Pusat Pengajian Sains Pergigian - Tesis

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    Evaluation 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 Salim
    This 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
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    Proteomics approaches in identification of key signalling pathways associated with collagen type 1-induced osteogenic differentiation of dental stem cells
    (2024-07)
    Nasir, Nur Julia Nabila
    Collagen type 1 (Col-1) is a promising scaffolding material in bone regeneration approach. However, the predominant signalling pathway involved when dental pulp stem cells (DPSC) cultured on the scaffold are still poorly understood. This study analysed the stemness of the DPSC prior to the studies of relevant signalling pathways involved and the proteomic profiles to determine the mechanism underlying the Col-1 induced osteogenesis. Characterisation of DPSC were analysed via its morphology, MSC surface markers, population doubling level as well as differentiation capacity. For the signalling pathways analysis, cells were grouped into complete culture medium (CCM; negative control), osteogenic induction medium (OIM; positive control) and Col-1 without and with three different pathway inhibitors: LY294002 (PI3K/AKT inhibitor), LY23200882 (TGF-β/Smad inhibitor) and PD98059 (MAPK/ERK inhibitor). Western blot analysis over 7, 14, and 21 days and LC-MS/MS proteomic profiling on day 21 revealed that the PI3K/AKT signalling pathway is crucial for the osteogenic differentiation of DPSC on both OIM and Col-1 group. PI3K/AKT pathway was predominant throughout the 21 days of Col-1 induced osteogenesis, while MAPK/ERK and TGF-β/Smad was more relevant at earlier and later stage, respectively. Crosstalk between signalling molecules showed bidirectional or unidirectional dependent to each other, where AKT activation can be influenced by Smad, but not vice versa. Likewise, Smad activation can be influenced by ERK1/2, but not the other way around. Proteomic profiling of Col-1 induced osteogenesis showed majority of the proteins were associated with glycolysis, carbon metabolism, biosynthesis of amino acid and focal adhesion.