Pusat Pengajian Sains Pergigian - Tesis

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Antimicrobial effects on streptococcus mutans and candida albicans and cytotoxicity study on human periodontal ligament fibroblast cell line of oxy-ionic solution at various ph levels - an in vitro study
(2025-04)
Ming, Xu
Oxy-ionic solutions, comprising hypochlorous acid, sodium hydroxide, and active chlorine, have gained recognition in dental care for their strong antimicrobial properties, especially against pathogens like Streptococcus mutans and Candida albicans. These solutions are produced through the electrolysis of saline water. However, the influence of pH on their antimicrobial effectiveness and cytotoxicity remains uncertain. This study investigates the antimicrobial efficacy of oxy-ionic solutions at varying pH levels (3, 5, and 7) against Streptococcus mutans and Candida albicans and their cytotoxicity on human periodontal ligament fibroblasts. This study evaluated the antimicrobial efficacy and cytotoxicity of oxy-ionic solutions using three complementary approaches. First, disk diffusion and broth microdilution assays quantified antimicrobial effects. Second, scanning electron microscopy (SEM) revealed microbial morphological changes. Third, ATP assays determined cytotoxicity against human periodontal ligament fibroblasts. The oxy-ionic solutions were tested at pH 3, 5, and 7 with concentrations of 100%, 75%, and 25%, except for pH 7 which was assessed only at 100% concentration. Disk diffusion results revealed that the pH 5 solution exhibited the largest zones of growth inhibition, with diameters of 13.79 mm for Streptococcus mutans and 19.67 mm for Candida albicans, indicating the strongest antimicrobial efficacy among the tested pH levels. Broth microdilution assays further confirmed this, with the pH 5 solution demonstrating the minimum inhibitory concentration of 50% for Streptococcus mutans and 25% for Candida albicans. Scanning electron microscopy analysis showed significant microbial cell wall damage and morphological changes when treated with the pH 5 solution. The ATP assay results on human periodontal ligament fibroblasts showed that all concentrations of oxy-ionic solutions at pH 3, pH 5, and pH 7 exhibited significant cytotoxicity after 2 minutes of exposure. Although cell viability improved with extended exposure time to 24 hours, it still remained below safe thresholds. These findings suggest that there is a therapeutic potential in the dental care of oxy-ionic solution pH 5 based on high antimicrobial effects, however further study on the dilution of the solution is necessary to ensure clinical safety and effectiveness.
Effect of low-level laser therapy on stability during retention phase after orhodontic treatment: a randomized controlled trial
(2025-03)
Yanpei, Wang
Low-level laser, also known as weak laser and low-intensity laser normally produce stimulating or positive effects on alveolar bone remodeling, inducing an increase osteoblasts and osteoclast resulting increased the incidence of orthodontic tooth movement (OTM) and inhibitory effects depending on the dose. The aim of this study is to investigate the stability in maxillary dentition after application of low-level laser therapy (LLLT) during leveling and alignment stage of fixed appliances. In this experiment, 20 eligible participants were selected from the random sampling samples of the previous experiments, and the Little's Irregularity Index (LII), intermolar width (IMW), intercanine width (ICW), arch length (AL), overbite(OB), and overjet(OJ) of the maxillary dentition were measured according to the ratio of the laser group: control group = 1;1. The results of the measurements were analyzed by SPSS version 26. Friedman's test and repeated-measures ANOVA were used for statistical comparison. The results of LII, ICW, OB, and OJ were not significant (P > 0.05). However, IMW (P = 0.038) and AL (P = 0.019) was statistically significant. Although the overall effects of LII, ICW, OB and OJ were not significant, the mean values in the laser group were generally smaller compared to control group. LLLT has no significant effects on LII, ICW, OB, and OJ. It was concluded that LLLT only had a subsequent effect on IMW and AL during 12 months of retention period. However, within group changes, LLLT has smaller mean values which indicate the stability over time in the laser group was clearly better than control group to prevent relapse.
Three-dimensional morphometric analysis of mandibular canal and foramina: a cone beam computed tomography study comparing Arabic and Kurdish ethnicities in Iraq
(2025-02)
Taha, Omar Basheer
Precise evaluation of the morphology of mandibular canal (MC) and foramina and their variations is highly recommended before any surgical procedures involve the mandible to avoid neurological complications after surgery. The primary goal of this study is to examine how inferior alveolar nerve (IAN) moves through the MC and terminates at the mental foramen (MentF), as well as to determine its variations and sexual dimorphism among the Arabic and Kurdish communities in Iraq. The study done on 400 CBCT images, 200 Arabs and 200 Kurds, for each ethnic group 100 males and 100 females, to measure the morphology of mandibular foramen (MandF), MC, and MentF and their variations, and compare the measurements between the genders of each ethnic group and between the Arabs and Kurds populations, to test whether the measurements of the size and location of MandF and MentF can predict the type of genders, and if possible, to predict the position of the MandF depending on the measurements of the position of the MentF. The results have shown that there were significant differences in the measurements of the size and position of the MC and its foramina between the genders and between the two ethnic groups; the variations of MC and its foramina were found in both Arabs and Kurds populations; a binary regression test of the measurements of MandF and MentF can predict the type of gender; and finally, a simple linear regression test showed that the prediction of the position of MandF depending on the measurements of the position of MentF is possible. In the current study, more details about the size, shape, and location of the MC and its foramina and their variations in the Kurdish and Arabic people of Iraq were presented to the literature. The findings of this study will offer crucial morphometric data needed to carry out an IAN block successfully and avoid difficulties during mandibular surgery.
The effect of choline based ionic liquids on antifungal, physical and mechanical properties of silicone denture liners
(2025-03)
Munir, Nadia
This in vitro study aimed to develop novel choline based ionic liquids incorporated silicone denture liners (SDBSLs) with better antifungal potential and compliance with standard criteria for long term liners. The modified liners were then assessed for their antifungal activity, mechanical and physical properties. Choline salicylate and choline borate ionic liquids were synthesised and characterised with Fourier transform infrared spectroscopy and nuclear magnetic resonance for surface and purity analysis, respectively. The prepared ionic liquids were incorporated into SDBSLs (Moloplast B; DETAX Germany) at varying concentrations (1%, 2%, and 5%) to constitute two experimental groups and six subgroups; CB (CB1, CB2 & CB5); choline borate incorporated SDBSLs and CS (CS1, CS2 & CS5); choline salicylate incorporated SDBSLs. Conventional and antifungal drug; itraconazole (1.25% wt/wt), incorporated silicone denture liners (SDBSL) served as negative control and positive control. The samples were subjected to mechanical testing with Shore A hardness test through durometer. While tear strength and tensile bond strength were evaluated through universal testing machine. Physical testing was conducted to evaluate water sorption, solubility, and weight change following immersion in distilled water for 1 week and 6 weeks with weighing through an analytical balance. Data was statistically processed by SPSS version 25using ANOVA and all pairwise multiple comparison with post hoc analysis of Tukey’s test with α= 0.05 (p < 0.001). The results revealed that choline borate 2% (CB2) had a considerable inhibitory impact on C. albicans fungal growth followed by choline salicylate 2% (CS2). Choline salicylate 1% (CS1) demonstrated the maximum tear strength when compared to the positive control. The experimental groups had significantly lower mean Shore A hardness values than the positive and negative controls respectively. The negative control group had the highest tensile bond strength, followed by CS1. Following 1 week of water immersion, the positive control had the highest water sorption whereas CS2 demonstrated the lowest sorption. In contrast, the positive control displayed consistently the least solubility after 6 weeks of immersion, whereas the negative control showed the highest solubility. The drug-impregnated liners (positive control) gained the most weight and CS1 gained the least weight following 1 week of immersion. After 6 weeks of immersion, all study groups gained weight, with CB5 acquired most weight and CS1 acquired the least. The study reveals that incorporation of choline salicylate in silicone liners has significant effect on enhanced antifungal potential and compliance with mechanical and physical properties. However, further studies including dynamic viscoelastic property and cytotoxicity are needed to be investigated before the clinical trials.
Alternative method to develop new strategy in ordinal regression: a case study in dental
(2025-03)
Lazin, Muhamamd Amirul Mat
Clinical data usually contain numerous features with a small sample size, resulting in higher dimensionality and poor accuracy. This reduces the performance of classifier systems in high-dimensional data sets because irrelevant features contribute to poor classification accuracy and add extra difficulties in finding potentially useful knowledge. The main objective is to develop an alternative model for ordinal regression through statistical methodology building. The methodology includes a computational study design and statistical techniques customised for dental science modelling. A combination of ordinal regression and bootstrap techniques in the developing an alternative model is the main key to the research focal point. Two case studies, tooth wear severity and tooth sensitivity, were used to test this technique, demonstrating its relevance to real-world dental data. All the fundamental programming was performed using R software. The results show that the alternative approach, especially with more bootstrap replications, offers improved model fitting and precision compared to traditional ordinal regression. This suggests its usefulness in improving the accuracy of health science research, especially in situations with small sample sizes. This study strengthens statistical methods in dental sciences by introducing a more robust alternative to ordinal regression, enabling researchers to obtain more accurate and reliable results even with limited datasets.

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