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Fulltext Taxon- and Growth Phase-Specific Antioxidant Production by Chlorophyte, Bacillariophyte, and Haptophyte Strains Isolated From Tropical Waters

Rahman NA, Katayama T, Wahid MEA, Kasan NA, Khatoon H, Yamada Y, et al.

Front Bioeng Biotechnol, 2020;8:581628.
PMID: 33330417 DOI: 10.3389/fbioe.2020.581628

Antioxidants found in microalgae play an essential role in both animals and humans, against various diseases and aging processes by protecting cells from oxidative damage. In this study, 26 indigenous tropical marine microalgae were screened. Out of the 26 screened strains, 10 were selected and were further investigated for their natural antioxidant compounds which include carotenoids, phenolics, and fatty acids collected in their exponential and stationary phases. The antioxidant capacity was also evaluated by a total of four assays, which include ABTS, DPPH, superoxide radical (O2•-) scavenging capacity, and nitric oxide (•NO-) scavenging capacity. This study revealed that the antioxidant capacity of the microalgae varied between divisions, strains, and growth phase and was also related to the content of antioxidant compounds present in the cells. Carotenoids and phenolics were found to be the major contributors to the antioxidant capacity, followed by polyunsaturated fatty acids linoleic acid (LA), eicosapentaenoic acid (EPA), arachidonic acid (ARA), and docosahexaenoic acid (DHA) compared to other fatty acids. The antioxidant capacity of the selected bacillariophytes and haptophytes was found to be positively correlated to phenolic (R2-value = 0.623, 0.714, and 0.786 with ABTS, DPPH, and •NO-) under exponential phase, and to carotenoid fucoxanthin and β-carotene (R2 value = 0.530, 0.581 with ABTS, and 0.710, 0.795 with O2•-) under stationary phase. Meanwhile, antioxidant capacity of chlorophyte strains was positively correlated with lutein, β-carotene and zeaxanthin under the exponential phase (R2 value = 0.615, 0.615, 0.507 with ABTS, and R2 value = 0.794, 0.659, and 0.509 with •NO-). In the stationary phase, chlorophyte strains were positively correlated with violaxanthin (0.755 with •NO-), neoxanthin (0.623 with DPPH, 0.610 with •NO-), and lutein (0.582 with •NO-). This study showed that antioxidant capacity and related antioxidant compound production of tropical microalgae strains are growth phase-dependent. The results can be used to improve the microalgal antioxidant compound production for application in pharmaceutical, nutraceutical, food, and feed industry.
Fulltext The Numerical Competency of Two Bird Species (Corvus splendens and Acridotheres tristis)

Rahman NA, Fadzly N, Dzakwan NM, Zulkifli NH

Trop Life Sci Res, 2014 Aug;25(1):95-103.
PMID: 25210590 MyJurnal

We conducted a series of experiments to test the numerical competency of two species of birds, Corvus splendens (House Crow) and Acridotheres tristis (Common Myna). Both species were allowed to choose from seven different groups of mealworms with varying proportions. We considered the birds to have made a correct choice when it selected the food group with the highest number of mealworms. Our overall results indicated that the Common Myna is able to count numbers (161 successful choices out of 247 trials) better than House Crows (133 successful choices out of 241 trials). We suspect that House Crows do not rely on a numerical sense when selecting food. Although House Crows mostly chose the cup with more mealworms (from seven food item proportions), only one proportion was chosen at rate above random chance. The Common Myna, however, were slow performers at the beginning but became increasingly more capable of numerical sense during the remainder of the experiment (four out of seven food proportion groups were chosen at a rate above random chance).
Fulltext Counting with Colours? Effect of Colours on the Numerical Abilities of House Crows (Corvus splendens) and Common Myna (Acridotheres tristis)

Rahman NA, Ali Z, Zuharah WF, Fadzly N

Trop Life Sci Res, 2016 Aug;27(2):1-12.
PMID: 27688847 MyJurnal DOI: 10.21315/tlsr2016.27.2.1

We conducted several aviary experiments to investigate the influence of colours in quantity judgments of two species of birds; house crow (Corvus splendens) and common myna (Acridotheres tristis). Different quantity (in seven different food proportions) of mealworms were presented nonsequentially to all birds using artificially coloured red mealworms, for experiment 1, and using artificially coloured green mealworms, for experiment 2. Both red and green coloured mealworms have no significant effect on house crow's quantity judgments (red:
Serotyping of Brunei pneumococcal clinical strains and the investigation of their capability to adhere and invade a brain endothelium model

Rahman NA, Sharudin A, Diah S, Muharram SH

Microb Pathog, 2017 Sep;110:352-358.
PMID: 28711510 DOI: 10.1016/j.micpath.2017.07.021

INTRODUCTION: Pneumococcal infections have caused morbidity and mortality globally. Streptococcus pneumoniae (pneumococci) are commensal bacteria that colonize the nasopharynx, asymptomatically. From there, pneumococci can spread in the lungs causing pneumonia and disseminate in the bloodstream causing bacteremia (sepsis) and reach the brain leading to meningitis. Endothelial cells are one of the most important components of the blood-brain barrier that separates the blood from the brain and plays the first protective role against pneumococcal entry. Thus this study aimed to investigate on the ability of non-meningitis pneumococcal clinical strains to adhere and invade a brain endothelium model.
METHODS: Two pneumococcal Brunei clinical strains were serotyped by multiplex PCR method using oligonucleotide sequences derived from Centers for Disease Control and Prevention. A validated immortalised mouse brain endothelial cell line (bEnd.3) was used as a brain endothelium model for the study of the pneumococcal breach of the blood-brain barrier using an adherence and invasion assay.
RESULTS: Both of the pneumococcal clinical strains were found to be serotype 19F, a common circulating serotype in Southeast Asia and globally and possess the ability to adhere and invade the brain endothelial cells.
CONCLUSION: In addition, this is the first report on the serotype identification of pneumococci in Brunei Darussalam and their application on a brain endothelium model. Further studies are required to understand the virulence capabilities of the clinical strains.
Induction of apoptosis and G2/M arrest by ampelopsin E from Dryobalanops towards triple negative breast cancer cells, MDA-MB-231

Rahman NA, Yazan LS, Wibowo A, Ahmat N, Foo JB, Tor YS, et al.

BMC Complement Altern Med, 2016;16:354.
PMID: 27609190 DOI: 10.1186/s12906-016-1328-1

Several compounds isolated from Dryobalanops have been reported to exhibit cytotoxic effects to several cancer cell lines. This study investigated the cytotoxic effects, cell cycle arrest and mode of cell death in ampelopsin E-treated triple negative cells, MDA-MB-231.
Fulltext Synthesis and characterizations of o-nitrochitosan based biopolymer electrolyte for electrochemical devices

Rahman NA, Abu Hanifah S, Mobarak NN, Su'ait MS, Ahmad A, Shyuan LK, et al.

PLoS One, 2019;14(2):e0212066.
PMID: 30768616 DOI: 10.1371/journal.pone.0212066

For the past decade, much attention was focused on polysaccharide natural resources for various purposes. Throughout the works, several efforts were reported to prepare new function of chitosan by chemical modifications for renewable energy, such as fuel cell application. This paper focuses on synthesis of the chitosan derivative, namely, O-nitrochitosan which was synthesized at various compositions of sodium hydroxide and reacted with nitric acid fume. Its potential as biopolymer electrolytes was studied. The substitution of nitro group was analyzed by using Attenuated Total Reflectance Fourier Transform Infra-Red (ATR-FTIR) analysis, Nuclear Magnetic Resonance (NMR) and Elemental Analysis (CHNS). The structure was characterized by X-ray Diffraction (XRD) and its thermal properties were examined by using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Whereas, the ionic conductivity of the samples was analyzed by electrochemical impedance spectroscopy (EIS). From the IR spectrum results, the nitro group peaks of O-nitrochitosan, positioned at 1646 and 1355 cm-1, were clearly seen for all pH media. At pH 6, O-nitrochitosan exhibited the highest degree of substitution at 0.74 when analyzed by CHNS analysis and NMR further proved that C-6 of glucosamine ring was shifted to the higher field. However, the thermal stability and glass transition temperatures were decreased with acidic condition. The highest ionic conductivity of O-nitrochitosan was obtained at ~10-6 cm-1. Overall, the electrochemical property of new O-nitrochitosan showed a good improvement as compared to chitosan and other chitosan derivatives. Hence, O-nitrochitosan is a promising biopolymer electrolyte and has the potential to be applied in electrochemical devices.
Work-related musculoskeletal symptoms and coping strategies among dental auxiliaries at hospital universiti Sains Malaysia

Rahman NA, Adnan MM, Yusoff A, Shu JMH, Rustam K

Indian J Dent Res, 2020 4 5;31(1):61-66.
PMID: 32246684 DOI: 10.4103/ijdr.IJDR_430_18

Background: Dental personnel are vulnerable to work-related musculoskeletal symptoms (WMSS) due to the nature of their profession.
Aim: To determine WMSS experienced by dental auxiliaries and their coping strategies toward these symptoms.
Setting and Design: A cross-sectional study was conducted on 82 dental auxiliaries at a university dental hospital in Malaysia.
Materials and Methods: Nordic musculoskeletal questionnaire and the Brief COPE questionnaire were used to measure the musculoskeletal symptoms and coping strategies of the respondents, respectively. Data were analyzed using IBM SPSS version 22.0.
Results: Dental auxiliaries consisted of dental staff nurses (30.5%), dental surgery assistants (40.2%), dental technologists (18.3%), and healthcare assistants (11.0%). Their mean [standard deviation (SD)] age was 33.4 (7.60) years. Most of the respondents had been troubled with ache, pain, and discomfort at the neck, 54.9% (95% confidence interval 44.0%, 66.0%]. In addition, they were troubled mainly with distress at the low back (34.1%) and the ankle or feet (34.1%) which had prevented the respondents from doing their regular job over the past 12 months. The most common areas that had troubled the respondents over the past 7 days were the neck (36.6%), low back (36.6%), and ankle or feet (36.6%). The coping strategy most commonly practiced by the respondents was religion with a mean (SD) score of 3.70 (2.15), followed by active coping [3.13 (0.68)] and acceptance [3.13 (0.69)].
Conclusion: The prevalence of WMSS was high in the dental auxiliaries particularly in the neck region. The most common coping strategy used was religion. Awareness programs on the prevention of WMSS among the dental auxiliaries should be increased.
Fulltext Foot ulcers and their association with diabetic Charcot foot complications

Rahman NA, Fauzi AA, Chung TY, Latif LA, Chan SC

Aust J Gen Pract, 2020 2 3;49(1-2):48-53.
PMID: 32008261 DOI: 10.31128/AJGP-07-19-4991

BACKGROUND AND OBJECTIVES: Diabetic Charcot foot (DCF) can cause gross structural deformities of the foot and ankle. The main objective of this study was to identify complications of DCF and its associated factors.
METHOD: This is a retrospective cohort study. Data on medical background, previous DCF treatment and complications were obtained. Multiple logistic regression analysis was performed to measure factors related to various complications of DCF.
RESULTS: Ninety-eight patient records were retrieved. Of the 83 patients who were still alive, 75.9% (n = 63) had recurrent ulcers, 53.0% (n = 44) had undergone foot surgery and 45.8% (n = 38) had undergone amputation. Patients with a history of recurrent ulcers have the highest predilection to amputation (odds ratio: 8.5; 95% confidence interval: 1.8, 39.1).
DISCUSSION: In terms of DCF complications, foot ulcers are an independent predictor of recurrent foot ulcers, foot surgery and amputation. Regular foot assessment of patients with DCF to prevent ulcers is strongly recommended.
Fulltext Floating teeth appearance: A radiographic dilemma

Rahman NA, Harun MH, Rahman SA, Mohammad NSA

J Taibah Univ Med Sci, 2020 Apr;15(2):160-165.
PMID: 32368214 DOI: 10.1016/j.jtumed.2020.02.005

Gorham disease (GD) is an extremely rare disorder that is characterised by massive osteolysis of the affected bone with unknown aetiology and an unpredictable prognosis. Additionally, no standard treatment is available for GD. This article describes a case report of a 61-year-old Malay woman who was diagnosed with GD of the anterior mandible without a prior history of trauma. She presented with pain and mobility of the dentoalveolar segment for 3 months. The radiographic findings showed "floating teeth" with widening of the periodontal ligament space and localized area of bony destruction. Histopathologically, there was proliferation of numerous dilated endothelial-lined channels within the intertrabecular tissue. Some areas of bone were replaced by fibrous connective tissue giving rise to the appearance of a benign fibroosseous lesion. The patient was managed with simple removal of the affected bone segment under local anaesthesia, followed by prosthodontic rehabilitation. Healing of the surgical site was uneventful, and no recurrence was reported at the 3-year follow-up.
Fulltext The impact of local surface changes in Borneo on atmospheric composition at wider spatial scales: coastal processes, land-use change and air quality

Pyle JA, Warwick NJ, Harris NR, Abas MR, Archibald AT, Ashfold MJ, et al.

Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3210-24.
PMID: 22006963 DOI: 10.1098/rstb.2011.0060

We present results from the OP3 campaign in Sabah during 2008 that allow us to study the impact of local emission changes over Borneo on atmospheric composition at the regional and wider scale. OP3 constituent data provide an important constraint on model performance. Treatment of boundary layer processes is highlighted as an important area of model uncertainty. Model studies of land-use change confirm earlier work, indicating that further changes to intensive oil palm agriculture in South East Asia, and the tropics in general, could have important impacts on air quality, with the biggest factor being the concomitant changes in NO(x) emissions. With the model scenarios used here, local increases in ozone of around 50 per cent could occur. We also report measurements of short-lived brominated compounds around Sabah suggesting that oceanic (and, especially, coastal) emission sources dominate locally. The concentration of bromine in short-lived halocarbons measured at the surface during OP3 amounted to about 7 ppt, setting an upper limit on the amount of these species that can reach the lower stratosphere.
Fulltext A Review on Oxidative Stress, Diabetic Complications, and the Roles of Honey Polyphenols

Pasupuleti VR, Arigela CS, Gan SH, Salam SKN, Krishnan KT, Rahman NA, et al.

Oxid Med Cell Longev, 2020;2020:8878172.
PMID: 33299532 DOI: 10.1155/2020/8878172

Despite the availability of various antidiabetic drugs, diabetes mellitus (DM) remains one of the world's most prevalent chronic diseases and is a global burden. Hyperglycaemia, a characteristic of type 2 diabetes mellitus (T2DM), substantially leads to the generation of reactive oxygen species (ROS), triggering oxidative stress as well as numerous cellular and molecular modifications such as mitochondrial dysfunction affecting normal physiological functions in the body. In mitochondrial-mediated processes, oxidative pathways play an important role, although the responsible molecular mechanisms remain unclear. The impaired mitochondrial function is evidenced by insulin insensitivity in various cell types. In addition, the roles of master antioxidant pathway nuclear factor erythroid 2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1)/antioxidant response elements (ARE) are being deciphered to explain various molecular pathways involved in diabetes. Dietary factors are known to influence diabetes, and many natural dietary factors have been studied to improve diabetes. Honey is primarily rich in carbohydrates and is also abundant in flavonoids and phenolic acids; thus, it is a promising therapeutic antioxidant for various disorders. Various research has indicated that honey has strong wound-healing properties and has antibacterial, anti-inflammatory, antifungal, and antiviral effects; thus, it is a promising antidiabetic agent. The potential antidiabetic mechanisms of honey were proposed based on its major constituents. This review focuses on the various prospects of using honey as an antidiabetic agent and the potential insights.
All serotypes of dengue virus induce HLA-A2 major histocompatibility complex class I promoter activity in human liver cells

Othman S, Rahman NA, Yusof R

Trans R Soc Trop Med Hyg, 2010 Dec;104(12):806-8.
PMID: 20800252 DOI: 10.1016/j.trstmh.2010.07.004

In contrast to many viruses that escape the host's immune responses by suppressing the major histocompatibility complex (MHC) class I pathway, flaviviruses have been shown to up-regulate the cell surface expression of MHC class I complex. The mechanism by which dengue virus (DV) achieves this up-regulation remains unclear. Our investigation on the HLA-A2 gene in human liver cells demonstrated that all four serotypes of dengue virus, DV1 to DV4, resulted in variable degrees of promoter induction. This illustrates the importance of MHC class I transcription regulation in primary infections by different DV serotypes that may have even greater impact in secondary infections, associated with increased disease severity.
Induction of MHC Class I HLA-A2 promoter by dengue virus occurs at the NFκB binding domains of the Class I Regulatory Complex

Othman S, Rahman NA, Yusof R

Virus Res, 2012 Jan;163(1):238-45.
PMID: 22001567 DOI: 10.1016/j.virusres.2011.09.040

Despite aggressive efforts in dengue research, the control of dengue diseases and discovery of therapeutics against them await complete elucidation of its complex immune-pathogenesis. Unlike many viruses that escape the host's immune responses by suppressing the major histocompatibility complex (MHC) Class I pathway, many Flaviviruses up-regulate the cell surface expression of MHC Class I complex. We recently reported MHC Class I HLA-A2 promoter activation by all serotypes of dengue virus (DV). The mechanism by which DV regulates this is further explored here in HepG2 human liver cell line. Using real-time PCR, evidence that, similar to infections by other Flaviviruses, DV infection has the ability to up-regulate the MHC Class I transcription and mRNA synthesis, is presented. The region responsive towards DV infection of all serotypes was mapped to the Class I Regulatory Complex (CRC) of the HLA-A2 promoter. Competition electrophoretic mobility shift assay (EMSA) with NFκB probe established the presence of specific DNA-protein complex in DV-infected nuclear extracts. Antibody-supershift assays identified the MHC Class I promoter activation by DV to occur through binding of p65/p50 heterodimers and p65 homodimers to κB1 and κB2 cis-acting elements, respectively, within the CRC, and not with the interferon consensus sequence (ICS). This study presents evidence of MHC Class I gene modulation by DV, hence providing a better understanding of dengue immune-pathogenesis that would consequently facilitate the discovery of antiviral therapeutics against dengue.
Docking of noncompetitive inhibitors into dengue virus type 2 protease: understanding the interactions with allosteric binding sites

Othman R, Kiat TS, Khalid N, Yusof R, Newhouse EI, Newhouse JS, et al.

J Chem Inf Model, 2008 Aug;48(8):1582-91.
PMID: 18656912 DOI: 10.1021/ci700388k

A group of flavanones and their chalcones, isolated from Boesenbergia rotunda L., were previously reported to show varying degrees of noncompetitive inhibitory activities toward Dengue virus type 2 (Den2) protease. Results obtained from automated docking studies are in agreement with experimental data in which the ligands were shown to bind to sites other than the active site of the protease. The calculated K(i) values are very small, indicating that the ligands bind quite well to the allosteric binding site. Greater inhibition by pinostrobin, compared to the other compounds, can be explained by H-bonding interaction with the backbone carbonyl of Lys74, which is bonded to Asp75 (one of the catalytic triad residues). In addition, structure-activity relationship analysis yields structural information that may be useful for designing more effective therapeutic drugs against dengue virus infections.
Analysis of secondary structure predictions of dengue virus type 2 NS2B/NS3 against crystal structure to evaluate the predictive power of the in silico methods

Othman R, Wahab HA, Yusof R, Rahman NA

In Silico Biol. (Gedrukt), 2007;7(2):215-24.
PMID: 17688447

Multiple sequence alignment was performed against eight proteases from the Flaviviridae family using ClustalW to illustrate conserved domains. Two sets of prediction approaches were applied and the results compared. Firstly, secondary structure prediction was performed using available structure prediction servers. The second approach made use of the information on the secondary structures extracted from structure prediction servers, threading techniques and DSSP database of some of the templates used in the threading techniques. Consensus on the one-dimensional secondary structure of Den2 protease was obtained from each approach and evaluated against data from the recently crystallised Den2 NS2B/NS3 obtained from the Protein Data Bank (PDB). Results indicated the second approach to show higher accuracy compared to the use of prediction servers only. Thus, it is plausible that this approach is applicable to the initial stage of structural studies of proteins with low amino acid sequence homology against other available proteins in the PDB.
The full-length clone of cucumber green mottle mosaic virus and its application as an expression system for Hepatitis B surface antigen

Ooi A, Tan S, Mohamed R, Rahman NA, Othman RY

J Biotechnol, 2006 Feb 24;121(4):471-81.
PMID: 16271415

A cucumber green mosaic mottle virus (CGMMV) full-length clone was developed for the expression of Hepatitis B surface antigen (HBsAg). The expression of the surface displayed HBsAg by the chimeric virus was confirmed through a double antibody sandwich ELISA. Assessment of the coat protein composition of the chimeric virus particles by SDS-PAGE analysis showed that 50% of the coat proteins were fused to the HBsAg. Biological activity of the expressed HBsAg was assessed through the stimulation of in vitro antibody production by cultured peripheral blood mononuclear cells (PBMC). PBMC that were cultured in the presence of the chimeric virus showed up to an approximately three-fold increase in the level of anti HBsAg immunoglobulin thus suggesting the possible use of this new chimeric virus as an effective Hepatitis B vaccine.
Enantioselective organocatalytic Diels-Alder reactions: a density functional theory and kinetic isotope effects study

Omar NY, Rahman NA, Zain SM

J Comput Chem, 2011 Jul 15;32(9):1813-23.
PMID: 21455954 DOI: 10.1002/jcc.21763

The mechanism and enantioselectivity of the organocatalytic Diels-Alder reaction were computationally investigated by density functional theory at the B3LYP/6-31G(d) level of theory. The uncatalyzed Diels-Alder reaction was also studied to explore the effect of the organocatalyst on this reaction in terms of energetics, selectivity, and mechanism. The catalyzed reaction showed improved endo/exo selectivity, and the free energy of activation was significantly lowered in the presence of the catalyst. Both uncatalyzed and catalyzed reactions exhibited concerted asynchronous reaction mechanism with the degree of asynchronicity being more evident in the presence of the catalyst. The Corey's experimentally derived predictive selection rules for the outcome of the organocatalytic Diels-Alder reaction were also theoretically analyzed, and an excellent agreement was found between experiment and theory.
Distributions and health risks of polycyclic aromatic hydrocarbons (PAHs) in atmospheric aerosols of Kuala Lumpur, Malaysia

Omar NY, Mon TC, Rahman NA, Abas MR

Sci Total Environ, 2006 Oct 1;369(1-3):76-81.
PMID: 16766020

The concentrations and distributions of particle bound polycyclic aromatic hydrocarbons (PAHs) collected over a 10 month period in ambient environment, at street levels as well as during a hazy episode are reported. Ambient and street level distributions of PAHs were similar and their occurrence was attributed to vehicular emissions. However, in haze particles, a different pattern of PAHs was observed, characterized by relatively low levels of benzo[a]pyrene (BaP) and high levels of benzofluoranthenes (BFs). The BaP equivalency results showed that the potential health risk associated with haze smoke particles was 4 times higher than that of street level particles whereas the lowest health risk was associated with ambient atmospheric particles.
Fulltext Nonprescription Bleaching versus Home Bleaching with Professional Prescriptions: Which One is Safer? A Comprehensive Review of Color Changes and Their Side Effects on Human Enamel

Omar F, Ab-Ghani Z, Rahman NA, Halim MS

Eur J Dent, 2019 Oct;13(4):589-598.
PMID: 31891975 DOI: 10.1055/s-0039-1700659

OBJECTIVES: This study evaluates the efficacy and safety of the professionally prescribed and nonprescription over-the-counter (OTC) bleaching agents.
MATERIALS AND: METHODS: Extracted human upper central incisors were prepared and stained with red wine for 14 days before being subjected to four different bleaching agents: professionally prescribed opalescence PF 15%, VOCO Perfect Bleach 10%, nonprescription OTC Crest 3D Whitestrips, and Whitelight Teeth Whitening System. Colorimetric measurement was performed with Vita Easyshade Handheld Spectrophotometer, enamel surface microhardness measured using Vickers Hardness machine, and surface roughness was evaluated with profilometer, before and after bleaching. Scanning electron microscope (SEM) evaluation and atomic force microscopy were conducted postbleaching.
STATISTICAL ANALYSIS: The data were analyzed with t-test, two-way ANOVA, one-way ANOVA, and Turkey's test at a significance level of 5%.
RESULTS: All bleaching products have the same efficacy to whiten stained enamel. Opalescence PF 15% showed significant increase in the microhardness (92.69 ± 68.316). All groups demonstrated significant increase in surface roughness (p < 0.05). SEM evaluation showed that Opalescence PF 15% resulted in same microscopic appearance as unbleached enamel, while VOCO Perfect Bleach 10%, Whitelight Teeth Whitening System and Crest 3D Whitestrips demonstrated mild to moderate irregularities and accentuated irregularities, respectively.
CONCLUSION: Professionally prescribed bleaching agent of Opalescence PF 15% is effective tin whitening the teeth, while the other bleaching products may be effective but also have deleterious effects on the enamel.
Fulltext Surface Electromyography (sEMG) Activity of Masticatory Muscle (Masseter and Temporalis) with Three Different Types of Orthodontic Bracket

Nishi SE, Rahman NA, Basri R, Alam MK, Noor NFM, Zainal SA, et al.

Biomed Res Int, 2021;2021:6642254.
PMID: 33969121 DOI: 10.1155/2021/6642254

Objective: This pre-post study is aimed at determining the effects of masticatory muscle activity (masseter and temporalis) measured via sEMG between conventional, self-ligating, and ceramic bracket after six months of orthodontic treatment.
Methods: A total of eighteen (18) malocclusion patients were identified. Malocclusion patients were subdivided into 3 groups based on the bracket selection (conventional, self-ligating, and ceramic bracket) with 6 patients for each group. sEMG of muscles were done using a two-channel electromyography device, where pregelled and self-adhesive electrodes (bilateral) were applied. Chewing and clenching of masseter and temporalis muscle activity were recorded for 20 s pre and 6 months of orthodontic treatment using sEMG (frequency 60 Hz). The data were analysed by using repeated measures ANOVA in IBM SPSS Statistics Version 24.0.
Results: Chewing and clenching for masseter muscle showed no significant difference (P > 0.05) in sEMG activity of three types of the brackets. However, for temporalis muscle, there was a significant difference found in sEMG activity during chewing (P < 0.05) and clenching (P < 0.05) between these three brackets.
Conclusion: The activity of temporalis muscle showed significant changes in chewing and clenching, where the conventional group demonstrated better muscle activity pre and at six months of fixed appliances.

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