Dynamic Response of human molar teeth

• Main Authors: Jen Chieh, 任杰
• Other Authors: Liren Tsai
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/9n3y3w

碩士 === 國立高雄應用科技大學 === 機械與精密工程研究所 === 102 === In recent years, tooth decay, wherein decalcification of the partial inorganic portion of the teeth causes consequent damage to the organic portion of the teeth, has become increasingly frequent. Decayed teeth do not heal without treatment and unlike other diseases are not restored to their original health after suitable treatment, but rather can only be kept from further deterioration. However, a mixture of epithelial cells, bacteria and food residue remains (referred to as a layer of white plaque when it becomes visible) on the surface of the teeth; and within the teeth acid bacteria (such as lactobacillus, streptococcus, yeasts, staphylococcus...etc) accumulate. Accordingly, when carbohydrate foods (carbohydrates) are eaten, the acid bacteria releases enzymes to break them down which then dissolve and weaken the surface of the tooth, causing decalcification of the inorganic portion of the teeth and damaging the organic portion of the teeth. After the teeth are decayed, corresponding measures can be taken according to the extent of the damage. If the decay is small, a dental filling procedure is performed. If the decay is serious, then the entire tooth might have to be replaced with an artificial denture. In producing both dental fillings and artificial dentures, factors such as the material characteristics of the teeth should be taken into account. Nonetheless, there are concerns to address with regards medical ethics and the safety of biological experiments. The experiments associated with this study were certified by the Institutional Review Board (IRB) of the Kaohsiung Municipal Kai-Syuan Psychiatric Hospital and conducted in conjunction with the Ming-Hua Dentist Clinic in Kaohsiung, in order to remove third molars as a result of routine healthcare procedures. This study was performed based on the related mechanical properties of the obtained molars. In experiments, the dynamic bi-axial stress test was performed on the teeth dentin. This test uses a Split Hopkinson Pressure Bar and a scanning electron microscope to observe the microstructure of the teeth. Lastly, a nano indenter was used to observe the microscopic mechanical properties of the teeth.