Ferrari Cagidiaco Edoardo, Zarone Fernando, Discepoli Nicola, Joda Tim, Ferrari Marco
Department of Periodontics, Complutense University, 28001 Madrid, Spain.
Department of Prosthodontic and Dental Materials, University of Siena, 53100 Siena, Italy.
J Clin Med. 2021 Mar 1;10(5):941. doi: 10.3390/jcm10050941.
The aim of this randomized controlled trial was to evaluate the capability of an IOS (Intra Oral Scanner) device, used in standardized conditions, to detect margins of abutments prepared with knife-edge finishing line located at three different levels in relation to the gingival sulcus.
sixty abutment teeth for treatment with full crowns were selected and randomly divided in three groups accordingly to the depth of the finishing line: Group A: supragingival margin; Group B: 0.5-1.0 mm into the sulcus; Group C: 1.5-2.0 mm into the sulcus. Temporary crowns were placed for two weeks and then digital impressions (Aadva IOS 100, GC, Japan) were made of each abutment. As controls, analog impressions were taken, poured, and scanned using a laboratory scanner (Aadva lab scanner, GC, Japan). Two standard tessellation language (STL) files were generated for each abutment, subsequently processed, and superimposed by Exocad software (Exocad GmbH, Darmstadt, Germany), applying the "best-fit" algorithm in order to align the scan of the conventional with the digital impressions. The distances between each preparation margin and the adjacent gingival tissue were measured. Four measures were taken, two interproximally and buccally, for a total of six measures of each abutment considering three modes of impressions. The data were statistically evaluated using two-way analysis of variance (ANOVA) for each site and the Bonferroni test.
there was no difference between the two kinds of impression in Group A in both sites, in Group B a difference of 0.483 mm and 0.682 mm at interproximal and buccal sites, respectively, and in Group C 0.750 mm and 0.964 mm at interproximal and buccal sites, respectively. The analysis performed on a site level (mesial/distal/vestibular) for the depth of both vertical preparations revealed significant differences ( < 0.0001). After a post hoc analysis (Bonferroni), vestibular sites of the shallow vertical preparations resulted in significantly lower values compared to the other sites prepared deeply.
the results showed that the location of the margin is an important factor in making a precise and complete impression when IOS (Intra Oral Scanner) is used. Moreover, deep preparation into the sulcus is not recommended for IOS (Intra Oral Scanner) impressions.
本随机对照试验的目的是评估在标准化条件下使用的口腔内扫描仪（IOS）设备检测在龈沟三个不同水平处制备的带刃状边缘线的基台边缘的能力。
选择60颗拟行全冠修复的基牙，并根据边缘线深度随机分为三组：A组：龈上边缘；B组：龈沟内0.5 - 1.0毫米；C组：龈沟内1.5 - 2.0毫米。放置临时冠两周，然后对每个基台进行数字印模（日本GC公司的Aadva IOS 100）。作为对照，采用传统印模，灌注后使用实验室扫描仪（日本GC公司的Aadva lab scanner）进行扫描。为每个基台生成两个标准镶嵌语言（STL）文件，随后进行处理，并由Exocad软件（德国达姆施塔特的Exocad GmbH公司）进行叠加，应用“最佳拟合”算法以使传统印模扫描与数字印模对齐。测量每个预备边缘与相邻牙龈组织之间的距离。在每个基台的三种印模模式下，在近中、远中及颊侧各测量两次，共测量六个部位。使用双向方差分析（ANOVA）对每个部位的数据进行统计学评估，并进行Bonferroni检验。
A组两个部位的两种印模之间无差异；B组近中及颊侧部位分别相差0.483毫米和0.682毫米；C组近中及颊侧部位分别相差0.750毫米和0.964毫米。对垂直预备深度在部位水平（近中/远中/前庭）进行的分析显示存在显著差异（<0.0001）。经过事后分析（Bonferroni检验），浅垂直预备的前庭部位的值明显低于其他深预备部位。
结果表明，当使用口腔内扫描仪（IOS）时，边缘位置是获得精确完整印模的重要因素。此外，不建议在龈沟内进行深预备以获取口腔内扫描仪（IOS）印模。
