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1.
PURPOSEThis study aimed to compare the marginal and internal fit of 3-unit monolithic zirconia restorations that were designed by using the data obtained with the aid of intraoral and laboratory scanners.MATERIALS AND METHODSFor the fabrication of 3-unit monolithic zirconia restorations using impressions taken from the maxillary master cast, plaster cast was created and scanned in laboratory scanners (InEos X5 and D900L). The main cast was also scanned with different intraoral scanners (Omnicam [OMNI], Primescan [PS], Trios 3 [T3], Trios 4 [T4]) (n = 12 per group). Zirconia fixed partial dentures were virtually designed, produced from presintered block, and subsequently sintered. Marginal and internal discrepancy values (in µm) were measured by using silicone replica method under stereomicroscope. Data were statistically analyzed by using 1-way ANOVA and Kruskal Wallis tests (P<.05).RESULTSIn terms of marginal adaptation, the measurements on the canine tooth indicated better performance with intraoral scanners than those in laboratory scanners, but there was no difference among intraoral scanners (P<.05). In the premolar tooth, PS had the lowest marginal (86.9 ± 19.2 µm) and axial (92.4 ± 14.8 µm), and T4 had the lowest axio-occlusal (89.4 ± 15.6 µm) and occlusal (89.1 ± 13.9 µm) discrepancy value. In both canine and premolar teeth, the D900L was found to be the most marginally and internally inconsistent scanner.CONCLUSIONWithin the limits of the study, marginal and internal discrepancy values were generally lower in intraoral scanners than in laboratory scanners. Marginal discrepancy values of scanners were clinically acceptable (< 120 µm), except D900L. 相似文献
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Mahtab Tabesh Farahnaz Nejatidanesh Ghazal Savabi Amin Davoudi Omid Savabi Hesam Mirmohammadi 《The Journal of prosthetic dentistry》2021,125(4):603-610
Statement of problemIntraoral scanners have been increasingly used in recent years. However, the accuracy of digital scans as it affects marginal adaptation is unclear.PurposeThe purpose of this systematic review and meta-analysis was to compare the marginal adaptation of single-unit zirconia crowns fabricated with digital scans or with conventional impressions.Material and methodsThe electronic databases PubMed (MEDLINE), Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science (ISI), Scopus, and EMBASE were searched and complemented by a manual search. Risks of bias were assessed by using a modified methodological index for nonrandomized studies (MINORS). Mean ±standard deviation (SD) values of marginal accuracy of studies were extracted for both methods. Mean marginal difference and 95% confidence interval (CI) were calculated to evaluate the marginal accuracy of each method. Pooled data were statistically analyzed by using a random-effect model.ResultsSeventeen studies were used to perform the meta-analysis. Subgroup analysis was performed based on intraoral scanners. Standardized mean marginal difference and 95% CI of each subgroup were as follows: Lava: -0.85 μm (95% CI: -1.67, -0.03) (P=.043); CEREC: -1.32 μm (95% CI: -2.06, -0.59) (P<.001); iTero: -0.44 μm (95% CI: -1.35, 0.47) (P=.338); TRIOS: -1.26 μm (95% CI: -2.02, -0.51) (P=.001); unknown scanner: -0.21 μm (95% CI: -1.14, 0.72); all studies: -0.89 μm (95% CI: -1.24, -0.54) (P<.001).ConclusionsDigital scanning of prepared teeth for single-unit zirconia restorations resulted in better marginal accuracy than conventional techniques using elastomeric impression materials. 相似文献
3.
Kazuhiko Ueda Florian Beuer Michael Stimmelmayr Kurt Erdelt Christine Keul Jan-Frederik Güth 《Clinical oral investigations》2016,20(2):283-289
Objectives
To evaluate the marginal and internal fit of CAD/CAM-generated frameworks for 4-unit, fixed dental prostheses (FDPs) from zirconia (Z) and cobalt-chromium alloy (C) made with conventional (CI) and digital impressions (DI).Materials and methods
A titanium model was digitized with an intraoral scanner (DI, LAVA? C.O.S.; 3M ESPE; Seefeld, Germany; n = 12). Additionally, 12 conventional impressions were taken, and referring plaster casts were digitized by a laboratory-scanner (CI, LAVA? Scan ST; 3M ESPE; n = 12). Frameworks were fabricated (3M ESPE) from cobalt-chromium (DI-C, n = 12; CI-C, n = 12) and zirconia (DI-Z, n = 12; CI-Z, n = 12) from the same datasets. A replica technique was applied to measure the accuracy. The Mann–Whitney U statistical test was applied to detect statistical differences between each material and methodology groups in terms of fit.Results
Frameworks from DI-C (median 19.07 μm) showed significantly better marginal fit than CI-C (median 64.64 μm, p < 0.001). Frameworks from DI-Z (median 52.50 μm) showed significantly better marginal fit than CI-Z (median 72.94 μm, p = 0.001). Additionally, frameworks from DI-C showed a significantly better marginal fit than DI-Z (p < 0.001).Conclusions
CI and DI led to a clinically acceptable marginal fit of 4-unit FDPs from cobalt-chromium and zirconia. DI leads to better marginal fit of the cobalt-chromium frameworks; however, no effect on zirconia was found.Clinical relevance
The results indicate that DI is suitable for fabricating 4-unit, cobalt-chromium and zirconia frameworks with regard to fit requirements.4.
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Júnio S. Almeida e Silva Kurt Erdelt Daniel Edelhoff Élito Araújo Michael Stimmelmayr Luiz Clovis Cardoso Vieira Jan-Frederik Güth 《Clinical oral investigations》2014,18(2):515-523
Objectives
The aim of this in vitro study was to evaluate the marginal and internal fit of CAD/CAM-generated four-unit zirconia fixed dental prostheses made with digital and conventional impressions.Materials and method
A titanium master model was used. For group conventional impression (CI), 12 polyether impressions of the master model with ImpregumTM were made. For group digital impression (DI), 12 digital impressions of the master model using LavaTM C.O.S. system were made. The replica technique was applied. The Mann–Whitney U statistical test was applied to detect statistical differences between the groups, in terms of marginal and internal fit. Face-by-face comparisons between groups were also carried out.Results
Groups DI and CI presented mean marginal fit of 63.96 and 65.33 μm, respectively, and showed no statistically significant difference. Groups DI and CI presented significantly different internal fit with mean values of 58.46 and 65.94 μm, respectively. Group DI showed statistically significantly lower values for marginal and internal fit on premolar mesial face, and on molar distal and palatal faces.Conclusions
Frameworks fabricated from digital and conventional impressions showed clinically acceptable marginal fit. Frameworks fabricated from digital impression demonstrated better internal fit than ones fabricated from conventional impression. Reviewing each retainer face, digital impression showed better marginal and internal fit at the premolar mesial and molar distal faces.Clinical relevance
The results of this in vitro study show that digital impressions made with the LavaTM C.O.S. system and its digital workflow are suitable for fabricating four-unit zirconia frameworks, with regard to marginal and internal fit requirements. 相似文献7.
Luciano Praça Fabrice Chuembou Pekam Rodrigo Otavio Rego Klaus Radermacher Stefan Wolfart Juliana Marotti 《Dental materials》2018,34(11):e280-e288
Objective
This in vitro study aimed to evaluate marginal and internal fit of single crowns produced from high-frequency ultrasound based digital impressions of teeth prepared with finish lines covered by porcine gingiva, in comparison with those obtained by optical scanners with uncovered finish lines.Methods
Ten human teeth were prepared and forty zirconia crowns were fabricated from STL-datasets obtained from four dental scanners (n = 10): extraoral CS2 (Straumann), intraoral Lava COS (3M), intraoral Trios (3Shape) and extraoral ultrasound scanner. The accuracy of the crowns was compared evaluating marginal and internal fit by means of the replica technique with measurements in four areas; P1: occlusal surface; P2: transition between occlusal and axial surfaces; P3: middle of axial wall; and P4: marginal gap. Restoration margins were classified according to their mismatch as regular, underextended or overextended. Kruskal–Wallis one-way ANOVA and Mann–Whitney U test were used to evaluate the differences between groups at p < 0.05.Results
The median value of marginal gap (P4) for Ultrasound (113.87 μm) differed statistically from that of CS2 (39.74 μm), Lava COS (41.98 μm) and Trios (42.07 μm). There were no statistical differences between ultrasound and Lava COS for internal misfit (P1–P3), however there were statistical differences when compared with the other two scanners (Trios and CS2) at P1 and P2.Significance
The ultrasound scanner was able to make digital impressions of prepared teeth through porcine gingiva (P4), however with less accuracy of fit than that of conventional optical scanners without coverage of the finish lines. Where no gingiva was available (P1–P3), the ultrasound accuracy of fit was similar to that of at least one optical scanner (Lava COS). 相似文献8.
目的:通过研究口内数字化扫描仪多次扫描的重复性来评价其扫描精度。方法:根据原始研究模型上牙备后基牙的分布不同分为5小组(1.右侧上颌中切牙为牙备后形态,余牙完整;2.右侧上颌第一磨牙为牙备后形态,余牙完整;3.右侧上颌中切牙和尖牙为牙备后形态,上颌侧切牙缺失,余牙完整;4.右侧上颌7颗牙齿为牙备后形态,左半侧完整;5.上颌全部牙齿为牙备后形态)。实验组中,每一小组的研究模型均用TRIOS口内扫描仪10次;对照组中,每一小组的研究模型先分别翻制10副石膏模型,再用3Shape口外扫描仪扫描。实验组和对照组分别得到扫描生成的50个STL三维图像文件,将总共100个STL文件通过Geomagic Studio 12软件进行处理和分析来评价两组扫描的重复性和精度。结果:实验组(口内组)3D标准偏差分别是第1小组:13.33μm,第2小组:7.0μm,第3小组:16.33μm,第4小组:41.56μm,第5小组:88.44μm。对照组的3D标准偏差分别是第1小组:14.89μm,第2小组:8.67μm,第3小组:24.33μm,第4小组:14.22μm,第5小组:12.67μm。实验组和对照组的3D标准偏差在第2,3,4,5小组中有统计学差异(P〈0.05)。结论:口内数字化印模扫描精度随着牙弓扫描范围增大而降低,其在扫描范围小于半个牙弓时表现出的精度符合临床要求;而口外台式扫描仪在扫描任意范围牙弓时均表现出较好的精度。 相似文献
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《Journal of prosthodontic research》2020,64(4):478-484
PurposeThe aim of this in vitro study was to evaluate the three-dimensional trueness and margin quality of monolithic zirconia restorations fabricated by additive 3D gel deposition, compared with those by subtractive milling.MethodsTen single crowns and ten 4-unit FPDs of different occlusal geometries and margin thickness were fabricated by additive 3D gel deposition (additive group) and subtractive milling (subtractive group). An intraoral scanner was used to digitalize the restorations. 3D deviation analysis was applied and root mean square (RMS) was used to assess the trueness. Margin quality was characterized using optical stereomicroscopy and 3D laser scanning microscopy.ResultsFor single crowns with shallow fossae and grooves and normal margin, RMS value of additive group and subtractive group showed no significant difference in external surface, while additive group showed higher RMS value in intaglio surface. As for 4-unit FPDs with deep fossae and grooves and thin margin, RMS value of additive group in external surface was significantly lower than that of subtractive group and in intaglio surface there was no significant difference between two groups. With a 0.5 mm chamfer design, single crowns in additive group showed flawless margin with a smooth contour line, whereas minor flaws could be observed in 4-unit FPDs with thin margin. In subtractive group, restorations showed minor flaws or defects of various number and severity.ConclusionsMonolithic zirconia restorations fabricated by additive 3D gel deposition have comparable trueness and better margin quality than those fabricated by subtractive milling. Besides it is more capable of enabling complex geometry. 相似文献
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Philipp Kohorst Henrike Brinkmann Jiang Li Lothar Borchers Meike Stiesch 《European journal of oral sciences》2009,117(3):319-325
Besides load-bearing capacity, marginal accuracy is a further crucial factor influencing the clinical long-term reliability of fixed dental prostheses (FDPs). The aim of this in vitro study was to evaluate the marginal fit of four-unit zirconia bridge frameworks fabricated using four different computer-aided design (CAD)/computer-aided manufacturing (CAM) systems. Ten frameworks were manufactured using each fabricating system. Three systems (inLab, Everest, Cercon) processed white-stage zirconia blanks, which had to be sintered to final density after milling, while with one system (Digident) restorations were directly milled from a fully sintered material. After manufacturing, horizontal and vertical marginal discrepancies, as well as the absolute marginal discrepancy, were determined by means of a replica technique. The absolute marginal discrepancy, which is considered to be the most suitable parameter reflecting restorations' misfit in the marginal area, had a mean value of 58 μ m for the Digident system. By contrast, mean absolute marginal discrepancies for the three other systems, processing presintered blanks, differed significantly and ranged between 183 and 206 μ m. Within the limitations of this study, it could be concluded that the marginal fit of zirconia FDPs is significantly dependent on the CAD/CAM system used, with restorations processed of fully sintered zirconia showing better fitting accuracy. 相似文献
12.
Hasan Kocaağaoğlu Halil Ibrahim Kılınç Haydar Albayrak 《The Journal of prosthetic dentistry》2017,117(1):102-108
Statement of problem
Proper marginal, axial, and occlusal adaptation of dental restorations is essential for their long-term success. Production protocols including digital impression systems have been developed, but little information is available on the adaptation of zirconia restorations produced via them.Purpose
The purpose of this in vitro study was to compare the effects of digital impression protocols on the marginal, axial, and occlusal adaptation of zirconia copings.Material and methods
Thirty extracted human maxillary premolar teeth without caries or defects were used. The teeth were prepared for zirconia crowns and randomly divided into 3 groups. Zirconia copings were designed at a thickness of 0.5 mm with 30 μm of simulated die spacer starting 1 mm from the margin of preparations. They were produced using computer-aided design-computer-aided manufacture (CAD-CAM) protocol with a conventional impression (group Cn) and 2 different production protocols with digital impressions (group C) and group Tr. The marginal, axial, and occlusal discrepancies of these copings were measured using the silicone replica technique with stereomicroscopy at ×50 magnification, and the data were analyzed with 1-way ANOVAs (α=.05).Results
The mean marginal discrepancy values were 85.6 μm for group Cn, 58.7 μm for group C, and 47.7 μm for the Tr group. Significant differences were found among the production protocols in marginal, axial, and occlusal discrepancies (P<.05). Copings fabricated with the aid of digital impressions had significantly fewer marginal discrepancies than those of group Cn (P<.05). Group Tr exhibited the lowest marginal discrepancy, whereas groups Cn and C demonstrated similar axial adaptations (P>.05), and group Tr revealed the lowest axial discrepancy (P<.05). With regard to the occlusal discrepancy evaluation, group Tr had the lowest discrepancy. However, no significant differences was found between groups C and Cn (P>.05).Conclusions
The copings produced with the aid of digital impression systems exhibited better marginal and occlusal adaptation than those of the copings produced with the aid of conventional impression. 相似文献13.
Marginal and internal fit of metal copings fabricated with rapid prototyping and conventional waxing
Ehsan Farjood Mahroo Vojdani Kiyanoosh Torabi Amir Ali Reza Khaledi 《The Journal of prosthetic dentistry》2017,117(1):164-170
Statement of problem
Given the limitations of conventional waxing, computer-aided design and computer-aided manufacturing (CAD-CAM) technologies have been developed as alternative methods of making patterns.Purpose
The purpose of this in vitro study was to compare the marginal and internal fit of metal copings derived from wax patterns fabricated by rapid prototyping (RP) to those created by the conventional handmade technique.Material and methods
Twenty-four standardized brass dies were milled and divided into 2 groups (n=12) according to the wax pattern fabrication method. The CAD-RP group was assigned to the experimental group, and the conventional group to the control group. The cross-sectional technique was used to assess the marginal and internal discrepancies at 15 points on the master die by using a digital microscope. An independent t test was used for statistical analysis (α=.01).Results
The CAD-RP group had a total mean (±SD) for absolute marginal discrepancy of 117.1 (±11.5) μm and a mean marginal discrepancy of 89.8 (±8.3) μm. The conventional group had an absolute marginal discrepancy 88.1 (±10.7) μm and a mean marginal discrepancy of 69.5 (±15.6) μm. The overall mean (±SD) of the total internal discrepancy, separately calculated as the axial internal discrepancy and occlusal internal discrepancy, was 95.9 (±8.0) μm for the CAD-RP group and 76.9 (±10.2) μm for the conventional group. The independent t test results showed significant differences between the 2 groups. The CAD-RP group had larger discrepancies at all measured areas than the conventional group, which was statistically significant (P<.01).Conclusions
Within the limitations of this in vitro study, the conventional method of wax pattern fabrication produced copings with better marginal and internal fit than the CAD-RP method. However, the marginal and internal fit for both groups were within clinically acceptable ranges. 相似文献14.
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Hilal Siriner Gumus Nilufer Tulin Polat Guler Yildirim 《The Journal of prosthetic dentistry》2018,119(6):959-964
Statement of problem
Data are lacking on the fracture resistance of monolithic zirconia inlay-retained fixed partial dentures as a conservative treatment for a single missing tooth.Purpose
The purpose of this in vitro study was to evaluate the fracture resistance of inlay-retained fixed partial dentures produced from 3 different monolithic zirconia materials and based on 2 preparation types and applications with and without thermocycling.Material and methods
A model with missing right and left mandibular first molars was used for different cavity preparations. A tube-shaped cavity and a box-shaped cavity were prepared. Seventy-two epoxy resin casts were prepared from an additional silicone impression. Twenty-four inlay-retained fixed partial dentures from each monolithic zirconia material (Prettau, Zirkonzahn; Katana, Noritake; and Copran, Whitepeaks) were fabricated for each preparation type and cemented to their epoxy model with dual-polymerizing adhesive resin cement; 50% of all specimens were thermocycled for 10 000 cycles. The specimens were subjected to a fracture resistance test using a universal testing machine with a crosshead speed of 0.5 mm/min. Fracture surfaces were examined with scanning electron microscopy (SEM), and a specimen from each group was examined for structural changes with differential thermal analysis (DTA).Results
No statistically significant differences in terms of fracture resistance were found among brands with both cavity designs and with and without thermal cycles (P>.05). However, SEM and DTA results showed some changes in monolithic zirconia structure after 1 year of aging.Conclusions
The brands and cavity preparation types for single posterior tooth loss generated similar fracture resistance. 相似文献17.
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Waldecker Moritz Rues Stefan Awounvo Awounvo Junior Sinclair Rammelsberg Peter Bömicke Wolfgang 《Clinical oral investigations》2022,26(11):6491-6502
Clinical Oral Investigations - This in vitro study compared the dimensional accuracy of conventional impressions (CI) with that of digital impressions (DI) in a partially edentulous maxilla. DIs... 相似文献
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Andreas Ender Moritz Zimmermann Thomas Attin Albert Mehl 《Clinical oral investigations》2016,20(7):1495-1504