Pusat Pengajian Sains Pergigian - Tesis

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Fracture Resistance Of Weakened Root Structure Reinforced With Two Types Of Composite Resin And Endodontic Sealer
(2009-02)
Ahmad Mahmood Ahmad
The aim of this study was to compare the fracture resistance of weakened roots obturated with a new nano HA endodontic sealer or an epoxy resin endodontic sealer and reinforced by either auto-cured or light-cured composite resin.
Three-dimensional morphometric analysis and development of new classification system of impacted canines in orthodontic patients using cone beam computed tomography
(2022-03)
Alfarra, Yahya H.Y.
Canine teeth are aesthetically most dominant teeth which can present a smile as either holy or evil. They define the mouth’s corner, are involved in the aesthetic smile, maintain occlusal stability, and design the shape of the dental arch. As the position of the impacted canines is amidst vital anatomical structures like the nasal cavity and sinuses in the maxilla and mental nerve in the mandible, a thorough radiographic evaluation to determine the position of the impacted canines is of utmost importance prior to any treatment planning. By using a CBCT image, a clinician can clearly identify its location. The present study aimed to determine the prevalence of impacted canines in orthodontic patients and conduct morphometric analysis on the effect of impacted canines on the dental arch form and dimension and develop a new classification system. CBCT images of patients aged 15 to 50 years who attended HUSM, Malaysia, for orthodontic treatment were analysed pertaining to their arch and categorised under the proposed 3D classification system based on their location and direction during the state of impaction. The results suggested that the prevalence of impacted canines in orthodontic patients was 17.5 %, with a female preponderance. Impacted canines occurred most frequently in Class I malocclusion subjects and least in Class III malocclusion. A significant relationship between the impacted canines and adjacent anatomical structures was found in most measured variables. The impacted canines appeared to be interrelated with arch dimension measurements. The findings showed significant changes in the study group compared to the control group. Interpremolar, intermolar widths and arch length were significantly deficient and narrower, with higher palatal vault seen in impacted canine patients as compared to the control group. Based on the new classification system, the most common type of impacted maxillary canines was V1AP, followed by V2BP, V2AP, and V2CP. V3BL, N2AP and N3AP were the least common. For impacted mandibular canines, M1AP was predominant, followed by M2AP, M1CP, and M2AL. Whilst M1AL and M1BP were the least prevalent. The present 3D investigation provides a new clinical reference value for the prevalence of impacted canines based on ethnicity, gender, and different types of malocclusion in addition to the relationship with surrounding anatomical structures and dental arch dimensions. Furthermore, this study established a new system for classifying impacted maxillary and mandibular canines to facilitate interdisciplinary communication for better treatment planning.
Assessment of inflammatory markers and periodontal outcomes in CKD patients with periodontitis
(2022-06)
Rahman, Nurul Aliya Abdul
Chronic kidney disease (CKD) and periodontitis have an impact on patient’s morbidity and mortality. The prevalence of comorbid CKD and periodontitis is shown to be frequent. Periodontitis increases the inflammatory burden, which has been shown to disrupt renal function by altering serum inflammatory levels, and potentially worsening CKD. Pro-inflammatory Interleukin-1 (IL-1) and anti-inflammatory Interleukin-10 (IL-10) have immunomodulatory properties that regulates host immune responses. Little is known about changes in the serum inflammatory markers of IL-1 and IL-10 following the periodontal therapy in CKD patients in our populations. Therefore, this study was aimed to assess and compare the levels of inflammatory markers IL-1 and IL-10 as well as periodontal parameters at baseline and after receiving NSPT. Twenty CKD patients (stage 3 and stage 4) with periodontitis (Group 1), twenty non-CKD patients with periodontitis (Group 2) and twenty healthy patients (Group 3) were selected. The dental parameters such as Periodontal Probing Depth (PPD), Clinical Attachment Loss (CAL), Gingival Bleeding Index (GI) and Plaque Score (PS) were measured in each patient during first visit (baseline) and six weeks later (second visit). Blood sample was collected during each visit and analysed for serum IL-1 and IL-10 concentration using Enzyme-Linked Immunosorbent Assay. Our findings shows that IL-1 and IL-10 levels were found significantly higher (p<0.05) in CKD patients with periodontitis (Group 1) as compared to non-CKD patients with periodontitis (Group 2) and healthy subjects (Group 3). When compared to other groups, the levels of dental parameters (PPD, PS and GBI in Group 1 were significantly higher (p<0.05). Following NSPT, there was significant reduction (p<0.05) in inflammatory markers and clinical periodontal parameters in Group 1 and Group 2. This study demonstrates that patients with CKD and periodontitis had a more severe systemic inflammatory response and poorer periodontal status than non-CKD. NSPT shown improvement in both inflammatory markers and dental parameters as well as delay the progression of CKD. IL-1 and IL-10 is a promising inflammatory marker to assess CKD progression. Therefore, multicentre and larger sample size studies are needed in the future.
Physical and mechanical characteristics evaluation of weakened endodontically treated teeth restored with fiber-reinforced composite: open apex and flared root canals
(2023-06)
Alshetiwi, Dawood Salman Dawood
Endodontically treated teeth (ETT) with compromised root canals due to pervasive damage induced by root canal over-instrumentation and incomplete physiological root formation are at high risk of fracture. The use of intra-radicular posts in these teeth is accompanied by a large resin cement layer due to the discrepency in the size and shape between the post and root canal. This study was conducted to assess the combination of different forms of Fiber-reinforced composites (FRC) used to enhance mechanical behavior of compromised ETT. Eighty extracted human premolar teeth were used in this study. Teeth were randomly allocated to five experimental groups with sixteen teeth per group (n = 16). Eight teeth from each group (n = 8) were submitted for objectives 1-3. The remaining eight teeth (n = 8) were prepared for objective 4. Groups were divided according to canal preparation methods and intra-radicular restoration with either a standard prefabricated fiber post or anatomically customized relined fiber post. Samples were then submitted for evaluation of intracanal adaptation using polyvinyl siloxane (PVS) light body impression material and artificial aging using computer-controlled chewing simulator. Fracture resistance and push-out bond strength tests were then carried out through a universal testing machine followed by mode of failure analysis via a stereomicrosope and scanning electron microscope. Assessment of intra-canal adaptation showed a statistically significant difference (p<0.05) in PVS material weight between the groups. Group 1 (control) had the lightest weight of PVS material, followed by groups restored with customized fiber posts (Group 4 and Group 5) and groups restored with standard fiber posts (Group 2 and Group 3). Artificial aging test results through Pairwise Log-Rank comparisons revealed that there was no statistically significant difference between Group 1 (control group), Group 5 and Group 4 (p>0.05). Group 2 and Group 3 showed a statistically significant lower survival rate compared to all other groups. Results of fracture resistance test showed the highest fracture resistance (1796 N) in Group 5, and it was significantly higher compared to other groups (p<0.05), while Group 2 showed the lowest mean fracture resistance (758 N) and was significantly lower compared to the other groups. In relation to push-out bond strength test, Group 5 and Group 4 demonstrated a significantly higher bond strength at all root thirds (p<0.05) than Group 3, Group 2, and Group 1. The most frequently observed failure occurred between the resin cement and radicular dentin for all the groups. In conclusion, the use of short fiber-reinforced composite (SFRC) to reline the prefabricated FRC post has been proven to improve intracanal adaptation and result in higher survival rate, superior fracture resistance with favorable failure patterns and increased push-out bond strength values compared to standard prefabricated FRC posts.
Development of a novel bioceramic root canal sealer and its effect on the dislodgement resistance and dentinal tubule penetration
(2023-06)
Lin, Galvin Sim Siang
The present study aimed to fabricate and characterise novel algin-incorporated bioactive glass 58S calcium-silicate root canal sealer (Bio-G) and evaluate its effect on the dislodgement resistance and dentinal tubule penetration to root dentinal walls in comparison to commercially available bioceramic-based sealers (BioRoot RCS and iRoot SP). Three groups of bioactive glass (BG) 58S powders were synthesised using sol-gel method and characterised using SEM, HRTEM and FTIR for optimisation: BG-1 (no ammonia), BG-2 (3 ml of ammonia), and BG-3 (5 ml of ammonia). Optimised BG-3 was used to fabricate the powder form of experimental Bio-G sealer with the addition of calcium silicate, zirconia dioxide, calcium carbonate and alginic acid powder. Meanwhile, the liquid form composed of 5% calcium chloride solution. The experimental 0-5% algin Bio-G sealers were then compared with BioRoot RCS and iRoot SP. Standardised disc specimens of mixed sealer materials (n=5 per group) were prepared and placed in an incubator to allow setting before characterising under SEM, HRTEM, EDS, FTIR and XRD. Next, one-hundred-and-seventy-six mandibular premolars were randomly assigned (n=16 per group): control, gutta-percha + 0-5% algin Bio-G, gutta-percha + BioRoot RCS, and gutta-percha + iRoot SP groups, with the exclusion of the control group in adhesive pattern and dentinal tubule penetration tests. They were instrumented, obturated and placed in an incubator for 72 hours to allow sealer set. For the dentinal tubule penetration test, sealers were mixed with 0.1% of rhodamine B dye. Subsequently, teeth were cut into a 1-mm-thick cross-section at 5-mm and 10-mm levels from the root apex, respectively. Push-out bond strength, adhesive pattern and dentinal tubule penetration tests were performed. Experimental Bio-G sealer revealed irregular micro-sized particles with a higher content of oxygen, silicon, and calcium, as well as trace of aluminium and chloride. Meanwhile, FTIR and XRD findings suggested that all sealers predominantly contained calcium silicate hydrate, calcium carbonate, and zirconium dioxide, while calcium aluminium silicate oxide was detected in 0-5% algin Bio-G. 5% algin Bio-G showed the highest mean push-out bond strength (p<0.05) with more favourable adhesion pattern, while iRoot SP showed the greatest sealer penetration (p<0.05). In addition, no significant association was noted between the dislodgement resistance and dentinal tubule penetration (p>0.05). In conclusion, the present novel Bio-G sealer demonstrated desirable particle size distribution and acceptable degree of purity. Algin-incorporated Bio-G showed favourable adhesive pattern with comparable dislodgement resistance and dentinal tubule penetration values to commercialised bioceramic-based sealers.
The Intrinsic Role Of Endoplasmic Reticulum Stress Sensors In The Mechanism Underlying The Depressive Symptoms And Kratom Dependence In Chronic Kratom Users
(2023-07)
Muhamad Fauzi, Nurul Atiqah Binti
Background: This study aimed to determine the differences in the mRNA and protein expression of ER stress sensors (such as BiP, XBP1, ATF4 and CHOP) in the peripheral blood mononuclear cells (PBMCs) between non-drug using healthy controls and regular kratom users, evaluate how alterations of ER stress sensors expression was associated with the kratom use patterns (such as first age of using kratom, kratom use duration, kratom use average daily frequency, kratom use average daily quantity, and time of last kratom use prior to blood collection) and assess the correlations between the mRNA and protein expression of ER stress sensors in the peripheral blood mononuclear cells (PBMCs) among regular kratom users and the severity of depressive symptoms on kratom abstinence and kratom dependence severity. Methods: Data on socio-demographic characteristics were collected from kratom users and healthy controls. While data on kratom use patterns, kratom dependence severity and depressive symptoms on kratom abstinence were collected from kratom users. The expression of mRNA and protein of selected ER stress sensors (such as BiP, XBP1, ATF4 and CHOP) in the PBMCs of kratom users and healthy controls were measured with qRT-PCR and western blot, respectively. Results: A total of 20 kratom users and 20 healthy controls completed the study. The levels of expression of mRNA and protein of BiP were significantly elevated in kratom users compared with healthy controls regardless of the kratom use patterns.
The development of a new prognostic logistic regression model: a case study on oral squamous cell carcinoma
(2023-07)
Azeem, Muhammad
Oral squamous cell carcinoma (OSCC) is the sixth most frequent cancer worldwide. It is responsible for 80-90% of all mouth malignant neoplasms and has a mortality rate of up to 50%. Oral cancer has multifactorial etiology, mainly smoking, tobacco, alcohol consumption, betel quid chewing, and high-risk human papillomavirus (HPV). A total of 57 patients were recruited from the clinic at the Hospital Universiti Sains Malaysia (USM). In this retrospective study, advanced computational statistical modeling techniques were used to evaluate data descriptions on three risk factors studies: sociodemographic, clinicopathological, and surgical margins features of OSCC patients. The R-Studio software and syntax were used to design and develop the hybrid biometry method, implement, and the odd ratio. The advanced approach was executed in three parts, such as developing syntax for R for the biometry hybrid method which consists of data bootstrap methodology, multiple layer feedforward neural network (MLFFNN), and logistic regression. Male gender, smoking, betel quid, and alcohol habit variables were significantly related to death (p < 0.05). Among clinicopathological features increasing tumour size, metastasis, moderately and poorly differentiated OSCC, and Ki67 expression were significantly related to deceased patients (p < 0.05). Furthermore, features of surgical margins perineural invasion, bone invasion, and involvement of surgical margins were significantly related to the death of OSCC patients (p < 0.05). This finding might contribute to the underlying cause of poor prognosis. In conclusion, there exist potential risk factors in relation to OSCC in the Malaysian population. The conclusion of the study might illustrate the superiority of the hybrid model technique used in the study.
Expression of inhibitory neurotransmitter gabaa receptors in human dental pulp: a potential role in dental nociceptive signalling
(2023-08)
Sivakumar, Diveyaa
Dental pain is a prevalent and distressing condition that can have a significant impact on a person's daily life. It can arise from various causes, including dental diseases and conditions, as well as during dental treatments. Development of effective pain management strategies in the dental setting remains a challenge due to the unclear mechanisms of pain signalling in the dental pulp. Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the mammalian central nervous system (CNS) and has a well-established role in pain signalling. While several studies have explored the expression GABA and its receptors in the dental pulp, the exact influence of these receptors on dental pain signalling is still not fully understood. Therefore, this study aimed to investigate the gene and protein expression of the two most abundantly expressed GABAA receptor subunits, α1 and β2, in the healthy human dental pulp. In order to achieve the objective of the study, techniques such as RNA isolation, reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) were employed. Prior to performing RT-PCR, the annealing temperature for amplification of both target genes were found to be 55°C. Gene expression analysis using RT-PCR demonstrated the presence of GABRA1 and GABRB2 in the dental pulp, and independent T-test analysis indicated that the expression of GABRA1 was significantly higher than GABRB2. Immunohistochemical staining provided visual evidence of GABRA1 and GABRB2 protein expression in the odontoblast layer of dental pulp, indicating their presence in cell bodies and odontoblastic processes extending into the dentin. Optimal IHC staining results were obtained by using Tris- EDTA (TE) buffer at pH9 for antigen retrieval with antibody concentrations of 1:50 and 1:200 for the GABRA1 and GABRB2 antibodies, respectively. These findings support the hypothesis that GABAA receptor α1 and β2 subunits are expressed in human dental pulp. The presence of gene and protein expression of these subunits offers valuable insights for further research into the potential roles of GABAA receptors in dental related pain signalling. Future studies using diseased samples and functional investigations are warranted to explore the precise mechanisms and implications of GABAA receptor α1 and β2 subunits in dental pain and their potential therapeutic applications.
Childrens’ behaviour and physiological parameters at recovery following dental general anaesthesia with and without premedication oral midazolam at Hospital Universiti Sains Malaysia: a preliminary study
(2023-08)
Hisham, Abdul Rauf Badrul
Oral midazolam premedication usually prescribed for controlling behaviour and reducing anxiety of children and the use under general anaesthesia (DGA) on the behavioural and physiological status of uncooperative paediatric patients have not yet been well explored. This study is aimed to evaluate the effect of oral midazolam premedication on recovery behaviour and physiologic parameters of children undergoing DGA. Thirty uncooperative children aged from 2–11 years were involved in this randomised control trial study. Group I: Received 0.5 mg/kg midazolam orally 30 minutes before entering the operation theatre, while Group II: Did not receive any premedication. Their physiologic parameters were measured at the post anaesthesia care unit (PACU). The recovery behaviour was also recorded for the evaluation using the Modified Houpt Behavior Rating Scale. There was no significant differences in all recovery behaviour and physiologic parameters for both groups (p>0.05). No significant association of premedication oral midazolam with successful recovery behaviour (p=0.381). However, an interesting trend of positive recovery behaviour and physiology was observed among children with oral midazolam premedication. More studies with larger sample size are needed to explore the effect of oral midazolam in paediatric DGA as to discover the optimum effect of premedication.
Development and characterization of honey-plga microparticles with antibacterial properties against streptococcus mutans in oral disease
(2023-08)
Imm, Chu Liu
Application of honey in a certain area of the human body like in the oral cavity might pose a problem due to its liquidity. Thus, honey also has been explored to be used in other forms for suitable application. One form of drug delivery system is through the incorporation of drugs into microparticles. Therefore, the aim of this study is to investigate the potential of honey to be incorporated into microparticles to enhance antibacterial activity. Three types of honey were used; Kelulut, Tualang and Manuka. Honey-PLGA microparticles were prepared using the double emulsion solvent evaporation method. Then the honey-PLGA microparticles were subjected to a variety of analyses and tests, including GC-MS analysis, FESEM, zetasizer analysis, in vitro release and an antibacterial test. Streptococcus mutans was used for antibacterial testing because this bacterium causes caries and periodontitis. The results showed that all types of honey used in this study could be incorporated into microparticles as a white powder. Based on FESEM analysis, honey-PLGA microparticles were spherical, and had a smooth surface, with a diameter ranging from 1 to 10 micrometer. GC-MS analysis showed the identified compounds found in raw Kelulut honey microparticles (RKHMP), raw Manuka honey microparticles (RMHMP) and raw Tualang honey microparticles (RTHMP) were 1, 11 and 5 compounds, respectively. The identified compounds found in extracted Kelulut honey microparticles (EKHMP), extracted Manuka honey microparticles (EMHMP) and extracted Tualang honey microparticles (ETHMP) were 15, 12 and 26 compounds, respectively. Extracted honey microparticles contain more identified compounds compared to raw honey microparticles. Zetasizer analysis showed the microparticles had low zeta potential and thus tended to precipitate in suspension. The microparticles showed slow-release character but no antibacterial activity against Streptococcus mutans. Within the limitation of the study, it can be concluded that, the three types of honey can be incorporated with other materials to produce honey-PLGA microparticles, however further study is needed in term of improving the formulation to produce microparticles that are highly effective against target microorganisms.
Effects of single dose low-level laser therapy, on pain and healing of extraction socket after extraction of premolars in orthodontic patients
(2023-09)
Karim, Meenaz
Tooth extraction for orthodontic purposes is a common procedure. However, extractions, just like other surgeries carry some complications and risk like pain, swelling, infections, and dry socket. Non-steroidal anti-inflammatory drugs (NSAIDs) are preferred medicines to reduce post-extraction pain, but it may have systemic effects. Low-level laser therapy (LLLT) has been found effective in decreasing the post-extraction pain and acceleration of wound healing after third-molar extraction. Orthodontic forces initiate osteoclastic activities in the alveolar bone which causes mobility of the tooth which also eases the extraction and reduces post-extraction pain, but it has not been investigated. The purpose of this research was to evaluate the effect of single dose of LLLT on the pain and healing of extraction socket before alignment and levelling stage, after initiation of orthodontic treatment. Forty-four Pakistani patients, age between 12 to 18 years who needed pre-molar extraction for orthodontic treatment were selected, which were then divided into 2 groups (A and B). Both groups had experimental (Ae, Be) and placebo sides (Ap, Bp), allocated randomly for split mouth design. Group A underwent extractions first, then orthodontic treatment. However, group B underwent extractions after alignment and leveling of teeth. Gallium-Aluminum- Arsenic diode laser (continuous-mode, wavelength 940nm) was applied on 6points buccally and palatally, 1cm apical to the extraction socket, immediately after extraction. Irradiation was applied for 30seconds at each point, emitting energy of 3joules. After extraction, pain was recorded for a week with numeric rating scale and wound healing was assessed clinically at baseline, 2nd, 7th and 15th day. SPSS version 22.0 was used to analyze the data. Experimental and placebo sides were compared to observe the effect of LLLT on pain and wound healing, while inter group comparison was made to see the effects of prior engagement of tooth with the arch-wire, on pain and wound healing. Non-parametric Mann Whitney U test and Krusker Wallis test were applied to compare the results amongst all the groups. Group A experienced significantly more pain when compared with group B (p<0.05). The difference in pain between experimental and placebo sides in both the groups was insignificant. No significant difference was observed regarding wound healing among groups. In conclusion, single visit application of LLLT did not reduce the post-extraction pain and did not affect the extraction wound healing in orthodontic patients. Prior engagement of pre-molars reduced the extraction pain, however wound healing remained unaffected.
Investigation of skeletal relationships, tooth abnormalities, and biochemical composition of saliva in cleft lip and palate patients
(2023-09)
Qadeer, Mustafa
Cleft lip and palate (CLP) that affects many neonates annually, is one of the most common birth deformities and has been found to be linked with various other orofacial abnormalities including dental enamel hypoplasia and skeletal defects. Several studies have investigated some dental anomalies associated with CLP patients. However, details of the internal tooth structure (enamel thickness, enamel density and dentine thickness) as well as biochemical composition of saliva in patients with CLP are not available. The overall goal of this study is to assess skeletal relationships, tooth structures, tooth size and biochemical composition of the saliva in patients with CLP. A retrospective record review was conducted in the Department of Orthodontics and Oral Radiology, CMH-Lahore Medical College and Institute of Dentistry. 4152 cone beam computed tomography (CBCT) data sorting was performed and 73 patients with cleft were included to identify skeletal relationships in different cleft-types. Meanwhile, 84 ‘non-syndromic’ CLP patients (41 unilateral cleft lip and palate (UCLP) and 43 bilateral cleft lip and palate (BCLP)) and 39 non cleft subjects were selected to identify tooth abnormalities. Enamel thickness, enamel density, dentin thickness, and tooth size of the permanent maxillary incisors and canines were measured from their CBCT scans. Two-way ANOVA with interaction effect was applied to examine if gender has an effect in addition to cleft on various measurements of teeth. A cross-sectional study was conducted where saliva samples were collected from 27 individuals with UCLP, 27 individuals with BCLP, and 27 non-cleft individuals. Precipitate and supernatant of this saliva samples were analised by using fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy/energy-dispersive X-ray (SEM/EDX). Results of the skeletal relationships showed that the skeletal class III were found to be predominant in both sexes, followed by class II and class I (p ˃ 0.05). For tooth abnormalities, the enamel thickness, enamel density, mesiodistal width, crown height, root length and tooth length were significantly smaller in patients with CLP compared to non-cleft individuals (p < 0.05) while dentine showed no significant difference in most of teeth measured (p ˃ 0.05). Missing lateral incisor (81.4%) was found to be more common in BCLP. Atypical root shape was more prevalent in right lateral incisor in BCLP (p < 0.05). FTIR analysis of saliva showed the presence of inorganic phosphates, proteins, lipids, and hormone in the samples tested. Visible difference between FTIR spectra of cleft and non-cleft individuals, specifically in bands of inorganic phosphates, amide I, and amide II were observed. SEM results revealed interconnected filamentous network in the saliva of normal individuals whereas this filamentous network was not present in patients with CLP. In addition to variation in tooth sizes and decreased enamel density, abnormal biochemical composition as well as surface morphology of saliva may contribute to increase caries susceptibility in patients with CLP. Implementation of early oral health care prevention strategy to improve oral health status are essential in patients with CLP.
Study of mild-moderate traumatic brain injury using tract-based spatial statistics (TBSS) and its relationship with cognitive function
(2023-09)
Abdullah, Aimi Nadhiah
Traumatic brain injury (TBI) is known to lead to cognitive function impairment. The degree of impairment, however, varies depending on the severity and time post-TBI. Diffuse axonal damage has been discovered as the underlying pathology even in mild TBI. Thus, this study aims to determine the state of white matter putative connectivity in patients with mild-moderate TBI in the subacute phase, or within 10 weeks of injury, and its correlation to cognitive scores. A case-control prospective study was conducted involving 11 male patients with mild-moderate TBI and an age-matched control group of 11 adult male volunteers. Diffusion MRI scanning and cognitive testing were performed within 10 weeks of injury. The difference in fractional anisotropy (FA) values between TBI patients and control group was studied using tract-based spatial statistics (TBSS). Then, the FA values that were significantly different between patients and controls were correlated with neuropsychological tests in the TBI group. When comparing patients to the control group, several clusters with peak voxels of substantial FA reductions (p < 0.05) in the white matter skeleton were seen. These clusters were later treated as region of interest and were found in the superior fronto-occipital fasciculus, superior longitudinal fasciculus, uncinate fasciculus, and cingulum. White matter fibres in the region of the genu of the corpus callosum, anterior corona radiata, superior corona radiata, anterior thalamic radiation, and a portion of the inferior frontal gyrus also contained these clusters. Region of interest analysis revealed FA values significantly correlated with Malay version of Auditory Verbal Learning Test (MAVLT) immediate recall scores in the region of genu of corpus callosum (r = 0.62, p = 0.004) and right superior fronto-occipital fasciculus (r = 0.50, p = 0.026). Matrix-reasoning scores positively correlated with FA values in the region of right superior fronto-occipital fasciculus (r = 0.45, p = 0.045) and left anterior corona radiate (r = 0.47, p = 0.036), while having negative correlation in the region of right superior fronto-occipital fasciculus (r = -0.49, p = 0.030). Mean diffusivity (MD) values significantly have positive correlation with both Rey Complex Figure Tests (RCFT) immediate (r = 0.593, p = 0.015) and delayed (r = 0.640, p = 0.002) scores in the right superior longitudinal fasciculus. During the sub-acute phase of TBI, the mild-moderate TBI patients showed unusually decreased FA values and increase MD values compared to controls, which suggested disruption of white matter tracts. The correlation between FA values with neuropsychological scores further provide evidence of cognitive impairment probably responsible by the structural disruption.
Investigation of chemicomechanical properties of polyamide 12 composite reinforced with fillers from agriculture biowaste as a potential dental post
(2024-04)
Babu, Nurul Syafika Atikah
Nanofillers and short fibres were added to polymer composites as the reinforcements to improve their mechanical properties. The synthetic E-glass fibres used in fibre- reinforced composite of commercial dental post was reported to be hazardous. Oil palm fibres and rice husk silica are cheaper and generally safer for workers than glass fibres in composite production. The aim of this research is to produce dental post and core which incorporated natural oil palm fibre (OPF) and rice husk (RH) silica from agricultural waste into the matrix and also to investigate the chemicomechanical properties of the produced post compared to the commercial post. Preparation of OPF/RH Silica/PA12 reinforced nanocomposite post was done by incorporating treated silica from rice husk and oil palm fibre crystallized nanocellulose (OPF CNC) into Polyamide 12 (PA12) matrix. Six samples with a size of 1.5mm x 2.0mm x 25.0mm were prepared for 7 groups (n=6, N=42) and six samples with the size 4mm diameter x 6mm height, were also prepared for 7 groups (n=6, N=42); Group 1 100% PA12, Group 2 PA12 (99%) + OPF CNC (1%), Group 3 PA12 (98%) + OPF CNC (2%), Group 4 PA12 (80%) + (20%) RH silica, Group 5 PA12 (80%) +(19%) RH silica + (1%) OPF CNC, Group 6 PA12 (80%) +(18%) RH silica + (2%) OPF CNC, Group 7 everStick post (flexure test)/ everX FlowTM (compressive test). The flexure and compressive tests were carried out using Instron Universal Testing Machine (Shimadzu, Japan) and the data were analysed using IBM SPSS version 26.0 (SPSS Inc, Chicago, IL, USA). Fourier- transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and Thermogravimetric analysis (TGA) were used to examine the fractured flexural strength samples. Flexural test showed that there was a statistically significant difference in flexural strength between different groups (χ2 (df) = 38.65 (6), whereby the PA12 with CNC fillers showed an increased in flexure strength value compared to unfilled PA12 and has no significant difference with commercial post. The incorporation of OPF CNC in the PA12 composite however did not increase the compressive value compared to unfilled PA12 and showed a significantly reduction in compressive strength compared to commercial composite. SEM analysis confirmed the presence of both fillers in the composite and showed smoother surface with presence of lesser voids and gaps with increment of filler wt% which suggested enhanced interfacial bonding. TGA analysis showed that OPF CNC lowered the thermostability of the composite while RH silica improved the thermostability of the composite. Incorporation of OPF CNC into PA12 matrix increased flexure strength of the composite. Incorporation of silica on the other hand reduced the flexure strength of PA12. However, the incorporation of OPF CNC or RH silica did not give any impact to the compressive strength of PA12.
Radiographic analyses of skeletal and dental parameters for age estimation in Malaysian population
(2024-04)
Sigali, Waleed Mohammed Petro
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 effects of sirna-targeting IL-17a receptor in regulating the osteogenic differentiation in stem cells from human exfoliated deciduous teeth
(2024-05)
Aduni, Wan Khairunnisaa Wan Nor
Interleukin-17-A holds significant roles in osteogenic differentiation and bone remodelling mechanism. To date, limited studies describe the effects of small interfering RNA (siRNA) on the expression of IL-17A receptor (IL-17RA) and how the modulation influences the process of osteogenic differentiation. Thus, the present study was to evaluate the effects of siRNA-targeting-IL-17RA on the osteogenic differentiation and the expression levels of osteogenic markers in stem cells from human exfoliated deciduous teeth (SHED). SHED were cultured in complete Minimum Essential Medium α supplemented with osteogenic medium which consists of 50 µg/mL L-ascorbic acid, 10 mM β-glycerophosphate, and 100 nM dexamethasone to induce osteogenic differentiation in SHED for 7 and 14 days. Differentiated SHED were cultured into two conditions: Group 1was treated with optimized concentration of IL- 17A (50 ng/mL) and Group 2 was treated with IL-17A and transfected with optimized concentration of siRNA-targeting-IL-17RA (50 nM) for 48 hours. Mineralisation activity by Alizarin red staining was performed on day 14 and day 21. The effects of siRNA were evaluated by measuring the expression levels of osteogenic markers such as ALP, OPG, RANKL, COL1A1, and RUNX2 by qPCR after 7 and 14 days. Untreated SHED were characterised by positively stained for stem cell markers such as CD90, CD73, and CD105 and were negatively stained for hematopoietic cell marker CD14. Differentiated-SHED showed significant expressions of ALP, COL1A1, and RUNX2 on day 7 and day 14 of differentiation. Staining of IL-17A-treated-SHED by Alizarin red demonstrated an increased calcium deposition compared to untreated SHED. Similarly, the expressions of ALP, OPG, COL1A1, and RUNX2 were significantly upregulated in IL-17A-treated SHED. However, RANKL expression was downregulated. Interestingly, siRNA- transfected SHED showed significant downregulation of ALP, OPG, COL1A1, and RUNX2 while RANKL was upregulated. These findings demonstrate that IL-17A enhances osteogenesis by promoting osteogenic differentiation and that siRNA- targeting-IL-17RA had interfered with the functions of IL-17A/IL-17RA, thus suggesting the importance of IL-17A in mediating the physiological mechanism of bone metabolism.

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