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  • 學位論文

利用牙科CAD/CAM數位掃描技術的三單位固定贋復物的精密度之評估

An evaluation of accuracy of three-unit fixed prostheses using dental CAD/CAM and digital scanning technology

指導教授 : 燕敏

摘要


目的:評估不同廠牌的口外與口內牙科數位掃描機對掃描數位模型的準確度影響,並比較利用不同類型掃描機得到的數位模型,以同一CAD/CAM系統設計和加工製作的牙冠牙橋的邊緣適合性。材料與方法:利用第四型牙科用石膏灌製三單位前牙橋組(11-22)與後牙橋組(14-16)的支台齒模型,以七台牙科掃描機,分別對2組石膏模型進行掃描,使用CAD/CAM軟體對各台掃描機的3D數位模型做3D重疊比較,並於模型之切緣或咬合面放置固定標準尺寸元件(20×2×2mm3),對其數位模型及標準元件之偏差值進行統計分析。使用同一CAD/CAM軟體在各組別的掃描模型上設計三單位前、後牙橋後輸入CNC加工機製造樹脂前、後牙橋,利用Micro-CT掃描各牙橋牙冠,測量牙橋牙冠在頰、舌側和近、遠心側與石膏模型的內部和邊緣間隙。結果顯示iTero口內掃描機的前、後牙組數位模型的偏差值顯著大於其他組(P<0.05),而在其他掃描機前、後牙組數位模型之間偏差值沒有顯著差異(P>0.05)。偏差值最大為F組iTero口內掃描機前牙橋194.6 μm與後牙橋217.2 μm;偏差值最小後牙橋為D810雷射掃描機4.3 μm,前牙橋為DS100藍光掃描機5.3 μm。在不同掃描機製作的各前牙橋的邊緣間隙及內部間隙上都有顯著影響(P<0.05),在前牙橋與其他的軸面相比,在舌側的內部間隙顯著的大(P<0.05),在後牙橋,掃描機的類型對牙橋的邊緣間隙有顯著的影響(P<0.05),但對牙橋的內部間隙沒有顯著影響(P>0.05)。結論:本研究的結果證實口外掃描機的準確度好於口內掃描機,牙齒型態會影響掃描模型的準確性,前牙橋的掃描誤差大於後牙橋。不同掃描檔案加工製造的牙橋邊緣間隙均大於臨床可接受的100μm值。

關鍵字

CAD/CAM 牙科掃瞄機 牙橋 準確度

並列摘要


The purpose of this study was to evaluate the accuracy of different extra-oral and intra-oral scanners by scanning the stone models. The effect of different scanners on accuracy of digital model, and margin discrepancy of dental bridge crowns made with the above-mentioned scanning the digital models were also investigated. The three unit anterior bridge (11 - 22) and posterior bridge (14 - 16) high stone models were prepared, and scanned by five dental extra-oral scanners and two intra-oral scanner, respectively. A standard part (20 × 2 × 2 mm3) was fixed at the incisal edge and occlusal surface of anterior and posterior abutment teeth. The model with and without standard part was scanned 5 times via each scanner, then the dimensional discrepancy of scanning 3D digital models were compared using the commercial CAD software, and statistical methods of analysis. The virtual three unit anterior and posterior bridges were designed by the dental CAD system. The dental resin anterior and posterior bridges were fabricated by a CAM machine. Each anterior or posterior bridge was placed on the original abutment of stone model to scan by Micro-CT scanner. The internal gap and margin gap between crown and abutment of stone model at dental buccal, lingual, mesial, and distal side of each resin crown was measured using a Micro-CT scanning image. The results showed that the discrepancy of 3D digital model in iTero intraoral scanner was significantly higher than that of other scanners (P <0.05), whether the anterior or posterior bridge. The discrepancies of 3D digital models of other scanners had no significant difference (P > 0.05). The maximum discrepancies of anterior and posterior bridge models for the iTero intraoral scanner were 217.2 μm and 194.6 μm, respectively. The minima discrepancy of the anterior bridge created model with DS100 blue light scanner or the posterior bridge model created with D810 laser scanner was 5.3μm or 4.3 μm, respectively. The results also showed that internal gap and margin gap between crown and abutment in each anterior bridge created with different scanners had significant influence (P <0.05). In the anterior bridge, compare with the other axial, the internal gap at lingual was significantly larger (P <0.05). In the posterior bridge, the type of scanner had significant influence on margin gap (P <0.05), but no significant impact on internal gap (P> 0.05). The results of this study suggested that accuracy of extraoral scanners is better than that of intraoral scanners. Dental morphology and scanner type could affect the accuracy of the 3D digital model. The discrepancy at anterior bridge model is more than at posterior bridge. The margin gaps between crown and abutment created with different scanners were bigger without the acceptable clinical limit 100μm.

並列關鍵字

CAD/CAM dental scanner dental bridge accuracy

參考文獻


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