scholarly journals Effect of multiple pouring on the accuracy of casts made using 3D-printed custom trays with different spacer thicknesses: A research study

2020 ◽  
Vol 14 (1) ◽  
pp. 37-40
Author(s):  
Sara Tavakolizadeh ◽  
Mohammad Javad Razaghi ◽  
Pedram Pakravan ◽  
Majid Sedaghat Monfared ◽  
Elaheh Beyabanaki ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dimensional Accuracy ◽  
Significance Level ◽  
Type Iv ◽  
Incisal Edge ◽  
Significant Difference ◽  
Cad Cam ◽  
3D Printed ◽  
Bonferroni Test ◽  
Spacer Thickness

Background . This study aimed to evaluate the effect of different pouring times and spacer thicknesses on the three-dimensional accuracy of casts made of 3D-printed custom trays. Methods. A partial edentulous maxillary model was scanned for fabricating custom acrylic trays. Twenty custom trays were created using a CAD/CAM system and divided into two groups in terms of their spacer thicknesses (2 mm and 4 mm). All the trays were designed with 2-mm thickness, multiple retentive holes measuring 2 mm in diameter, and three interior seating stops (two on the edentulous ridge and one on the incisal edge of the central incisors). Impressions were made using monophasic polyvinyl siloxane and poured in two different times (one hour and 24 hours after removal) with type IV dental stone. All the casts were scanned to measure three distances (inter-buccal cusps, inter-palatal cusps, and inter-fossa distances) between the two first premolars. The data were analyzed with two-way ANOVA and Bonferroni test at a significance level of 0.05. Results. There was no significant difference between the 3D accuracy of casts made using two different spacer thicknesses poured at 1-hour and 24-hour intervals. However, there was a difference between casts made after 1 hour and 24 hours when using custom trays with 2 mm of spacer thickness in terms of inter-buccal distance. Conclusion. There was no significant difference between the accuracy of casts made using custom trays with either 2 or 4 mm of spacer thickness, which were poured 1 hour or 24 hours after tray removal.

scholarly journals Dimensional Accuracy of Dental Models for Three-Unit Prostheses Fabricated by Various 3D Printing Technologies

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1550
Author(s):  
Soo-Yeon Yoo ◽  
Seong-Kyun Kim ◽  
Seong-Joo Heo ◽  
Jai-Young Koak ◽  
Joung-Gyu Kim
Keyword(s):  
Surface Roughness ◽  
Three Dimensional ◽  
Dimensional Accuracy ◽  
3D Analysis ◽  
Digital Light Processing ◽  
Test Models ◽  
Reference File ◽  
Significant Difference ◽  
Jet Printing ◽  
3D Printed

Previous studies on accuracy of three-dimensional (3D) printed model focused on full arch measurements at few points. The aim of this study was to examine the dimensional accuracy of 3D-printed models which were teeth-prepped for three-unit fixed prostheses, especially at margin and proximal contact areas. The prepped dental model was scanned with a desktop scanner. Using this reference file, test models were fabricated by digital light processing (DLP), Multi-Jet printing (MJP), and stereo-lithography apparatus (SLA) techniques. We calculated the accuracy (trueness and precision) of 3D-printed models on 3D planes, and deviations of each measured points at buccolingual and mesiodistal planes. We also analyzed the surface roughness of resin printed models. For overall 3D analysis, MJP showed significantly higher accuracy (trueness) than DLP and SLA techniques; however, there was not any statistically significant difference on precision. For deviations on margins of molar tooth and distance to proximal contact, MJP showed significantly accurate results; however, for a premolar tooth, there was no significant difference between the groups. 3D color maps of printed models showed contraction buccolingually, and surface roughness of the models fabricated by MJP technique was observed as the lowest. The accuracy of the 3D-printed resin models by DLP, MJP, and SLA techniques showed a clinically acceptable range to use as a working model for manufacturing dental prostheses

Investigation of three-dimensional printing materials for printing aorta model replicating Type B aortic dissection

2021 ◽  
Vol 17 ◽  
Author(s):  
Chia-An Wu ◽  
Andrew Squelch ◽  
Zhonghua Sun
Keyword(s):  
3D Printing ◽  
Aortic Dissection ◽  
Three Dimensional ◽  
Ct Images ◽  
Patient Specific ◽  
Type B ◽  
Type B Aortic Dissection ◽  
Ct Attenuation ◽  
Significant Difference ◽  
3D Printed

Aim: To determine a printing material that has both elastic property and radiology equivalence close to real aorta for simulation of endovascular stent graft repair of aortic dissection. Background: With the rapid development of three-dimensional (3D) printing technology, a patient-specific 3D printed model is able to help surgeons to make better treatment plan for Type B aortic dissection patients. However, the radiological properties of most 3D printing materials have not been well characterized. This study aims to investigate the appropriate materials for printing human aorta with mechanical and radiological properties similar to the real aortic computed tomography (CT) attenuation. Objective: Quantitative assessment of CT attenuation of different materials used in 3D printed models of aortic dissection for developing patient-specific 3D printed aorta models to simulate type B aortic dissection. Method: A 25-mm length of aorta model was segmented from a patient’s image dataset with diagnosis of type B aortic dissection. Four different elastic commercial 3D printing materials, namely Agilus A40 and A50, Visijet CE-NT A30 and A70 were selected and printed with different hardness. Totally four models were printed out and conducted CT scanned twice on a 192-slice CT scanner using the standard aortic CT angiography protocol, with and without contrast inside the lumen.Five reference points with region of interest (ROI) of 1.77 mm2 were selected at the aortic wall and intimal flap and their Hounsfield units (HU) were measured and compared with the CT attenuation of original CT images. The comparison between the patient’s aorta and models was performed through a paired-sample t-test to determine if there is any significant difference. Result: The mean CT attenuation of aortic wall of the original CT images was 80.7 HU. Analysis of images without using contrast medium showed that the material of Agilus A50 produced the mean CT attenuation of 82.6 HU, which is similar to that of original CT images. The CT attenuation measured at images acquired with other three materials was significantly lower than that of original images (p<0.05). After adding contrast medium, Visijet CE-NT A30 had an average CT attenuation of 90.6 HU, which is close to that of the original images with statistically significant difference (p>0.05). In contrast, the CT attenuation measured at images acquired with other three materials (Agilus A40, A50 and Visiject CE-NT A70) was 129 HU, 135 HU and 129.6 HU, respectively, which is significantly higher than that of original CT images (p<0.05). Conclusion: Both Visijet CE-NT and Agilus have tensile strength and elongation close to real patient’s tissue properties producing similar CT attenuation. Visijet CE-NT A30 is considered the appropriate material for printing aorta to simulate contrast-enhanced CT imaging of type B aortic dissection. Due to lack of body phantom in the experiments, further research with simulation of realistic anatomical body environment should be conducted.

Investigations for Wax Coated 3D Printed Hybrid Patterns for Partial Dentures

2019 ◽  
Author(s):  
Kamaljit Singh Boparai ◽  
Gurpartap Singh ◽  
Rupinder Singh ◽  
Sarabjit Singh
Keyword(s):  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Surface Hardness ◽  
Dimensional Accuracy ◽  
Acrylonitrile Butadiene Styrene ◽  
Processing Technique ◽  
Patient Specific ◽  
Fused Deposition ◽  
3D Printed

Abstract In this work, 3D printed master patterns of acrylonitrile butadiene styrene (ABS) thermoplastic material have been used for the preparation of Ni-Cr based functional prototypes as partial dentures (PD). The study started with patient specific three dimensional (3D), CAD data (fetched through scanning). This data was used for preparation of .STL file for printing of master patterns on fused deposition modeling (FDM) setup. The 3D printed master patterns were further wax coated to reduce the surface irregularities (as cost effective post processing technique). The hybrid patterns were subjected to investment casting for the preparation of Ni-Cr based PD. The finally prepared functional prototypes as PD were optimized for dimensional accuracy, surface finish and surface hardness as responses. The results are visualized and supported by photomicrographs and in-vitro analysis.

scholarly journals Dentinal Microcrack Formation after Root Canal Instrumentation by XP-Endo Shaper and ProTaper Universal: A Microcomputed Tomography Evaluation

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Sarah M. Alkahtany ◽  
Ebtissam M. Al-Madi
Keyword(s):  
The Body ◽  
Micro Ct ◽  
Cross Sectional ◽  
Significance Level ◽  
Root Canals ◽  
Type Iv ◽  
Significant Difference ◽  
Before And After ◽  
Microcrack Formation ◽  
Group 2

Aim. To evaluate dentinal microcrack formation on root canals instrumented, continuously in the body temperature, with XP-endo shaper (XPES) and ProTaper Universal (PTU), by means of microcomputed tomographic (micro-CT) analysis. Methodology. Nineteen mesial roots with two separate canals (Vertucci Type IV) of extracted mandibular molars were used in this study. The root canals (N = 38) were divided into 2 groups. Group 1 (n = 19): all MB canals were instrumented with XPES. Group 2 (n = 19): all ML canals were instrumented with PTU. All roots were scanned with micro-CT before and after instrumentation. Two precalibrated examiners evaluated the cross-sectional images of each sample with DataViewer program. The dentinal microcracks (complete and incomplete) were counted in each third of the root for the preinstrumentation and the postinstrumentation images. Wilcoxin signed-rank and Mann–Whitney U tests were used for statistical analysis at a significance level of P<0.05. Results. The number of microcracks increased significantly (P<0.05) after instrumentation with XPES in the middle and cervical thirds. The number of microcracks increased significantly (P<0.05) after instrumentation with PTU in the cervical third only. There was no significant difference between the groups in the cervical and apical thirds. In the middle third, the XPES induced more incomplete microcracks than PTU (P<0.05). Conclusion. Within the limitations of this study, there was no significant difference in the dentinal microcrack formation between XPES and PTU in the apical and cervical thirds of the root. However, XPES instrumentation induced more incomplete microcracks than PTU in the middle third of human roots.

Additive vs. Subtractive CAD/CAM Procedures in Manufacturing of the PMMA Interim Dental Crowns. A Comparative in vitro Study of Internal Fit

2020 ◽  
Vol 71 (1) ◽  
pp. 405-410
Author(s):  
Kamel Earar ◽  
Alexandru Andrei Iliescu ◽  
Gabriela Popa ◽  
Andrei Iliescu ◽  
Ioana Rudnic ◽  
...  
Keyword(s):  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Vitro Study ◽  
Dental Crowns ◽  
S 100 ◽  
Cad Cam ◽  
Dental Models ◽  
3D Printed ◽  
Internal Fit

CAD/CAM procedures are increasingly used to the manufacturing of 3D-designed PMMA interim dental crowns. The aim of this in vitro study was to compare the internal fit of interim PMMA crowns fabricated by subtractive versus additive CAD/CAM procedures. Starting from a Co-Cr CAD/CAM master abutment model, 20 standardized dental models of dental stone were done by double impression technique. Subsequently two groups of interim PMMA interim crowns, each of them having 10 specimens, were CAM obtained either by milling or 3D printing, using Exocad software package, milling machine Rolland DWX-50, and the 3D printer MoonRay S 100 respectively. An electronic digital caliper Powerfix Profi+ was used for measurements of the chrome cobalt abutment and crowns inner diameter in 4 directions (mesial-distal gingival, buccal-lingual gingival, mesial-distal occlusal, and buccal-lingual occlusal). The null hypothesis that the internal dimensional accuracy of interim PMMA crowns fabricated by DLP additive method would not be different compared to those obtained by milling procedure was rejected since the printed PMMA interim crowns were more accurate. This study concluded that the milled PMMA interim crowns show larger internal dimensional variations than the 3D printed ones. However, the fit variation among interim crowns fabricated by both procedures was statistically non significant, so that both CAM technologies may be equally used in manufacturing process.

Application of CNC Programming Technology in the during of Processing for the Key Parts of Disappearing Mould

2012 ◽  
Vol 249-250 ◽  
pp. 1195-1200
Author(s):  
Xian Zhang Feng ◽  
Li Ping Wang ◽  
Li Hong Yu ◽  
Zhi Qiang Jiang ◽  
Liang Ji Chen ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dimensional Accuracy ◽  
Complex Surface ◽  
Machining Process ◽  
Taper Angle ◽  
Design And Manufacturing ◽  
Cad Cam ◽  
Cnc Programming ◽  
Expendable Pattern ◽  
Mould Casting

Disappearing mould casting is a new accurately processes with nearly free margin and precision forming, in which is no modulus, no parting, no sand core, so the casting without splash, burr and taper angle. It can improve the dimensional accuracy of the core portfolio for complex surface of the key compose of the disappearing mould. It has completed the design and manufacturing of these by the three-dimensional CAD/CAM technology, and obtains a series of effective methods and experience for the development of the products. The researched results have important directive to production practices for the design and machining process for the expendable pattern casting.

scholarly journals Clinical Report of Six-Month Follow-Up After Cementing PEEK Crown On Molars

2021 ◽  
Author(s):  
Hitomi Kimura ◽  
Koji Morita ◽  
Fumiko Nishio ◽  
Hiroshi Abekura ◽  
Kazuhiro Tsuga
Keyword(s):  
Patient Satisfaction ◽  
Rank Test ◽  
Prosthetic Material ◽  
Clinical Report ◽  
Occlusal Force ◽  
Significance Level ◽  
Masticatory Ability ◽  
Significant Difference ◽  
Cad Cam ◽  
The Difference

Abstract To investigate the therapeutic effect of polyetheretherketone (PEEK) crowns, a six-month clinical study on CAD/CAM-fabricated molar PEEK crowns was conducted. Twenty-three cases of PEEK crowns placed on the molars of 20 subjects (7 males and 13 females, mean age: 60.6 ± 14.4 years) were included in the study. The evaluation items were the condition of the crowns at the time of cementation and after six months, patient satisfaction, masticatory ability, and occlusal force. A Wilcoxon signed-rank test with a significance level of 5% was used to examine the difference in masticatory ability with and without PEEK crowns. The occlusion, margin fit, and contact of all 23 cases at the time of cementing was good. Six months after cementation, there was no crown desorption, no fracture or crack, and no prosthodontics was needed in the 22 cases where one patient dropped out. No wear of the dental antagonist was observed. Patient satisfaction was generally high. There was no significant difference in masticatory ability between the groups with and without PEEK crowns. The subject's occlusal force was within normal range. PEEK crowns on molars are highly therapeutic methods and can be fully used as a crown prosthetic material to replace metal.

scholarly journals Influence of Voxel Size on CBCT Images for Dental Implants Planning

2021 ◽  
Author(s):  
Ricardo Kehrwald ◽  
Hebert Sampaio de Castro ◽  
Samira Salmeron ◽  
Ricardo Alves Matheus ◽  
Gustavo Machado Santaella ◽  
...  
Keyword(s):  
Gold Standard ◽  
Three Dimensional ◽  
Reference Points ◽  
Bone Thickness ◽  
Voxel Size ◽  
Significance Level ◽  
Significant Difference ◽  
Bone Height ◽  
Digital Caliper

Abstract Objective This study was developed to evaluate the influence of voxel size on bone measurements for implant planning. Materials and Methods The research was performed by using edentulous synthetic human mandibles with different levels of bone resorption. For each mandible, height and bone thickness were measured with a digital caliper. The PaX-i3d device was used to acquire the volumes of the five mandibles, with 50kVp, 4 mA, and a voxel size of 0.08 mm. After the acquisition, the images were reconstructed in the software CS three-dimensional Imaging, with four different sizes of voxels: 0.1, 0.2, 0.3, and 0.4 mm. All volumes were analyzed by a single evaluator who performed measurements to obtain bone height and thickness, using the reference points that were considered in obtaining the gold standard. The data were analyzed by ANOVA with a significance level of 5%. Results There was no significant difference in the measurements obtained with different voxel sizes, both for bone height measurements and bone thickness. There was no statistically significant difference in measurements in thickness in comparison to the gold standard. Conclusion When necessary, to measure height and bone thickness, it is possible to recommend voxel images of larger size (0.40 mm) without compromising the quality of the patient's clinical planning.

scholarly journals Comparative Evaluation of Adaptation of Esthetic Prefabricated Fiberglass and CAD/CAM Crowns for Primary Teeth: Microcomputed Tomography Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Ece Irem Oguz ◽  
Tuğba Bezgin ◽  
Ayse Isıl Orhan ◽  
Kaan Orhan
Keyword(s):  
Clinical Success ◽  
Three Dimensional ◽  
Repeated Measure ◽  
Linear Measurements ◽  
Factorial Anova ◽  
Mandibular Molar ◽  
Significant Difference ◽  
Cad Cam ◽  
Ceramic Blocks ◽  
Molar Teeth

Adaptation is an important factor for the clinical success of restorations. However, no studies are available evaluating the adaptation of primary crowns. The aim of this study was to compare the adaptation of crowns fabricated by CAD/CAM technology versus prefabricated fiberglass primary crowns. Typodont maxillary central, canine, and mandibular molar teeth were prepared to serve as master dies after the size of Figaro crowns was determined ( n = 10 ). Master dies were scanned with an intraoral scanner, and 10 identical CAD/CAM crowns were fabricated from resin-ceramic blocks. Figaro and CAD/CAM crowns were placed on the corresponding master dies and scanned via micro-CT. Three-dimensional volumetric gap measurements were performed to evaluate the overall adaptation. A total of 255 location-based linear measurements were allocated into 4 categories: marginal, cervical-axial, middle-axial, and occlusal. Statistical analyses were performed with factorial ANOVA, repeated measure ANOVA, and LSD tests ( α = 0.05 ). CAD/CAM crowns showed significantly lower overall and location-based gap measurements than Figaro crowns regardless of tooth number ( p < 0.05 ). For all groups, mean marginal discrepancies were lower than occlusal measurements ( p < 0.05 ). Both crown types showed higher marginal gaps for molar teeth than for canine and central incisors with no significant difference between them ( p > 0.05 ). CAD/CAM-fabricated crowns showed better marginal and internal adaptation than prefabricated Figaro crowns.

scholarly journals Study of the quality of the marginal gap of artificial crown frames made with the use of traditional and digital technologies

2020 ◽  
Vol 20 (1-2) ◽  
pp. 85-90
Author(s):  
Evgenii N. Zhulev ◽  
Yuliya A. Vokulova
Keyword(s):  
Laser Scanner ◽  
Dimensional Accuracy ◽  
Marginal Gap ◽  
Casting Method ◽  
Significance Level ◽  
Average Value ◽  
Cad Cam ◽  
Grinding Machine ◽  
Made In

The aim of the study is to evaluate the quality of the marginal gap of the frames of artificial crowns made with the use of CAD/CAM system and by casting method. Materials and methods. The article presents an assessment of the quality of the edge fitting of artificial crown frames made by means of CAD/CAM system KaVo ARCTICA on digital images of dentition created by intraoral laser scanner iTero Cadent and frames made of Co-Cr by the method of casting. The Image J computer program was used to study the quality of the marginal gap of artificial crown frames. For statistical analysis of the obtained data nonparametric Wilcoxon-Mann-Whitney test was used for the evaluation of the related samples. Results. We found that the average value of the marginal gap between the tooth stump of the experimental model and the frames of artificial crowns made in the KaVo ARCTICA Engine milling and grinding machine from the titanium blank Titan-Blank is 21.79 microns. The average value of the cement gap of the frames of artificial crowns made by the traditional casting method is 77.18 microns. The value of the marginal gap of artificial crown frames made by using the CAD/CAM system KaVo ARCTICA was 2.8 times less than the value of the marginal gap of frames made by the traditional casting method with a significance level of р 0.05 (V-Wilcoxon criterion for related samples = 0, р = 0.001). Conclusion. The results of our study indicate that the frames of artificial crowns made with the use of CAD/CAM system KaVo ARCTICA have a greater dimensional accuracy of the marginal gap compared to the frames of artificial crowns made by the traditional casting method.

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