Age of First Dental Visit and Predictors for Oral Healthcare Utilisation in Preschool Children

Purpose: To assess the age the of the first dental visit and the association of self-perceived oral health, socioeconomic and clinical indicators with healthcare utilisation in Brazilian preschool children. Materials and Methods: An epidemiological survey with 455 5- to 59-month-old children was conducted on National Children's Vaccination Day in Santa Maria, RS, Brazil. Data about age and reasons for the first dental visit, healthcare utilisation, socioeconomic status and self-perceived oral health were collected by means of a parental semi-structured questionnaire. Calibrated examiners evaluated the prevalence of dental caries (WHO) and dental trauma. The assessment of the association used Poisson regression models (prevalence ratio; 95% confidence interval [Cl]). Results: A total of 24.2% (95% Cl: 20.3% to 28.4%) of the study sample had already had a first dental visit. Older children, those with dental caries and dental trauma and whose mothers had a higher level of education were more likely to have gone to the dentist. Children of low socioeconomic status were more likely to have visited public than private healthcare services. The reasons for the first dental visit were associated with clinical indicators of the sample. The distribution of utilisation of the types of oral healthcare services (public or private) varied across the socioeconomic groups. Non-white children with dental caries and dental trauma tended to visit a dentist only for treatment reasons. Conclusion: Socioeconomic and clinical indicators are associated with the use of dental services, indicating the need for strategies to promote public health and reorientation of services that facilitate dental access for preschool children.

Recoupled separated-local-field experiments and applications to study intermediate-regime molecular motions

A specific separated-local-field NMR experiment, dubbed Dipolar-Chemical-Shift Correlation (DIPSHIFT) is frequently used to study molecular motions by probing reorientations through the changes in XH dipolar coupling and T-2. In systems where the coupling is weak or the reorientation angle is small, a recoupled variant of the DIPSHIFT experiment is applied, where the effective dipolar coupling is amplified by a REDOR-like pi-pulse train. However, a previously described constant-time variant of this experiment is not sensitive to the motion-induced T-2 effect, which precludes the observation of motions over a large range of rates ranging from hundreds of Hz to around a MHz. We present a DIPSHIFT implementation which amplifies the dipolar couplings and is still sensitive to T-2 effects. Spin dynamics simulations, analytical calculations and experiments demonstrate the sensitivity of the technique to molecular motions, and suggest the best experimental conditions to avoid imperfections. Furthermore, an in-depth theoretical analysis of the interplay of REDOR-like recoupling and proton decoupling based on Average-Hamiltonian Theory was performed, which allowed explaining the origin of many artifacts found in literature data. (C) 2012 Elsevier Inc. All rights reserved.