124 research outputs found
Odontoblast markers and dentine reactions in carious primary molars with and without hypomineralised enamel defects
Background: Wnt/β-Catenin signalling and DMP1 have key roles in tertiary dentinogenesis. Aim: To compare the relationship between remaining dentine thickness (RDT), tertiary dentine thickness (TDT), β-catenin and dentine matrix protein 1 (DMP1) in carious second primary molar teeth with normal (SPM) and hypomineralised enamel (HSPM). Design: Extracted carious SPM and HSPM were fixed, sectioned (5 Οm) and stained with haematoxylin and eosin or with indirect immunofluorescence for β-catenin and DMP1. Image analysis was performed to determine RDT, TDT, β-catenin and DMP1 intensity in the odontoblast layer and dentine-pulp complex. Results: Carious SPM (n = 11; mean RDT = 1536.1 Οm) and HSPM (n = 12; mean RDT = 1179.9 Οm) had mean TDT 248.6 Οm and 518.1 Οm, respectively (P =.02). There were no significant differences in intensity values in the odontoblast layer and dentine-pulp complex for β-catenin and DMP1 for both groups. Conclusion: There was no observable variation in Wnt/β-catenin and DMP1 expression between HSPM and SPM despite a statistically significant twofold increased TDT in HSPM compared with SPM that had similar RDT. Thus, the observed increased TDT in HSPM is more likely due to an earlier onset of repair processes rather than an amplified response to caries
Medical and dental characteristics of children with chromosome 22q11.2 deletion syndrome at the Royal Children's Hospital, Melbourne
Background: Chromosome 22q11.2 deletion syndrome (22q11.2DS) is a multifaceted syndrome with a variable phenotype. Few studies have described the associated dental characteristics and their relationship with medical co-morbidities; and no Australian data exist. Aim: To determine the clinical manifestations and correlations between oral and medical conditions in children with 22q11.2DS. Design: A retrospective observational study. Children genetically diagnosed with 22q11.2DS at the Royal Children's Hospital Melbourne were selected; their medical and dental characteristics were collated and analysed. Results: The study population (n = 57; mean age 11.5 years, range 2-27 years) experienced a range of medical conditions involving multiple medical systems; of whom 44 (77.2%) had caries experience, 7 (12.3%) developmentally missing teeth, and 31 (54.4%) developmental defects of enamel (DDE). Smaller proportions of primary teeth were affected by DDE in children with congenital heart disease (2.2% vs 9.7%; P = .02), and cardiac surgery (0.2% vs 9%; P = .001). Conversely, children with hypoparathyroidism (n = 2) had significantly higher proportions of primary teeth affected by DDE (27.5% vs 4%; P = .02). Conclusions: Significant associations existed between medical conditions (congenital heart disease, history of cardiac surgery, and hypoparathyroidism) and primary dentition DDE in children with 22q11.2 DS
Soliton form factors from lattice simulations
The form factor provides a convenient way to describe properties of
topological solitons in the full quantum theory, when semiclassical concepts
are not applicable. It is demonstrated that the form factor can be calculated
numerically using lattice Monte Carlo simulations. The approach is very general
and can be applied to essentially any type of soliton. The technique is
illustrated by calculating the kink form factor near the critical point in
1+1-dimensional scalar field theory. As expected from universality arguments,
the result agrees with the exactly calculable scaling form factor of the
two-dimensional Ising model.Comment: 5 pages, 3 figures; v2: discussion extended, references added,
version accepted for publication in PR
Remineralising effects of fluoride varnishes containing calcium phosphate on artificial root caries lesions with adjunctive application of proanthocyanidin
Objectives: To evaluate the remineralising effects of fluoride (F) varnishes containing bioavailable calcium-phosphate compound (Ca-P) based remineralisation systems and 5000 ppm F toothpaste (FTP) on root caries lesions (RCLs) and the potential effects of proanthocyanidin (PA) for the treatments of RCLs when used as an adjunct to F regimens. Methods: Demineralised root dentine and a pH-cycling model were used to mimic RCLs and the oral environment. Remineralising effects of MI VarnishTM (MIV) containing casein phosphopeptideâamorphous calcium phosphate (CPP-ACP) and Clinpro⢠White Varnish (CPWV) containing tri-calcium phosphate (TCP) along with FTP and PA were evaluated regarding the birefringence, elemental composition, mechanical properties and mineral density of remineralised dentine with DuraphatTM as a comparison. Results: MIV, CPWV and DuraphatTM promoted the incorporation of F into RCLs and increased mineral density but did not change microhardness of root dentine significantly. Surface microhardness increased significantly when MIV or CPWV was used with 5000 ppm FTP. Application of PA with F regimens significantly increased subsurface mineral density. When PA was applied with MIV or CPWV along with FTP, the highest ion uptake and relative mineral gain (%ÎZ) was achieved, and significant increase of microhardness was up to 30 Îźm depth. Generally, MIV was associated with a higher mineral content gain than CPWV. Significance: Treatment of carious root surfaces remains challenging due to the complex pathological processes and difficulty in restoring the highly organised structure of root dentine. Treatment strategies targeting both remineralisation and preservation of the dentinal organic matrix have the potential to improve the fluoride-mediated remineralisation approaches
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Ellipsoid Localisation Microscopy
Multilayered protein coats are crucial to the dormancy, robustness, and germination of bacterial spores. In Bacillus subtilis spores, the coat contains over 70 distinct proteins. Identifying which proteins reside in each layer may provide insight into their distinct functions. We present image analysis methods that determine the order and geometry of concentric protein layers by fitting a model description for a spheroidal fluorescent shell image to optical micrographs of spores incorporating fluorescent fusion proteins. The radius of a spherical protein shell can be determined with <10Â nm error by fitting an equation to widefield fluorescence micrographs. Ellipsoidal shell axes can be fitted with comparable precision. The layer orders inferred for B. subtilis and B. megaterium are consistent with measurements in the literature. The aspect ratio of elongated spores and the tendency of some proteins to localize near their poles can be quantified, enabling measurement of structural anisotropy.We gratefully acknowledge support from MedImmune through the Beacon collaboration, the EPSRC Centre for Doctoral Training in Sensor Technologies and Applications (EP/L015889/1), and thank Clemens Kaminski, Romain Laine and Jose Casas-Finet for inspiring discussions.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.bpj.2015.09.02
Evaluation of a communityâbased early childhood caries (ECC) intervention in Cambodia
Objective: To critically evaluate an early childhood caries (ECC) intervention performed by non-dental primary healthcare providers. Methods: This mixed-methods investigation includes data from three sources: (a) a pilot non-randomized controlled trial to examine clinical outcomes at four health centres; (b) stakeholder focus group interviews; and (c) a survey of parents whose children were exposed to the intervention. The pilot study involved four Community Health Centres in rural Cambodia whereby mother-child (6-24Â months of age)dyads received oral health education (OHE), toothbrushes, fluoride toothpaste and fluoride varnish on up to six occasions as part of the routine vaccination schedule. Outcomes were as follows: presence of ECC; impacts on oral health-related quality of life (OHRQoL); stakeholder perceptions of intervention delivery; and parental perceptions of fluoride varnish. Results: Participants in the intervention group had six times lower odds of developing ECC than those in the comparison group after controlling for socio-economic status (OR 0.13). Those in the intervention group also had a large reduction OHRQoL scale scores. Key knowledge and practice gaps were identified among stakeholders. Surveyed parents had favourable views of the fluoride varnish placement by medical professionals, and four out of five stated that they would recommend fluoride varnish for other children. Primary healthcare providers, commune council representatives and community health promoters supported oral health interventions being provided in CHCs. Conclusions: OHE and fluoride varnish interventions provided by non-dental primary health workers were feasible and acceptable for stakeholders in a Cambodian setting. The intervention group had lower ECC experience and better OHRQoL at 2Â years of age
Electric Dipole Moment of a BPS Monopole
Monopole ``superpartner'' solutions are constructed by acting with finite,
broken supersymmetry transformations on a bosonic N=2 BPS monopole. The terms
beyond first order in this construction represent the backreaction of the the
fermionic zero-mode state on the other fields. Because of the quantum nature of
the fermionic zero-modes, the superpartner solution is necessarily operator
valued. We extract the electric dipole moment operator and show that it is
proportional to the fermion zero-mode angular momentum operator with a
gyroelectric ratio g=2. The magnetic quadrupole operator is shown to vanish
identically on all states. We comment on the usefulness of the monopole
superpartner solution for a study of the long-range spin dependent dynamics of
BPS monopoles.Comment: 8 pages, references and note adde
The Moduli Space of BPS Domain Walls
N=2 SQED with several flavors admits multiple, static BPS domain wall
solutions. We determine the explicit two-kink metric and examine the dynamics
of colliding domain walls. The multi-kink metric has a toric Kahler structure
and we reduce the Kahler potential to quadrature. In the second part of this
paper, we consider semi-local vortices compactified on circle. We argue that,
in the presence of a suitable Wilson line, the vortices separate into domain
wall constituents. These play the role of fractional instantons in
two-dimensional gauge theories and sigma-models.Comment: 16 pages, LaTex, 2 figures; factors of zeta corrected, meaning of
cross-terms elucidated, further clarifying comments; (more) references adde
Prevention of incipient carious lesions with various interventions during fixed and removable orthodontic treatment. A systematic review and meta-analysis
Objective: To systematically review and quantify the effectiveness of interventions in reducing caries development during orthodontic treatment and evaluate the quality of evidence for the development of clinical guidelines. Materials and methods: A comprehensive literature search of the Cochrane, EMBASE and MEDLINE databases was conducted to identify eligible randomised controlled trials (RCTs). The risk of bias was assessed using the Cochrane risk of bias (RoB 2) tool. In order to facilitate the development of clinical guidelines, the quality of the evidence was assessed using Grading of Recommendations, Assessment, Development and Evaluation (GRADE). Results: A total of 18 RCTs were included in the qualitative synthesis, of which 10 had a high risk of bias, and eight had minor concerns. Three RCTs that investigated the efficacy of fluoride interventions during fixed orthodontic treatment were included in the quantitative synthesis. The pooled effect size resulted in a risk reduction of 0.23 (95% CI:-0.35,-0.11, p < 0.001) in the intervention group compared to controls. The GRADE evaluation identified the evidence as moderate due to the limited number of RCTs and moderate heterogeneity (I-squared statistic of 49.3%). Conclusions: Although fluoride is the most effective evidence-based preventive intervention during orthodontic treatment, large RCTs are required to provide high quality evidence. Further studies are needed to evaluate the caries preventive effects of oral hygiene programs, chlorhexidine, CPP-ACP and other interventions
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