以激振方法分析人工牙根穩固度之相關性研究
Excitation assessment for the stability of dental implants
中文摘要
近年來，利用人工植體為缺牙患者進行口腔贗復的比例已逐漸增加，然直至目 前為止，仍沒有一套簡單可靠的儀器可非侵入性地提供客觀量化的數值，以便 臨床醫師能隨時有效地評估人工牙根植入後的骨整合或穩固程度。利用振動方法 分析骨成長或流失的研究，於骨科醫學應用上已行之多年，而與骨頭同屬硬組 織的牙齒包埋於齒槽骨中亦有類似的特性。若骨整合逐漸完成，植體周圍骨質的 剛性會逐漸增加，其穩固度相對增加，共振頻率也隨之增加。但骨整合為軟組織 逐漸轉變為硬組織的過程，植體周邊物質具有不等程度的黏彈性發展，若以不 同外力推動植體，其移動度可能不與外力成正比，而表現出不同的剛性係數。為 了能夠快速、精確地監測植體穩固度的改變，並符合臨床醫學需求，本研究發展 出激振式人工牙根檢測儀，將振動裝置與訊號感測器合而為一，置於待測人工 牙根上方，利用振動裝置激發待測牙根後，取激振後所輸出最大振幅頻率來觀 察比較。當特定頻率振幅有變化時，表示植體與骨邊界間的穩固度有相對的變化 以體外模擬試驗來評估人工牙根振動頻率與三種手術條件（標準型、下端固定型 浮動型）及骨整合時間的關係，並於量測時改變檢測儀的控制電壓，以取得電 壓與共振頻率之相對關係，藉以瞭解植體周邊物質於骨整合過程中之剛性係數 變化。實驗結果顯示（1）單一控制電壓下，共振頻率會隨邊界物質剛性的增加 而上升，共振頻率的上升曲線隨植床情況之不同而有差異，並分別在不同時間 達到高原期(p<0.05)。（2）骨整合的過程中植體-骨邊界物質具有黏彈性，量 測不同電壓下的剛性變化似乎更易區分植體穩固與否。因此，激振式人工牙根檢 測儀有助於臨床醫師評估植體的骨整合或穩固程度，以達到縮短治療時間或提 高成功率的效果。
英文摘要
The establishment of osseointegration following dental implant placement is a major contributing factor to the clinical success and long-term function of implant-retained prosthesis. The application of a simple, clinically applicable, noninvasive test to assess implant stability and osseointegration is considered highly desirable. Vibration methods have been widely used for many years to evaluate the mechanical
performance and integrity of a structure. Many investigations have shown the
technique capable of eliciting quantitative information related to implant stability and stiffness. Whereas, for osseointegrated and failure implants in which a non-bony layer exist at the bone-implant interface, there is the possibility of implant movement relative to bone, suggesting that a poorly integrated implant may show increased mobility through a limited range of motion. The investigation was designed to study
the use of excitation analysis in search of the stability of the implant-tissue interface in vitro. Resonance frequency was measured when test implants were embedded in bakelites. There are three surgical models prepared in bakelites, which includes:
standard type, immediate implantation type, and floating type. The change in stiffness observed during bone healing was modeled by embedding implants in gypsum during setting period. This research provides 4 main findings that may be value in studies of osseointegration. First, the starting resonance frequency under different surgery conditions can be measured by the self-designed diagnosis system, which can be used as the reference standard for implant following up. Second, there was an increase in resonance frquency related to stiffness increment during osseointegration (p<0.05).
Third, due to variations from different surgical and bone conditions, the time needed for osseointegration would differ from one to the others. Finally, the range of stiffness in high and low voltage groups is correlated with implant stability. Excitation analysis technique is capable of eliciting quantitative information related to implant stability and stiffness. Using excitation frequency to evaluate osseointegration is benefit in clinical examination.
