bluuebunny/crossref_metadata_2025 huggingface dataset:
Explaining differences in sport participation rates among young adults: Evidence from the South Caucasus
Authors: Birchwood Diane , Roberts Ken , Pollock Gary
Published: January 2009

This paper presents and discusses evidence about the sport careers of representative samples of 31—37 year olds from the capital city and a comparator region in each of the three South Caucasus countries —Armenia, Azerbaijan and Georgia. This is one of the few surveys to measure sport participation that allows change over time at the aggregate and individual levels to be distinguished. The evidence suggests that many differences in sport participation rates that are commonly attributed to circumstances and experiences after age 16 (higher education, for example) already exist at age 16, and that family cultures are the source of crucial predispositions to participate which have lasting effects. The evidence, from countries that up to 1991 shared the Soviet education and sport systems, also suggests that ethnic/national cultures that predate communism have outlived communism and are now a major explanation of inter-country differences in rates of sport participation in the South Caucasus. Finally, the evidence indicates that sport facilities do indeed make a difference, but only by enabling those who are predisposed to take part in sport.
Children's motivational experiences following autonomy-supportive games lessons
Authors: Mandigo James , Holt Nicholas , Anderson Andy , Sheppard Joanna
Published: January 2009

The objectives of this study were (a) to examine students' motivational experiences arising from their participation in games lessons based on autonomy-supportive strategies; and (b) to examine the interaction between boys' and girls' motivational experiences across different categories of games. A total of 759 students (380 F, 379 M) from 37 classes (grades four to seven) were taught a lesson from one of four game categories (i.e. target, net/wall, batting/fielding, invasion) using autonomy-supportive techniques. Following the lessons children completed various measures to assess their motivational experiences. Significant between-subject differences did emerge for both gender and games category. Girls reported higher levels of optimal challenge, perceived autonomy-support, and enjoyment whereas boys reported higher levels of perceived competence. For the games category, participants reported higher levels of self-determined motivation in net/wall games whereas invasion games received the lowest motivational ratings of the four games categories.
Developing a Culture of Evaluation in the Irish Public Sector
Authors: McNamara Gerry , O'Hara Joe , Boyle Richard , Sullivan Conor
Published: January 2009

This article is a case study of the emergence of an evaluation culture in the public sector and particularly in education in Ireland. It suggests that the emergence of this culture was strongly influenced by external bodies, particularly the EU and, to a lesser but significant degree, the OECD. It is further argued that the continuation of systematic evaluation is still dependent on external forces, since a commitment to evaluation as a tool of governance has not taken hold among key policy-makers in Ireland. However it is postulated that, notwithstanding its arguably insecure foundations, evaluation practice has moved beyond the confines of externally funded EU programmes, which saw its first introduction into Ireland. In recent years a broad quality assurance agenda within the public service and to an extent beyond has emerged.The article concludes by making the point that an evaluation culture in a particular country is hugely contextualized and influenced by the constraints of existing ideologies and relationships between different interest groups.Thus, in Ireland, in line with the corporatist and partnership-driven approaches to economic policy and industrial relations which have been dominant in recent decades, the form of evaluation which has emerged is consensual, collaborative and negotiated.
Realistic Evaluation and Case Studies
Authors: Kœnig Gerard
Published: January 2009

Embedded in the critical realist tradition, this article aims to explore the potentialities of the case study for evaluation purposes when complexity and specificity are moderate.Three objectives are pursued. First, it is stated that the focus of the evaluation effort is not necessarily the programme itself, but can be one premise upon which the programme is built. Second, taking into account Donald Campbell's contributions, it is asserted that, under favourable conditions, not only deterministic propositions, but also probabilistic ones can be rejected as highly improbable via case studies. Third, making use of the Context—Mechanism—Outcome model proposed by Pawson and Tilley, this article demonstrates the capacity of a critical case study to sustain theory building.
Empowerment Evaluation for Violence Prevention Public Health Programs
Authors: Goodman Robert M. , Noonan Rita K.
Published: January 2009

The formative evaluation consultation and systems technique (FORECAST) approach to evaluating complex community programs is described as an empowerment evaluation strategy. First, empowerment evaluation is defined and contrasted with more-traditional approaches, such as experimental and quasi-experimental designs. Then FORECAST is described, illustrating how it was applied in four community projects. One of the projects is used to demonstrate the application of FORECAST evaluation in programs addressing the prevention of first-time male perpetration of sexual violence.
“Like a Family but Better Because You Can Actually Trust Each Other”
Authors: Ball Barbara , Kerig Patricia K. , Rosenbluth Barri
Published: January 2009

Expect Respect, a teen dating violence prevention program, was among four programs selected by the Centers for Disease Control and Prevention to participate in an empowerment evaluation project. As one aspect of this project, a qualitative study was designed to investigate the effects of Expect Respect support groups for at-risk youth. The goal was to understand the “how and why” of the program's impact on participants. Group interviews were conducted with five boys' and five girls' support groups after completion of the program. Settings included public middle and high schools and alternative schools in juvenile detention. Participants were asked to describe significant learning experiences in support groups as well as changes in their relationships resulting from program participation. Youths across all groups reported learning new skills including improved communication, anger control, and alternatives to violence. They reported increased knowledge about healthy relationships and warning signs of dating violence and expanded awareness of their own and others' abusive behaviors. Changed relationship norms were uniquely expressed by a boys' group in juvenile detention. Findings indicate that the experience of emotional safety in groups and positive relationships among group members were instrumental in the learning process.
Empowerment Evaluation With Programs Designed to Prevent First-Time Male Perpetration of Sexual Violence
Authors: Noonan Rita K. , Gibbs Deborah
Published: January 2009

This special issue captures several threads in the ongoing evolution of sexual violence prevention. The articles that follow examine an empowerment evaluation process with four promising programs dedicated to preventing first-time male perpetration of sexual violence, as well as evaluation findings. Both the evaluation approach and the programs examined shed light on how sexual violence prevention can continue to be improved in the future.
Refractory In-stent Restenosis Following Carotid Artery Stenting: A Case Report and Review of Operative Management
Authors: King Brian N. , Scher Larry A. , Lipsitz Evan C.
Published: January 2009

In-stent restenosis following carotid artery stenting is a challenging problem that vascular surgeons will likely encounter with increasing frequency. The following describes a patient who developed progressive in-stent restenosis 3 years after carotid artery stenting, which was treated with operative therapy after failed balloon angioplasty. A review of the literature describing surgical approaches to the treatment of in-stent restenosis was also performed.
Autogenous Arterial and Venous Reconstruction for Femoral Vein Leiomyosarcoma—A Case Report
Authors: Propper Brandon , Zonies David , Smith David , Rasmussen Todd E.
Published: January 2009

This report describes the removal of a large, symptomatic leiyomyosarcoma arising from the proximal femoral vein necessitating removal of the femoral venous and arterial circulations. Reconstruction was accomplished with autologous vein and initial coverage with ipsilateral rectus abdominus flap. Persistent, early postoperative lymphatic leak and groin sepsis secondary to staph aureus was managed with reoperation and coverage with contralateral rectus abdominus muscle flap. Negative pressure dressing device was used as a wound management adjunct and splint thickness skin graft providing final successful coverage. Two years following the operation the patient was without evidence of disease, had a patent vascular reconstruction and a well healed groin. Femoral vein leiyomyosarcoma is a rare vascular tumor, which is especially challenging to manage in the proximal location. Successful outcome is predicated on revascularization with autologous vein and on a multidisciplinary approach using various soft tissue coverage strategies and wound management adjuncts.
Endovascular Treatment for Traumatic Popliteal Artery Pseudoaneurysms After Knee Arthroplasty
Authors: Sloan Keren , Mofidi Reza , Nagy John , Flett Murray M. , Chakraverty Sam
Published: January 2009

Trauma to the popliteal artery is a recognized complication of knee arthroplasty (total knee arthroplasty). It can present in a variety of ways, one of which is the development of popliteal artery pseudoaneurysm. We report the successful endovascular management of 2 patients who developed popliteal artery pseudoaneurysms following total knee arthroplasty using covered stent grafts. From presented evidence, endovascular therapy is a safe treatment modality and it appears to be a viable alternative to open surgery.
Heparan Sulfate Interacting Protein (HIP/L29) Negatively Regulates Growth Responses to Basic Fibroblast Growth Factor in Gingival Fibroblasts
Authors: Ta T.-V. , Baraniak D. , Julian J. , Korostoff J. , Carson D.D. , Farach-Carson M.C.
Published: January 2009

Basic fibroblast growth factor (bFGF) modulates gingival growth, and its release from heparan sulfate (HS) in the extracellular matrix (ECM) governs local tissue bioavailability. We identified a heparin/HS interacting protein (HIP/L29) that recognizes specific HS sequences. We hypothesize that HIP/L29, by modulating the interactions of bFGF with HS chains on proteoglycans, could regulate bFGF bioavailability. To investigate interactions between bFGF and HIP/L29, we isolated and cultured fibroblasts from normal gingiva and overgrown gingiva from patients on cyclosporine (CSA). bFGF significantly stimulated gingival fibroblast proliferation with or without heparin. Recombinant human HIP/L29 dramatically decreased bFGF-induced proliferation, but did not alter responses to insulin-like growth factor-1 (IGF-1). Analysis of mitogen-activated protein kinase (MAPK) phosphorylation patterns showed that bFGF stimulation of p44 (Erk-1), but not p42 (Erk-2), also was inhibited by HIP/L29 in a dose-dependent manner. Together, these results support our hypothesis that HIP/L29 modulates the bioavailability and action of bFGF.
Components of Dentinal Adhesives Modulate Heat Shock Protein 72 Expression in Heat-stressed THP-1 Human Monocytes at Sublethal Concentrations
Authors: Noda M. , Wataha J.C. , Kaga M. , Lockwood P.E. , Volkmann K.R. , Sano H.
Published: January 2009

Few studies have investigated the ability of dental resins to induce cellular stress at sublethal concentrations. Cellular stress, especially in immune cells such as monocytes, may modulate the biological response to materials or the host's ability to respond to bacterially mediated inflammation. The current study examined the ability of sublethal concentrations of 2-hydroxylethylmethacrylate (HEMA) and triethyleneglycol dimethacrylate (TEGDMA) to induce heat shock protein 72 (HSP72) in human monocytes. HEMA and TEGDMA significantly suppressed heat-induced HSP72 expression, even at sublethal levels, but did not induce HSP72 by themselves. The results of the current study suggest that components released from dental resin could modulate the HSP stress response without altering cellular metabolic activity.
The Role of MSX1 in Human Tooth Agenesis
Authors: Lidral A.C. , Reising B.C.
Published: January 2009

MSX1 has a critical role in craniofacial development, as indicated by expression assays and transgenic mouse phenotypes. Previously, MSX1 mutations have been identified in three families with autosomal-dominant tooth agenesis. To test the hypothesis that MSX1 mutations are a common cause of congenital tooth agenesis, we screened 92 affected individuals, representing 82 nuclear families, for mutations, using single-strand conformation analysis. A Met61Lys substitution was found in two siblings from a large family with autosomal-dominant tooth agenesis. Complete concordance of the mutation with tooth agenesis was observed in the extended family. The siblings have a pattern of severe tooth agenesis similar that in to previous reports, suggesting that mutations in MSX1 are responsible for a specific pattern of inherited tooth agenesis. Supporting this theory, no mutations were found in more common cases of incisor or premolar agenesis, indicating that these have a different etiology.
Determining the Explanatory Potential of Variables
Authors: Abraham D. , Bronkhorst E.M. , Truin G.J. , Severens J.L. , Felling A.J.A.
Published: January 2009

A meta-analysis may not be the most appropriate method for the extraction of information on independent variables from the scientific literature. A formal quantitative review method is proposed for reducing a literature review variable list to a manageable list of explanatory variables. The proposed method synthesizes the information in a standard literature review into two steps. First, the hypothesis “independent variable ‘X’ had no effect on utilization” is tested by means of binomial, one-sided testing. If it is rejected, then the hypothesis “The effect of independent variable ‘X’ is as likely to be in the same direction as it is to be in the opposite direction” is tested, by an extended version of the binomial formula. In two steps, the presence of a consistent direction of significant effects is calculated. This method is tested on dental utilization publications. It is concluded that the method is an effective tool for the creation of a manageable variable list.
The IADR Missions: Promoting Dental Research
Authors: Clarkson John
Published: January 2009

This is the text of the IADR President-elect's address, delivered on March 6, 2002, during the Opening Ceremonies of the 80th General Session of the International Association for Dental Research, San Diego, CA.
P. gingivalis-specific T-cell Lines Produce Th1 and Th2 Cytokines
Authors: Gemmell E. , Carter C.L. , Grieco D.A. , Sugerman P.B. , Seymour G.J.
Published: January 2009

Cytokines produced by T-cells in periodontal lesions may determine the nature of the adaptive immune response. Since different antigen-presenting cells (APC) may direct the Th1/Th2 response, P. gingivalis-specific T-cell lines were established by different APC subpopulations, and their cytokine profiles were determined. Peripheral blood mononuclear cells induced similar percentages of IL-4+ and IFN-gamma+ T-cells and lower percentages of IL-10+ T-cells. Epstein-Barr virus-transformed B-cells (LCL) induced higher percentages of IL-4+ cells than IFN-gamma+ cells, with lower percentages of IL-10+ cells. Peripheral blood mononuclear cells induced a higher percent of IFN-gamma+ CD8 cells than LCL (p = 0.004). Purified B-cells, monocytes, and dendritic cells induced similar percentages of IL-4+ and IFN-gamma+ cells, although again, the percentage of IL-10+ cells was lower. The results of the present study have demonstrated that, as measured by FACS analysis of intracytoplasmic cytokines, P. gingivalis-specific T-cells produce both Th1 and Th2 cytokines, regardless of the APC population.
Severe Impairment of Secretory Ig Production in Parotid Saliva of Down Syndrome Individuals
Authors: Chaushu S. , Yefenof E. , Becker A. , Shapira J. , Chaushu G.
Published: January 2009

Infections associated with Down Syndrome (DS) are prevalent in the mucosal-gastrointestinal and respiratory systems, for reasons that are uncertain. The purpose of the present study was to assess the levels of parotid salivary immunoglobulins (Ig) in a group of DS individuals as a possible factor in the susceptibility of mucosal surfaces to infections. Twenty-nine DS and 10 age- and sex-matched healthy individuals were included. Salivary flow rate and IgA, IgG, and IgM concentrations were recorded. The secretion rates of IgA and IgG were diminished by 83% (p < 0.001) and 75% (p = 0.05), respectively, whereas the secretion rate of IgM was not statistically significantly lower. Analysis of the data suggests that DS individuals are immunodeficient in the humoral mucosal immune response. This may explain, in part, the high incidence of recurrent infections in target organs of the secretory immune system in DS subjects.
Fluoride Uptake, Retention, and Remineralization Efficacy of a Highly Concentrated Fluoride Solution on Enamel Lesions in situ
Authors: Buchalla W. , Attin T. , Schulte-Mönting J. , Hellwig E.
Published: January 2009

Repeated topical application of concentrated fluorides is known to reduce caries. Little is known about fluoride retention and remineralization in incipient caries lesions following a single application. We investigated fluoride and the remineralization kinetics of a single application of elmex® fluid (GABA International AG, Münchenstein, Switzerland; 10,000 ppm F) in initial enamel lesions. In this double-blind, placebo-controlled, randomized, crossover in situ study that conformed to good clinical practice, volunteers received intra-oral removable appliances carrying demineralized enamel samples after application of elmex fluid or placebo. After 5 min, 1, 2, 3, and 4 weeks in situ, KOH-soluble fluoride (KOHF), structurally bound fluoride (SBF), mineral gain, and lesion depth reduction were measured. Elmex fluid promoted higher KOHF and SBF at all times, decreased KOHF with time, increased SBF up to 3 weeks, and registered a higher mineral gain than placebo. Volunteers with higher stimulated salivary flow rates had lower fluoride uptake, but higher mineral gain. In conclusion, a single application of highly concentrated fluoride solution increases remineralization.
Hormonal Regulation of Androgen Receptor Messenger Ribonucleic Acid Expression in Human Tooth Pulp
Authors: Dale J.B. , Sarich S.L. , Bretz T.M. , Hatton J.F. , Zachow R.J.
Published: January 2009

Tooth pulp contains steroid receptors and therefore is likely to respond to steroids. Steroids and cytokines together can alter steroid receptor content in many tissues; thus, similar mechanisms may exist in tooth pulp. In this study, reverse-transcription/polymerase chain-reaction was used to screen human pulp for the mRNAs encoding receptors for androgen (AR), estrogens (ERβ), and hepatocyte growh factor (HGF: c-Met). AR mRNA content was greater in male pulp vs. female pulp in all age groups. In both genders, AR mRNA content diminished with age. In pulp cell cultures, androstenedione, estradiol-17β, and HGF each stimulated AR mRNA accumulation. Testosterone inhibited, whereas 5α-dihydrotestosterone did not affect, AR mRNA content. ERβ was not hormonally altered in pulp cell cultures. By showing steroid- and cytokine-orchestrated regulation of AR mRNA in vitro, it is possible that age- and/or pathogen-dependent changes in available steroids and cytokines can affect any androgen-responsiveness of pulp.
Disquieting Change– Extraordinary Challenge
Authors: Bertolami Charles
Published: January 2009

This is the text of the AADR President-elect's address, delivered on March 6, 2002, during the Opening Ceremonies of the International and American Associations for Dental Research, 80th General Session and 31st Annual Meeting, respectively, in San Diego, CA.
The Expression of Dentin Sialophosphoprotein Gene in Bone
Authors: Qin C. , Brunn J.C. , Cadena E. , Ridall A. , Tsujigiwa H. , Nagatsuka H. , Nagai N. , Butler W.T.
Published: January 2009

Dentin sialoprotein (DSP) and dentin phosphoprotein (DPP) are expressed as a single mRNA transcript coding for a large precursor protein termed dentin sialophosphoprotein (DSPP). DSP, DPP, and DSPP have been considered to be tooth-specific. To test for the expression of the dspp gene in bone, we performed Western immunoblots and reverse-transcription polymerase chain-reaction (RT-PCR). With Western immunoblots, we detected DSP in the Gdm/EDTA extracts of rat long bone, at a level of about 1/400 of that in dentin. Using RT-PCR, we detected DSPP mRNA in mouse calvaria. Similar to Western immunoblots, the results of RT-PCR indicated that the dspp gene is expressed at a lower level in bone than in dentin and odontoblasts. Analysis of the data shows that DSPP is not a tooth-specific protein, and that dramatically different regulatory mechanisms governing DSPP expression are involved in the bone and dentin.
Identification of Genes Differentially Expressed in Cultured Human Periodontal Ligament Fibroblasts vs. Human Gingival Fibroblasts by DNA Microarray Analysis
Authors: Han X. , Amar S.
Published: January 2009

Despite their similar spindle-shaped appearance, periodontal ligament fibroblasts (PDLF) and gingival fibroblasts (GF) appear to display distinct functional activities in the maintenance of tissue integrity and during inflammatory/immune responses. We postulated that different characteristics of PDLF and GF are defined by the differential expression of specific genes. To test this, we investigated the possible variance of gene expression profile between cultured PDLF and GF, using DNA microarray technology. One hundred sixty-three genes were found differentially expressed by at least three-fold between PDLF and GF. Genes encoding transmembrane proteins and cytoskeleton-related proteins tended to be up-regulated in PDLF, whereas genes encoding cell-cycle regulation proteins and metabolism-related proteins tended to be up-regulated in GF. We concluded that PDLF and GF appear to display different gene expression patterns that may reflect intrinsic functional differences of the two cell populations and may well coordinate with their tissue-specific activities.
Volume Changes in Human Masticatory Muscles between Jaw Closing and Opening
Authors: Goto T.K. , Tokumori K. , Nakamura Y. , Yahagi M. , Yuasa K. , Okamura K. , Kanda S.
Published: January 2009

Most jaw muscles are complex, multipennate with multiple components. The morphologic heterogeneity of masticatory muscles reflects their functions. We hypothesized that the volume of masticatory muscles changes between jaw closing and opening, and that there is a difference in the volume change among the muscles. Magnetic resonance images of the entire head were obtained in ten normal young adult subjects before and after maximum jaw opening. The volume changes of the masseter, medial, and lateral pterygoid muscles were measured. Only slight changes were seen in the masseter and medial pterygoid muscles. The lateral pterygoid muscle, however, significantly decreased its volume during jaw opening. The results provide normative values of muscle volume in living subjects, and suggest that the volume changes differ among jaw muscles.
Validity and Reliability of a Questionnaire for Measuring Child Oral-health-related Quality of Life
Authors: Jokovic A. , Locker D. , Stephens M. , Kenny D. , Tompson B. , Guyatt G.
Published: January 2009

Oral-health-related quality of life measures that exist are designed for adults. This study aimed to develop and evaluate the CPQ11-14, a self-report measure of the impact of oral and oro-facial conditions on 11- to 14-year-old children. An item pool was generated with the use of a literature review and interviews with health professionals, parents, and child patients. The 36 items rated the most frequent and bothersome by 83 children were selected for the CPQ11-14. Validity testing involved a new sample of 123 children. Test-retest reliability was assessed in a subgroup of these children (n = 65). Mean CPQ11-14 scores were highest for oro-facial (31.4), lower for orthodontic (24.3), and lowest for pedodontic (23.3) patients. There were significant associations between the CPQ11-14 score and global ratings of oral health (p < 0.05) and overall well-being (p < 0.01). The Cronbach's alpha and intraclass correlation coefficient for the CPQ11-14 were 0.91 and 0.90, respectively. These results suggest that the CPQ11-14 is valid and reliable.
A 13C NMR Study on the Adsorption Characteristics of HEMA to Dentinal Collagen
Authors: Nishiyama N. , Suzuki K. , Komatsu K. , Yasuda S. , Nemoto K.
Published: January 2009

To develop a more effective primer, we must understand how 2-hydroxyethylmethacrylate, the HEMA primer, enhances bonding at the resin-dentin interface. In this study, to obtain an insight into the adhesion mechanisms of adhesive resin to etched dentin through HEMA, we examined the adsorption characteristics of HEMA to dentinal collagen by using the 13C NMR technique. The addition of dentinal collagen to the HEMA solution resulted in a decrease in T 1 values of carbons attributed to the HEMA, thus reflecting an interaction between HEMA and collagen. Specifically, a reduction in the T 1 value in the ester carbonyl carbon attributed to HEMA greater than that in the other carbons suggested the formation of a hydrogen bond between the ester carbonyl group in HEMA and the dentinal collagen.
Two Modes of Nanoleakage Expression in Single-step Adhesives
Authors: Tay F.R. , Pashley D.H. , Yoshiyama M.
Published: January 2009

Self-etch adhesives that etch, prime, and bond simultaneously should not exhibit incomplete resin infiltration within hybrid layers. We hypothesized that nanoleakage patterns in these systems are artifacts caused by mineral dissolution in mildly acidic silver nitrate. Resin-dentin interfaces bonded with four single-step, self-etch adhesives were examined for nanoleakage by conventional (pH 4.2) and basic ammoniacal (pH 9.5) silver nitrate and prepared for transmission electron microscopy. All adhesives exhibited a reticular mode of nanoleakage within hybrid layers when conventional silver nitrate was used. With ammoniacal silver nitrate, an additional spotted pattern of nanoleakage was observed within adhesive and hybrid layers. The reticular mode of nanoleakage in self-etch adhesives probably represents sites of incomplete water removal that leads to regional suboptimal polymerization. The spotted pattern identified with the use of ammoniacal silver nitrate probably represents potentially permeable regions in the adhesive and hybrid layers that result from the interaction of the basic diamine silver ions with acidic/hydrophilic resin components.
Reversal of Compromised Bonding in Bleached Enamel
Authors: Lai S.C.N. , Tay F.R. , Cheung G.S.P. , Mak Y.F. , Carvalho R.M. , Wei S.H.Y. , Toledano M. , Osorio R. , Pashley D.H.
Published: January 2009

Oxygen inhibits polymerization of resin-based materials. We hypothesized that compromised bonding to bleached enamel can be reversed with sodium ascorbate, an anti-oxidant. Sandblasted human enamel specimens were treated with distilled water (control) and 10% carbamide peroxide gel with or without further treatment with 10% sodium ascorbate. They were bonded with Single Bond (3M-ESPE) or Prime&Bond NT (Dentsply DeTrey) and restored with a composite. Specimens were prepared for microtensile bond testing and transmission electron microscopy after immersion in ammoniacal silver nitrate for nanoleakage evaluation. Bond strengths of both adhesives were reduced after bleaching but were reversed following sodium ascorbate treatment (P < 0.001). Resin-enamel interfaces in bleached enamel exhibited more extensive nanoleakage in the form of isolated silver grains and bubble-like silver deposits. Reduction of resin-enamel bond strength in bleached etched enamel is likely to be caused by a delayed release of oxygen that affects the polymerization of resin components.
Cystic Fibrosis Transmembrane Regulator Gene (CFTR) is Associated with Abnormal Enamel Formation
Authors: Arquitt C.K. , Boyd C. , Wright J.T.
Published: January 2009

Cystic fibrosis (CF), a chloride ion transport disorder, is caused by mutations of the cftr gene and is the most common autosomal-recessive heritable disease in Caucasians. CFTR knockout mice have enamel with crystallite defects, retained protein, and hypomineralization, suggesting a role for CFTR in enamel formation and mineralization. This investigation examined CFTR expression and elemental composition in developing murine incisor teeth. RT-PCR showed cftr mRNA expression in the normal mouse apical incisor tissue but not in the CFTR knockout tissue. Elemental analysis by energy-dispersive x-ray spectroscopy showed relatively decreased chloride in secretory-stage CF enamel. Iron and potassium were significantly increased, and calcium was significantly decreased ( p value = 0.05) in the CF mature enamel. Abnormal enamel mineralization, ion concentrations, and molecular evidence of cftr mRNA expression by odontogenic cells strongly suggest that CFTR plays an important role in enamel formation.
Amelogenin is a Cell Adhesion Protein
Authors: Hoang A.M. , Klebe R.J. , Steffensen B. , Ryu O.H. , Simmer J.P. , Cochran D.L.
Published: January 2009

Amelogenin, the major protein component of tooth enamel, is shown to be a cell adhesion protein. Since it had been shown that an amelogenin-containing preparation, Emdogain®, possessed cell-adhesive activity, we tested the hypothesis that amelogenin was responsible for cell-adhesive activity. Recombinant amelogenin was found to promote adhesion at less than 15 μg/60-mm plate and requires divalent cations for activity. While we found that amelogenin does not bind to collagen or heparin under physiological conditions, it was demonstrated previously that amelogenin does bind to hydroxyapatite. The cell-adhesive activity of amelogenin may play a role in development and may provide a partial explanation for the therapeutic effects of Emdogain® in periodontal regeneration.
Novel Sucrose-dependent Adhesion Co-factors in Streptococcus mutans
Authors: Tao L. , Tanzer J.M.
Published: January 2009

Streptococcus mutans glucosyltransferases form extracellular glucans from sucrose to promote adhesion to the teeth. We tested whether additional factors are involved in S. mutans sucrose-dependent adhesion. By screening a pVA891-insertion mutant library of S. mutans LT11, we isolated four clones deficient in adhesion to glass in the presence of sucrose, but normal in glucosyltransferase activities. The genetic loci flanking the insertion sites were retrieved and identified. They encode glycerol-3-phosphate dehydrogenase, an ABC transporter, a multidrug-efflux pump, and either the ribulose monophosphate operon or ascorbate metabolism operon. The four mutants were analyzed for their phenotypic expression and in vivo colonization in rats. The multidrug efflux pump mutant failed to colonize the rats. Three other mutants colonized the rats by reverting to the wild type. Therefore, these four factors may contribute to S. mutans sucrose-dependent adhesion.
Biglycan is a Repressor of Amelogenin Expression and Enamel Formation: An Emerging Hypothesis
Authors: Goldberg M. , Septier D. , Rapoport O. , Young M. , Ameye L.
Published: January 2009

The authors suggest that biglycan acts as a repressor of the expression of amelogenin in the two unique groups of cells involved in amelogenin synthesis, namely, the secretory ameloblasts and odontoblasts.
R-Curve Behavior of Dental Ceramic Materials
Authors: Fischer H. , Rentzsch W. , Marx R.
Published: January 2009

Some technical ceramics exhibit the R-curve effect, i.e., an increasing fracture resistance with crack extension which is a desirable material property because more energy is necessary to propagate a microscopic crack. The objective of this study was to prove whether dental ceramic materials exhibit R-curve behavior. Nine dental ceramics were examined by the indentation-strength method. It was found that all of the tested ceramic materials exhibt a rising R-curve with crack extension. The R-curve behavior was more pronounced for the high-strength materials In-Ceram Alumina, monolithic alumina, and especially Empress 2. We conclude from our results that the mechanical behavior of a dental ceramic material can be judged more comprehensively, if the R-curve of the respective material is known.
Infrared Spectrometric Study of Acid-degradable Glasses
Authors: De Maeyer E.A.P. , Verbeeck R.M.H. , Vercruysse C.W.J.
Published: January 2009

The composition of glasses used in glass-ionomer cements affects their leaching behavior and hence the properties of the cement. The aim of this study was to correlate the composition and leaching behavior of these glasses with their infrared absorption characteristics. The wavenumber of the absorption band of the Si-O asymmetric stretching vibration ῡAS shifts to a higher value with decreasing content of mono- and bivalent cations in the glass. This effect can be ascribed to the influence of these extraneous ions on the glass network order and connectivity. Preferential leaching of these ions induces an increase of ῡAS and a general modification of the band profile. The results can be correlated with the x-ray diffraction characteristics of the glass.

A decrease in the Si-O-Si angle could be caused by a decrease in the distortions in the (arrangement of the) SiO4 tetrahedra; the tetrahedra as well as their arrangement can be distorted.
Predicting Caries in Permanent Teeth from Caries in Primary Teeth: An Eight-year Cohort Study
Authors: Li Y. , Wang W.
Published: January 2009

Several cross-sectional studies report that caries in primary teeth is correlated with caries in permanent teeth. This eight-year cohort study sought to determine if caries in the primary dentition can predict caries in the permanent dentition of the same individuals and, if so, with what degree of prediction accuracy. A total of 362 Chinese children, from 3 to 5 years old at the time of the 1992 baseline study, were re-examined in 2000. The study found statistically significant associations between caries prevalence in primary and permanent dentitions (p < 0.01). Children having caries in their primary teeth were three times more likely to develop caries in their permanent teeth (relative ratio = 2.6, 95% CI = 1.4-4.7; p < 0.001). Caries on primary molars had the highest predictive value (85.4%). This study demonstrates that caries status in the primary teeth can be used as a risk indicator for predicting caries in the permanent teeth.
Visual and Spectrophotometric Shade Analysis of Human Teeth
Authors: Paul S. , Peter A. , Pietrobon N. , Hämmerle C.H.F.
Published: January 2009

Due to interhuman differences in the perception of color, visual shade assessment of human teeth is lacking standardization that may be improved by the use of a spectrophotometer. In this study, we tested the hypothesis that spectrophotometric assessment of tooth color is comparable with human visual determination. On 30 patients, three operators with unreported visual color deficiency independently selected the best match to the middle third of unrestored maxillary central incisors, using a Vita Classical Shade Guide. The same teeth were measured by means of a reflectance spectrophotometer. In the human group, all 3 visual shade selections matched in only 26.6%. In the spectrophotometric group, all 3 shade selections matched in 83.3%. In 93.3%, ▵E values of visually assessed tooth shades were higher than spectrophotometrically assessed ▵E values (p < 0.0001). The results suggest that spectrophotometric shade analysis is more accurate and more reproducible compared with human shade assessment.
Two Decades of Computerized Information Technologies in Dental Radiography
Authors: Wenzel Ann
Published: January 2009

The author describes her experiences in developing a radiology department utilizing digital radiography in dentistry.
Effect of Serotonin (5-HT) on Trigeminal Rhythmic Activities Generated in in vitro Brainstem Block Preparations
Authors: Mori A. , Kogo M. , Ishihama K. , Tanaka S. , Enomoto A. , Koizumi H. , Matsuya T.
Published: January 2009

We used rat isolated brainstem block preparations to analyze the functional roles of serotonin receptors in the generation of trigeminal rhythmic activities. We previously reported that trigeminal rhythmic activities could be induced by some pharmacological applications in an isolated brainstem preparation with a rostral boundary at the border between the inferior and superior colliculus, and a caudal border at the level of the rostral facial nucleus. However, the same stimulation did not induce trigeminal rhythmic activities in a whole brainstem block preparation with the same rostral boundary and a caudal border at the obex level. In the present study, both the 5-HT1A phthalimido-butyl-piperazine, and the 5-HT2C agonist, 1-2,5-dimethoxy-4-iodophenyl-2-aminopropane, combined with N-methyl-D,L-aspartate and bicuculline, elicited trigeminal rhythmic activities in a whole brainstem block preparation. Our results suggest that serotonin has both facilitation and inhibition effects on the generation of trigeminal rhythmic activities in an isolated brainstem block preparation in vitro.
Bone Strain Patterns of the Zygomatic Complex in Response to Simulated Orthopedic Forces
Authors: Oberheim M.C. , Mao J.J.
Published: January 2009

Craniofacial bone strain upon orthopedic loading has rarely been characterized, despite its fundamental importance in our understanding of the anabolic and catabolic effects of orthopedic forces. The present study tested the hypothesis that zygomatic bone strain is modulated upon loading by headgear, a device widely used in craniofacial orthopedics. Ramp forces from 0 to 50 Newtons were applied via headgear attached to the permanent maxillary first molars in four juvenile and five adult human skulls. The average peak bone strain of the juvenile temporal articular eminence was significantly higher than the adult articular eminence (p < 0.05). Contrasting bone strain patterns were identified in the zygomatic arch: tensile in its lateral surface but compressive in its medial surface. The peak bone strain of the temporal articular eminence and the zygomatic arch both depend upon loading direction. Thus, headgear-generated orthopedic forces evoke bending of the zygomatic arch and stresses of the temporal articular eminence in vitro, suggesting the need to verify whether bone strain induces in vivo bone modeling and remodeling.
Capsaicin-induced Muscle Pain Alters the Excitability of the Human Jaw-stretch Reflex
Authors: Wang K. , Arendt-Nielsen L. , Svensson P.
Published: January 2009

The pathophysiology of painful temporomandibular disorders is not fully understood, but evidence suggests that muscle pain modulates motor function in characteristic ways. This study tested the hypothesis that activation of nociceptive muscle afferent fibers would be linked to an increased excitability of the human jaw-stretch reflex and whether this process would be sensitive to length and velocity of the stretch. Capsaicin (10 μg) was injected into the masseter muscle to induce pain in 11 healthy volunteers. Short-latency reflex responses were evoked in the masseter and temporalis muscles by a stretch device with different velocities and displacements before, during, and after the pain. The normalized reflex amplitude increased with an increase in velocity at a given displacement, but remained constant with different displacements at a given velocity. The normalized reflex amplitude was significantly higher during pain, but only at faster stretches in the painful muscle. Increased sensitivity of the fusimotor system during acute muscle pain could be one likely mechanism to explain the findings.
Expression of MMP-8 and MMP-13 mRNAs in Rat Periodontium during Tooth Eruption
Authors: Tsubota M. , Sasano Y. , Takahashi I. , Kagayama M. , Shimauchi H.
Published: January 2009

The present study was designed to investigate mRNA expression of matrix metalloproteinase-8 (MMP-8) and MMP-13 in forming periodontium during tooth eruption in the rat. RT-PCR for the decalcified paraffin sections indicated expression of MMP-8 and MMP-13 in the periodontal tissues. In situ hydridization demonstrated expression of MMP-8 in osteoblasts, osteocytes, periodontal ligament cells, cementoblasts, and cementocytes along with collagen types I and III. In contrast, transcripts of MMP-13 were confined to a small population of osteoblasts and osteocytes in alveolar bone. The results suggested that MMP-8 may be involved in remodeling the periodontium during tooth eruption, and its expression may be coordinated with that of collagen types I and III, whereas the participation of MMP-13 may be rather limited.
Tissue Engineering of Complex Tooth Structures on Biodegradable Polymer Scaffolds
Authors: Young C.S. , Terada S. , Vacanti J.P. , Honda M. , Bartlett J.D. , Yelick P.C.
Published: January 2009

Tooth loss due to periodontal disease, dental caries, trauma, or a variety of genetic disorders continues to affect most adults adversely at some time in their lives. A biological tooth substitute that could replace lost teeth would provide a vital alternative to currently available clinical treatments. To pursue this goal, we dissociated porcine third molar tooth buds into single-cell suspensions and seeded them onto biodegradable polymers. After growing in rat hosts for 20 to 30 weeks, recognizable tooth structures formed that contained dentin, odontoblasts, a well-defined pulp chamber, putative Hertwig’s root sheath epithelia, putative cementoblasts, and a morphologically correct enamel organ containing fully formed enamel. Our results demonstrate the first successful generation of tooth crowns from dissociated tooth tissues that contain both dentin and enamel, and suggest the presence of epithelial and mesenchymal dental stem cells in porcine third molar tissues.
Amplified Crevicular Leukocyte Activity in Aggressive Periodontal Disease
Authors: Buchmann R. , Hasilik A. , Van Dyke T.E. , Lange D.E.
Published: January 2009

Exaggerated neutrophil responses are a critical component in the pathogenesis of periodontal disease. We investigated whether leukocyte activity in aggressive periodontitis (AP) is increased compared with that in chronic periodontitis (CP) by gingival crevicular fluid (GCF) analysis of myeloperoxidase (MPO), beta-N-acetyl-hexosaminidase (beta-NAH), cathepsin D (CD), and elastase-alpha-1-proteinase inhibitor complex (alpha-1-EPI) before and 6 months after therapy. Initial AP neutrophil responses were significantly amplified compared with those in CP (MPO, 3.2-fold; beta-NAH, 37.5-fold; CD, 2.2-fold; alpha-1-EPI, 1.4-fold; p < 0.05). Surgical therapy resulted in a significant reduction of GCF markers compared with non-surgical treatment. However, the changes in clinical parameters were not different between AP and CP (P > 0.05). Analysis of the results suggests that the local inflammatory response in AP is characterized by increased release of inflammatory mediators of neutrophil origin into the GCF. Analysis of the data further suggests that surgical therapy is a more predictable method for removal of the pro-inflammatory etiology.
Is Reduction of Pocket Probing Depth Correlated with the Baseline Value or is it “Mathematical Coupling”?
Authors: Tu Y.-K. , Gilthorpe M.S. , Griffiths G.S.
Published: January 2009

Previous studies using correlation or regression analysis have showed that treatment effects measured by the change in clinical parameters are often associated with baseline values of the same parameters. These studies, however, have a methodological weakness. Correlation/regression between baseline measures and the derived change variable invalidates the statistical procedures of testing the null hypothesis: that the coefficient of correlation/regression is zero. This is due to the phenomenon of mathematical coupling. To investigate the impact that this has on the observed correlation/regression coefficient when in reality this is zero, we used random simulations of hypothetical data to model the treatment of periodontal pockets. Results showed a strong probability of obtaining statistically significant correlation/regression coefficients. To separate this artificial effect of mathematical coupling from the true underlying biological relationship, one must apply appropriate analytical strategies to re-evaluate previous evidence within the periodontal literature.
Matrix Metalloproteinases have a Role in Palatogenesis
Authors: Brown N.L. , Yarram S.J. , Mansell J.P. , Sandy J.R.
Published: January 2009

Mammalian palatogenesis depends on palatal shelf elevation, medial edge epithelium (MEE) breakdown, and mesenchyme flow. These all require matrix remodeling, which is controlled in part by the family of matrix metalloproteinases (MMPs). We used an organ culture system to examine the effect of a general MMP inhibitor (BB3103) on mouse palatogenesis. Palates cultured in 20 μM BB3103 contained no active MMP-2, and only one palate fused from a sample size of 15. In this single palate, MMP-3 was present at higher levels than in palates that failed to fuse. MMP-3 is known to be involved in epithelial mesenchymal transformation (EMT), and its persistence may explain why this palate fused. This implies a role for MMPs in normal palatogenesis, and disruption of their activity may result in cleft palate.
Accumulation of Ciprofloxacin and Minocycline by Cultured Human Gingival Fibroblasts
Authors: Yang Q. , Nakkula R.J. , Walters J.D.
Published: January 2009

Through a mechanism that is unclear, systemic fluoroquinolones and tetracyclines can attain higher levels in gingival fluid than in blood. We hypothesized that gingival fibroblasts take up and accumulate these agents, thereby enhancing their redistribution to the gingiva. Using fluorescence to monitor transport activity, we characterized the accumulation of fluoroquinolones and tetracyclines in cultured human gingival fibroblast monolayers. Both were transported in a concentrative, temperature-dependent, and saturable manner. Fibroblasts transported ciprofloxacin and minocycline with Km values of 200 and 108 μg/mL, respectively, at maximum velocities of 4.62 and 14.2 ng/min/μg cell protein, respectively. For both agents, transport was most efficient at pH 7.2 and less efficient at pH 6.2 and 8.2. At steady state, the cellular/extracellular concentration ratio was > 8 for ciprofloxacin and > 60 for minocycline. Thus, gingival fibroblasts possess active transporters that could potentially contribute to the relatively high levels these agents attain in gingival fluid.