- 學位論文
口內掃瞄機之精確度及操作因素影響之探討
The Effects of Operation Factors and Accuracy of an Intraoral Scanner
摘要
中文摘要 研究目的及背景： 電腦輔助設計與製造 (CAD/CAM)的應用在牙科領域已經是近三十年來不斷發展的主題。近幾年更發展出口內數位掃瞄機(digital intraoral scanner)，以數位印模法來取代傳統印模，也使假牙的設計和製作得以數位化。如此一來不但可提高效率，也減少因繁複的技工步驟或傳統印模材印模方法的變形和誤差，甚或印模後的儲存、消毒方式，造成的時間、成本和材料變形。然而儘管各廠牌的口內掃瞄機在近幾年不斷推陳出新，有逐漸部分取代傳統印模方法的趨勢，但探討其精確度與操作因素影響方面的文獻仍有限，因此本研究以四位操作者來操作 TRIOS (intraoral scanner, 3shape)，並掃瞄兩種不同性質之模型，來探討口內掃瞄機之特性及精確性。 材料與方法： 本研究操作以四位操作者(代號S, A, B, C)操作TRIOS。其中操作者S為廠商委派之專業操作人員；A為臨床經驗不滿一年之實習醫師；B為臨床經驗三年之補綴科研究生；C為臨床經驗豐富之補綴科主治醫師。四位操作者分別對金屬標準模型和石膏標準模型做掃瞄並分析測量結果。石膏模型為使用個人印模托搭配VPS (vinyl polysiloxane) 印模材以雙相一次印模法從金屬模型翻印出來之超硬石膏(type IV dental stone)模型。金屬模型支柱牙之間隨機貼上牙科用蠟(Intraoral Dental Wax)和人工牙(Acrylic Resin Teeth)，但不影響支柱牙外型。兩標準模型使用三維座標測量儀(Crystal-Plus M443, Mitutoyo Inc.)作測量當作參考基準；掃瞄得到之數位模型輸出成STL檔並使用逆向工程軟體(Rapidform XOR3, 3D Systems, Inc.)作測量。所有模型之測量參數包括四顆支柱牙No.1到No.4彼此間的距離(D)、支柱牙高度(H)以及上半段高度(H-u)。每位操作者掃瞄所得之每個參數平均值稱為掃瞄測量值，座標測量儀對每個參數之測量結果平均值稱之為參考基準值。 結果： 比較四位操作者所得掃瞄測量值與參考基準值，石膏模型之掃瞄測量值整體而言與參考基準值較接近，但在支柱牙距離(D)的部分，各操作者掃瞄測量值之標準差較大，但操作者S除外。金屬模之掃瞄測量值中，有較多組參數與參考基準值呈現顯著差異，尤其在支柱牙高度(H)部分。 比較四位操作者所得結果彼此是否相異，發現跨越模型中線兩側的支柱牙距離、石膏模型的H-u、拍攝張數、掃瞄時間皆出現顯著差異，且大部分之差異出現在操作者S與其他操作者之間。在不考慮操作者的情況，金屬模和石膏模本身在拍攝張數和掃瞄時間也有顯著差異。 結論： 從本研究可發現TRIOS以下幾項特性： 1. 口內掃瞄機的操作精確度與熟練度有關，但與醫師臨床經驗較無關。 2. 掃瞄結果會受到金屬反光以及模型本身過度平整對稱而影響其精確性。反光面不但影響其精確性亦影響其掃瞄速度。過度平整則會容易造成數位模產生變形。 關鍵詞：口內掃瞄機；數位印模；CAD/CAM；3shape TRIOS
並列摘要
Abstract Background: CAD/CAM system utilization in the field of dentistry has be-come more and more widely used for the past several years, with the development of intraoral scanner playing an important role. Moreover, the use of intraoral scanners has replaced tradi-tional impression taking while digitalizing the design and fabri-cation procedure. Digitization of clinical and technician proce-dure can reduce the error caused by complicated steps, distor-tion or deformation of the cast model, or impression material caused by saliva, disinfection agent, storage condition, etc. Despite the innovation of the intraoral scanner by different companies worldwide, the accuracy and operation details re-garding the scanners are not clear enough for routine clinical procedure. In this study, we operate TRIOS (3shape) to gain more understanding about the special feature of the intraoral scanner. Material and Method: Four operators coded S, A, B, C operated the TRIOS to scan two standard models for measurement and analysis. Operator S is a professional operator; Operator A is an intern with less clini-cal experience; Operator B is a graduate student majoring in prosthetics with 3 years of clinical experience; Operator C is a prosthetic visiting staff with decades of clinical experience. One of the standard model is metallic, another one is made by taking impression of the metal model with VPS impression material (Aquasil Ultra Monophase/Regular Set和Aquasil Ultra XLV/Regular Set)and poured with the super-hard dental stone. The interproximal area of the abutments of the metal standard model was covered by utility wax (Intraoral Dental Wax) and ar-tificial teeth (Acrylic Resin Teeth, SHOFU Inc, Japan) while the dental stone model is not. The two standard models was meas-ured using a CMM device (Crystal-Plus M443, 3D Systems, Inc.) as a reference. Meanwhile the digital models from the scanner were exported as STL files and measured by Rapidform XOR3 software (3D Systems, Inc.). The measured parameters included the distance (D) between an abutment to each other (No.1 to No.4), the height (H) of the abutments and upper part of height (H-u) of the abutments. Result: The scanning measurements of the dental stone model are closer to its reference measurements in comparison to the metal standard model. However, the standard deviations are much bigger, especially in distance between abutments except the measurements of the Operator S. The overall difference between scanning measurements of the metal model and its reference measurements is bigger, especially over the height of the abut-ments. When comparing the measurement results between the 4 operators, significant difference were found in regards to the parameters of D which across the midline of the models, the images taken by the scanner, and the duration of the scanning process. Most of the significant differences were found when comparing results from Operator S to the others. This outcome implies that proficiency and practice may improve the scanning procedure. Conclusion: In this study, we found that proficiency and practice im-proves the scanning procedure, while clinical experience has lit-tle influence. Scanning results are also affected by reflective feature of metal and the symmetry or flatness of the models shape. The reflective metal model has negative affect to the accuracy and scanning time. Symmetry and flatness of the model shape may cause de-formation of the digital model. Keynote: intraoral scanner, digital impression, CAD/CAM, 3shape TRI-OS