| THE EFFECTS OF THERMAL STIMULI TO THE FILLED TOOTH STRUCTURE |
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| 온도자극이 충전된 치질에 미치는 영향 |
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백병주, 노용관, 이영수, 양정숙, 김재곤 |
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전북대학교 치과대학 소아치과학교실 및 구강생체과학연구소 |
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| Abstract |
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The dental structure substituted by restorative materials may produce discomfort resulting from hot or cold stimuli. To investigate the effects of this stimuli on the human teeth, thermal analysis was carried out by calculation of general heat conduction equation in a modeled tooth using numerical method. The method has been applied to axisymmetric and two-dimensional model, analyzing the effects of constant temperature 4℃ and 60℃. That thermal shock was provided for 2 seconds and 4 seconds, respectively and recovered to normal condition of 20℃ until 10 seconds. The thermal behavior of tooth covered with a crown of gold or stainless steel was compared with that of tooth without crown. At the same time, the effects of restorative materials(amalgam, gold and zinc oxide-eugenol(ZOE)) on the temperature of PDJ(pulpo-dentinal junction) has been studied. The geometry used for thermal analysis so far has been limited to two-dimensional as well as axisymmetric tooth models. But the general restorative tooth forms a cross shaped cavity which is no longer two-dimensional and axisymmetric. Therefore, in this study, the three-dimensional model was developed to investigate the effect of shape and size of cavity. This three-dimensional model might be used for further research to investigate the effects of restorative materials and cavity design on the thermal behavior of the real shaped tooth. The results were as follows; 1. When cold temperature of 4℃ was applied to the surface of the restored teeth with amalgam for 2 seconds and recovered to ambient temperature of 20℃, the PDJ temperature decreased rapidly to 29℃ until 3 seconds and reached to 25℃ after 9 seconds. This temperature decreased rather slowly with stainless steel crown, but kept similar temperature within 1℃ differences. Using the gold as a restorative material, the PDJ temperature decreased very fast due to the high thermal conductivity and reached near to 25℃지 but the temperature after 9 seconds was similar to that in the teeth without crown. The effects of coldness could be attenuated with the ZOE situated under the cavity. The low thermal conductivity caused a delay in temperature decrease and keeps 4℃ higher than the temperature of other conditions after 9 seconds. 2. The elapse time of cold stimuli was increased also until 4 seconds and recovered to 20℃ after 4 seconds to 9 seconds. The temperature after 9 seconds was about 2-3℃ lower than the temperature of 2 seconds stimuli, but in case of gold restoration, the high thermal conductivity of gold caused the minimum temperature of 21℃ after 5 seconds and got warm to 23℃ after 9 seconds. 3. The effects of hot stimuli was also investigated with the temperature of 60℃. For 2 seconds stimuli, the temperature increased to 40℃ from the initial temperature of 35℃ after 3 seconds of stimuli and decreased to 30℃ after 9 seconds in the teeth without crown. This temperature was sensitive to surface temperature in the teeth with gold restoration. It increased rapidly to 41℃ from the initial temperature of 35℃ after 2 seconds and decreased to 28℃ after 9 seconds, which showed 13℃ temperature variations for 9 seconds upon the surface temperature. This temperature variations were only in the range of 5℃ by using ZOE in the bottom of cavity and showed maximum temperature of 37℃ after 3 seconds of stimuli. |
| Key Words:
thermal analysis, restorative material, temperature |
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