Pusat Pengajian Sains Pergigian - Tesis
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- PublicationTranscriptional profiling of shed-epithelial differentiation in co-culture model(2025-02)Hashim, Siti Nurnasihah MdRegenerating epithelial tissue through stem cell differentiation gives new hope for wound healing. However, stem cell’s origin and potency need to be considered to achieve high efficiency epithelial differentiation, as it is a crucial step in wound healing. In this study, ectodermal stem cells, known as stem cells from human exfoliated deciduous teeth (SHED), were used because they arose from a similar origin to the skin. The aim of this study was to investigate the transcriptional profiling of SHED-epithelial differentiation in a co-culture model. Here, SHED were grown in the epithelial-like microenvironment along with human epidermal keratinocytes (HEK001) cultured in the induction medium, keratinocyte serum free medium (KSFM), to promote epithelial differentiation. SHED cultured in the basal medium, minimum essential medium alpha (α-MEM) (SA) and KSFM (SK), and HEK001 cultured in KSFM (HK) were used as controls. The treatment consisted of co-cultured SHED cultured in the KSFM (CC SK) on days 1, 3, 5, 7, 10, and 14. The epithelial gene expression markers were screened using reverse transcriptase-polymerase chain reaction (RT-PCR). The subsequent experiment used microarray gene expression, subjected to bioinformatics analysis. Then, microarray validation was done using reverse transcriptase-qualitative real-time PCR (RT-qPCR). The bioinformatics analysis suggested that the TGFβ signalling pathway is involved in SHED-epithelium differentiation. Therefore, a downstream TGFβ pathway inhibition study was conducted using A83-01 (1 μM) to inhibit TGFβR1 that blocks SMAD2/3 activity. The inhibitory effects were analysed using RT-qPCR, flow cytometry, and immunocytochemistry. RT-PCR analysis showed that the genes involved in the early epithelial formation like, CK18 and AQP3, were expressed in SHED with or without co-cultured. Notably, only ΔNp63 were expressed in co-cultured SHED. Bioinformatics analysis has determined that SUSD2, CXCL1, and GGT5 were found to be highly regulated differentially expressed genes (DEGs). The overall result of the bioinformatics analysis suggested that the DEGs on days 5 and 7 were mainly associated with cell cycle activity and epithelial differentiation. In addition, the high enrichment of the DEGs related to the TGFβ signalling pathway marked its involvement in regulating SHED-epithelial differentiation. The gene expression analysis through RT-qPCR confirmed the involvement of the TGFβ pathway in regulating the process due to the high expression of markers associated with this pathway, TGFβ3 and BMP8A. Captivatingly, the result demonstrated that the TGFβ inhibition by A83-01 inhibitor regulated glandular epithelial-like differentiation in the co-cultured SHED, which was supported by the morphological change and expression of gene markers associated with glandular epithelial cells, such as SUSD2, GGT5, PPARG, and COL6A2, and protein marker, such as Muc 1. This study proved the regulatory role of the TGFβ pathway in the SHED early differentiation into epithelial-like cells. Nevertheless, the TGFβ inhibition by A83-01 has been suggested could manipulate this pathway to regulate glandular epithelial-like cells. Our co-cultured SHED model demonstrated epithelial differentiation, which holds promise in future studies for application in epithelial tissue regeneration, especially in wound healing.
- PublicationEvaluation of the effectiveness of the removable mandibular retractor with slow maxillary expansion compared to the bone-anchored intermaxillary traction with rapid maxillary expansion in the correction of skeletal class iii malocclusion associated with maxillary constriction in growing patients: a randomized controlled trial(2025-08)Zakaria, Ahmad SalimThis randomized controlled trial aimed to evaluate the effectiveness and acceptability of the bone-anchored intermaxillary traction (BAIMT) with rapid maxillary expansion (RME) in comparison with removable mandibular retractor (RMR) with slow maxillary expansion (SME) in the correction of skeletal class III malocclusion associated with a maxillary constriction in terms of treatment time. Moreover, sagittal and transverse skeletal changes, dento-alveolar and soft tissue changes, and Patient-Reported Outcome Measures (PROMs) were also assessed. The final sample consisted of 26 patients (13 males, 13 females), ages ranging 12-15 years who were assigned to two groups randomly: BAIMT with RME group (14 patients, mean age 14.09±1.12 years) and RMR with SME group (12 patients, mean age 13.04±1.46 years). After correction of malocclusion in the sagittal and transverse planes, patients underwent a 3-month retention phase. Lateral and anteroposterior cephalograms and dental casts were taken of all patients participating at two assessment times: before the beginning of the treatment, and at the end of the retention phase. Furthermore, the levels of pain, discomfort, functional impairment, and shyness were evaluated using a standardized questionnaire that was distributed to the patients at five assessment times: (T1) after one day of the beginning of the active treatment, (T2) after one week (T3) after four weeks, (T4) after 3 months, and (T5) after 6 months. Intraclass correlation coefficients (ICCs) were applied to determine the reproducibility of the employed method, i.e. intra-observer reliability (or random error), whereas paired t-tests were applied to determine any systematic error. The data distribution for all study variables was initially tested using the Shapiro-Wilk normality test. Thereafter, Two-sample t-test, or its nonparametric counterpart, the Mann-Whitney U test, was used to detect the significance of the differences between the two groups regarding treatment duration, cephalogram data, and dental cast. For PROM questionnaire data, the Chi-square test was used. For all variables, Intraclass correlation coefficients values were in the range of excellent correlation. The results showed that the duration of both expansion and active treatment phase was significantly lower in BAIMT group compared to the RMR group (p<0.001). Sagittal skeletal and soft tissue analysis showed a significant difference between the two groups only regarding Co-Gn (p=0.039) and ANS-Me (p=0.008) in favor of RMR with SME. However, no significant differences were found between the two groups regarding the variables studied on both the anteroposterior cephalograms and dental casts (p>0.05). Regarding Patient-Reported Outcome Measures assessment, the speech difficulties level was significantly greater in the RMR group compared to the other one only at T1 (p=0.006). In contrast, mandibular movement restriction was significantly greater in the BAIMT with RME group compared to the other one only at T2 (p=0.042). Both BAIMT with RME and RMR with SME are capable of correcting Class III malocclusion associated with a maxillary constriction in growing patients with permanent dentition by making similar skeletal, dental, and soft tissue changes
- PublicationThe synthesis and characterization of hydroxylapatite microtubules/polylactic acid GTR membranes and its effect on periodontal bone regeneration(2024-11)Junyan, WangThe general objective of the study is to develop novel hydroxylapatite microtubules/PLA GTR membranes and evaluate them for mechanical and biological properties. HAp microtubules were prepared through hydrothermal synthesis. The composition and morphology of the synthesized materials were examined by a scanning electron microscope (SEM), transmission electron microscopy (TEM), Xray powder diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Then the novel hydroxylapatite microtubules/PLA GTR membranes were fabricated. The membranes were verified whether they met the clinical mechanical requirements in degradation and stretching properties. In addition, we examined its interaction with human periodontal ligament stem cells (hPDLSCs), harvested from healthy teeth. The osteogenic effect of the membrane on hPDLSCs was examined by evaluating the gene and protein expressions of the RUNX2, OPN, and OCN using Quantitative PCR (qPCR) and Western blotting analysis, respectively. In this study, all data for the mechanical property tests, which include water contact angle tests, tensile tests, swelling analysis and biodegradation analysis were expressed as mean and standard deviation. For cell proliferation and osteogenic differentiation experiments, the data were numerical. The normality of distribution was assessed using Q-Q plot analysis. In some cases, natural log transformation was employed to aid in representing data that exhibited normal distribution. The significance level was set at p = 0.05. The HAp microtubules/PLA membrane had better tensile and breaking strengths and lower fracture productivity than the PLA membrane. The expansion rate reached 34% after 2 h, and the degradation rate exceeded 25% after 40 days. Water contact angle measurement results showed that the bilayer membrane was hydrophilic on one side and hydrophobic on the other side. The results of the cell experiments also showed that the membrane had no cytotoxicity. The number of cells in the HAp microtubule/PLA membrane group was found to be significantly higher than that observed in the group with a PLA membrane (p<0.05). Furthermore, the expression of genes and proteins associated with bone composition was significantly elevated in the HAp microtubule/PLA membrane group compared to the HAp powder/PLA membrane and hPDLSCs group (p<0.05). The HAp microtubule side can promote the expression of genes and proteins related to osteogenesis, while the PLA side can inhibit cell adhesion. The HAp microtubules/PLA membrane has stability and good mechanical properties. The double-layer structure has the function of a biological barrier and promotes bone formation.
- PublicationA novel classification for coronal remaining dentine thickness in carious teeth(2025-01)Maqbool, ManahilDental caries is a prevalent issue impacting a significant portion of the population. The part of coronal dentine that remains following a carious attack is referred to as the remaining dentine thickness (RDT). The amount of RDT left after caries significantly influences diagnosis and treatment planning. This study aimed to introduce a novel classification that categorises coronal RDT based on its decreasing thickness and information on its related factors. A comprehensive study design incorporating a systematic review (SR), an in vitro experiment, and a modified Delphi technique was employed. Articles measuring coronal RDT were screened for the SR. For the in vitro experiment, human extracted carious molars and premolars were used, in which the RDT was measured utilising digital periapical radiographs, cone-beam computed tomographic (CBCT) scanning, and Hirox stereomicroscopy (histological sections). The classification framework was constructed using the identified factors, and validated using the modified Delphi technique with the help of international experts in the field of caries management. A content analysis was conducted on the articles included for the SR, one-way ANOVA was applied to compare the RDT measurements obtained during the in vitro experiment, and a content validity index (CVI) was utilised to assess the consensus agreement among international experts participating in the modified Delphi process. A total of 17 articles were included in the SR after the full-text screening, upon which the content analysis was performed. Only 63 teeth were used in the in vitro experiment, that met the inclusion and exclusion criteria. No significant difference was observed in RDT values acquired using CBCT and Hirox. Nonetheless, a significant difference (p<0.05) was observed between digital radiographs and CBCT, as well as between digital radiographs and Hirox. A total of 10 components were identified from the SR/content analysis and in vitro experiment, that helped in constructing the Dentinal Triage framework. Next, this framework underwent validation utilising three rounds of modified Delphi with 22 international experts, yielding item-CVI scores of 0.89 (89%), 0.97 (97%), and 0.98 (98%), respectively; indicating a strong consensus agreement among the international expert panel in regards to the entire Dentinal Triage by the end of round three. In conclusion, it was observed that digital radiography overestimated RDT relative to CBCT and Hirox microscopy. Nevertheless, it still served as the most practical chairside tool for assessing coronal RDT. The novel coronal RDT classification, the Dentinal Triage, was developed and successfully validated with a 98% consensus agreement amongst the international dental experts in caries management.
- PublicationPrevalance of sleep-disorded breathing and efficacy of twin block appliance treatment in saudi children with class ii malocclusion and obstructive sleep apnoea(2024-12)Zreaqat, Ma’en Hussni RashidObstructive sleep apnoea (OSA) is a disorder of breathing during sleep characterized by prolonged partial upper airway obstruction and/or intermittent complete obstruction that disrupts normal ventilation during sleep and normal sleep patterns. It is an increasing major public health concern worldwide, partly resulting from the obesity epidemic which has encroached into the pediatric population. Individuals with a Class II skeletal malocclusion may suffer from snoring due to a retrognathic position of the mandible resulting in a retro-glossal tongue position which restricts posterior pharyngeal airway space which may result in obstructive sleep apnoea. This sleep pathology carries devastating health consequences resulting in hypertension, ischemic heart disease and stroke and associated with insulin resistance. Children who are sleep deprived often demonstrate nocturnal enuresis, daytime fatigue, hyperactivity and poor performance at school. Early recognition of this condition through routine dental clinical examination, standard screening questionnaires, and further craniofacial cephalometric analysis may help in early diagnosis and treatment. There is a growing body of evidence that shows the effective role of myofunctional appliances in the management of obstructive sleep apnoea associated with Class II skeletal malocclusion. The anterior displacement of the mandible guided by this device is able to widen the posterior pharyngeal airway space, reducing the upper airway resistance and improves airflow while breathing throughout the night. The aims of this study were first: To determine the prevalence of sleep disordered breathing among Saudi school children as a population-based study using the Pediatric Sleep Questionnaire (PSQ), and second: To evaluate the impact of twin block management on upper airway CBCT dimensions, oropharynx parameters, biochemical levels, and quality of life in OSA children with Class II skeletal malocclusion. This prospective cohort study comprised polysomnography-proven OSA growing children with class II skeletal malocclusion and mandibular retrognathia in the age range of 8 to 12 years who have completed twin block treatment and matched corresponding controls. Results showed that twenty three percent of Saudi school children were at high risk of developing SDB with male predilection as a risk factor. Snoring, sleep apnoea, and mouth breathing were prevalent in high-risk SDB children. There is a strong association between increased body mass index (BMI) and SDB. The epidemic spread of obesity among Saudi school children and its negative impacts merit serious discussion in future health strategies. Male gender, increased BMI, high tonsil and Mallampati scores were clinical indicators of the presence of OSA. However, only Mallampati scale was associated with severity of OSA. Due to the financial burden for of polysomnography (PSG), clinical diagnostic indicators should be established and encouraged especially in community based studies. The results of CBCT scans analysis showed that children with OSA have a smaller oropharynx volume, minimum cross-sectional area (CSAmin), anterio-posterior and lateral dimensions of CSAmin, hypopharynx CSAmin, and increased upper airway length compared to corresponding controls. A small CSAmin seems to be the most relevant anatomical variable in the pathogenesis of OSA. The current study shows that correction of class II skeletal malocclusion and mandibular retrognathia with twin-block appliance resulted in significant increase of upper air way parameters.