牙齒自然頻率特性之臨床探討

Due to the fact that studies regarding the dynamic features of natural frequency (NF) have not yet been systematically discussed up to the present time, therefore, modal analysis was carried out in this study to test the frequencies of incisors, canies, first premolar and first molar. A total number of 1007 teeth were tested based on tooth morphology, location, age and gender to analyze the effects of the above mentioned physiological factors to the natural frequency of the sample teeth. Our results showed that no significant difference in the natural frequency was found among teeth in four different quadrants. However, tooth anatomy, age and gender imposed an effect on the NF value of teeth. Regardless of teeth anatomy, NF value of teeth in female subjects was found to be apparently higher than the male counterpart by approximately 100Hz (p＜0.1). Moreover, the NF value of teeth in males subjects vary with age (p＜0.05). The highest mean frequency of incisors, canines and first premolars in the male population was found between ages 40 to 49. On the other hand , the same set of teeth in the female population was in no way shown to be associated with age (p＜0.05)but still lower in value compared with the three other types of teeth by approximately 100-150 Hz (p＜0.01) before age 50. Although the NF value of first molars remained comparably low after 50, no significant difference was found statistically.