student profile: Miss Jane Zhong


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Thesis work

Thesis title: In-vivo Effects of Different Orthodontic Loading on Root Resorption and Correlation to Mechanobiological Stimulus in Periodontal Ligament

Supervisors: Qing LI , Michael SWAIN

Thesis abstract:

Orthodontic root resorption (ORR) is a common side effect of orthodontic therapy. High pressure in the periodontal ligament (PDL) generated by orthodontic forces will trigger recruitment of odontoclasts, leaving resorption craters on root surfaces. The patterns of resorption craters are the traces of odontoclast activity. This study aimed to investigate resorptive patterns by: 1) quantifying spatial root resorption under different in-vivo orthodontic loadings with micro-CT imaging technique; and 2) correlating the induced mechanobiological stimulus distribution in PDL with in-silico nonlinear finite element analysis (FEA).
Results indicated that the heavy load (225 g) led to a larger total resorption volume than the light load, mainly by having larger individual crater volumes (p < 0.001) than increasing crater numbers, suggesting that increased mechanobiological stimulus predominantly boosted cellular resorption activity rather than recruiting more odontoclasts. Furthermore, buccal-cervical and lingual-apical regions in both groups were found to have significantly larger resorption volumes than other regions (p < 0.005). These results are consistent with our FEA outcomes, suggesting that compressive hydrostatic pressure exceeding human systolic pressure (16 kPa) was more likely to induce resorption.

Keywords: orthodontic root resorption, microCT quantification, nonlinear finite element analysis, hydrostatic pressure, periodontal ligament, osteoclastic / odontoclastic activity

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