What are the visuo-motor tendencies of omnidirectional scene free-viewing in virtual reality?

Central and peripheral vision during visual tasks have been extensively studied on two-dimensional screens, highlighting their perceptual and functional disparities. This study has two objectives: replicating on-screen gaze-contingent experiments removing central or peripheral field of view in virtual reality, and identifying visuo-motor biases specific to the exploration of 360 scenes with a wide field of view. Our results are useful for vision modelling, with applications in gaze position prediction (e.g., content compression and streaming). We ask how previous on-screen findings translate to conditions where observers can use their head to explore stimuli. We implemented a gaze-contingent paradigm to simulate loss of vision in virtual reality, participants could freely view omnidirectional natural scenes. This protocol allows the simulation of vision loss with an extended field of view (>80°) and studying the head''s contributions to visual attention. The time-course of visuo-motor variables in our pure free-viewing task reveals long fixations and short saccades during first seconds of exploration, contrary to literature in visual tasks guided by instructions. We show that the effect of vision loss is reflected primarily on eye movements, in a manner consistent with two-dimensional screens literature. We hypothesize that head movements mainly serve to explore the scenes during free-viewing, the presence of masks did not significantly impact head scanning behaviours. We present new fixational and saccadic visuo-motor tendencies in a 360° context that we hope will help in the creation of gaze prediction models dedicated to virtual reality.     

Cellular and Molecular Tissue Response to Triple Antibiotic Intracanal Dressing

Introduction

The aim of this study was to characterize the response of mouse subcutaneous tissue to triple antibiotic paste (TAP) using conventional light microscopy and real-time PCR (qRT-PCR).

Methods

Polyethylene tubes containing TAP or calcium hydroxide (CH) (ie, the control group) were implanted in mouse subcutaneous tissue. Animals that received empty tubes or no tubes were used as additional controls. After periods of 7, 21, and 63 days postimplantation, the specimens were removed and subjected to histologic processing. The number of inflammatory cells and vessels, vessel areas, vascular density, and relative percentage of collagen were evaluated. Gene expression of proinflammatory (interleukin-1 beta, tumor necrosis factor alpha, and interleukin 17) and anti-inflammatory (transforming growth factor beta) cytokines and angiogenic factors (vascular endothelial growth factor and hypoxia-inducible factor-1 alpha) was quantified by 7 and 21 days postimplantation. Results were analyzed using the Student t test, analysis of variance, and the Tukey test (α = 0.05).

Results

TAP induced an exuberant inflammatory and angiogenic response, with higher numbers of inflammatory cells, higher vascular area and density, and lower relative percentage of collagen compared with CH. In general, the expression of genes involved in inflammation and angiogenesis was higher in the TAP group compared with animals that received CH or empty tubes.

Conclusions

The response of mouse subcutaneous tissue to TAP was characterized by exuberant and persistent inflammatory and angiogenic responses with no repair and high gene expression of biomarkers associated with inflammation and angiogenesis.     

Periodontal Conditions in Human Immunodeficiency Virus–Positive Patients Under Highly Active Antiretroviral Therapy From a Metropolitan Area of Rio De Janeiro

Background: The aim of this study is to evaluate the periodontal status and the presence of opportunistic oral lesions in human immunodeficiency virus–positive (HIV+) patients under highly active antiretroviral therapy (HAART) and their association with cluster of differentiation (CD)4+ and CD4+ nadir T‐cell counts and viral load levels. Methods: Clinical periodontal parameters and the presence of opportunistic oral lesions along with records of CD4+ counts and viral load levels were evaluated in 29 individuals (16 females; mean age: 42.7 years) with previous serologic diagnosis of HIV, from the acquired immunodeficiency syndrome program of the Health Center of Duque de Caxias, Rio de Janeiro, Brazil. Results: All individuals presented gingivitis or periodontitis. A higher non‐significant prevalence of periodontitis was found in smokers (93.8%) compared with non‐smokers (76.9%). A significant weak positive correlation was observed between CD4+ counts and missing teeth (ρ = 0.380, P <0.05), CD4+ nadir and periodontal diagnosis (ρ = 0.418, P <0.005), and CD4+ nadir and moderate probing depth (PD) (ρ = 0.424, P <0.05). When only non‐smokers were analyzed, a significant moderate positive association was found between viral load and moderate clinical attachment level (CAL) (ρ = 0.638, P <0.05), CD4+ nadir and diagnosis (ρ = 0.586, P <0.05), and CD4+ nadir and moderate CAL (ρ = 0.680, P <0.05). Analysis considering only smokers found no correlations between serologic parameters and demographic or clinical parameters. Conclusions: The current investigation demonstrates that HIV+ individuals under HAART presents a high prevalence of mild to moderate periodontal disease. Viral load levels, CD4+ nadir, and CD4+ counts may present a weak to moderate correlation to the number of missing teeth, periodontal diagnosis, moderate PD, and moderate CAL, which may also reflect some effect of these systemic conditions on the periodontal status.     

Clinical Effects of Lactobacillus rhamnosus in Non‐Surgical Treatment of Chronic Periodontitis: A Randomized Placebo‐Controlled Trial With 1‐Year Follow‐Up

Background: Probiotics are living microorganisms that provide beneficial effects for the host when administered in proper quantities. The aim of this double‐masked placebo‐controlled parallel‐arm randomized clinical trial is to evaluate the clinical effects of a Lactobacillus rhamnosus SP1‐containing probiotic sachet as an adjunct to non‐surgical therapy. Methods: Twenty‐eight systemically healthy volunteers with chronic periodontitis were recruited and monitored clinically at baseline and 3, 6, 9, and 12 months after therapy. Clinical parameters measured included plaque accumulation, bleeding on probing, probing depths (PDs), and clinical attachment loss. Patients received non‐surgical therapy, including scaling and root planing (SRP), and were assigned randomly to a test (SRP + probiotic, n = 14) or control (SRP + placebo, n = 14) group. The intake, once a day for 3 months, of an L. rhamnosus SP1 probiotic sachet commenced after the last session of SRP. Results: Both test and control groups showed improvements in clinical parameters at all time points evaluated. However, the test group showed greater reductions in PD than the control. Also, at initial visits and after 1‐year follow‐up, the test group showed a statistically significant reduction in the number of participants with PD ≥6 mm, indicating a reduced need for surgery, in contrast to the placebo group. Conclusion: The results of this trial indicate that oral administration of L. rhamnosus SP1 resulted in similar clinical improvements compared with SRP alone.     

Prevalence of periodontitis and DMFT index in patients with Crohn's disease and ulcerative colitis

Aim: To compare the prevalence of periodontal disease and the decayed, missing and filled teeth (DMFT) index in patients with Crohn's disease (CD) and ulcerative colitis (UC) with those without these diseases. Material and Methods: Ninety‐nine CD (39.0 SD±12.9 years), 80 UC (43.3 SD±13.2) and 74 healthy controls (40.3 SD±12.9) were compared for DMFT index and presence of periodontitis. Probing pocket depth (PPD), clinical attachment loss (CAL), bleeding on probing (BOP), plaque and DMFT index were measured on all subjects. The presence of periodontitis was defined as having CAL 3 mm in at least four sites in different teeth. Results: Significantly more patients with UC (90.0%; p<0.001) and CD (81.8%; p=0.03) had periodontitis than controls (67.6%). Among smokers, UC patients had significantly more periodontitis. CD had a greater mean DMFT score (18.7 versus 13.9; p=0.031) compared with controls and UC had greater median PPD (2.2 versus 1.7 mm; p<0.0001) than controls. Among non‐smokers, CD (2.4 mm; p<0.0001) and UC showed deeper pockets (2.3 mm; p<0.0001) compared with controls (1.5 mm). UC had a greater mean DMFT score (15.3 versus 12.1; p=0.037) compared with controls. Conclusions: CD and UC patients had higher DMFT and prevalence of periodontitis than controls, but smoking was an effect modifier.     

Effect of professional cleaning and dental brushing with or without fluoridated dentifrice on enamel remineralization

An in situ evaluation of the potential rehardening effect of fluoridated and non-fluoridated toothpastes with or without air polishing was conducted. Ten volunteers, using acrylic palatal appliances containing two bovine enamel blocks with artificial carious lesions, took part in this study. Four times a day, after the main meals and at night, the volunteers, in a habitual way, brushed their natural teeth with the dentifrice indicated to the experimental design and after that the appliances were put again into the mouth. They were divided into 4 different groups: G1 - control - non-fluoridated dentifrice; G2 - fluoridated dentifrice; G3 - non-fluoridated dentifrice, but having a previous prophylaxis using air polishing; G4 - fluoridated dentifrice and previous air polishing. The effects of treatments on enamel rehardening were evaluated in the blocks that were assessed by surface microhardness, and the percentage of surface microhardness change (%reh) was calculated in relation to the baseline values. The results showed that %reh was higher in the groups with fluoridated dentifrice, and professional prophylaxis did not have an additional effect in the groups of fluoridated dentifrices (p<0.05). The data suggested that, in the absence of fluoride, removal of dental plaque helped to increase the process of enamel rehardening.     

Fetal diagnosis of cleft lip: natural history and outcomes

Previous studies have suggested that most fetuses diagnosed prenatally with cleft lip have multiple associated anomalies, that fetuses with isolated cleft lip/palate are uncommon, and that their ultimate outcome is poor (Lopoo, 1999). However, our clinical experience failed to make a similar connection. The purpose of this study was to examine the natural history and current outcomes of fetuses diagnosed with cleft lip. A retrospective study was performed on all patients undergoing fetal ultrasonography over a 7-year period (1993-2001) in a tertiary referral center. All patients who had a fetal diagnosis of cleft lip were reviewed (N = 57). Fifty-seven fetuses with cleft lip were identified. Forty-three of 57 patients have complete records. Of these, 18 patients (43%) had terminations for associated severe malformations. Three fetuses (7%) had intrauterine or neonatal demise. The remainder, 22 fetuses (53%) survived to term. Of this group, 18 (82%) of 22 infants were diagnosed postnatally with isolated cleft lip/palate and no associated anomalies. Only 4 of 22 had associated anomalies. All recorded terminations were performed with known karyotyping. We demonstrate that a significant percentage of fetuses diagnosed ultrasonographically with cleft lip/palate in our study were isolated and that this subset of patients has an excellent prognosis and outcome. This may provide further or alter implications for genetic counseling and management.     

Pesticides as risk factors for head and neck cancer: A review

Humans may be exposed to pesticides such as fungicides, herbicides, and insecticides, during occupational and non‐occupational activities. Pesticides could be related to cancer development mainly because of their effects on the endocrine and immune systems and their cumulative effect. The present review evaluated in current literature evidence of an association between exposure to pesticides and the occurrence of head and neck cancer (HNC). A literature search for cohort studies was conducted in the PubMed, Web of science, and Cochrane databases. Methodological quality of each study was rated with the Scottish Intercollegiate Guidelines Network (SIGN) checklist. One thousand one hundred and thirty‐two studies were identified. Thirty‐two were included. Most of the studies found addressed occupational exposure to pesticides and were conducted in Europe and North America. Eleven high‐quality studies were found. Most of them found no association between exposure to pesticides and increased risk of HNC. Two studies found some evidence of a positive association between pesticide (malathion and atrazine) exposure and thyroid cancer. The literature review does not support a clear evidence for association between pesticides exposure and HNC. Only limited evidence points to a positive association between exposure to some pesticides and thyroid cancer. Further standardized studies based on appropriate designs are required to clarify the effect of pesticides on the genesis of HNC, considering dose, length of exposure, and type of pesticide.