Neuroprotective effect of omega-3 polyunsaturated fatty acids in the 6-OHDA model of Parkinson's disease is mediated by a reduction of inducible nitric oxide synthase

Objective: Parkinson's disease (PD) is characterized by deterioration of the nigrostriatal system and associated with chronic neuroinflammation. Glial activation has been associated with regulating the survival of dopaminergic neurons and is thought to contribute to PD through the release of proinflammatory and neurotoxic factors, such as reactive nitric oxide (NO) that triggers or exacerbates neurodegeneration in PD. Polyunsaturated fatty acids (PUFAs) exert protective effects, including antiinflammatory, antiapoptotic, and antioxidant activity, and may be promising for delaying or preventing PD by attenuating neuroinflammation and preserving dopaminergic neurons. The present study investigated the effects of fish oil supplementation that was rich in PUFAs on dopaminergic neuron loss, the density of inducible nitric oxide synthase (iNOS)-immunoreactive cells, and microglia and astrocyte reactivity in the substantia nigra pars compacta (SNpc) and striatal dopaminergic fibers.

Methods: The animals were supplemented with fish oil for 50 days and subjected to unilateral intrastriatal 6-hydroxydopamine (6-OHDA)-induced lesions as a model of PD.

Results: Fish oil mitigated the loss of SNpc neurons and nerve terminals in the striatum that was caused by 6-OHDA. This protective effect was associated with reductions of the density of iNOS-immunoreactive cells and microglia and astrocyte reactivity.

Discussion: These results suggest that the antioxidant and antiinflammatory properties of fish oil supplementation are closely related to a decrease in dopaminergic damage that is caused by the 6-OHDA model of PD.     

Correlation between implant stability quotient and bone-implant contact: a retrospective histological and histomorphometrical study of seven titanium implants retrieved from humans

Background: Primary stability has a relevant role in the long‐term success of dental implants. A quantitative method for the measurement of implant stability has been introduced (resonance frequency analysis RFA]). Information about the significance of RFA measurements and about the relationship between RFA values and their association with implant osseointegration, success, or failure is important from a clinical point of view. Purpose: The aim of the present histological and histomorphometric study was to see if a correlation existed between the bone‐implant contact (BIC) percentage of retrieved human implants and RFA values. Materials and Methods: Seven implants inserted in the posterior mandible, with a sandblasted and acid‐etched surface and retrieved after a 6‐month period, were evaluated in the present study. These seven implants had been retrieved for different causes. All these implants were submerged and were retrieved with a 5‐mm trephine bur and immersed in 10% buffered formalin to be processed for histology. Results: A statistically significant correlation could be detected between implant stability quotient and BIC (p=.016). Conclusions: Even if the relationship between bone structure and RFA is still not fully understood, in our study, a statistically significant correlation was found between RFA and BIC values. Further studies are needed to evaluate a correlation of RFA and BIC in human implants retrieved after a range of healing periods.     

Toothache prevalence and associated factors: a life course study from birth to age 12 yr

This study estimated the lifetime prevalence of toothache at ages 6 and 12 yr, the prevalence of toothache during the last month, and their association with social, behavioural and clinical exposures in the course of life of 339 12-yr-old children from a birth cohort in Pelotas, Brazil. Exploratory variables were collected in the perinatal study and during several follow-up studies. Prevalence ratios were calculated using Poisson regression, following a hierarchical conceptual model. The lifetime prevalence of toothache at ages 6 and 12 yr were 39% [95% confidence interval (CI) = (34;45)] and 63% [95% CI = (58;69)], respectively. Toothache during the last month was reported by 11% [95% CI = (8;15)]. Children who did not live with their biological father at birth, and children with higher dmf-t counts, reported a higher lifetime prevalence of toothache at age 6 yr. Children experiencing poverty between ages 0 and 4 yr, with higher dmf-t and DMF-T indexes presented a greater lifetime prevalence of toothache at 12 yr. Toothache within the last month was more likely to be reported by girls and by children who did not live with their biological father at birth. Preventive strategies should be implemented in early stages of the life cycle, taking into account the socio-economic and family context in which pain mostly occurs.     

Multilevel assessment of determinants of dental caries experience in Brazil

OBJECTIVE: To examine contextual and individual determinants of dental caries experience, documenting levels of the disease in Brazil. METHODS: The dental status of 34 550 12-year-old schoolchildren was informed by a country-wide survey of oral health comprising 250 towns and performed in 2002-2003. Indices assessing dental caries experience were compared by sociodemographic characteristics of examined children (gender, ethnic group, localization and type of school), and geographic characteristics of participating towns [the human development index (HDI), and access to fluoridated tap water]. A multilevel model fitted the adjustment of untreated caries to individual and contextual covariates. RESULTS: Better-off Brazilian regions presented an improved profile of dental health, besides having a less unequal distribution of restorative dental treatments between blacks and whites, rural and urban areas, and public and private schools. Girls [odds ratio (OR)=1.1; 95% confidence interval (CI): 1.0-1.1], blacks (OR=1.6; 95% CI: 1.5-1.7), and children studying in rural areas (OR=1.9; 95% CI: 1.7-2.0) and public schools (OR=1.7; 95% CI: 1.6-1.9) presented higher odds of having untreated decayed teeth. The multilevel model identified the fluoride status of tap water (beta=-0.3), the proportion of households linked to the water network (beta=-0.3), and the HDI (beta=-0.2), as town-level variables associated with caries levels. CONCLUSION: Dental caries experience is prone to sociodemographic and geographic inequalities. The monitoring of contrasts in dental health outcomes is relevant for programming socially appropriate interventions aimed both at overall improvements and at the targeting of resources for groups of population presenting higher levels of needs.     

Accuracy of computerized tomography for the evaluation of mandibular sites prior to implant placement

The objective of the present study was to observe the effect of positioning of the mandible on the accuracy of cross-sectional images obtained by reformatting computerized tomographic (CT) scans. An additional aim was to evaluate the ability of a software program (DentalVox, Era Scientific) to reconstruct these measurements on the reformatted images, regardless of the positioning of the mandible, accurately and without distortion. The test was carried out by examining a partially edentulous dry human mandible with an acrylic radiologic template. Through the use of an acrylic glass support, the mandible was positioned at angles of 0, 10, 15, 20, and 30 degrees relative to the scanning gantry, and a series of CT scans was performed that provided five sets of axial images. Each set of original axial images was reformatted by the DentalVox software, used first in its basic function, which is typical of all software for axial CT measurement (control group), and again in its function of site-specific multiplanar reconstruction (test group). The results showed that the position of the mandible in relation to the CT gantry can influence the precision of the linear measurements. The error ranged from 2% to 51%. The DentalVox software allowed the reconstruction of cross-sectional images with very little distortion regardless of the mandibular position.