三维打印及功能引导路径技术获得诊断性全冠功能性[牙合]面形态初探

目的通过在三维打印诊断性全冠上运用功能引导路径(functional generated path,FGP)技术获得修复体功能性牙合]面形态,探索减少修复体面调改量以及避免干扰的临床方法。方法选择2018年7月至2018年12月于北京大学口腔医学院·口腔医院修复科就诊、需行下颌第一磨牙全冠修复的患者10例,其中男性4例,女性6例,年龄(29.6±7.4)岁;进行基牙预备体模型扫描并获得数字化模型;分别为每例患者制作两种全冠修复体。试验组:制作三维打印聚乳酸基底冠和蜡面,通过口内FGP法直接获得具有功能接触形态的面,扫描后制作计算机辅助设计与辅助制作氧化锆全冠修复体;对照组:按照数据库及经验常规设计制作氧化锆全冠修复体。临床试戴后用逆向工程软件(Geomagic Sudio&Quality)对修复体牙合]面调改前后的咬合接触位置及面积、咬合接触程度、面调改高度和体积等指标进行数字化定量分析,并对两组数据进行配对t检验。结果10例患者均顺利通过FGP法获得面形态。试验组修复体牙合]面调改体积(7.320±4.238)mm3]显著小于对照组(20.178±9.650)mm3](P<0.05);调改前试验组咬合高点高度(0.043±0.019)mm]显著低于对照组(0.594±0.201)mm](P<0.05),咬合接触面积(11.430±4.102)mm2]显著大于对照组(4.808±3.223)mm2](P<0.05)。结论运用三维打印及功能引导路径技术可获得修复体牙合]面的个性化功能接触形态,可比常规方法显著减少修复体牙合]调改量并降低咬合高点。

Study on functional occlusal morphology by using three-dimensional printed diagnostic crown and functional generated path technology

Objective To establish the functional occlusal morphology of fixed prostheses by using functional generated path(FGP)technology on a three-dimensional-printed diagnostic crown in order to decrease the chance of occlusal adjustment during try-in procedure of the complete crown,and to avoid the risk of occlusal interference after cementation of prosthesis.Methods A double-blind clinical trial was performed.Ten subjects(4 males,6 females)who needed a first molar complete crown restoration were enrolled in Department of Prosthodontics,Peking University School and Hospital of Stomatology from July 2018 to December 2018.The working models with the abutment teeth of the ten participants were scanned to obtain the digital models,then the occlusal surfaces of crown were formed by either FGP technology on a three-dimensional(3D)printed diagnostic crown and then were scanned directly for computer aided design and computer aided manufacture(CAD/CAM)crown fabrication as experiment group,or conventional technology based on database as control group.Then zirconia crowns were fabricated for two groups.During crown try-in of the two groups,preferred crowns of subjects were recorded,the occlusal contact criteria including the occlusal contact area(mm2),the heights of occlusal high spot(mm)before and after the adjustment of crowns were digitally analyzed,and the amount of adjustment(mm and mm3)were calculated on digital models by using a reverse engineering software(Giomagic Sudio&Quality).Differences of values were compared statistically with paired t-test(α=0.05).Results The amount for occlusal adjustment for crowns in the experiment group(7.320±4.238)mm3]was statistically less than that in the control group(20.178±9.650)mm3](P<0.05),the occlusal contact area of experiment group(11.430±4.102)mm2]was statistically bigger than that of the control group(4.808±3.223)mm2](P<0.05),the heights of occlusal high spots for crowns in the experiment group was(0.043±0.019)mm while it was(0.594±0.201)mm in the control group with statistically significant differences(P<0.05).Conclusions This method could lead to a crown with less adjustment of occlusion,less occlusal high spot and less risk of occlusal interferences.