共查询到20条相似文献，搜索用时 31 毫秒
1.
Sven Mühlemann Goran I. Benic Vincent Fehmer Christoph H.F. Hämmerle Irena Sailer 《The Journal of prosthetic dentistry》2019,121(2):252-257
Statement of problem
Clinical trials are needed to evaluate the digital and conventional fabrication technology for providing fixed partial dentures (FPDs).Purpose
The purpose of the second part of this clinical study was to compare the laboratory production time for tooth-supported, 3-unit FPDs by means of computer-aided design and computer-aided manufacturing (CAD-CAM) systems and a conventional workflow. In addition, the quality of the 3-unit framework of each treatment group was evaluated clinically.Material and methods
For each of 10 participants, a 3-unit FPD was fabricated. Zirconia was used as the framework material in the CAD-CAM systems and included Lava C.O.S. CAD software (3M) and centralized CAM (group L); CARES CAD software (Institut Straumann AG) and centralized CAM (group iT); and CEREC Connect CAD software (Dentsply Sirona) and centralized CAM (group C). The noble metal framework in the conventional workflow (group K) was fabricated by means of the traditional lost-wax technique. All frameworks were evaluated clinically before veneering. The time for the fabrication of the cast, the 3-unit framework, and the veneering process was recorded. In addition, chairside time during the clinical appointment for the evaluation of the framework was recorded. The paired Wilcoxon test together with appropriate Bonferroni correction was applied to detect differences among treatment groups (α=.05).Results
The total effective working time (mean ±standard deviation) for the dental technician was 220 ±29 minutes in group L, 217 ±23 minutes in group iT, 262 ±22 minutes in group C, and 370 ±34 minutes in group K. The dental technician spent significantly more time in the conventional workflow than in the digital workflow, independent of the CAD-CAM systems used (P<.001).Conclusions
Irrespective of the CAD-CAM system, the overall laboratory time for the dental technician was significantly less for a digital workflow than for the conventional workflow. 相似文献2.
3.
4.
Hiba Al-Imam Mia Gram Ana R. Benetti Klaus Gotfredsen 《The Journal of prosthetic dentistry》2018,119(4):580-585
Statement of problem
Despite the increasing demand for a digital workflow in the fabrication of indirect restorations, information on the accuracy of the resulting definitive casts is limited.Purpose
The purpose of this in vitro study was to compare the accuracy of definitive casts produced with digital scans and conventional impressions.Material and methods
Chamfer preparations were made on the maxillary right canine and second molar of a typodont. Subsequently, 9 conventional impressions were made to produce 9 gypsum casts, and 9 digital scans were made to produce stereolithography additive (SLA) casts from 2 manufacturers: 9 Dreve SLA casts and 9 Scanbiz SLA casts. All casts were then scanned 9 times with an extraoral scanner to produce the reference data set. Trueness was evaluated by superimposing the data sets obtained by scanning the casts with the reference data set. Precision was evaluated by analyzing the deviations among repeated scans. The root mean square (RMS) and percentage of points aligned within the nominal values (±50 μm) of the 3-dimensional analysis were calculated by the software.Results
Gypsum had the best alignment (within 50 μm) with the reference data set (median 95.3%, IQR 16.7) and the least RMS (median 25.8 μm, IQR 14.6), followed by Dreve and Scanbiz. Differences in RMS were observed between gypsum and the SLA casts (P<.001). Within 50 μm, gypsum was superior to Scanbiz (P<.001). Gypsum casts exhibited the highest precision, showing the best alignment (within 50 μm) and the least RMS, followed by Scanbiz and Dreve.Conclusions
This study found that gypsum casts had higher accuracy than SLA casts. Within 50 μm, gypsum casts were better than Scanbiz SLA casts, while gypsum casts and Dreve SLA casts had similar trueness. Significant differences were found among the investigated SLA casts used in the digital workflow. 相似文献5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
