以模擬骨塊測試不同鑽針轉速之植牙手感區分骨質能力之比較

Abstract

中文摘要 實驗目的 骨質的軟硬一直被認為是影響人工植牙成功率的重要因子之一。過硬或過軟的骨質可能影響人工牙根植體植入時的初期穩定度、進而影響等待骨整合的時間以及植體的成功率。臨床上手術醫師常以鑽骨時的手感來診斷骨質並決定手術步驟。由於不同醫師鑽骨時認知的手感可能不同，且受到鑽針轉速的影響，因此可能需要累積足夠的經驗才有能力診斷骨質。 本實驗目的是探討不同的鑽針轉速對於鑽骨手感的影響, 藉此找出區分不同骨質的合適鑽針轉速，以提供缺乏植牙手術經驗的牙醫師選用合適的鑽針轉速, 協助以鑽骨手感來判定骨質軟硬的能力養成。 實驗材料與方法 本實驗邀請牙醫師以不同鑽針轉速在不同密度的模擬骨塊上鑽孔，以反饋手感確認骨塊的硬度並填寫問卷作答。本實驗分前導實驗與正式實驗兩部分 1. 前導實驗 甲、受試者招募： 前導實驗收錄 10 位少植牙經驗但領有牙醫師執照之台灣大學醫學院附設醫院醫師，其中含 5 位女性、5 位男性，平均年齡: 29.2 歲。 乙、實驗設計: 使用 Sawbone®(Pacific Research Laboratories, Inc. Vashon, Washington,USA) 所出品聚氯酯生物力學模擬骨塊(biomechanical test block) 模擬人體海綿骨。使用之模擬骨塊密度為 5pcf、10pcf、15pcf、30pcf、50pcf，pcf 是密度單位 pounds per cubic foot 的縮寫。將骨塊切割成尺寸50mm(長) X 50mm(寬) X 20mm(高)的長方體並依標準水粉比(100g powder : 23c.c.water )包埋於 type IV die stone (Silky-Rock, Whip-Mix Corporation, USA)，以石膏研磨機整平表面後在骨塊表面貼上 PVC 膠帶，完成標準模型備製。 使用的植牙手機為日本 NSK Nakanishi 公司出產的 Surgic XT Plus machine (Mont Blanc 20:1 Push Button Dental Implant Handpiece Low Speed Contra-angle, NSK Nakanishi, Japan )，設定扭力 25N-cm。 每位受試者共測試一次，每次四輪，每輪為不同鑽針轉速，總共四種轉速(500RPM, 1000RPM, 1500RPM, 2000RPM)，四種轉速順序為隨機順序，每輪開始測試時由主持人設定好轉速後請受試者對 50pcf 模擬骨塊鑽孔並告知為最硬的骨塊，接著對 5pcf、10pcf、10pcf、15pcf、30pcf 共五塊模擬骨塊隨機順序鑽骨，感受鑽骨時的阻抗。每次鑽骨後以視覺類比樣表(Visual analog scale, VAS )作答該骨塊之硬度，每輪測試結束後即更換下一輪之骨塊與鑽針轉速直到四輪測試完成。 丙、結果測量與統計 : 記錄群體受試者對於不同硬度骨塊的鑽骨手感 VAS 值及敘述性統計。以 ANOVA 評估鑽針轉速對鑽骨手感的影響。統計骨塊在不同鑽針轉速設定下的排序正確率，並兩兩進行 paired t-test 是否有統計上的差異。所有統計分析 p-value 設定在<0.05 表示在統計學上其有差異。 丁、實驗結果： One way ANOVA 顯示在 30pcf 骨塊中不同轉速組別的 VAS 值有顯著差異(P<0.05)，其餘骨塊則無顯著差異。兩次相同密度骨塊(10pcf) 的平均 VAS 值比較結果顯示沒有顯著差異。骨塊 10pcf 中 1000 RPM 以及 1500 RPM 的平均 VAS 值比 2000RPM來得高(paired t-test, p<0.05)。骨塊 30pcf 中 500RPM 的平均 VAS 值比2000RPM 來得高(paired t-test, p<0.05)。全部骨塊的排序正確比例在較低鑽針轉速(500RPM 1000RPM)高於較高鑽針轉速(1500RPM 2000RPM)。在配對排序骨塊中(10pcf 原始-15pcf)，較低鑽針轉速的排序正確率高於較高鑽針轉速。 戊、前導實驗結論： 鑽針轉速在模擬骨塊上的測試顯示對鑽骨手感有影響，較高鑽針轉速鑽骨手感的阻抗有比較低鑽針轉速下降的趨勢。在骨塊排序正確率方面較高鑽針轉速有正確率較低的趨勢。 確立鑽針轉速可能對鑽骨手感的影響，需進一步完成正式實驗確認結果。在正式實驗中將樣本人數提高為 30 位，並經統計專家的建議在實驗設計上有微幅更改。 2. 正式實驗 甲、受試者招募： 正式實驗收錄 30 位少植牙經驗但領有牙醫師執照之台灣大學醫學院附設醫院醫師，其中含 20 位女性、10 位男性，平均年齡: 27.3 歲。 乙、實驗設計: 同前導實驗方式製作標準模型。同前導實驗之實驗設計，但每輪測試骨塊由原本 5 塊(5pcf、10pcf、 10pcf、15pcf、30pcf)改至 7 塊(5pcf、5pcf、10pcf、10pcf、15pcf、15pcf、30pcf)。 丙、結果測量與統計 : 同前導實驗敘述。 正式實驗結果： One way ANOVA 顯示在各硬度骨塊中不同鑽針轉速群組之間沒有明顯差異。骨塊 5pcf 中 500 RPM 的平均 VAS 值比 2000RPM 來得低(paired t-test, p<0.05)。全部骨塊的排序正確比例依原始值在較低鑽針轉速(500RPM 1000RPM)高於較高鑽針轉速(1500RPM 2000RPM)，其中 500RPM 與 1000RPM 對上 1500RPM時有顯著差異(p<0.05)。在配對排序骨塊中，骨塊 5pcf 對 10pcf、10pcf 對 15pcf、15pcf 對 30pcf 都顯示鑽針較低轉速(500RPM 1000RPM)的排序正確率高於鑽針較高轉速(1500RPM 2000RPM)，其中在骨塊 10pcf 對 15pcf 組別裡的 500RPM 與1000RPM 對上 1500RPM 時有顯著差異(p<0.05)。再測信度顯示在 500RPM、1000RPM、2000RPM 各有組別的 Pearson correlation約在 57%~70%，在 1500RPM 組別 Pearson correlation 約 39%。 結論： 鑽針轉速在模擬骨塊上的測試顯示對鑽骨手感有影響。在骨塊排序正確率方面較低鑽針轉速(500RPM 1000RPM)有正確率較高的趨勢。臨床植牙鑽骨可依照本實驗的結果來選擇合適的鑽針轉速。本實驗受限於受試者之主觀感受經驗彼此差異，實驗結果之可重復性仍待更進一步實驗證實。影響鑽骨手感的因素眾多，本實驗僅針對鑽針轉速一節研究討論，未來研究應討論其他因素對於鑽骨手感的影響，用以修正訓練模組並提供臨床醫師更好的環境數據，提高人工植牙成功率，增進病人福祉。

Abstract Research goal Since the concept of “osseointegration” introduced by Dr.Bråanemark in 1952, dental implants have becoming a long-term and predictable treatment option for patients with missing teeth. The establishment of osseointegration is affected by multiple factors.Bone quality is believed as one of most important factors. Many surgeons use their tactile sensation to evaluate the bone quality while drilling at implant site, then adapt or modifiy the following implant placement protocol. However, individual tactile sensation is affected by other factors like surgeon’s personal experience, drilling speed, bur size,…etc. The purpose of this study was to evaluate the effects of drilling speed on tactile sensation while drilling on artificial bone blocks(Sawbone ®) and tried to find the proper drilling speed when bone quality was evaluated. Material and Methods 1. Study enrollment: Thirty operators (10 men and 20 women), were voluntarily recruited from the junior residents of National Taiwan University Hospital since July 2019 to August 2019. They were all board-certified dentists (starting to practice within 5 years) with few implant surgery experiences(less than 10 implants). The average age of participants was 27.3 years (range: 25~34). The study protocol was approved by NTUH institutional research ethic committee (Approval number:201901021RINB). 2. Study designs: Each participant used a new 2-mm twist drill (Twist Drill w Tip 2x15mm, REF 32297, Nobel Biocare AB, Sweden) attached to an implant motor machine (Surgial XT Plus, NSK Nakanishi Inc., Japan) to drill the artificial bone blocks (Biomechnical Test Material, Sawbones® , Pacific Research Laboratories, Inc. Vashon, Washington, USA). They were asked to drill each artificial bone block to a depth of 10mm and to report the drilling resistance by a 100-mm visual analog scale, while VAS=100 was defined as the same drilling resistance as on 50pcf bone block and VAS=0 was defined as no drilling resistance. Each participant had one test, containing 4 rounds. Each round was only assigned to one drilling speed. Four drilling speeds (500rpm, 1000rpm, 1500rpm, and 2000rpm) were set in 4 rounds randomly. Seven artificial bone blocks (5pcf, 5pcf, 10pcf, 10pcf, 15pcf, 15pcf, and 30pcf) were tested in a random sequence in each round. The participants answered the drilling resistance immediately after drilling each block and couldn’t modify their answer later. After they finished one round, the drilling speed was changed in the next round. The test was finished after four rounds were performed. Results Difference in operator’s tactile sensation among different drilling speed was noted.In the group of harder artificial bone block(15pcf, 30pcf), mean VAS score decreased with higher drilling speeds(1500RPM, 2000RPM).There is different ability of each drilling speed to classify bone quality. Lower drilling speeds(500RPM, 1000RPM) seem to be more accurate to classify the overall artificial bone block(5pcf, 10pcf, 15pcf and 30pcf) than higher drilling speeds. The correct rate in drilling speed 500 RPM(77.5%) and 1000 RPM(77.5%) was higher than in 1500 RPM(59.2%) (p<0.05) and 2000 RPM(67.1%) (p>0.05). And also lower drilling speed is more accurate to classify low to low-medium bone density(5pcf and 10pcf).The correct rate in drilling speed 500 RPM (89.2%)and 1000RPM (90.8%) was higher than 1500 RPM(77.5%)(p<0.05) and 2000 RPM(85%)(p>0.05). Conclusions The result of this study showed that drilling speed may affect tactile sensation. Lower drilling speeds(500RPM 1000RPM) may have higher ability to differentiate the bone quality than higher drilling speeds. The result of this study suggested clinicians to apply drilling speed of 1000 rpm at most surgical areas while 500 rpm at maxillary posterior area for better differentiation of bone quality