Eligibility and efficacy of a CPC- and CHX-based antiviral mouthwash for the elimination of SARS-CoV-2 from the saliva: A randomized, double-blind, controlled clinical trial.

AIM: This study aimed at investigating the efficacy of a 0.05% cetylpyridinium chloride-0.05% chlorhexidine (CPC-CHX) mouthwash in reducing viral load in the saliva as compared with sterile water. MATERIALS AND METHODS: Forty SARS-CoV-2 positive patients were asked to dispense 4 mL of saliva. Half the patients rinsed for 60 s with 15 mL CPC-CHX, and the remaining patients rinsed with sterile water (control). Four millilitres of saliva were collected after 15, 30 and 60 min after rinsing. Quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) specific for SARS-CoV-2 nucleocapsid protein were performed. For ELISA, the intact (representing the active virus) to total virus load (I/T) was calculated. RESULTS: SARS-CoV-2 copy numbers/mL from RT-qPCR tended to decrease in the control group, whereas in the CPC-CHX group, an increase was observed after T30. However, mixed linear model analysis revealed no statistical differences between groups (p = .124), time points (p = .616) and vaccinated or non-vaccinated patients (p = .953). Similarly, no impact of group (p = .880), time points (p = .306) and vaccination (p = .711) was observed for I/T ratio values. CONCLUSIONS: Within the limitation of this study, there was no evidence that the intervention reduced salivary SARS-CoV-2 viral load during the course of 60 min. Therefore, commonly used pre-procedural rinsing might not be clinically relevant.

Micro-angiogenic patterns around orthodontic implants migrating in bone: A micro-CT study in the rat tail model.

AIM: Recent studies revealed that implants can migrate in bone when subjected to continuous loading. Since this process is suspected to be accompanied by bone remodelling, which requires blood vessel formation, the present work aimed at assessing the micro-angiogenic patterns around migrating implants. MATERIALS AND METHODS: In 16 rats, two customized implants were placed in a single tail vertebra and connected with contraction springs (forces: 0 N, 0.5 N, 1.0 N, 1.5 N). After 2 or 8 weeks of loading, the animals were scanned by micro-CT before and after vasculature perfusion with a silicone rubber. Vessels were segmented by subtraction of the two micro-CT scans. Vessel thickness (V.Th), vessel volume per total volume (VV/TV), and vascular spacing (V.Sp) were assessed in a peri-implant volume of interest (VOI) around each implant. RESULTS: At 2 weeks of loading, force magnitude was significantly associated with VV/TV and V.Th values (χ2  = 10.942, p < .001 and χ2  = 6.028, p = .010, respectively). No significant differences were observed after 8 weeks of loading. CONCLUSIONS: Within the limitations of an animal study, peri-implant vessel thickness and density were associated with force magnitude in the early loading phase, whereas effects diminished after 8 weeks of loading.

Bone remodelling patterns around orthodontic mini-implants migrating in bone: an experimental study in rat vertebrae.

BACKGROUND: Orthodontic implant migration has been clinically observed in presence of continuous loading forces. Recent studies indicate that osteocytes play a crucial role in this phenomenon. OBJECTIVES: Aim of this study was to investigate local osteocytic gene expression, protein expression, and bone micro-structure in peri-implant regions of pressure and tension. MATERIAL AND METHODS: The present work reports a complementary analysis to a previous micro-computed tomography study. Two customized mini-implants were placed in one caudal rat vertebra and connected by a nickel-titanium contraction spring generating different forces (i.e. 0, 0.5, 1.0, and 1.5 N). Either at 2 or 8 weeks, the vertebrae were harvested and utilized for 1. osteocytic gene expression using laser capture micro-dissection on frozen sections coupled with qPCR, 2. haematoxylin-eosin staining for qualitative and quantitative analyses, 3. immunofluorescence staining and analysis, and 4. bone-to-implant contact on undecalcified samples. RESULTS: At the two time points for all the performed analyses no significant differences were observed with respect to the applied force magnitudes and cell harvesting localization. However, descriptive histological analysis revealed remarkable bone remodelling at 2 weeks of loading. At 8 weeks the implants were osseointegrated and, especially in 1.0 and 1.5 N groups, newly formed bone presented a characteristic load bearing architecture with trabecula oriented in the direction of the loading. CONCLUSIONS: The present study confirmed that stress-induced bone remodelling is the biological mechanism of orthodontic implant migration. Bone apposition was found at 'tension' and 'pressure' sites thus limiting implant migration over time.

Bmal1-deficiency affects glial synaptic coverage of the hippocampal mossy fiber synapse and the actin cytoskeleton in astrocytes.

Bmal1 is an essential component of the molecular clockwork, which drives circadian rhythms in cell function. In Bmal1-deficient (Bmal1-/-) mice, chronodisruption is associated with cognitive deficits and progressive brain pathology including astrocytosis indicated by increased expression of glial fibrillary acidic protein (GFAP). However, relatively little is known about the impact of Bmal1-deficiency on astrocyte morphology prior to astrocytosis. Therefore, in this study we analysed astrocyte morphology in young (6-8 weeks old) adult Bmal1-/- mice. At this age, overall GFAP immunoreactivity was not increased in Bmal1-deficient mice. At the ultrastructural level, we found a decrease in the volume fraction of the fine astrocytic processes that cover the hippocampal mossy fiber synapse, suggesting an impairment of perisynaptic processes and their contribution to neurotransmission. For further analyses of actin cytoskeleton, which is essential for distal process formation, we used cultured Bmal1-/- astrocytes. Bmal1-/- astrocytes showed an impaired formation of actin stress fibers. Moreover, Bmal1-/- astrocytes showed reduced levels of the actin-binding protein cortactin (CTTN). Cttn promoter region contains an E-Box like element and chromatin immunoprecipitation revealed that Cttn is a potential Bmal1 target gene. In addition, the level of GTP-bound (active) Rho-GTPase (Rho-GTP) was reduced in Bmal1-/- astrocytes. In summary, our data demonstrate that Bmal1-deficiency affects morphology of the fine astrocyte processes prior to strong upregulation of GFAP, presumably because of impaired Cttn expression and reduced Rho-GTP activation. These morphological changes might result in altered synaptic function and, thereby, relate to cognitive deficits in chronodisruption.

Eligibility of a novel BW + technology and comparison of sensitivity and specificity of different imaging methods for radiological caries detection.

OBJECTIVES: Bitewing radiography is considered to be of high diagnostic value in caries detection, but owing to projections, lesions may remain undetected. The novel bitewing plus (BW +) technology enables scrolling through radiographs in different directions and angles. The present study aimed at comparing BW + with other 2D and 3D imaging methods in terms of sensitivity, specificity, and user reliability. MATERIALS AND METHODS: Five human cadavers were used in this study. In three cadavers, natural teeth were transplanted post-mortem. BW + , two-dimensional (digital sensors, imaging plates, 2D and 3D bitewing radiographs) and 3D methods (high and low dose CBCT) were taken. Carious lesions were evaluated on 96 teeth at three positions (mesial, distal, and occlusal) and scored according to their level of demineralization by ten observers, resulting in 35,799 possible lesions across all observers and settings. For reference, µCT scans of all teeth were performed. RESULTS: Overall, radiographic evaluations showed a high rate of false-negative diagnoses, with around 70% of lesions remaining undetected, especially enamel lesions. BW + showed the highest sensitivity for dentinal caries and had comparatively high specificity overall. CONCLUSIONS: Within the limits of the study, BW + showed great potential for added diagnostic value, especially for dentinal caries. However, the tradeoff of diagnostic benefit and radiation exposure must be considered according to each patient's age and risk.

Deficiency of the clock gene Bmal1 affects neural progenitor cell migration.

We demonstrate the impact of a disrupted molecular clock in Bmal1-deficient (Bmal1-/-) mice on migration of neural progenitor cells (NPCs). Proliferation of NPCs in rostral migratory stream (RMS) was reduced in Bmal1-/- mice, consistent with our earlier studies on adult neurogenesis in hippocampus. However, a significantly higher number of NPCs from Bmal1-/- mice reached the olfactory bulb as compared to wild-type littermates (Bmal1+/+ mice), indicating a higher migration velocity in Bmal1-/- mice. In isolated NPCs from Bmal1-/- mice, not only migration velocity and expression pattern of genes involved in detoxification of reactive oxygen species were affected, but also RNA oxidation of catalase was increased and catalase protein levels were decreased. Bmal1+/+ migration phenotype could be restored by treatment with catalase, while treatment of NPCs from Bmal1+/+ mice with hydrogen peroxide mimicked Bmal1-/- migration phenotype. Thus, we conclude that Bmal1 deficiency affects NPC migration as a consequence of dysregulated detoxification of reactive oxygen species.

Premature aging of the hippocampal neurogenic niche in adult Bmal1-deficient mice.

Hippocampal neurogenesis undergoes dramatic age-related changes. Mice with targeted deletion of the clock geneBmal1 (Bmal1(-/-)) show disrupted regulation of reactive oxygen species homeostasis, accelerated aging, neurodegeneration and cognitive deficits. As proliferation of neuronal progenitor/precursor cells (NPCs) is enhanced in young Bmal1(-/-) mice, we tested the hypothesis that this results in premature aging of hippocampal neurogenic niche in adult Bmal1(-/-) mice as compared to wildtype littermates. We found significantly reduced pool of hippocampal NPCs, scattered distribution, enhanced survival of NPCs and an increased differentiation of NPCs into the astroglial lineage at the expense of the neuronal lineage. Immunoreaction of the redox sensitive histone deacetylase Sirtuine 1, peroxisomal membrane protein at 70 kDa and expression of the cell cycle inhibitor p21(Waf1/CIP1) were increased in adult Bmal1(-/-) mice. In conclusion, genetic disruption of the molecular clockwork leads to accelerated age-dependent decline in adult neurogenesis presumably as a consequence of oxidative stress.