目的: 建立利用三维扫描、计算机辅助设计和三维打印制作数字化个齿托盘的方法,通过体外研究评价数字化个齿托盘法和常规法制取全牙列全冠预备体印模的效果。方法: 在标准下颌牙列模型上进行14颗树脂牙全冠预备,通过三维扫描获取预备体表面数据。利用牙科修复设计软件在每个预备体上确定边缘线位置,设计作为个齿托盘主体部分的解剖全冠和连接体形态,以及作为容纳印模材料空间的基底冠形态。在生成的个齿托盘主体数据外表面增加辅助固位装置,内表面生成组织终止点。设计及打印全牙列预备体模型1副,常规全牙列个别托盘A、B以及数字化个齿托盘各4副。使用个别托盘A采用一步法对全牙列预备体模型进行聚醚印模制取,使用个别托盘B和数字化个齿托盘采用分段取模方式完成聚醚印模制取,各重复制取4次。记录每次印模制取的时间及印模中每个预备体肩台及轴面/牙合面缺陷的数目,对每个预备体印模质量进行评价,比较两种方法制取印模的预备体合格率和预备体质量分布。结果: 常规法制取全牙列全冠预备体印模中肩台缺陷数目显著多于数字化个齿托盘法,轴面/牙合面缺陷数目差异无统计学意义。数字化个齿托盘法制取印模的预备体合格率高于常规法,预备体质量分布优于常规法。结论: 通过数字化方法可以实现个齿托盘的设计和制作,与常规法相比,数字化个齿托盘法制取全牙列全冠预备体印模效果更好。

Objective: To establish a method for the production of digital individual tooth tray based on three-dimensional (3D) scan, computer-aided design (CAD) and 3D printing, and to evaluate the effect of impression taking of full-arch crown abutments by digital individual tooth tray technique and conventional method through in vitro study.Methods: The full crown preparation was performed on all the fourteen resin teeth in a standard model of mandibular dentition. The surface data of prepared abutments was collected by 3D scanning. A new project was created in a dental CAD software including all the fourteen teeth in the mandibular dentition. The design modules of anatomy crown and coping were selected for each tooth. The dentition was divided for three sections: right posterior teeth, anterior teeth, and left posterior teeth areas. The connector design was added between the abutments within the same section. The scanned data of the abutments were imported. The occlusal plane and insertion path were determined. The position of margin line, as well as the shape of anatomy crown and connector as the main body of the individual tooth tray were designed for each abutment. The shape of coping was generated as the space for holding the impression material. The finalized data of the main body was imported into Geomagic software. The retentive attachment was added at the external surface and the tissue stop was formed at the internal surface. The completed individual tooth tray was manufactured by 3D printing with resin material. The data of full-arch crown abutments were modified and printed. The conventional dentition trays A and B, as well as digital individual tooth tray were designed and printed for four copies each. The polyether impressions of the full-arch abutments were made by conventional one-step method using dentition tray A, and by sectional-impression technique using digital individual tooth tray and dentition tray B for four times each. The time spent for each impression taking and the numbers of defects at the shoulder and axial/occlusal surface in each impression were recorded. The impression quality of each abutment was evaluated. The overall quality distribution and the pass rate of abutments between the two methods were analyzed.Results: The impressions made by conventional method had more defects at shoulder than those made by digital individual tooth tray technique. No difference of the number of defects at axial/occlusal surface between the two methods was observed. The digital individual tooth tray technique for the full-arch abutment impression exhibited higher pass rate of abutments and better quality of impression, compared with conventional methods.Conclusion: A new method for the production of digital individual tooth tray based on digital scanning, CAD and 3D printing was established. Compared with conventional method, using digital individual tooth tray technique for impression taking of full-arch abutments can achieve better effect.