分析在不同傾斜程度的骨表面上使用靜態導引板植牙的精準度

Abstract

實驗目的 使用靜態導引板植牙可以幫助植體植入時的位置更加精準，和原來設計的位置誤差變小。因為靜態導引板的設計可以在鑽骨的過程中全程導引植牙鑽針到設計的植體位置。 在鑽骨過程中，容易受到骨面傾斜程度的影響而造成鑽針位置偏移。在即拔即種的案例或是在齒槽骨吸收嚴重的骨表面植牙經常會遇到這樣的情形，導致最終的植牙位置和原始的設計有偏差，進而影響未來假牙的製作。 在傾斜的骨表面上使用靜態導引板植牙也可能會產生鑽針偏移的情形，因此本實驗目的是探討在不同傾斜程度的骨表面上使用靜態導引板植牙的精準度。 實驗材料與方法 1. 實驗設計 : 同一位操作者在3種不同傾斜程度的骨表面上，使用靜態導引板鑽骨及植入植體，在植體上裝上掃描桿桌掃，再以軟體計算設計檔和實際植體植入位置的誤差，最後統計分析骨頭傾斜程度對植體精準度的影響。 2. 實驗的術前準備: 甲、 模擬骨塊製備 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30pcf，相當於Misch分類D1骨質的抗壓強度。使用Snapmaker 2.0 A350T的CNC模組3.0 mm鑽針頭來做切割，將模擬骨塊切割成為尺寸8mm(長) X 8mm(寬) X 25mm(高)的立體方塊。骨表面分為三組，分別為0度、30度、60度的斜面，每個組別有10個骨塊，總共30個模擬骨塊。 乙、 實驗標準模型設計: 以3 Shape E4桌掃機 (Lab scanner) 掃描模擬病人的實體模型得到stl檔，使用Meshmixure 3D模型編輯軟體在欲植入植體的牙位設計出模擬骨塊放入的凹槽，以Phrozen Sonic XL 4K列印機列印出實驗模型3個，分別為模型A、模型B、模型C，使用的材料為耐高溫樹脂 (TR250LV,Phrozen)。 丙、 30個模擬骨塊平均分配於A、B、C三個模型。實驗模型的設計使每個模擬骨塊結束實驗後可以被拆除，替換下一個模擬骨塊，繼續實驗。 丁、 植體位置設計: 使用3 Shape TRIOS Design Studio中Implant Studio設計植體位置，匯入模擬病人的錐狀射束電腦斷層掃描dicom檔和模型的桌掃檔後，進行疊合，設計虛擬假牙的位置，齒位為12，再根據假牙的位置設計植體。規劃植入NobelParallel Conical connection RP 4.3、長度13mm的植體。 戊、 靜態導引板製備: 手術導引板設計橫跨欲植牙位置左右兩側兩顆牙齒的咬合面上，並各開一個窗在兩側咬合面上，手術導引板材料使用DD guide植牙導引板材料(陽明數位牙材)，以Phrozen Sonic 4K列印機產出。並將Nobel Biocare Guided Sleeve 4.3金屬導環放入手術導引板，以三秒膠黏著。 己、 術前標準模型準備: 模擬骨塊以石膏包埋於實驗模型凹槽內，將靜態手術導引板戴上標準模型，從導板兩側的窗口確定手術導引板戴至定位，術前準備完成。 3. 植入植體的流程 使用的植牙手機為日本NSK Nakanishi公司出產的Surgic XT Plus machine 搭配彎機手機為 Mont Blanc 20:1 Push Button Dental Implant Handpiece Low Speed Contra angle，設定扭力25N-cm，轉速設定為1000RPM。手術器械使用Nobel Biocare Guided surgery中NobelParallel Conical connection surgery Kit。依原廠的手術指引，依序鑽骨，並植入植體。 4. 術後階段 植入的植體接上掃描桿(Elos Accurate IO Nobel CC RP Single Abt)，以桌掃機(Lab scanner) 掃描，得到掃描後的stl檔。 5. 植體精準度的分析 使用Geomagic ControlX2020.1分析軟體進行疊合和精準度的計算，將術前的設計檔和術後桌掃得到的stl檔在軟體內疊合並進行分析。根據五個測量值來推算精準度，分別為: (a)植體進入點的差值、(b) 植體根尖端的差值、(c)植體軸向的差值、(d)植體垂直距離的差值、(e)植體水平距離的差值。 6. 統計分析 以one way repeated measured ANOVA來評估骨面傾斜程度對精準度有無顯著差異。當One way ANOVA 檢測結果有顯著差異時，以事後多重比較(proc hoct test) Bonferroni test來檢測哪些組別間有顯著差異。所有統計分析 p value 設定在p <0.05 表示在統計學上具有差異。 實驗結果： 1. 結果顯示在植體進入點的差值、植體根尖端的差值、植體軸向的差值、植體垂直距離的差值這四個測量值有顯著差異(p<0.05)，在植體水平距離的差值沒有顯著差異。 2. 植體的偏移方向分成頰側和顎側、近心側和遠心側這兩個組別。由於頰側組別有23個，比起其他組別數量顯著較多，因此以One sample proportion test檢測，p值為0.0031，有顯著差異。 結論： 1. 在骨頭表面傾斜的情況下使用靜態手術導引板，植牙的精準度還是會受骨頭表面傾斜程度影響。 2. 在植體進入點的差值、植體根尖端的差值、植體軸向的差值、植體垂直距離的差值這幾個組別有顯著差異。 3. 骨頭表面往頰側下傾，最終植體位置也容易往頰側偏移。

Objective Using a static fully guide to provide guidance through the whole drilling procedure for accurate implant position is more frequently applied in implant placement now. However, the inclination of the bone surface, such as extraction sockets or severely atrophic ridge, may affect the 3D position of the drill during osteotomy preparation. The purpose of the study was to evaluate the effects of bone surface inclination on the accuracy of static fully guided implant surgery. Materials and methods 1. Preparation of experimental models A patient’s cone beam computed tomography (CBCT) and the laboratory scan of the maxillary cast were used to fabricate experimental models. Three identical models with a missing upper right lateral incisor were 3D printed. There was a volume (8x8x25mm3) at right lateral incisor for placement of artificial bone blocks in each model. Three groups of artificial bone blocks (Sawbones®) with different surface inclinations (0, 30, and 60 degrees) at buccal side were shaped to fit the space in the model. There were 10 blocks in each group (n=30). Before each test, the artificial bone block was cemented in the model with dental plaster. 2. Fabrication of static fully surgical guides The patient’s CBCT and the model scan were mapped (3Shape Implant Studio) to plan the implant position according to the outline form of the virtual prosthesis. A fully surgical guide supported by the adjacent teeth was designed and three copies were printed with resin. Each surgical guide was adjusted to fit one corresponding model. 3. Implant placement A single operator drilled and placed implants in the artificial bone blocks with different inclination surfaces by using fully surgical guides and following the protocol for NobelParallel Conical Connection. A NobelParallel Conical connection RP implant (4.3x13mm) was placed in each artificial bone block. 4. Evaluation of the accuracy of implant position The scan body was attached to the implant and scanned with a lab scanner (3Shape E4). The scanned data was mapped with the virtual surgical plan in a metrology software (Geomagic Control X). Five outcomes were measured: (1) deviation at entry point, (2) deviation at apex, (3) angular deviation, (4) deviation at vertical implant position, and (5) deviation at horizontal implant position. One-way ANOVA and Bonferroni test were used for statistical analysis. A significance level of P < .05 was set. Results There were significant differences in the deviation at entry point, deviation at apex, angular deviation, and deviation at vertical implant position. However, there was no significant difference in deviation at horizontal implant position. Among 30 implants, there were 23 implants deviating to buccal side. Conclusion The accuracy of implant placement by using static fully guides was affected by the degree of bone surface inclination.