Predicting the biomechanics in aramany class i obturator prostheses using different designs and materials: a combined finite element modeling and experimental study

There is a direct relationship between biomechanics and the success of maxillofacial prostheses (MFPs). The linear (LDP) and tripodal designs (TDP) are the only designs used for unilateral MFPs. Besides, most literature showed only Co-Cr-based obturators. This study explored the biomechanics in obturators for Aramany's Class I defect using a new design named fully tripodal (FTDP) and seven materials in terms of retention, stress, and strain using finite element analysis (FEA), photoelastic stress analysis (PESA), digital image correlation (DIC), and a universal testing machine. Nine FE models, 30 epoxy resin models (12 for PESA and 18 for DIC), and 54 frameworks divided into nine for AP retained with Adam's clasps, LDP, TDP, FTDP, PEEK-based, and biotone-based MFPs were fabricated from casts obtained from archived scanned human skull. The data on retention, PESA, DIC, and FEA data were collected and evaluated to identify the displacement, stress, and strain in the MFPs with assorted designs and materials. Regarding retention, there were no significant differences between FTDP and TDP regarding retention, stress, and strain. Regarding the materials, the metalbased produced the highest retention, the highest stress on the abutments, and the lowest stress and strain on the defective side. The flexible materials-based MFPs demonstrated the lowest retention, the lowest stress and strain on the abutments of the contralateral side, and the highest stress and strain on the defective side (P<0.05)

Antibiotic resistance during covid-19 pandemic and perspective of healthcare providers towards antibiotic resistance: a mixed-method study

During the Novel coronavirus disease 2019 (COVID-19), there was an overuse of antibiotics in hospitals. The improper use of antibiotics during COVID-19 has increased the antibiotic resistance (AR), which was reported by multiple studies. The main objective of this study was to study the AR during COVID-19 and perspective of healthcare providers towards AR. This study employed a mixed method design throughout two phases. Phase Ⅰ study (ⅰ): A retrospective cross-sectional study was employed to identify patients who had positive AR bacteria before, during and after COVID-19 as well as the bacterial isolates; Phase Ⅰ study (ⅱ): A cross sectional design was employed to assess the knowledge, attitude, and practice (KAP) of healthcare worker (HCWs) in Najran, Kingdom of Saudi Arabia (KSA); Phase Ⅱ study: A qualitative multi-centre study was carried out in the KSA to explore the experience of health commissioners toward AR during COVID-19. Results of Phase Ⅰ study (ⅰ) showed the prevalence of Pan Drug Resistance (PDR) during COVID-19 pandemic (85.7%) was higher as compared to the time before (0%) and after (14.3%), p= 0.001. S. aureus showed a negligible resistance after pandemic, while the resistance Gramnegative bacteria decreased during and after pandemic compared to the time before. Results of Phase Ⅰ study (ⅱ) revealed poor knowledge, negative attitude and poor practice of HCWs. The significantly associated factors with good knowledge were nationality, cadre, qualification, and working place. Positive attitude was significantly associated with cadre, qualification, and working place. Good practice was significantly associated with gender, cadre, qualification, and working place. In Phase Ⅱ, seven themes emerged from data. Therefore, despite the AR increased globally during COVID-19 pandemic, it dropped gradually in Najran region, KSA. Knowledge, attitude and practice of HCWs in Najran, KSA regarding AR during pandemic need improvement, whereas healthcare commissioners showed scientific and up to date knowledge about the AR. Antibiotics’ prescription should be strictly implemented, relying on the antimicrobial stewardship programs (ASP) and guidelines from the world health organization (WHO) or ministry of health (MOH). Implementation of effective educational and training programs are urgently needed. Findings of this study could be used to inform policy and practice for governmental HCWs and public to reduce the impact of pandemics on the AR

Histochemical, biochemical and ultrastructural assessment on mitochondrial functions in patients with non-syndromic cleft lip

Non-syndromic cleft lip/ palate (NSCL/P) is one of the congenital malformations that affects upper lip and/ or palate of an infant. Despite intensive research, the underlying factors of this craniofacial deformity are still vague. It is believed that oral clefts have a complex aetiology including genetic and environmental factors. The pathogenesis of clefts occurs during the embryonic phase, hence, the role of mitochondria in regulating cells during this phase is crucial. Inconsistent findings have been discovered by previous studies, therefore, the association of mitochondrial metabolic defects with cleft pathogenesis remains vague. Therefore, we aim to discover the role of mitochondria in cleft tissues of our population to obtain extensive findings. In this study, the objective is to explore the histological alteration of orbicularis oris muscle and the role of mitochondria in terms of their structure and activity in causing cleft lip formation. Cleft lip tissues were obtained from consented patients with non-syndromic cleft lip, whereas control normal tissues were obtained from consented patients who were unaffected by cleft lip. A normal human primary gingival fibroblast was used as a control for the assay. Forty cleft lip tissues and seven controls were obtained and processed according to the respective analysis: haematoxylin and eosin (H&E), modified Gomori trichrome, cytochrome c-oxidase (COX), adenosine triphosphatase (ATP-ase), transmission electron microscopy (TEM), and adenosine triphosphate (ATP) assay. Histological and histochemical findings were analysed using a light microscope and imaging cellSens software, ultrastructural findings were examined using JEOL JEM2100F Field Emission TEM, and a statistical analysis of ATP assay was analysed using independent samples t-test. A few skin conditions, such as inflammation in the epidermal layer and Fordyce spot formation, were noted in the cleft lip tissues. The presence of the pathological hallmark of mitochondrial myopathy, which is ragged red fibers, and the presence of novel COX-negative fibers were observed in the tissues of cleft lip. Also, light microscopy revealed fibrotic and disorganised fibers, including a high percentage of type II fibers. A minimal accumulation of mitochondria and lipid droplets in the fibers were detected by electron microscopy. By means of biochemical assessment, ATP concentrations were significantly lower in cleft tissues compared to the control (P = 0.0344). The report on the series of mitochondrial myopathic features in patients with non-syndromic cleft lip provides more evidence and further supports the hypothesis that a metabolic defect at the mitochondrial level occurs in non-syndromic cleft lip

BOE203 -Microscopy and Histological Techniques (Mikroskopi dan Teknik Histologi)

First Semester Examination 2023/2024 Academic Session February 2024 BOE203 -Microscopy and Histological Techniques (Mikroskopi dan Teknik Histologi) Duration : 2 hours (Masa : 2 jam

Mechanical properties and cytotoxicity studies of calcia stabilized zirconia (Ca-SZ) for dental application

Several studies can be found on zirconia as dental application but only few of them use calcium oxide (CaO) as its stabilizer. Mechanical aspects and cell studies were not covered, leaving a gap in the evidence regarding the mechanical properties and biocompatibility of Ca-SZ as dental materials. CaO synthesis from calcium nitrate tetrahydrate was used as metal precursor to produce Ca-SZ. Bioceramic Ca-SZ was sintered at three different sintering temperatures 1200°, 1300° and 1400°C. Ca-SZ was characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) element analysis, X-ray Diffraction (XRD) for composition studies. Ca-SZ sample shows a good morphology under SEM observation. Increment of sintering temperature enhance the surface morphologies, the phase of Ca-SZ become intensified and transformed from monoclinic to tetragonal ZrO2 and the flexural strength increases. The mechanical properties for Ca-SZ at temperature 1400°C displayed a good result that was comparable with commercial CEREC Zirconia. Ca-SZ bioceramic sintered at 1400°C had comparable mechanical strength especially with regard to flexural that reach up to 535.3 MPa while CEREC Zirconia goes up to 683.18 MPa and fracture toughness 4.73 MPa m1/2 as that of CEREC Zirconia 4.91 MPa m1/2 The highest viability of Ca-SZ was at 24 hours incubation that reached 95% comparable with CEREC Zirconia at 97%. The LogIC50 of Ca-SZ at 24 hours incubation was 0.20417 mg/ml and comparable with CEREC Zirconia at 0.1995 mg/ml. The development of Ca-SZ can act as an alternative material for dental applications

Antibacterial activity and mechanisms of action of the semi-purified fractions from melaleuca cajuputi leaves against selected bacterial strains

The increasing incidence of bacterial infections and the rapid spread of antimicrobial resistance underscores the need to find novel alternative medications from natural sources, especially medicinal plants. Thus, this study aimed to investigate the antibacterial activities of Melaleuca cajuputi leaf extract and unveil the possible antibacterial mechanisms of the most potent semi-purified fractions against selected bacterial strains. The mineral content in M. cajuputi leaf was analyzed using inductively coupled plasma-mass-spectrometry (ICP-MS). Methanolic, ethanolic, and aqueous extracts were obtained by cold maceration. Subsequently, the most potent crude extract was fractionated to obtain semi-purified fractions by bioassay-guided fractionation technique. The antibacterial activity of the crude extracts and semi-purified Melaleuca fractions (MFs) was evaluated using a broth microdilution assay. Ultraviolet-visible (UV-Vis), Fourier transform infrared (FTIR) spectroscopies, and gas chromatography-mass spectrometry (GC-MS) were employed to identify the chemical compositions of the most potent extract and semi-purified MFs. Mechanisms of action of the most potent MFs were investigated using time-kill assay, cell morphology examination, and in-silico molecular docking studies. The toxicity profile was evaluated using the brine shrimp lethality test (BSLT). Macronutrients such as potassium (7182.042 mg/kg), sodium (3895.795 mg/kg), calcium (3730.259 mg/kg), and trace elements including iron (89.394 mg/kg), manganese (57.070 mg/kg), and zinc (51.626 mg/kg) were detected in M. cajuputi leaf extract. The antibacterial assays demonstrated that MF2c and MF2d were the most potent, with minimum inhibitory concentration (MIC) values ranging from 0.13 mg/mL to 0.25 mg/mL and 0.063 mg/mL to 0.25 mg/mL, respectively. The bioactive compounds identified in MF2c were β-eudesmol (71.96%), α-eudesmol (18.83%), and γ-eudesmol (9.21%). Meanwhile, 2-isopropyl-10-methylphenanthrene (83.09%), 10-methylanthracene-9-carboxaldehyde (10.95%), trimethyl gallic acid (2.60%), methyl-lathodoratin (2.10%), and methoxyamine (0.28%) were identified in MF2d. Time-kill assay revealed that MF2c and MF2d exhibited concentration-dependent bactericidal effects against the tested bacterial strains. The scanning electron micrographs of the treated bacteria showed apparent cell membrane damage characterized by abnormal cell elongation, shrinkage, and organic debris on the cell surfaces. Furthermore, the in-silico molecular docking analysis revealed that 2-isopropyl-10-methylphenanthrene had the highest binding propensity against DNA-dependent RNA polymerase, D-alanyl transferase, DNA gyrase, and dihydropteroate synthase, with docking energy scores of -8.4, -6.9, -6.5, and -6.1 kcal/mol respectively. Based on the toxicity results, M. cajuputi methanolic extract (LC50 781 μg/mL showed mild toxicity, whereas MF2c (LC50 6621 μg/mL) and MF2d (LC50 1165 μg/mL) were non-toxic. In conclusion, the semi-purified MFs showed remarkable antibacterial effects and were non-toxic. The findings hold promise for developing alternative therapeutic strategies to combat bacterial infectio

BST211 - Limnology and Oceanography (Limnologi dan Oseanografi)

First Semester Examination 2023/2024 Academic Session February 2024 BST211 - Limnology and Oceanography (Limnologi dan Oseanografi) Duration: 2 hours (Masa: 2 jam

BST305- Environmental Pollution (Pencemaran A/am Sekitar)

First Semester Examination 2023/2024 Academic Session February 2024 BST305- Environmental Pollution (Pencemaran A/am Sekitar) Duration: 2 hours (Masa: 2 jam

Radiographic analyses of skeletal and dental parameters for age estimation in Malaysian population

To formulate a new prediction model for the age estimation range between 17-30 years old for both genders in the Malaysian population using oral parameters (root pulp visibility, periodontal ligament visibility, mental foramen and mandibular canal location) and stages of ossification of the medial clavicular epiphyseal cartilage. The study was a cross-sectional comparative study among the Malaysian population attending the clinic in the hospital set up at the Universiti Kebangsaan Malaysia and Universiti Sains Malaysia. Root pulp and periodontal ligament visibility showed a significant mean difference of age, mainly for stage 0 in the ethnic groups involved in the study between males and females. Measurements between right and left mental foramina and mental foramen to the inferior border of the mandible found a significant difference in mean between the ethnic groups after being adjusted for age and sex. There was also a significant difference in mean when measuring the distance from the midline to the right mental foramen between males and females after being adjusted for age and ethnic groups. Measurements from the right and left mandibular canal to the inferior border of the mandible found that there was a significant difference of mean between the ethnic groups after adjusted for age and sex, p-value < 0.001. The age prediction model using a combination of mandible variables, pulp, periodontal ligament visibility, mental foramen, and mandibular canal location showed R2 = 0.561. Hence, the model is considered to have a medium fit. Chest radiograph samples (390) showed a significant mean age difference between males and females, p-value = 0.017, using an independent t-test. Furthermore, there was a significant mean age difference between the ethnic groups, p-value < 0.001, by using a one-way ANOVA test. As for the age prediction model using right medial clavicle union, the ANOVA showed R2 = 0.767. This indicates that the final model explains 76.7% of the total variance in age. Hence, the model is considered to have an excellent fit. Using multi-factorial radiological methods showed good results while consuming less time and effort. Digital chest radiographs were a useful tool for predicting age

The comparison of radiographic dental characteristics, mid-palatal suture morphology and development of artificial neural network model in children with unilateral cleft lip and palate with non-cleft individuals

Cleft lip and palate (CLP) refers to a condition characterized by the lack of union between the upper lip and the roof of the mouth. This congenital defect may present with significant alterations in their shape and extent. Among different types of CLP, unilateral cleft lip and palate (UCLP) was the most frequently observed. In Malaysia, the overall prevalence rate of CLP is estimated to be one in every 611 live births. CLP impacts craniofacial development in three planes: sagittal, vertical, and transverse planes. There are several techniques for assessing the craniofacial system, maxillary morphometry, dental arch relationships, and distinct features of CLP such as cephalometric radiographs, cone-beam computed tomography (CBCT), and maxillofacial morphologic parameters. In the first phase of the study, 100 subjects (50 cases and 50 controls) aged between 8-16 years were recruited; data were obtained from patients’ records of Hospital Universiti Sains Malaysia (Hospital USM) and Hospital Raja Perempuan Zainab II (HRPZ II). An artificial intelligence (AI) enabled WebCeph software was used to compare the 14 dental characteristics (DC) between UCLP and NC individuals. A dataset was created based on socio-demographic factors such as age, gender, cleft type, and category of malocclusion associated with the cleft. A model was developed by incorporating a novel method that combines a bootstrap, the multi-layer feed-forward neural network (MLFFNN), and ordinal logistic regression (OLR) utilizing R-syntax. The main goal was to predict the maxillary arch growth and evaluate the maxillary arch dimensions in children with UCLP and NC. In the second phase of the study, the mid-palatal suture (MPS) morphology via its bone densities was compared between UCLP and NC individuals. The CBCT images of the CLP patients which were obtained for diagnostic purposes and also CBCT images of the non-cleft (NC) individuals of the same age group were collected from patients who attended specialist clinics before receiving orthodontic treatment. In this phase, the advanced strategy was implemented in three sections, including the creation of R-syntax for the biometry hybrid approach consisting of data bootstrap, MLFFNN, and binary logistic regression (BLR). The purpose of developing a BLR model was to predict the technique of rapid maxillary expansion (RME). The findings revealed significant variations among the 10 DC in the UCLP group compared to the NC group. The hybrid OLR model developed with R-syntax has shown exceptional modelling with a greater accuracy of 97.53% in predicting the maxillary arch growth. Among the MPS maturation stages assessed from the study population, Stage E (37%) was the most prevalent, followed by Stage D (27%) and Stage C (20%), while Stage B and Stage A were equally prominent (8%). The proposed hybrid method with BLR using R-syntax has demonstrated excellent performance of the model with a higher accuracy of 99.98%. The outcome of the study suggests a strong correlation between sex, age, and cleft occurrence. It has been concluded that patients with CLP and cleft palate (CP) have smaller maxillary dimensions in sagittal and transverse planes compared to healthy individuals. The MPS fusion was found to be highest in children aged between 14-16 years. A greater percentage of fusion D (27%) and E (37%) of MPS stages were observed in female children. This information is vital for clinicians in making precise clinical decisions, especially in managing children with UCLP