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Environmental Pollution (Barking, Essex... Oct 2022Many communities around the country are undergoing contentious battles over the installation of artificial turf. Opponents are concerned about exposure to hazardous... (Review)
Review
Many communities around the country are undergoing contentious battles over the installation of artificial turf. Opponents are concerned about exposure to hazardous chemicals leaching from the crumb rubber cushioning fill made of recycled tires, the plastic carpet, and other synthetic components. Numerous studies have shown that chemicals identified in artificial turf, including polycyclic aromatic hydrocarbons (PAHs), phthalates, and per- and polyfluoroalkyl substances (PFAS), are known carcinogens, neurotoxicants, mutagens, and endocrine disruptors. However, few studies have looked directly at health outcomes of exposure to these chemicals in the context of artificial turf. Ecotoxicology studies in invertebrates exposed to crumb rubber have identified risks to organisms whose habitats have been contaminated by artificial turf. Chicken eggs injected with crumb rubber leachate also showed impaired development and endocrine disruption. The only human epidemiology studies conducted related to artificial turf have been highly limited in design, focusing on cancer incidence. In addition, government agencies have begun their own risk assessment studies to aid community decisions. Additional studies in in vitro and in vivo translational models, ecotoxicological systems, and human epidemiology are strongly needed to consider exposure from both field use and runoff, components other than crumb rubber, sensitive windows of development, and additional physiological endpoints. Identification of potential health effects from exposures due to spending time at artificial turf fields and adjacent environments that may be contaminated by runoff will aid in risk assessment and community decision making on the use of artificial turf.
Topics: Environmental Exposure; Hazardous Substances; Humans; Polycyclic Aromatic Hydrocarbons; Recycling; Rubber
PubMed: 35948114
DOI: 10.1016/j.envpol.2022.119841 -
Dental Press Journal of Orthodontics May 2020Endodontically treated teeth may be moved, as endodontic treatment is not a contraindication for orthodontic treatment. Apical periodontal repair begins when the...
Endodontically treated teeth may be moved, as endodontic treatment is not a contraindication for orthodontic treatment. Apical periodontal repair begins when the periapical or pulp lesion has completely resolved. This may happen immediately after treatment if the filling material causes little or no irritation of periapical tissues, and particularly if the material is fully contained within the canal. When it leaks, a foreign body granuloma forms and persists for some months or indefinitely, depending on the composition of the filling material. Materials containing calcium hydroxide with no resin components undergo phagocytosis and disappear in some months, as macrophages gradually remove them. Materials containing resins, silicone, ionomers, zinc oxide-eugenol, bioceramics or gutta-percha remain in the site and induce the formation of foreign body granulomas. Although this does not preclude tooth movement, patients should be followed up every three months using periapical images to control the position of the material in relation to the tooth apex. "Pseudo" overfilling may be avoided if permanent filling is delayed until the time when orthodontic treatment is completed.
Topics: Calcium Hydroxide; Clinical Decision-Making; Endodontics; Gutta-Percha; Humans; Orthodontics; Zinc Oxide-Eugenol Cement
PubMed: 32844973
DOI: 10.1590/2177-6709.25.3.020-029.oin -
Complementary Therapies in Medicine May 2022Ankle proprioception and balance impairments are usual consequences of chronic ankle instability (CAI). The impairments affect functional and sport activities and can... (Randomized Controlled Trial)
Randomized Controlled Trial
Comparative effect of walking meditation and rubber-band exercise on ankle proprioception and balance performance among persons with chronic ankle instability: A randomized controlled trial.
BACKGROUND
Ankle proprioception and balance impairments are usual consequences of chronic ankle instability (CAI). The impairments affect functional and sport activities and can lead to recurrent ankle sprain. Mind-body practice is claimed to improve ankle proprioception and balance.
OBJECTIVE
To investigate the effects of walking meditation, a mind-body practice, and compare it with the rubber-band exercise on ankle proprioception and balance among individuals with CAI.
STUDY DESIGN
A randomized controlled trial.
METHODS
Thirty-two participants with CAI aged 20.3 ± 1.8 years were randomized into three groups; 1) walking meditation (WM, n = 10), 2) Rubber-band exercise (RE, n = 11) and 3) control (n = 11). WM and RE were enrolled on a 4-week training regimen (30 min/day, 3 days/week). Before and after the training, ankle proprioception was evaluated by angular error of the ankle reposition test (AEA) at three positions, randomly, i.e., plantarflexion-5°, plantarflexion-10° and dorsiflexion-5°. Balance performance was assessed by the star excursion balance test (SEBT).
RESULTS
As adjusted by pre-training baseline, no significant difference in AEA and SEBT was found among three groups. However, after training, only the WM group revealed a significant decrease in AEA at plantarflexion-5° (p = 0.007) and plantarflexion-10° (p = 0.04) compared to the baseline. For SEBT, the WM and RE groups showed significant improvements compared to the baseline in 4 directions each (p < 0.05), while the control group improved only 2 directions (p < 0.05).
CONCLUSIONS
WM and RE groups significantly improved SEBT after 4-week training when compared to before training. Additionally, WM group also improved ankle proprioception. Therefore, WM demonstrates feasibility as a promising intervention that could be applied for balance and ankle proprioceptive rehabilitations in persons with CAI.
Topics: Adolescent; Adult; Ankle; Chronic Disease; Humans; Meditation; Postural Balance; Proprioception; Rubber; Walking; Young Adult
PubMed: 35093512
DOI: 10.1016/j.ctim.2022.102807 -
Scanning 2021The aim of this study was to evaluate the quality of four root canal obturation techniques using microcomputed tomography (micro-CT).
PURPOSE
The aim of this study was to evaluate the quality of four root canal obturation techniques using microcomputed tomography (micro-CT).
MATERIALS AND METHODS
A total of 36 mandibular first premolars with mostly round canals were decoronated, then instrumented up to a size F3 rotary file, and dressed with an epoxy resin-based sealer. Subsequently, they were divided into 4 different groups ( = 9) based on the method of obturation: lateral condensation using 0.02 tapered master cone (LC2), lateral condensation using 0.04 tapered master cone (LC4), matched single-cone technique (MS), and matched single cone-mediated ultrasonic activation (MSUA). All the teeth were scanned using micro-CT (resolution of 19 m), and the percentage volume of voids was calculated. One-way analysis of variance and Tukey test were used to analyze the data ( = 0.05).
RESULTS
The total percentage volume of voids was significantly lower in the MSUA group compared to all other groups ( < 0.05). The total percentage volume of voids was significantly lower in the MS group compared to the LC4 ( < 0.001) and LC2 ( < 0.001) groups. However, there was no significant difference between the LC2 and LC4 groups ( < 0.65).
CONCLUSIONS
MSUA, significantly, showed the least root canal filling voids amongst all the obturation techniques studied. MSUA can be considered an effective method for the filling of the round root canals. In general, lateral condensation using either 0.02 or 0.04 tapered master cones had significantly the highest volume percentage of voids amongst the experimental groups.
Topics: Dental Pulp Cavity; Gutta-Percha; Root Canal Filling Materials; Root Canal Obturation; Root Canal Preparation; X-Ray Microtomography
PubMed: 33717394
DOI: 10.1155/2021/6632822 -
Journal of Oral Science Jan 2022The aim of this study was to use dye penetration to measure apical and coronal leakage simultaneously in single-canal teeth that had been treated endodontically using a... (Randomized Controlled Trial)
Randomized Controlled Trial
PURPOSE
The aim of this study was to use dye penetration to measure apical and coronal leakage simultaneously in single-canal teeth that had been treated endodontically using a single-cone obturation technique.
METHODS
One hundred single-canal, extracted human teeth were cleaned and shaped with ProTaper NEXT rotary files to size-X5 (50/.06), then randomly assigned to five sealer groups for single-cone gutta-percha obturation. The teeth were soaked in 0.6% rhodamine B at 37°C for seven days, then the roots were ground mesiodistally and the maximum apical and coronal dye penetration was measured. Differences in leakage among the sealer groups were examined using the Kruskal-Wallis test. Pairwise comparisons were made using the Mann-Whitney test with Bonferroni correction.
RESULTS
The mean values (mm) of dye penetration for AH Plus, Pulp Canal Sealer, NeoSEALER Flo, EndoSequence BC, and Super-Bond RC Sealer were 0.200, 0.300, 0.675, 0.850, and 0.900 apically, whereas 1.675, 2.075, 4.800, 6.500, and 4.125 coronally. Pairwise comparisons showed significant apical differences between AH Plus/Super-Bond RC Sealer (P = 0.047) and significant coronal differences between AH Plus/NeoSEALER Flo (P = 0.001), AH Plus/EndoSequence BC (P < 0.01), AH Plus/Super-Bond RC Sealer (P < 0.01), Pulp Canal Sealer/NeoSEALER Flo (P = 0.010), Pulp Canal Sealer/EndoSequence BC (P < 0.01), and Pulp Canal Sealer/Super-Bond RC Sealer (P < 0.01).
CONCLUSION
Coronal leakage was worse than apical leakage for all sealers. AH Plus exhibited the least leakage apically and coronally; Super-Bond RC Sealer showed the most leakage apically, and EndoSequence BC showed the most leakage coronally.
Topics: Dental Pulp Cavity; Epoxy Resins; Gutta-Percha; Humans; Root Canal Filling Materials; Root Canal Obturation
PubMed: 34980828
DOI: 10.2334/josnusd.21-0433 -
International Journal of Environmental... Oct 2022In this review, we evaluated the clinical efficacy of interventions used for the treatment of endo-perio lesions (EPL). (Review)
Review
BACKGROUND
In this review, we evaluated the clinical efficacy of interventions used for the treatment of endo-perio lesions (EPL).
METHODS
A systematic scoping review of clinical trials was developed.
RESULTS
Seven clinical trials were studied. In at least one study group of six of the seven evaluated trials, endodontic and periodontal treatments were performed simultaneously. All trials showed improvement in probing depth in the studied groups; nevertheless, the experimental groups of five studies demonstrated a statistically significant reduction in this parameter. An increase in clinical attachment level was also reported ( < 0.05). Most trials reported an increase in the filling of the bone defect following therapy ( < 0.05). Mechanical periodontal therapy implemented simultaneously with endodontic therapy demonstrated efficacy in the treatment of concurrent EPL without communication. Endodontic treatment and immediate periodontal surgery did not affect the result of the management of combined EPL with apical communication. The use of diode laser, the management of platelet-rich fibrin (PRF) and titanium-prepared PRF, and the implementation of bone grafts plus endodontic treatment with mineral-trioxide or gutta-percha seems to be an adequate strategy in patients with EPL.
CONCLUSIONS
The treatment of EPL using simultaneous endodontic and periodontal therapies seems to be an acceptable treatment alternative.
Topics: Humans; Gutta-Percha; Titanium; Treatment Outcome
PubMed: 36294232
DOI: 10.3390/ijerph192013649 -
Brazilian Dental Journal 2021These case reports aimed to describe the management of lateral perforation in the middle cervical third of the root in two maxillary incisors with pulp canal...
These case reports aimed to describe the management of lateral perforation in the middle cervical third of the root in two maxillary incisors with pulp canal calcification using Bio-C Repair, with safe and viable clinical treatment strategies. Digital radiographic exams were obtained with different angles and analyzed using different filters. Cone-beam computed tomography (CBCT) images were requested to show the actual position of the canal, location of the perforation, and guide the strategic planning of the case. Subsequently, cavity access was prepared with the aid of dental operating microscopy. After perforation was identified, granulation tissue was removed and the original canal was identified and then dressed with calcium hydroxide. In the second visit, the perforation was filled with Bio-C Repair and the canal system filled with gutta-percha points and a root canal sealer (Bio-C Sealer). The teeth were restored with glass fiber post, 4 mm beyond the perforation level, and provisory crowns. Both teeth treated as described above were functional and asymptomatic with a 1-year clinical and radiographic assessment. The Bio-C Repair is suggested as a new cement option for the management of lateral canal perforations, with effective results as observed after a one-year follow-up.
Topics: Calcium Hydroxide; Dental Pulp Cavity; Gutta-Percha; Humans; Root Canal Filling Materials; Root Canal Obturation; Root Canal Preparation
PubMed: 33913996
DOI: 10.1590/0103-6440202103568 -
International Journal of Environmental... Nov 2022Antioxidants are prevalently used during rubber production to improve rubber performance, delay aging, and extend service life. However, recent studies have revealed... (Review)
Review
Antioxidants are prevalently used during rubber production to improve rubber performance, delay aging, and extend service life. However, recent studies have revealed that their transformation products (TPs) could adversely affect environmental organisms and even lead to environmental events, which led to great public concern about environmental occurrence and potential impacts of rubber antioxidants and their TPs. In this review, we first summarize the category and application of rubber antioxidants in the world, and then demonstrate the formation mechanism of their TPs in the environment, emphasizing their influence on the ozone oxidative degradation. The potential toxic effects of antioxidants and their TPs are further reviewed to improve understanding of their biological health impact and environmental risks. Finally, the environmental occurrences of antioxidants and their TPs are summarized and their environmental impacts are demonstrated based on the recent studies. Due to the currently limited understanding on the toxic and biological effects of these compounds, further studies are required in order to better assess various TPs of these antioxidants and their environmental impact. To our knowledge, this is the first review on antioxidants and their TPs in the environment, which may elevate the environmental risk awareness of rubber products and their TPs in the near future.
Topics: Water Pollutants, Chemical; Rubber; Antioxidants
PubMed: 36361475
DOI: 10.3390/ijerph192114595 -
Nature Communications Aug 2023Understanding the genetic basis of rubber tree (Hevea brasiliensis) domestication is crucial for further improving natural rubber production to meet its increasing...
Understanding the genetic basis of rubber tree (Hevea brasiliensis) domestication is crucial for further improving natural rubber production to meet its increasing demand worldwide. Here we provide a high-quality H. brasiliensis genome assembly (1.58 Gb, contig N50 of 11.21 megabases), present a map of genome variations by resequencing 335 accessions and reveal domestication-related molecular signals and a major domestication trait, the higher number of laticifer rings. We further show that HbPSK5, encoding the small-peptide hormone phytosulfokine (PSK), is a key domestication gene and closely correlated with the major domestication trait. The transcriptional activation of HbPSK5 by myelocytomatosis (MYC) members links PSK signaling to jasmonates in regulating the laticifer differentiation in rubber tree. Heterologous overexpression of HbPSK5 in Russian dandelion (Taraxacum kok-saghyz) can increase rubber content by promoting laticifer formation. Our results provide an insight into target genes for improving rubber tree and accelerating the domestication of other rubber-producing plants.
Topics: Hevea; Rubber; Domestication; Sequence Analysis, DNA; Genomics; Gene Expression Regulation, Plant
PubMed: 37532727
DOI: 10.1038/s41467-023-40304-y -
Plant Biotechnology Journal Nov 2019Natural rubber (NR) is a nonfungible and valuable biopolymer, used to manufacture ~50 000 rubber products, including tires and medical gloves. Current production of NR... (Review)
Review
Natural rubber (NR) is a nonfungible and valuable biopolymer, used to manufacture ~50 000 rubber products, including tires and medical gloves. Current production of NR is derived entirely from the para rubber tree (Hevea brasiliensis). The increasing demand for NR, coupled with limitations and vulnerability of H. brasiliensis production systems, has induced increasing interest among scientists and companies in potential alternative NR crops. Genetic/metabolic pathway engineering approaches, to generate NR-enriched genotypes of alternative NR plants, are of great importance. However, although our knowledge of rubber biochemistry has significantly advanced, our current understanding of NR biosynthesis, the biosynthetic machinery and the molecular mechanisms involved remains incomplete. Two spatially separated metabolic pathways provide precursors for NR biosynthesis in plants and their genes and enzymes/complexes are quite well understood. In contrast, understanding of the proteins and genes involved in the final step(s)-the synthesis of the high molecular weight rubber polymer itself-is only now beginning to emerge. In this review, we provide a critical evaluation of recent research developments in NR biosynthesis, in vitro reconstitution, and the genetic and metabolic pathway engineering advances intended to improve NR content in plants, including H. brasiliensis, two other prospective alternative rubber crops, namely the rubber dandelion and guayule, and model species, such as lettuce. We describe a new model of the rubber transferase complex, which integrates these developments. In addition, we highlight the current challenges in NR biosynthesis research and future perspectives on metabolic pathway engineering of NR to speed alternative rubber crop commercial development.
Topics: Hevea; Metabolic Engineering; Rubber; Transferases
PubMed: 31150158
DOI: 10.1111/pbi.13181