Caries indicators in relation to healthcare access and hygienic-dietary habits in Spanish preschoolers

INTRODUCTION

Dental caries continues to be a public healthcare problem due to its high prevalence and morbidity. It was proposed to evaluate caries indicators in relation to healthcare access and hygienic-dietary habits in Spanish preschoolers.

MATERIALS AND METHODS

A cross-sectional study was carried out on a random sample consisting of 343 patients ranging from 3 to 5 years of age in the primary care setting, the main measurements were: dental care access, hygienic-dietary habits, and caries registration according to WHO criteria.

RESULTS

The prevalence of caries was 35.3% and mean ± standard deviation (SD) dft was 1.51 ± 2.93. Preschoolers who had ever visited the dentist had a higher dft occurrence than those who had never attended the dentist. The lower prevalence of caries was significantly associated with the frequency of two daily brushings versus non-daily brushing (p = 0.007; 25.3% vs. 47.1%) and was 10.7% lower in patients who had the habit of night brushing (p = 0.041). The consumption of sugary liquids between meals implied a higher dft index.

CONCLUSIONS

The high prevalence of early childhood caries and the dental care access associated with poor oral health suggest the need to implement a multidisciplinary oral healthcare program that involves both healthcare and dental healthcare professionals in Primary Health Care Units without forgetting the participation of the community and local administrations.

Relevance of Sociocultural Inequalities and Parents' Origins in Relation to the Oral Health of Preschoolers in Lanzarote, Spain

Approaching inequalities to achieve health equity requires joint action. Early childhood caries affects disadvantaged population groups. The objective of this study was to determine the relevance of sociocultural inequalities and parental origin with respect to oral health in preschool children in Lanzarote. A transversal epidemiological study was carried out. Sociocultural data and information about parental origin were collected via a questionnaire. The decayed and filled teeth (dft), decayed teeth (dt), filled teeth (ft), restorative index (RI), plaque index (PI) and gingival index (GI) were obtained via an investigator's examination. Statistical analysis of the data indicated that children of semi-skilled manual workers (28.15%) had the highest prevalence of caries (46.9%). Additionally 43.7 of the mothers had second grade and first cycle studies. When relating the medium and high level of education, there were statistically significant differences in relation to the cod index (p = 0.046). When the origin was foreign (48.4%), preschoolers presented 10.7% more active or untreated caries than Spaniards (p = 0.038). Low socioeconomic cultural level and foreign origin is associated with a more deficient state of oral health in preschoolers. Oral health programs are needed to minimize social inequalities.

Prevalence of traumatic injuries in deciduous dentition and associated risk factors in a Spanish children population

Background

The frequency of traumatic dental injuries (TDI) in primary dentition and those agents that favor them present a great variability. Therefore, the objective of this study was to determine the prevalence of TDI in a population of Spanish preschoolers in temporary dentition and identify the factors associated with these injuries.

Material and Methods

An epidemiological observational prevalence study was carried out. A total of 343 children aged between 3 and 5 years were selected. A questionnaire was completed in relation to socioeconomic factors, cultural level, dietary habits and oral parafunction. Through an intraoral examination, information was collected on the occlusal characteristics and the presence of TDI. Data analysis was performed using the SPSS Statistics 25.0 program for Windows, using the descriptive and frequencies procedure, contingency tables, Chi-square test, and logistic regression analysis.

Results

The prevalence of TDI in the total sample was 12.2%. The most frequent lesion was crown discoloration (0.4%) followed by crown fracture (0.1%) and avulsion (0.1%). The most affected tooth was the deciduous upper central incisor. In the multivariate logistic regression analysis the presence of dental trauma did correlate significantly with the age (5 years in reference to 3 years: OR = 4.209; 95% C.I. = 1.591-11.134; p = 0.004) and overjet (OR = 2.609; 95% C.I. = 1.306-5.214; p = 0.007).

Conclusions

The prevalence of these lesions in a Spanish infant population with temporary dentition is low. Only age and overjet are risk factors. Key words:Dental trauma, deciduous dentition, risk factors.

Emergent magnetic texture in driven twisted bilayer graphene

The transport properties of a twisted bilayer graphene barrier are investigated for various twist angles. Remarkably, for small twist angles around the magic angle θm ∼ 1.05°, the local currents around the AA-stacked regions are strongly enhanced compared to the injected electron rate. Furthermore, the total and counterflow (magnetic) current patterns show high correlations in these regions, giving rise to well-defined magnetic moments that form a magnetic Moiré superlattice. The orientation and magnitude of these magnetic moments change as a function of the gate voltage and possible implications for emergent spin-liquid behaviour are discussed.

Nonlocal Quantum Effects in Plasmons of Graphene Superlattices

By using a nonlocal, quantum mechanical response function we study graphene plasmons in a one-dimensional superlattice (SL) potential V_{0}cosG_{0}x. The SL introduces a quantum energy scale E_{G}∼ℏv_{F}G_{0} associated with electronic subband transitions. At energies lower than E_{G}, the plasmon dispersion is highly anisotropic; plasmons propagate perpendicularly to the SL axis, but become damped by electronic transitions along the SL direction. These results question the validity of semiclassical approximations for describing low energy plasmons in periodic structures. At higher energies, the dispersion becomes isotropic and Drude-like with effective Drude weights related to the average of the absolute value of the local chemical potential. Full quantum mechanical treatment of the kinetic energy thus introduces nonlocal effects that delocalize the plasmons in the SL, making the system behave as a metamaterial even near singular points where the charge density vanishes.

Chiral Response of Twisted Bilayer Graphene

We present an effective (minimal) theory for chiral two-dimensional materials. These materials possess an electromagnetic coupling without exhibiting a topological gap. As an example, we study the response of doped twisted bilayers, unveiling unusual phenomena in the zero frequency limit. An in-plane magnetic field induces a huge paramagnetic response at the neutrality point and, upon doping, also gives rise to a substantial longitudinal Hall response. The system also accommodates nontrivial longitudinal plasmonic modes that are associated with a longitudinal magnetic moment, thus endowing them with a chiral character. Finally, we note that the optical activity can be considerably enhanced upon doping and our general approach would enable systematic exploration of 2D material heterostructures with optical activity.

Extraordinary absorption of decorated undoped graphene

We theoretically study absorption by an undoped graphene layer decorated with arrays of small particles. We discuss periodic and random arrays within a common formalism, which predicts a maximum absorption of 50% for suspended graphene in both cases. The limits of weak and strong scatterers are investigated, and an unusual dependence on particle-graphene separation is found and explained in terms of the effective number of contributing evanescent diffraction orders of the array. Our results can be important to boost absorption by single-layer graphene due to its simple setup with potential applications to light harvesting and photodetection based on energy (Förster) rather than charge transfer.

Measurable lattice effects on the charge and magnetic response in graphene

The simplest tight-binding model is used to study lattice effects on two properties of doped graphene: (i) magnetic orbital susceptibility and (ii) regular Friedel oscillations, both suppressed in the usual Dirac cone approximation. (i) An exact expression for the tight-binding magnetic susceptibility is obtained, leading to orbital paramagnetism in graphene for a wide range of doping levels which is relevant when compared with other contributions. (ii) Friedel oscillations in the coarse-grained charge response are considered numerically and analytically and an explicit expression for the response to lowest order in lattice effects is presented, showing the restoration of regular 2d behavior, but with strong sixfold anisotropy.

Evolution of caries and fluorosis in schoolchildren of the Canary Islands (Spain): 1991, 1998, 2006

The aim of this work is to assess the evolution of caries and fluorosis prevalence and indices at 7 and 12 years of age in the Canary Islands through three cross epidemiological studies conducted in 1991, 1998 and 2006. The three studies followed a similar methodology, using the WHO diagnosis criteria and indications, except for the assessment of fluorosis, which was measured with the "Thylstrup and Fejerskov" index. The examining dentists were trained and calibrated in an area with high endemic fluorosis. The three studies took a sample of 1000 students for each age group. At 7 years of age, the decayed, and filled teeth (dft) varied from 1.42 in 1991 to 1.14 in 1998 and 1.37 in 2006. At 12 years of age, the Decayed, Missing, and Filled Teeth (DMFT) went from 1.86 to 1.21 and 1.51 in the three studies respectively and the significant caries index (SiC) went from 4.28 to 3.15 and 3.72. At this age, the Filled Rate rose from 24.05% in 1991 to 30.43% in 1998 and to 37.20% in 2006. In relation to fluorosis, at 12 years of age the percentage of healthy or fluorosis-free schoolchildren in the Canary Islands between the first and the second studies went down from 73% to 61.3% and went up to 78.5% in 2006, with a noticeable fall in the prevalence of children with severe and moderate fluorosis. Despite the fluctuations of caries shown in the three studies, at 12 years of age the Canary Islands have remained in the low level of caries of the WHO classification from 1991 up to now. The evolution in the prevalence of dental fluorosis shows the effect of the measures taken, 10 years after they were started.

Tunneling mechanism of light transmission through metallic films

A mechanism of light transmission through metallic films is proposed, assisted by tunneling between resonating buried dielectric inclusions. This is illustrated by arrays of Si spheres embedded in Ag. Strong transmission peaks are observed near the Mie resonances of the spheres. The interaction among various planes of spheres and interference effects between these resonances and the surface plasmons of Ag lead to mixing and splitting of the resonances. Transmission is proved to be limited only by absorption. For small spheres, the effective dielectric constant of the resulting material can be tuned to values close to unity, and a method is proposed to turn the resulting materials invisible.

Universal features of the time evolution of evanescent modes in a left-handed perfect lens

The time evolution of evanescent modes in Pendry's perfect lens proposal for ideally lossless and homogeneous, left-handed materials is analyzed. We show that time development of subwavelength resolution exhibits universal features, independent of model details. This is due to the unavoidable near degeneracy of surface electromagnetic modes in the deep subwavelength region. By means of a mechanical analog, it is shown that an intrinsic time scale (missed in stationary studies) has to be associated with any desired lateral resolution. A time-dependent cutoff length emerges, removing the problem of divergences claimed to invalidate Pendry's proposal.