changes on both jaws.
Pain Intensity and Discomfort Following Surgical Placement of Orthodontic Anchoring Units and Premolar Extraction
Authors: Feldmann Ingalill , List Thomas , Feldmann Hartmut , Bondemark Lars
Published: May 2007

Objective: To evaluate and compare perceived pain intensity and discomfort between the placement of two different orthodontic anchoring units designed for osseointegration and premolar extraction in adolescent patients.

Materials and Methods: A total of 120 adolescent patients (60 girls and 60 boys) were recruited and randomized into three groups. Group A underwent installation of an onplant, group B installation of an Orthosystem implant, and group C premolar extraction. Pain intensity and discomfort, analgesic consumption, limitations in daily activities, and functional jaw impairment were evaluated the first evening and one week after the intervention.

Results: Pain intensity following surgical installation of an onplant was comparable to the pain intensity experienced after premolar extraction, but there was significantly less pain after surgical installation of an Orthosystem implant compared to installation of an onplant (P = .002) or premolar extraction (P = .007). The protective, vacuum-formed stent caused great discomfort, even more discomfort than the surgical sites following installation of the onplant or the Orthosystem implant.

Conclusion: The Orthosystem implant was better tolerated than the onplant in terms of pain intensity, discomfort, and analgesic consumption and was, therefore, the anchorage system of choice in a short-term perspective.
A Comparison of Hand-wrist Bone and Cervical Vertebral Analyses in Measuring Skeletal Maturation
Authors: Gandini Paola , Mancini Marta , Andreani Federico
Published: May 2007

Objective: To compare skeletal maturation as measured by hand-wrist bone analysis and by cervical vertebral analysis.

Materials and Methods: A radiographic hand-wrist bone analysis and cephalometric cervical vertebral analysis of 30 patients (14 males and 16 females; 7–18 years of age) were examined. The hand-wrist bone analysis was evaluated by the Bjork index, whereas the cervical vertebral analysis was assessed by the cervical vertebral maturation stage (CVMS) method. To define vertebral stages, the analysis consisted of both cephalometric (13 points) and morphologic evaluation of three cervical vertebrae (concavity of second, third, and fourth vertebrae and shape of third and fourth vertebrae). These measurements were then compared with the hand-wrist bone analysis, and the results were statistically analyzed by the Cohen κ concordance index. The same procedure was repeated after 6 months and showed identical results.

Results: The Cohen κ index obtained (mean ± SD) was 0.783 ± 0.098, which is in the significant range. The results show a concordance of 83.3%, considering that the estimated percentage for each case is 23.3%. The results also show a correlation of CVMS I with Bjork stages 1–3 (interval A), CVMS II with Bjork stage 4 (interval B), CVMS III with Bjork stage 5 (interval C), CVMS IV with Bjork stages 6 and 7 (interval D), and CVMS V with Bjork stages 8 and 9 (interval E).

Conclusions: Vertebral analysis on a lateral cephalogram is as valid as the hand-wrist bone analysis with the advantage of reducing the radiation exposure of growing subjects.
A Self-Disinfecting Irreversible Hydrocolloid Impression Material Mixed with Chlorhexidine Solution
Authors: Wang Jian , Wan Qianbing , Chao Yonglie , Chen Yifan
Published: May 2007

Objective: To examine the antibacterial effect and several physical properties of an irreversible hydrocolloid impression material mixed with chlorhexidine solution.

Materials and Methods: The experimental irreversible hydrocolloid specimens were prepared and allocated into four groups (Group0.1 g/L, Group0.2 g/L, Group0.5 g/L, Group1.0 g/L) according to the concentrations of chlorhexidine solution used as the mixing liquid. Specimens mixed with distilled water served as a control. The antibacterial effect, three-dimensional accuracy, flowability, and setting time were tested. Statistical analysis was performed using a one-way analysis of variance and a Tukey test, which was used for multiple comparisons (α = .05).

Results: Zones of growth inhibition were observed around the test specimens, but not around the control specimens, and there were significant intergroup differences in the diameters of the inhibition zones. In the accuracy test, no significant differences (P > .05) were detected among all the measurements for all groups, and the accuracy was clinically acceptable. Also, no significant differences in the flowability (P = .987) and setting time (P = .103) were detected.

Conclusion: Chlorhexidine self-disinfecting irreversible hydrocolloid impression material can exhibit varying degrees of antibacterial activity without influencing the three-dimensional accuracy, flowability, and setting time.
Effects of Gradually Increasing Force Generated by Permanent Rare Earth Magnets for Orthodontic Tooth Movement
Authors: Tomizuka Ryo , Kanetaka Hiroyasu , Shimizu Yoshinaka , Suzuki Akihiro , Igarashi Kaoru , Mitani Hideo
Published: May 2007

Objective: To examine the effects of gradually increasing force generated by permanent rare earth magnets for orthodontic tooth movement by using a novel experimental rat model and computer simulation.

Materials and Methods: Fifty-five male rats (age 18 weeks) were used as animal experiments. Magnetic (experimental groups) or titanium (control group) cuboids (1.5 × 1.5 × 0.7 mm) were bonded to the lingual surface of the maxillary first molars. The initial distance between materials was 1.0 mm, generating 4.96 gf (experimental group I), or 1.5 mm, generating 2.26 gf (experimental group II). Tooth movement was measured and periodontal structures were observed with microfocus x-ray computed tomography radiographs.

Results: The distance between the magnets decreased with time in experimental groups I and II (P < .001), whereas there was no tooth displacement in the control group. Experimental group I showed rapid tooth movement in the initial phase followed by slower tooth movement. Experimental group II showed gradual tooth movement. Horizontal sections on microfocus computed tomgraphy radiographs revealed no pathological changes, such as root resorption, on the compressed side in the experimental groups.

Conclusions: The initial light force and gradual increasing force in magnetic attractive force induced effective tooth movement in rats without inducing any pathological changes.
Microbiological Evaluation of 0.2% Chlorhexidine Gluconate Mouth Rinse in Orthodontic Patients
Authors: Sari Emel , Birinci Ilhan
Published: May 2007

Objective: To assess the effectiveness of 0.2% chlorhexidine gluconate mouth rinse on Streptococcus mutans and lactobacilli in orthodontic patients with fixed appliances.

Materials and Methods: Twenty patients, aged 13–18, with fixed orthodontic appliances participated in the study. The levels of S mutans and lactobacilli in saliva samples were evaluated at four stages: at the beginning of the orthodontic treatment, at least 2 weeks after the bonding of brackets, 1 week after the introduction of 0.2% chlorhexidine gluconate mouth rinse, and at the fourth week. The changes in S mutans and lactobacilli levels were analyzed via Wilcoxon test.

Results: Increases in bacterial levels of S mutans and lactobacilli were detected after the orthodontic appliances were bonded. A significant decrease in S mutans levels was observed 1 week after the introduction of chlorhexidine mouth rinse.

Conclusions: An 0.2% chlorhexidine gluconate mouth rinse decreased S mutans levels, but had no effect on lactobacilli levels.
Developmentally Regulated Expression of Msx1, Msx2 and Fgfs in the Developing Mouse Cranial Base
Authors: Nie Xuguang
Published: May 2007

Objective: To examine the expression pattern of the Fgf and Msx genes in cranial base development.

Materials and Methods: To detect the expression of these genes, antisense riboprobes were synthesized by in vitro transcription. Radioactive in situ hybridization was performed on parasagittal sections of embryonic mouse heads.

Results: Msx2 was observed in the underlying perichondrium at restricted stages. Msx1 was not observed in cranial base development. Fgf1 was localized in osteogenic cells from the time of ossification; Fgf10 was highly expressed in the occipital-vertebral joint during E13 to E14; Fgf2, Fgf7, and Fgf18 were localized in the perichondria; Fgf12 was transitorily expressed at early chondrocranium; Fgf9 was seen in the hypertrophic chondrocytes.

Conclusions: The Fgf and Msx gene expression in the cranial base was different from that of other skeletons.
Treatment of a Patient with Metal Hypersensitivity after Orthognathic Surgery
Authors: Kitaura Hideki , Fujimura Yuji , Nakao Noriko , Eguchi Toshiko , Yoshida Noriaki
Published: May 2007

In this case report, orthodontic materials may have induced metal allergic reactions in the form of lip swelling and redness after orthognathic surgery. Two months after surgery, the patient suffered continuous lip swelling and redness. She visited a dermatological hospital and was diagnosed with herpes. However, since her symptoms did not improve after 1-month of drug therapy, a metal allergy was subsequently suggested. Patch tests conducted in the dental hospital revealed reactions to chromium, which is not used in prosthetic appliances. For confirmation, the metal composition of all prosthetic appliances was examined using a fluorescent x-ray analyzer, but no chromium was detected (copper, gold, palladium, and silver were detected). However, the orthodontic brackets, wires, and bands do contain chromium and, considering that they may have induced the metal allergic reactions, they were replaced with materials made of polymer with no metals. As a result, the lip swelling and redness improved. For retention, the anterior part of the retainer was bonded on the lingual side of the anterior lower and upper jaws. During retention, no further symptoms of hypersensitivity were observed, suggesting that the nonmetal polymer is useful for treatment of metal allergic patients.
Interdisciplinary Treatment of an Adult Patient with Old Extraction Sites
Authors: Taner Tülin Ugur , Germec Derya , Er Nuray , Tulunoglu Ibrahim
Published: May 2007

This case report describes the interdisciplinary treatment of a 31-year-old female patient showing a protrusive profile, maxillary constriction, mandibular crowding, a Class III canine relationship complicated with multiple missing teeth, old atrophic extraction sites, and periodontal defects. The lower dental arch irregularity was eliminated by air-rotor stripping (ARS). The upper extraction site was opened for prosthetic rehabilitation, whereas closure of the lower extraction space was preferred. The narrow alveolar crest of the atrophic bone was augmented with the use of autogenous bone, beta-tricalcium phosphate (Cerasorb®), and autogenous platelet-rich plasma. A functional and esthetic occlusion in an improved facial profile was established at the end of orthodontic treatment combined with ARS technique, surgery, and prosthodontics.