Alikhasi Marzieh, Siadat Hakime, Nasirpour Alireza, Hasanzade Mahya
Dental Research Center, Dentistry Research Institute, Department of Prosthodontics, Tehran University of Medical Sciences, Tehran, Iran.
Dental Student Research Center, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
Int J Dent. 2018 Jun 4;2018:3761750. doi: 10.1155/2018/3761750. eCollection 2018.
The aim of this in vitro study was to compare the accuracy of different implant impression techniques of the maxillary full arch with tilted implants of two connection types.
Two maxillary edentulous acrylic resin models with two different implant connections (internal or external) served as a reference model. Each model had two anterior straight and two posterior angulated implants. Ninety impressions were made using an intraoral scanner (Trios 3Shape) with scan bodies for digital impression (groups DII and DIE), a custom open tray with additional silicone for the conventional direct group (groups CDI and CDE), and a custom closed tray with additional silicone for the conventional indirect group (groups CII and CIE) from both internal and external models, respectively. A coordinate-measuring machine (CMM) was used to measure linear and angular displacement for conventional specimens. For digital groups, an optical CMM was used to scan the reference model. STL data sets from the digital specimen were superimposed on STL reference data sets to assess angular and linear deviations. Data were analyzed with three-way ANOVA and -test at =0.05.
There were significant angular and linear distortion differences among three impression groups ( < 0.001), angular distortion differences between internal and external connections ( < 0.001), and between straight and tilted implants for either linear ( < 0.001) or angular (=0.002) distortion. The type of the connection and implant angle did not have any effect on linear and angular distortion of the digital technique ( > 0.05). Minimum angular and linear distortion was seen for tilted implants in DII and DIE groups (0.36° ± 0.37 and 0.16 ± 0.1 mm).
Impression techniques (digital versus conventional) affected the transfer accuracy. Digital techniques demonstrated superior outcome in comparison with conventional methods, and the direct technique was better than the indirect conventional technique. Connection type and implant angulation were other factors that influenced accuracy. However, when digital impression was applied, accuracy was not affected by the type of connection and angulation.
本体外研究的目的是比较两种连接类型的倾斜种植体在上颌全牙弓不同种植体印模技术的准确性。
两个具有不同种植体连接方式（内部或外部）的上颌无牙丙烯酸树脂模型作为参考模型。每个模型有两个前部直型种植体和两个后部成角种植体。使用口内扫描仪（Trios 3Shape）和扫描体进行数字印模，从内部和外部模型分别制作了90个印模，用于数字印模组（DII组和DIE组）；使用带有额外硅橡胶的定制开放托盘用于传统直接印模组（CDI组和CDE组）；使用带有额外硅橡胶的定制封闭托盘用于传统间接印模组（CII组和CIE组）。使用坐标测量机（CMM）测量传统标本的线性和角位移。对于数字印模组，使用光学CMM扫描参考模型。将数字标本的STL数据集与STL参考数据集叠加，以评估角度和线性偏差。数据采用三因素方差分析和α = 0.05的t检验进行分析。
三个印模组之间存在显著的角度和线性变形差异（P < 0.001），内部和外部连接之间存在角度变形差异（P < 0.001），对于线性（P < 0.001）或角度（P = 0.002）变形，直型和倾斜种植体之间也存在差异。连接类型和种植体角度对数字技术的线性和角度变形没有任何影响（P > 0.05）。DII组和DIE组中倾斜种植体的角度和线性变形最小（0.36°±0.37和0.16±0.1mm）。
印模技术（数字印模与传统印模）影响转移准确性。与传统方法相比，数字技术显示出更好的结果，并且直接技术优于间接传统技术。连接类型和种植体角度是影响准确性的其他因素。然而，当应用数字印模时，准确性不受连接类型和角度的影响。
