多色多硬度牙颌模型感光聚合物喷射一体化三维打印精度初探

Quantitative evaluation of printing accuracy of multi-color and multi-hardness three-dimensional printing dental model with photopolymer jetting

目的通过感光聚合物喷射(photopolymer jetting,PJ)一体化三维打印多色多硬度牙颌模型,定量评价打印精度,以期为PJ的临床应用提供参考。方法选择经扫描和软件处理的上颌Kennedy第二类第一亚类牙列缺损的牙颌模型数据为参考数据,通过基于数字光处理(digital light processing,DLP)技术的单色单硬度打印机(DLP-800d)打印单色单硬度DLP模型5个(DLP组),通过基于PJ技术的多色多硬度打印机(J300Plus)打印多色多硬度PJ模型5个(PJ组)。三维扫描打印模型,将打印模型扫描数据在Geomagic Studio 2013软件中配准于参考数据,计算整体及各区域(余留牙列、邻缺隙基牙、完整牙龈、非游离缺失区牙龈、游离缺失区牙龈、可摘局部义齿黏膜支持区)的三维偏差,以均方根值表示,均方根值越小,打印正确度越高;将同组5个模型的扫描数据进行两两配准后计算三维偏差,均方根值越小,打印精密度越高。以200μm为临床可接受误差的阈值。比较两组牙颌模型打印正确度和精密度的差异。结果两组牙颌模型整体及各分区打印正确度均方根值均小于200μm;DLP组整体打印正确度[57.70(2.10)μm]显著优于PJ组[71.00(7.70)μm](P<0.05);DLP组整体打印精密度[15.20(5.05)μm]显著优于PJ组[37.55(15.55)μm](P<0.05)。结论本项研究采用的国产PJ打印机能以较好的正确度和精密度打印多色多硬度牙颌模型,可为实现牙颌模型软硬组织区域硬度差异化仿真提供一体化三维打印。

Objective To quantitatively evaluate the accuracy of multi-color and multi-hardness dental models printed by using the photopolymer jetting(PJ)technology,and to provide protocol for the clinical application.Methods A maxillary partially edentulous(Kennedy classⅡsubclass 1)standard digital model obtained through scanning and processing was selected as reference data.Five monochromatic DLP(digital light processing)models with single hardness were printed by printer DLP-800d based on DLP technology(DLP group),and five multi-color and multi-hardness PJ models were printed by printer J300Plus based on PJ technology(PJ group).Scan the printed model and register the scanning data to the reference data in Geomagic Studio 2013 software.The three-dimensional(3D)deviations of the whole and each area,including residual dentition,abutments adjacent to the edentulous area,gingiva,gingiva in the distal-extended edentulous area,gingiva in other edentulous areas,gingiva supporting the removable partial denture(RPD),were calculated and represented by the root mean square error(RMS)value.The smaller the RMS value was,the higher the trueness of printing was.The scanning data of the five models in the same group were registered in pairs to calculate the 3D deviation.The smaller the RMS value was,the higher the precision of printing was.The threshold of clinical acceptability was 200μm.Statistical analysis was performed to compare the difference of trueness and precision between the two groups.Results The overall trueness of the DLP group[57.70(2.10)μm]was significantly better than that of the PJ group[71.00(7.70)μm].The overall precision of the DLP group[15.20(5.05)μm]was significantly better than that of the PJ group[37.55(15.55)μm].The overall trueness and precision of both groups were within the clinically acceptable range.Conclusions The domestic PJ printer used in this study can print multi-color and multi-hardness dental models with good trueness and precision,which can provide integrated 3D printing technology support for realizing the simulation of regional hardness differentiation between soft and hard tissues of dental models.