- 學位論文
共振頻率與牙釘柱鬆動程度探討
The Relationship between Resonance Frequency and Degree of Cemented Post Looseness
摘要
使用超音波裝置配合拆冠器可以移除大部份的牙釘柱，但經常因為無法判定使用拆冠器的適當時機，導致臨床操作時間的浪費並且增加牙齒斷裂之危險。因此本研究目的是希望藉由探討共振頻率與牙釘柱的鬆動關係，找出有效評估牙釘柱固持程度的檢測方式，有效率且安全的將牙釘柱移除。在本研究中，我們使用13 mm的parapost，以Zinc phosphate cement (ZPC)為黏著劑置入口外前牙的根管內7 mm，並以環氧樹脂為模擬骨質包埋於塑膠盒作為本實驗中待測樣品。本研究第一部份，將三種不同黏著條件設置完成的樣品，在進行樣本共振頻率測試之後，以萬能拉力測試機檢測牙釘柱的固持力。本研究的第二部分，使用超音波裝置振動牙釘柱使其黏劑界面鬆動，在超音波裝置每操作40秒後，使用共振頻率分析儀進行共振頻率的偵測，直到頻率無法檢測出為止。本研究的第三部份，使用超音波裝置震動牙釘柱使其黏劑界面鬆動後，分別在牙釘柱共振頻率下降時，偵測牙釘柱殘餘的固持力大小。研究結果顯示，牙釘柱的共振頻率與固持力之間相關係數(r)為0.937，(p＜0.01) ，證實共振頻率與牙釘柱固持程度有高度相關。此外，隨著超音波拆除裝置的使用，牙釘柱的平均共振頻率從8.6±0.9 kHz明顯下降至4.9±0.6 kHz，平均下降比率為42.7±6.7％。另外，在使用超音波裝置震動牙釘柱使其黏劑界面鬆動後，將牙釘柱樣品已下降的共振頻率與其對應的殘餘固持力平均值作相關性分析，發現兩者具有高度線性相關性(y = 46.97x - 182.80，R² = 0.996)。依據本研究結果，本研究假說：共振頻率可以作為檢測牙齒與牙釘柱間黏劑的鬆動程度的參考依據，應可成立。並且可作為未來利用共振頻率發展牙釘柱鬆動偵測裝置相關設備及後續深入研究之參考資料。
關鍵字
共振頻率,牙釘柱鬆動並列摘要
Clinically, most posts could be removed by ultrasonic device and crown remover. However, the timing of use of crown remover is still unclear, thus increasing treatment time as well as the risk of tooth fracture become a challenge of dentists. The aim of this study was to investigate the relationship between resonance frequency(RF) and loosing degree of cemented post. Our hypothesis is that RF could be an efficient and safe method for testing the retention of the posts. Crown removed maxillary incisors were extracted and treated endodontically. For all the test samples, 7 mm post spaces were prepared and 13-mm para-post were cemented in the prepared spaces with Zinc phosphate cement (ZPC). The prepared and post-inserted teeth were then embedded in resin blocks, which was defined as“prepared sample”in this study. The prepared samples were divided into three groups. For the first group, RF values of para-posts were detected in different cemented situations. The retention forces of the tested para-posts were evaluated by an universal testing machine. For the second group, posts were removed by ultra-sonic device. During the removal process, the RF values of para-posts were recorded after every forty seconds until the RF values could not be detected. In the third group, the RF values of para-posts were recorded after treating with ultra-sonic device, and the residual retention forces of the tested para-posts were evaluated by an universal testing machine. Our results showed that correlation could be found between the RF value and the retention force of para-post(r：0.937，p＜0.01). The RF values of para-posts significantly decreased from 8.6± 0.9 kHz to 4.9 ± 0.6 kHz during the removal process. The average decline rate was 42.7 ± 6.7%. Furthermore, a linear relationship could be observed between the RF value and the residual retention force of para-post(y = 46.97x - 182.80，R² = 0.996). These results demonstrate that the RF analysis has potential to be a useful tool for detecting the loosing degree of post. According to these results, we suggested the method presented here is feasible for further more advanced human studies .