Oregon Health & Science University, Portland, OR, USA.
Oper Dent. 2010 May-Jun;35(3):324-9. doi: 10.2341/09-178-L.
This study evaluated the marginal gaps on several surfaces of onlays created with the Cerec 3D system using one intraoral and two extraoral optical impression methods.
A human molar (#19) was mounted with its adjacent teeth on a typodont (Frasaco) and prepared for a MODL onlay. The typodont was assembled in the mannequin head in order to simulate clinical conditions. The same operator took 36 individual optical impressions using a CEREC 3D camera. For group 1 (IP), a thin layer of titanium dioxide powder (CEREC powder-VITA) was applied directly onto the surface of the preparation for imaging (n = 12). For group 2 (EP), a sectional impression was taken with hydrocolloid Identic Syringable (Dux Dental), a die made with polyvinylsiloxane KwikkModel Scan (R-dental Dentalerzeugnisse GmbH) and powdered with titanium dioxide for imaging (n = 12). For group 3 (ES), a sectional impression was taken with PVS and a sectional stock tray, a die fabricated in stone (Diamond die- HI-TEC Dental Products) and the die being imaged without powdering (n = 12). One operator designed and machined the onlays in VitaBlocks Mark II for Cerec (VITA) using a CEREC 3D. The marginal gaps (microm) were measured with an optical microscope (50x) at 12 points, three on each surface of the MODL. The results were analyzed by two-way ANOVA/ Tukey's (p = 0.05).
The overall mean marginal gaps (microm) for the three methods were: IP = 111.6 (+/- 34.0); EP = 161.4 (+/- 37.6) and ES = 116.8 (+/- 42.3). IP and ES were equal, but both were significantly less than EP. The pooled mean marginal gaps (microm) for the occlusal = 110.5 (+/- 39) and lingual = 111.5 (+/- 30.5) surfaces were equivalent and significantly less than the distal = 136.5 (+/- 42.5) and mesial = 161.1 (+/- 43.3).
The marginal gap of CEREC 3D onlay restorations was not different when the optical impression was taken intraorally vs extraorally using a stone cast that does not require powdering. The lingual and occlusal surfaces showed the lowest gaps.
本研究通过一种口内和两种口外光学印模方法，评估 Cerec 3D 系统制作嵌体的各个表面的边缘间隙。
将一颗人磨牙（#19）及其相邻牙齿安装在仿头模型（Frasaco）上，预备 MODL 嵌体。将仿头模型安装在头模中，以模拟临床条件。同一位操作人员使用 CEREC 3D 相机进行了 36 次独立的光学印模。对于第 1 组（IP），在预备体表面直接涂一层二氧化钛粉末（CEREC 粉末-VITA）进行成像（n = 12）。对于第 2 组（EP），使用 hydrocolloid Identic Syringable（Dux Dental）进行分段印模，使用 polyvinylsiloxane KwikkModel Scan（R-dental Dentalerzeugnisse GmbH）制作模具并涂覆二氧化钛进行成像（n = 12）。对于第 3 组（ES），使用 PVS 和分段stock tray 进行分段印模，使用石质模具（Diamond die-HI-TEC Dental Products）制作模具，并且在不涂覆粉末的情况下对模具进行成像（n = 12）。一位操作人员使用 VitaBlocks Mark II for Cerec（VITA）中的 CEREC 3D 设计并加工嵌体。使用光学显微镜（50x）在 12 个点测量 MODL 的三个表面上的边缘间隙（微米）。使用双向方差分析/ Tukey 检验（p = 0.05）对结果进行分析。
三种方法的总体平均边缘间隙（微米）分别为：IP = 111.6（+/-34.0）；EP = 161.4（+/-37.6）和 ES = 116.8（+/-42.3）。IP 和 ES 相等，但均显著小于 EP。近中面和颌面的平均边缘间隙（微米）为 110.5（+/-39）和 111.5（+/-30.5），与远中面和舌面的平均边缘间隙（微米）为 136.5（+/-42.5）和 161.1（+/-43.3）相比，均显著较小。
当使用不需要粉末的石质铸型进行口内或口外光学印模时，CEREC 3D 嵌体修复的边缘间隙没有差异。舌面和颌面显示出最小的间隙。
