Serial Extraction Research Articles

Correction of Impacted Maxillary Permanent Anteriors - A Case Report.

The maxillary anteriors play the most prominent role in an individual's aesthetics, speech, and majorly psychology. The impaction of maxillary anterior teeth can be a challenging orthodontic problem that can be managed by interceptive orthodontics in early mixed dentition. In this particular case report, interceptive orthodontics alone may not bring desirable results because two problems need to be dealt simultaneously, namely, intraosseous crowding and midline shift due to impaction on the affected quadrant. In the article, a novel approach is being discussed, where aesthetics of the child was compromised due to impacted rotated maxillary anteriors that were exposed using soft tissue laser and allowed to erupt by selective removal of primary and permanent first premolar teeth on the affected side alone, leading to spontaneous alignment of arch discrepancy and relative correction of midline shift. A unilateral serial extraction sequence (D-4-C) would be effective treatment of choice. This approach adds psychological benefit to the child by using soft tissue lasers and unilateral serial extraction.

Tactile sensation in relation to roughness and reflection of active initial lesions in primary (deciduous) and permanent dentition in vitro

ObjectivesThis study evaluated whether a relationship exist between tactile sensation, roughness and reflection intensity in active enamel lesions of primary (deciduous) and permanent dentition. MethodsFreshly extracted teeth of the primary (n=29) and permanent (n=60) dentition of patients who underwent serial extractions under general anesthesia due to multiple deep caries lesions showing active lesions (International Caries Detection and Assessment System scores of 2) were selected. The mean linear (Ra), area-related (Sa), volume-related (Vmc) roughness and vertical reflection intensity (VRI) of sound (S) and carious (C) areas were determined by using a 3D-laser-scanning-microscope and a multi-sensor microscope with two different chromatic-confocal optics. Furthermore, two blinded examiners evaluated the roughness by tactile examination using three different explorers (S23H,405CP11, S3C). ResultsMean differences (95%CI) between S and C for teeth of the primary dentition were: Ra:-1.9(-2.3;-0.4)µm, Sa:-31.8(-1.8;0.0)µm, Vmc:-1.8(-1.6;-0.0)ml/m2, VRI:29(20;43) and for teeth of the permanent dentition: Ra:-4.0(-2.5;-1.0)µm, Sa:-4.8(-3.0;-1.1)µm, Vmc:-4.6(-3.4;-0.5)ml/m2, VRI:34(19;44) differing significantly between S and C (p<0.05,Wilcoxon test). No significant difference was observed between 1st and 2nd dentition (p>0.05, Kruskal-Wallis test) as well as commercial and experimental optic (p>0.05). The highest positive predictive value (PPV) was achieved by examiner 1 with explorer S3C (1st dentition 67%;2nd dentition 100%;pooled dentition 88%)), while examiner 2 revealed the highest PPV with explorer S23H (89%;86%;88%). ConclusionDifferences in roughness and reflectance between sound and caries-active enamel surfaces could be evaluated in both primary and permanent dentition. These differences could also be reliably detected using three different explorers with good validity. However, the most predictive explorer seems to differ between examiners. Clinical SignificanceIn both primary (deciduous) and permanent dentition active caries lesions exhibit significantly higher roughness and lower vertical reflection intensity compared with sound enamel. These differences are detectable by blind tactile examination and objective methods such as 3D-laser-scanning or multi-sensor microscopy, highlighting their utility in caries diagnosis in both dentitions.

Parental Knowledge, Attitudes, and Utilization of Preventive Dentistry Modalities in Al Qassim, Saudi Arabia: A Cross-Sectional Study.

Background Parents play a vital role in modeling good oral hygiene practices for their children; thus, their attitude, knowledge, and awareness toward preventive dentistry can be one of the major factors contributing to children's oral health. Objectives The objective of this study is to determine the parental knowledge and attitudes toward the modalities of preventive dentistry for their children in Al Qassim, Saudi Arabia. Materials and methods A cross-sectional study was carried out using an online self-administered questionnaire designed for parents living in the Al Qassim region. The questionnaire included demographic data, parent knowledge and attitude toward preventive dentistry, and awareness of preventive dentistry procedures. The data collected were analyzed using RStudio. Results Data were collected from 392 Saudi parents (male: n = 190 (48.5%), female: n = 202 (51.5%)). The majority of participants (n = 336, 85.7%) considered the importance of primary teeth for general body health, while 320 participants (81.6%) believed that primary dentition influences permanent teeth. Awareness regarding special preventive measures like using toothpaste with fluorides comprised 87.5% (n = 343), and that of the benefits of early dental visits was 77.3% (n = 303). However, there was marked unawareness and use of preventive procedures such as serial extraction (n = 226, 57.7% of respondents unaware) and silver diamine fluoride (n = 276, 70.4% unaware). The higher levels of education and income were positively related to better knowledge and attitudes about preventive dentistry. Conclusions The current paper highlights the importance of educational interventions for enhancing parental knowledge and awareness about preventive dentistry. Community-based educational programs and increased availability of preventive dentistry services might be helpful in eliminating the knowledge gap among parents about good oral health practice.

A longitudinal study of endocrinology and foraging ecology of subadult gray whales prior to death based on baleen analysis

Individual-level assessments of wild animal health, vital rates, and foraging ecology are critical for understanding population-wide impacts of exposure to stressors. Large whales face multiple stressors, including, but not limited to, ocean noise, pollution, and ship strikes. Because baleen is a continuously growing keratinized structure, serial extraction, and quantification of hormones and stable isotopes along the length of baleen provide a historical record of whale physiology and foraging ecology. Furthermore, baleen analysis enables the investigation of dead specimens, even decades later, allowing comparisons between historic and modern populations. Here, we examined baleen of five sub-adult gray whales and observed distinct patterns of oscillations in δ15N values along the length of their baleen plates which enabled estimation of baleen growth rates and differentiation of isotopic niche widths of the whales during wintering and summer foraging. In contrast, no regular patterns were apparent in δ13C values. Prolonged elevation of cortisol in four individuals before death indicates that chronic stress may have impacted their health and survival. Triiodothyronine (T3) increased over months in the whales with unknown causes of death, simultaneous with elevations in cortisol, but both hormones remained stable in the one case of acute death attributed to killer whale predation. This parallel elevation of cortisol and T3 challenges the classic understanding of their interaction and might relate to increased energetic demands during exposure to stressors. Reproductive hormone profiles in subadults did not show cyclical trends, suggesting they had not yet reached sexual maturity. This study highlights the potential of baleen analysis to retrospectively assess gray whales' physiological status, exposure to stressors, reproductive status, and foraging ecology in the months or years leading up to their death, which can be a useful tool for conservation diagnostics to mitigate unusual mortality events.

Screening of Antimicrobial Activity of Murraya koenigii Leaf Extracts Against Pathogenic Bacterial Strains Staphylococcus aureus and Escherichia coli Isolated from Contaminated Water

Aim: Murraya koenigii is a widely used plant both as a potential medicinal agent and also for common cooking purposes. Aim of this present study was to determine the antimicrobial activity of Murraya koenigii leaf extracts on Staphylococcus aureus and Escherichia coli. &#x0D; Study Design: Screening and isolation of pathogenic bacterial strains from contaminated water. Preparation of Murraya koenigii leaf extracts using petroleum ether, acetone and ethyl acetate by using serial extraction method with Soxhlet apparatus.&#x0D; Place and Duration of Study: Department of microbiology, Agro biotec research centre Ltd, Poovanthuruthu, Kottayam, Kerala, India, between 2014 January to 2014 May.&#x0D; Methodology: Staphylococcus aureus and Escherichia coli were the bacterial strains used in this study. Morphological and biochemical analysis of microorganisms were conducted to identify the strains. Leaf extracts (petroleum ether, acetone and ethyl acetate) of Murraya koenigii were screened using MHA disc diffusion methods.&#x0D; Results: Various concentration of plant extracts were used to check its activity against isolated pathogens. Acetone extract of curry leaves exhibit maximum zone of inhibition against Staphylococcus aureus and petroleum ether extracts shown maximum inhibition against Escherichia coli.

Pedodontists' awareness of orthodontics: An online survey.

This study aimed to document knowledge, awareness, and ability to provide different aspects of orthodontic treatment currently provided by pedodontists. A 14-item online questionnaire was sent to 120 pedodontists in different countries. Responses received within 2 months were analyzed as frequency and percentage. The response rate was 68.3%. Most respondents demonstrated adequate information about the etiology and diagnosis of different malocclusions and paid attention to patients' facial characteristics. The desire to learn from continuing education programs was higher for preventive and interceptive orthodontics. Space maintainers, habit breakers, management of anterior crossbite, and serial extraction were the orthodontic services most provided by pedodontists. Pedodontists should attend to continuing education about the etiology, diagnosis, and treatment planning for various malocclusions.

Comparative evaluation of three different regression-equation-based mixed dentition analysis of children for prediction of the mesiodistal width of permanent canine and premolars.

Dental malocclusion is common all over the world, and it is caused by a difference in arch length and tooth size. This necessitates mixed dentition analysis for early intervention treatment planning such as eruption guiding, serial extraction, space maintainer, space regainer, and jaw extension. The aim of the study is to comparatively evaluate three different regression equation based mixed dentition analysis of children for prediction of the mesiodistal width of permanent canine and premolars in population of Vidarbha region. This study comprised of 300 patients aged 13 to 16 years old. The impressions of patients were poured, and the mesiodistal width of their teeth was measured and documented. Three independent analyses were performed using the Ling and Wong method (L&W), the Bernabe and Flores-Mir method (B&F), and the Tanaka and Johnston method (T&J), and the results were compared to the sum of permanent canine and premolar teeth (SPCP). ANOVA with post hoc analysis was used to compare the predicted mesiodistal diameter (MDD) by analysis to the SPCP observed on cast. The mesiodistal width of SPCP of maxilla and mandibular teeth had statistically significant difference (P<0.001) with the predicted width by Ling and Wong method, Bernabe and Flores method and Tanaka and Johnston method for patients of Vidarbha region. The study concluded that all the three analysis overestimated the mesiodistal width of the sum of permanent canine and premolar in the patients. Tananka and Johnston analysis method was better in predicting the SPCP of the children of Vidarbha region.

Comparative &lt;i&gt;in-vitro&lt;/i&gt; antioxidant studies of crude methanol extract and four solvent fractions of red cultivar &lt;i&gt;Allium cepa&lt;/i&gt; l. bulbs

Oxidative stress-induced disease conditions are on the increase and there is need for natural sources of antioxidant for relieving stress. The crude extract of Allium cepa L. has been well published as a potential natural source of antioxidant. But there is inadequate information on the antioxidant activities of fractionated extracts of the plant. The in-vitro antioxidant capacity of crude extract of red cultivar A. cepa bulbs and its four solvent fractions were studied and compared using Nitric oxide radical inhibitory assay (NORIA), FRAP and DPPH antioxidant models. The results of the three models revealed that the crude methanol extract exhibited very good antioxidant activities. However, with the aid of DPPH, the crude methanol extract, ethyl acetate and methanol fractions exhibited excellent antioxidant activities in comparison with ascorbic acid. Serial extraction did not make any of the fractionated extracts better than the crude extract of the red cultivar A. cepa bulbs. These results also showed that red cultivar A. cepa bulbs is a natural source of antioxidants and could serve as therapeutic agent in the prevention or slowing down of oxidative stress. Further studies are currently underway to identify the active component responsible for the observed antioxidant properties.

Machine learning based orthodontic treatment planning for mixed dentition borderline cases suffering from moderate to severe crowding: An experimental research study.

Pedodontists and general practitioners may need support in planning the early orthodontic treatment of patients with mixed dentition, especially in borderline cases. The use of machine learning algorithms is required to be able to consistently make treatment decisions for such cases. This study aimed to use machine learning algorithms to facilitate the process of deciding whether to choose serial extraction or expansion of maxillary and mandibular dental arches for early treatment of borderline patients suffering from moderate to severe crowding. The dataset of 116 patients who were previously treated by senior orthodontists and divided into two groups according to their treatment modalities were examined. Machine Learning algorithms including Multilayer Perceptron, Linear Logistic Regression, k-nearest Neighbors, Naïve Bayes, and Random Forest were trained on this dataset. Several metrics were used for the evaluation of accuracy, precision, recall, and kappa statistic. The most important 12 features were determined with the feature selection algorithm. While all algorithms achieved over 90% accuracy, Random Forest yielded 95% accuracy, with high reliability values (kappa = 0.90). The employment of machine learning methods for the treatment decision with or without extraction in the early treatment of patients in the mixed dentition can be particularly useful for pedodontists and general practitioners.

Reinventing serial extraction with a fresh perspective: does it inspire a change in current practice?

To analyze the skeletal and dental effects of serial extraction with and without expansion on severe crowding. A retrospective controlled study using lateral cephalograms of 78 children of age 8.5 + /- 1.4 years. The study sample involved 52 orthodontic patients treated for severe crowding and 26 age matched controls who did not undergo orthodontic treatment. The treated cases were sorted into serial extraction (EX) only group and serial extraction and expansion (EX-EXP) group. Vertical and anteroposterior skeletal and dental cephalometric measurements of these subjects were analyzed at baseline time point and following eruption of posterior permanent dentition. The study found significant changes in vertical skeletal dimensions with a decrease in mandibular and occlusal plane angles in the experimental groups at the follow up. The facial height index was noted to be increased. The upper gonial angle decreased significantly in the groups that had extractions. There was no significant change in the inter-incisal angle among the groups, yet at follow-up the inter-incisal angle of the control group was significantly smaller than the intervention groups. The article concludes that serial extraction alone or in combination with expansion treatment performed prior to pubertal growth phase have comparable skeletal cephalometric findings primarily affecting the vertical dimension.

Assessment of Erosive Effect of Various Beverages on Esthetic Restorative Materials Used in Primary Teeth: An In Vitro Study.

The purpose of the current study was to evaluate the erosive impact of various beverages on the esthetic restorative materials utilized in primary teeth. One hundred and twenty primary molars indicated for serial extraction or over-retention reason with sound buccal surfaces were collected. One millimeter above the cemento-enamel junction, standard Class V cavities were prepared. Following cavity preparation, all teeth were randomly assigned (20 samples per group for each beverage) to one of the three experimental groups based on the type of filling materials: group I: resin-modified glass ionomer cement (GC), group II: nanocomposite resin and group III nanohybrid ormocer-based composite. The samples were kept suspended in various containers containing 250 mL of each orange juice and cola at a temperature of 37°C for three hours per day and rest of day in distilled water. This procedure was repeated for 15 days. Using a 3D optical profilometer, a profilometric reading was recorded for each specimen. The minimum surface roughness was found in nanohybrid ormocer‑based composite (1.816 ± 0.16 and 1.302 ± 0.08) followed by resin-modified glass ionomer cement (3.101 ± 0.12 and 2.946 ± 0.09) and nanocomposite resin (5.242 ± 0.20 and 4.488 ± 0.16) after immersed in the cola and orange juice, respectively. And there was a statistically significant difference found between the different esthetic restorative materials in both media. On conclusion, the current investigation demonstrates that when exposed to both beverages, the erosive effect was much lesser in nanohybrid ormocer-based composite, followed by resin-modified glass ionomer cement and nanocomposite resin. Consuming high-calorie, low pH acidic foods and beverages such as carbonated beverages and fruit juices can lead to erosion, a frequent condition that results in irreparable damage to dental hard tissues and early deterioration of dental restorations.

Phytochemistry, Proximate Analysis and Acute Toxicity Study of Ethanolic Moringa Oleifera Root Bark Extract.

Moringa Oleifera is a fast growing deciduous tree with its different plant parts commonly used in herbal medicine, also with good socio-economic and industrial values. The ethanolic extract of M.Oleifera root bark is shown to be rich in nutrients, owing to the presence of essential phytochemicals in the root bark. The phytochemicals or secondary metabolites of the ethanolic extract of the root bark were screened and identified. Also, acute toxicity study of the ethanolic extract of the root bark was carriedout in Albino Rats according to Institutional Animal Care and Use (IACU) guidelines. The fresh M.Oleifera root was harvested at the inception of the rainy season at Pil Gani District of Langtang North LGA and excess soil washed off as the root bark was properly peeled, air dried, pulverized to powdered form and stored for subsequent use. Serial extractions using water, acetone, ethanol, and ethyl acetate were carriedout by Simple Maceration. The ethanolic extract was seen to have the best yield of the phytochemicals qualitatively identified as tannins, saponins, carbohydrates, flavonoids, alkaloids, steroids, terpenes, cardiac glycosides and anthraquinones. Acute toxicity test was determined by Lorke’s method and the LD50 was shown to be at the highest limit dose of 5000mg/kg, which signifies that the extract is non toxic at such single dosage. The ethanolic M.Oleifera root bark extract contains nutritive phytochemicals with vast medicinal uses. No sign of acute toxicity was observed on oral administration as the median lethal dose was shown to be safe at the highest limit single dose of 5000mg/kg.

Biological investigation of resinous endodontic sealers containing calcium hydroxide.

The purpose of this study was to evaluate, in vivo, the biocompatibility, biomineralization, collagen maturation and the in vitro antibacterial and cytotoxicity of resinous endodontic sealers containing calcium hydroxide. Forty rats were implanted with polyethylene tubes containing Sealer 26, Sealer Plus, Dia-ProSeal and an empty tube, examined after 7, 15, 30 and 60 days. Antimicrobial activity was evaluated against Enterococcus faecalis by Agar Diffusion Test (ADT) through inhibition zones. For cytotoxicity, undifferentiated pulp cells (OD-21) were cultured and assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, exposed to dilution of serial extracts at 6, 24, 48h. Cytotoxicity was analyzed by two-way ANOVA and Bonferroni correction. Kruskal-Wallis test followed by Dunn test was performed for nonparametric data (p<0.05). MTT assay revealed cell proliferation affected by sealers extract in all periods (p<0.0001), except for Dia-Proseal and Sealer Plus ⅛ dilution. Subcutaneous analysis showed at day 7th moderate inflammatory infiltration. After 30 days, Sealer 26 still showed moderate inflammatory infiltrate compared to mild inflammation from control and Dia-ProSeal (p = 0.006). At day 60th, all groups showed similar mild inflammatory infiltrate (p>0.05). Sealer 26 induced more biomineralization than other sealers in all periods. At 7 and 15 days, all sealers had significant percentage of immature collagen fibers. After 60 days Sealer 26 showed more mature fibers compared to other sealers (p<0.001). All sealers had a smaller zone of inhibition than chlorhexidine, but with no significant difference among any group (p>0.05). All sealers showed satisfactory biological responses with in vitro/in vivo biocompatibility and antimicrobial activity against planktonic bacteria. Sealer 26 induced more biomineralization than Sealer Plus and Dia-ProSeal.

A potent bioactive fraction against colon cancer from Plectranthus vettiveroides.

This study was designed to investigate the anticancer efficacy of the organic leaf extracts of the plant, Plectranthus vettiveroides (P. vettiveroides), and to analyze the molecular mechanism of the anticancer activity. The leaf extracts were prepared by polarity-graded serial extraction of the dried leaf powder. The cytotoxic effect of the extracts was analyzed by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. The most active ethyl acetate extract was subjected to bioactivity-guided fractionation by column chromatography, which yielded a cytotoxic fraction designated as the P. vettiveroides fraction (PVF). The anticancer property of PVF was confirmed further by clonogenic assay. The mechanism of PVF-induced cell death was analyzed by flow cytometry and fluorescence microscopy. Additionally, the effects of PVF on apoptotic and cell survival pathways were analyzed using western immunoblot analysis. A bioactive fraction PVF, was isolated from the ethyl acetate leaf extract. PVF showed significant anticancer activity against colon cancer cells, whilst normal cells were comparatively less affected. PVF induced strong apoptotic stimuli in colorectal carcinoma cell line HCT116, involving both extrinsic and intrinsic pathways. Investigation into the molecular mechanism of anticancer activity of PVF in HCT116 cells revealed that the fraction activates the pro-apoptotic pathway via tumor suppressor protein 53 (p53) and inhibits the anti-apoptotic pathway by regulating phosphatidylinositol 3-kinase (PI3K) signaling. The findings of this study demonstrate, with mechanism-based evidence, the chemotherapeutic potential of a bioactive fraction PVF, derived from the leaves of the medicinal plant P. vettiveroides against colon cancer.

Skeletal and dental effects of serial extractions performed with or without maxillary expansion-A retrospective controlled study.

The study aimed to compare severe crowding treatment's skeletal and dental effects by serial extractions or maxillary expansion and serial extractions in the mixed dentition phase. The retrospective controlled study included lateral cephalograms of 78 subjects aged 8.5 ± 1.4 years, 52 consecutively treated because of severe crowding, and 26 untreated controls matched for baseline age and observational period. Subjects were clustered according to the treatment modality, either serial extraction (EX) or expansion and extraction (EXP-EX) group. Sagittal and vertical skeletal as well as dental cephalometric parameters were assessed at baseline and after the eruption of all permanent posterior teeth, and group comparisons were performed. Both treatment modalities significantly affected the vertical skeletal parameters in terms of decreasing the mandibular and occlusal plane inclination and increasing the facial height index. A distinct treatment effect on the gonial angle was observed, with a significant decrease in its superior part observed in both extraction groups. The annualized changes in the superior part of the gonial angle significantly differ (P = .036) between the Control (-0.04 ± 0.6), EX (-0.44 ± 0.6) and EXP-EX (-0.34 ± 0.5) groups. Upper and lower incisor inclination did not change significantly in any of the groups; however, the interincisal angle at follow-up was significantly smaller in the Control compared with both treated groups. Serial extractions and a combination of maxillary expansion and serial extractions have similar significant skeletal effects, mainly affecting vertical cephalometric parameters if performed during the pre-pubertal growth phase.

Acute and Subchronic Toxicity of Forastero Cocoa from Côte d'Ivoire

In Côte d'Ivoire, forastero cocoa is used by traditional healers to treat metabolic and chronic diseases like diabetes. This study aims to assess the toxicity of extracts from forastero cocoa. Serial extraction was performed from cocoa powder using ethanol, distilled water and hexane. The phytochemical screening of aqueous and hydroethanolic extracts and crude cocoa powder was carried out using appropriate specific reagents. Acute and subchronic oral toxicity studies were performed in rats according to OECD guidelines 423 and 408. The phytochemical screening reveals the presence of polyterpenes, polyphenols, alkaloids and saponosides in the aqueous, hydroethanolic extracts and crude cocoa powder. Regarding acute toxicity, the LD50 value is higher than 5000 mg/kg body weight. In subchronic toxicity, results show that for all the doses there is a significant increase in the weight of male and female rats. Furthermore, no signs of intoxication or mortality were observed during 90 days. Analysis of hematological and biochemical parameters reveals that there is no significant change in blood parameters values and liver, kidneys and heart serum markers. On the whole, the results show that extracts from forastero cocoa are not toxic.

Scanning electron microscopic study of smear layer changes following ultrasonic endoactivator irrigation system during root canal treatment of primary teeth

AimsEvaluation of smear layer changes following ultrasonic endoactivator irrigation system during root canal treatment of primary teeth under Electron Microscope.Settings and designThe study was conducted as a clinical trial. The laboratory part was carried out at Pediatric Dentistry Department, Faculty of Dentistry, Tanta University, scanning electron microscopic analysis was conducted at electron microscope unit, Faculty of Science, Alexandria University.Patients and methodsA total of 40 intact, extracted primary canines (due to serial extraction) were collected and randomly divided into four equal groups' including 10 teeth for each. Group I: irrigation of root canal with sodium hypochlorite by a plastic syringe with end-vented needle. Group II: irrigation of root canal by a plastic syringe with side-vented needle. Group III: the same of group I in conjunction with ultrasonic endoactivator. Group IV: the same of group II in conjunction with ultrasonic endoactivator. Then preparation of specimens was done for scanning electron microscope.ResultsIt was noticed that groups III and IV that used ultrasonic endoactivator had lower scores of smear layer amount than the other groups.ConclusionsUltrasonic endoactivator system in conjunction with conventional irrigation could improve disinfection of the root canals of primary teeth.

Germectomy (Therapeutic Enucleation) of First Bicuspids and Eruption Guide to Treat Dental Crowding without Using Orthodontic Treatment. Case Report

Germectomy (enucleation) of the first bicuspids has shown to be an effective treatment in the management of dental crowding in mixed dentition because it produces intraosseous decongestion of the dental mass between permanent canines and second bicuspids. This provides early available space for the autonomic eruption without interference from the first bicuspid to the permanent canine which erupts into a highly stable position within the dental arch, facilitating and accelerating orthodontic treatment (if required) which would be terminating before the difficult adolescent age. This procedure differs from the orthodontic treatment of extracting the first bicuspids after they erupt when they are already facing a frank crowding, mature periodontal ligament, and deformity of the alveolar process. In our opinion, Germectomy of first bicuspids will replace serial extractions during which time the treating specialist will concentrate on preventive eruption guidance and the management of habits in general such as tongue, thumb, lips, and mouth breathing, in addition to performing Functional orthopedics of the jaws as in deep bites, deficiency or maxillary protrusion among others.

Mechanistic investigation of formation of highly-dispersed silver nanoparticles using sea buckthorn extract

Nowadays, the greener pathways for the synthesis of nanostructures are being explored. The extracts of different parts of plants viz leaves, stems, and roots have been investigated. However, these extracts have been prepared by simply boiling or microwaving, or sonicating the parts of plants with water. Therefore, to have deeper insight and to investigate the full potential of plant extracts, serial extraction of leaves of sea buckthorn (Hippophae rhamnoides L.) which is a medicinally important plant was attempted using the soxhlet apparatus. The as-obtained polyphenolic-rich extract was employed for the preparation of silver nanoparticles (Ag−NPs). Under optimized reaction conditions viz 60 °C temperature and 500 μl of extract solution (5 mg ml−1) highly disperse spherical nanoparticles of the average size of 15.8 ± 4.8 nm were obtained. Further, the optical band gap of Ag−NPs prepared using optimized reaction conditions was found to be 2.6 eV using the Tauc equation. Additionally, to understand the reduction by the extract, kinetic studies were also carried out which suggest the predominant occurrence of pseudo-first-order reaction. Furthermore, the mechanism of formation of Ag−NPs using major components of extract viz gallic acid and catechin which were identified by HPLC were also investigated using DFT. The mechanistic investigation was performed for both the keto-enol and radical-mediated preparation of Ag−NPs. Such theoretical investigations will help in the efficient designing of greener and novel routes for the synthesis of Ag−NPs. Additionally, the prepared silver was also employed for the colorimetric detection of H2O2.

Metal transfer to sediments, invertebrates and fish following waterborne exposure to silver nitrate or silver sulfide nanoparticles in an indoor stream mesocosm

The fate of engineered nanomaterials in ecosystems is unclear. An aquatic stream mesocosm explored the fate and bioaccumulation of silver sulfide nanoparticles (Ag2S NPs) compared to silver nitrate (AgNO3). The aims were to determine the total Ag in water, sediment and biota, and to evaluate the bioavailable fractions of silver in the sediment using a serial extraction method. The total Ag in the water column from a nominal daily dose of 10 μg L−1 of Ag for the AgNO3 or Ag2S NP treatments reached a plateau of around 13 and 12 μg L−1, respectively, by the end of the study. Similarly, the sediment of both Ag-treatments reached ~380 μg Ag kg−1, and with most of it being acid-extractable/labile. The biota accumulated 4–59 μg Ag g−1 dw, depending on the type of Ag-treatment and organism. The oligochaete worm, Lumbriculus variegatus, accumulated Ag from the Ag2S exposure over time, which was similar to the AgNO3 treatment by the end of the experiment. The planarian, Girardia tigrina, and the chironomid larva, Chironomus riparius, showed much higher Ag concentrations than the oligochaete worms; and with a clearer time-dependent statistically significant Ag accumulation relative to the untreated controls. For the pulmonate snail, Physa acuta, bioaccumulation of Ag from AgNO3 and Ag2S NP exposures was observed, but was lower from the nano treatment. The AgNO3 exposure caused appreciable Ag accumulation in the water flea, Daphnia magna, but accumulation was higher in the Ag2S NP treatment (reaching 59 μg g−1 dw). In the rainbow trout, Oncorhynchus mykiss, AgNO3, but not Ag2S NPs, caused total Ag concentrations to increase in the tissues. Overall, the study showed transfer of total Ag from the water column to the sediment, and Ag bioaccumulation in the biota, with Ag from Ag2S NP exposure generally being less bioavailable than that from AgNO3.