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Farghal A, Dewedar K, AbdElaziz MH, Saker S, Hassona M, Algabri R, Alqutaibi AY. Effect of ceramic materials and tooth preparation design on computer-aided design and computer-aided manufacturing endocrown adaptation and retentive strength: An in vitro study. Clin Exp Dent Res 2024; 10:e843. [PMID: 38345492 PMCID: PMC10828905 DOI: 10.1002/cre2.843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/23/2023] [Accepted: 01/04/2024] [Indexed: 02/15/2024] Open
Abstract
OBJECTIVES To evaluate how various tooth preparation designs impact the adaptation-both at the margins and internally-and the retentive strength of computer-aided design and computer-aided manufacturing (CAD/CAM) produced endocrowns. MATERIALS AND METHODS 60 extracted human mandibular first molars were endodontically treated and assigned into three groups (n = 20) according to the tooth preparation design: Group N: butt joint design, Group F and F1 received 1- and 2-mm circumferential ferrule preparation, respectively. Endocrowns were milled using either lithium disilicate glass-ceramic (IPS emax ceramic) or monolithic zirconia. The internal and marginal adaptation of the endocrowns were evaluated using the replica technique. After cementation, the endocrowns of all test groups were dislodged axially at 0.5 mm/min using a universal testing machine. A 2-way ANOVA and the independent samples t-test (α = .05) were performed to statistically analyze the data. RESULTS The effect of changing the design of the tooth preparation (butt joint, ferrule) on the marginal and internal gap was shown to be statistically significant (p < .05); the lower gap values were recorded at the axial followed by cervical, marginal, and pulpal floor walls in both ceramic groups regardless of the teeth preparation design. The ANOVA test revealed similar average removal forces and stresses for the two types of tested ceramic materials. CONCLUSION IPS emax ceramic adapted better than monolithic zirconia ceramic, regardless of the preparation design. Ferrule preparation design is more retentive than butt joint preparation, regardless of the type of ceramic material used.
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Cho JH, Çakmak G, Yi Y, Yoon HI, Yilmaz B, Schimmel M. Tooth morphology, internal fit, occlusion and proximal contacts of dental crowns designed by deep learning-based dental software: A comparative study. J Dent 2024; 141:104830. [PMID: 38163455 DOI: 10.1016/j.jdent.2023.104830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/13/2023] [Accepted: 12/29/2023] [Indexed: 01/03/2024] Open
Abstract
OBJECTIVES This study compared the tooth morphology, internal fit, occlusion, and proximal contacts of dental crowns automatically generated via two deep learning (DL)-based dental software systems with those manually designed by an experienced dental technician using conventional software. METHODS Thirty partial arch scans of prepared posterior teeth were used. The crowns were designed using two DL-based methods (AA and AD) and a technician-based method (NC). The crown design outcomes were three-dimensionally compared, focusing on tooth morphology, internal fit, occlusion, and proximal contacts, by calculating the geometric relationship. Statistical analysis utilized the independent t-test, Mann-Whitney test, one-way ANOVA, and Kruskal-Wallis test with post hoc pairwise comparisons (α = 0.05). RESULTS The AA and AD groups, with the NC group as a reference, exhibited no significant tooth morphology discrepancies across entire external or occlusal surfaces. The AD group exhibited higher root mean square and positive average values on the axial surface (P < .05). The AD and NC groups exhibited a better internal fit than the AA group (P < .001). The cusp angles were similar across all groups (P = .065). The NC group yielded more occlusal contact points than the AD group (P = .006). Occlusal and proximal contact intensities varied among the groups (both P < .001). CONCLUSIONS Crowns designed by using both DL-based software programs exhibited similar morphologies on the occlusal and axial surfaces; however, they differed in internal fit, occlusion, and proximal contacts. Their overall performance was clinically comparable to that of the technician-based method in terms of the internal fit and number of occlusal contact points. CLINICAL SIGNIFICANCE DL-based dental software for crown design can streamline the digital workflow in restorative dentistry, ensuring clinically-acceptable outcomes on tooth morphology, internal fit, occlusion, and proximal contacts. It can minimize the necessity of additional design optimization by dental technician.
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Mangano FG, Cianci D, Pranno N, Lerner H, Zarone F, Admakin O. Trueness, precision, time-efficiency and cost analysis of chairside additive and subtractive versus lab-based workflows for manufacturing single crowns: An in vitro study. J Dent 2024; 141:104792. [PMID: 38013004 DOI: 10.1016/j.jdent.2023.104792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 11/21/2023] [Accepted: 11/23/2023] [Indexed: 11/29/2023] Open
Abstract
PURPOSE To evaluate the trueness, precision, time efficiency, and cost of three different workflows for manufacturing single crowns (SCs). METHODS A plaster model with a prepared tooth (#15) was scanned with an industrial scanner, and an SC was designed in computer-assisted-design (CAD) software. Ten SCs were printed with a hybrid composite (additive chairside) and a stereolithographic (SLA) printer (Dfab®), 10 SCs were milled in lithium disilicate (subtractive chairside) using a chairside milling unit (inLab MC XL®), and 10 SCs were milled in zirconia (lab-based) using a five-axis laboratory machine (DWX-52D®). All SCs were scanned with the same scanner after polymerization/sinterization. Each scan was superimposed to the marginal area of the original CAD file to evaluate trueness: absolute average (ABS AVG), root mean square (RMS), and (90˚-10˚)/2 percentile were calculated for each group. Marginal adaptation and quality of the occlusal and interproximal contact points were also investigated by two prosthodontists on 3D printed and plaster models. Finally, the three workflows' time efficiency and costs were evaluated. RESULTS Additive chairside and subtractive lab-based SCs had significantly better marginal trueness than subtractive chairside SCs in all three parameters (ABS AVG, p < 0.01; RMS, p < 0.01; [90˚-10˚]/2, p < 0.01). However, the two prosthodontists found no significant differences between the three manufacturing procedures in the quality of the marginal closure (p = 0.186), interproximal (p = 0.319), and occlusal contacts (p = 0.218). Both time efficiency and cost show a trend favoring the chairside additive workflow. CONCLUSIONS Chairside additive technology seems to represent a valid alternative for manufacturing definitive SCs, given the high marginal trueness, precision, workflow efficiency and low costs. STATEMENT OF CLINICAL RELEVANCE Additive chairside manufacturing of definitive hybrid composite SCs is now possible and shows high accuracy, time efficiency, and competitive cost.
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Schierz O, Hirsch C, Krey KF, Ganss C, Kämmerer PW, Schlenz MA. DIGITAL DENTISTRY AND ITS IMPACT ON ORAL HEALTH-RELATED QUALITY OF LIFE. J Evid Based Dent Pract 2024; 24:101946. [PMID: 38401951 DOI: 10.1016/j.jebdp.2023.101946] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 10/04/2023] [Accepted: 10/13/2023] [Indexed: 02/26/2024]
Abstract
Over the past 50 years, digitization has gradually taken root in dentistry, starting with computer tomography in the 1970s. The most disruptive events in digital dentistry were the introduction of digital workflow and computer-aided manufacturing, which made new procedures and materials available for dental use. While the conventional lab-based workflow requires light or chemical curing under inconsistent and suboptimal conditions, computer-aided manufacturing allows for industrial-grade material, ensuring consistently high material quality. In addition, many other innovative, less disruptive, but relevant approaches have been developed in digital dentistry. These will have or already impact prevention, diagnosis, and therapy, thus impacting patients' oral health and, consequently, their oral health-related quality of life. Both software and hardware approaches attempt to maintain, restore, or optimize a patient's perceived oral health. This article outlines innovations in dentistry and their potential impact on patients' oral health-related quality of life in prevention and therapy. Furthermore, possible future developments and their potential implications are characterized.
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Ibrahim H, El Kateb M, Morsy N. Effect of modifying occlusal cement spacer on the fit accuracy of digitally manufactured zirconia crowns. J Prosthet Dent 2024; 131:93.e1-93.e6. [PMID: 37867014 DOI: 10.1016/j.prosdent.2023.09.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 09/27/2023] [Accepted: 09/27/2023] [Indexed: 10/24/2023]
Abstract
STATEMENT OF PROBLEM Cement spacer has a crucial influence on the adaptation of fixed restorations. Recently, digitally fabricated zirconia crowns have become more popular, but studies on the effect of occlusal cement spacer on the fit accuracy of digitally designed and milled zirconia crowns are lacking. PURPOSE The purpose of this in vitro study was to investigate the effect of modifying digital occlusal spacer on the marginal and internal fit of digitally manufactured zirconia crowns. MATERIAL AND METHODS A maxillary molar typodont tooth was prepared for a zirconia crown, scanned with the Medit i700 intraoral scanner (IOS), and the standard tessellation language (STL) file was used to produce 3-dimensionally (3D) printed definitive dies assigned to 3 groups (n=12). All dies were scanned with the IOS, and the obtained STL files were exported to a computer-aided design (CAD) software program for the designing and milling of 36 complete contour zirconia crowns. The zirconia crown design was identical in the 3 groups for all parameters (default parameters in the CAD software program) with a 80-µm radial spacer 1 mm from the finish lines. The occlusal cement spacer was adjusted to 80 µm, 40 µm, and 0 µm for group 80-80, group 40-80, and group 0-80 respectively. The internal and marginal fit of the crowns were measured on their corresponding definitive dies with the replica technique. The Kruskal-Wallis test followed by the Dunn test with the Bonferroni correction was used for statistical analysis of the results (α=.05). RESULTS The modification of occlusal cement spacer significantly affected the marginal and internal fit of digitally manufactured crowns (P<.05). Group 0-80 and group 40-80 had similar marginal gap values, which were significantly lower than those of group 80-80 (P<.017). For internal fit accuracy, group 0-80 displayed significantly lower gap values than group 40-80 and group 80-80 for all measured areas. Group 40-80 had significantly lower gap values than group 80-80 at the mid-occlusal and axio-occlusal areas (P<.017). CONCLUSIONS Modifying occlusal cement spacer significantly affected the fit of digitally fabricated zirconia crowns. Reducing or eliminating occlusal spacer resulted in significantly improved fit accuracy.
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Edelhoff D, Schubert O, Stimmelmayr M, Schweiger J. CAD/CAM full-mouth rehabilitation of an elderly patient: One-piece digital complete denture meets multilayered zirconia with gradient technology. J ESTHET RESTOR DENT 2024; 36:174-185. [PMID: 36866726 DOI: 10.1111/jerd.13031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/02/2023] [Accepted: 02/11/2023] [Indexed: 03/04/2023]
Abstract
OBJECTIVE This article highlights a CAD/CAM complete-mouth rehabilitation in an 82-year-old patient by means of a complete maxillary prosthesis and mandibular implant- and tooth-supported fixed restorations made from multilayered zirconia. CLINICAL CONSIDERATIONS Comprehensive complete-mouth rehabilitations in elderly patients with adaptation of the occlusal vertical dimension (OVD) often present particular challenges. This applies especially when exacting functional and esthetic requirements are to be met and the treatment should not cause the patient too much effort, still ensuring the highest level of quality and efficiency and a low intervention rate. CONCLUSION The digital approach used for the present patient allowed for an efficient treatment procedure, facilitated virtual evaluations using a face-scan, and enhanced the predictability of the prosthodontic outcome. The approach enabled some steps required in the conventional protocol to be omitted, resulting in a straightforward clinical treatment with minimal strain on the patient. CLINICAL SIGNIFICANCE Because of the comprehensive recording of extraoral and intraoral data, for example with a facial scanner, it was possible to transfer a digital replica of the patient to the dental laboratory technician. With this protocol, many steps can be performed in the absence of the real patient.
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Liu CM, Lin WC, Lee SY. Evaluation of the efficiency, trueness, and clinical application of novel artificial intelligence design for dental crown prostheses. Dent Mater 2024; 40:19-27. [PMID: 37858418 DOI: 10.1016/j.dental.2023.10.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 09/05/2023] [Accepted: 10/05/2023] [Indexed: 10/21/2023]
Abstract
OBJECTIVE The unique structure of human teeth limits dental repair to custom-made solutions. The production process requires a lot of time and manpower. At present, artificial intelligence (AI) has begun to be used in the medical field and improve efficiency. This study attempted to design a variety of dental restorations using AI and evaluate their clinical applicability. METHODS Using inlay and crown restoration types commonly used in dental standard models, we compared differences in artificial wax-up carving (wax-up), artificial digital designs (digital) and AI designs (AI). The AI system was designed using computer calculations, and the other two methods were designed by humans. Restorations were made by 3D printing resin material. Image evaluations were compared with cone beam computed tomography (CBCT) by calculating the root mean squared error. RESULTS Surface truth results showed that AI (68.4 µm) and digital-designed crowns (51.0 µm) had better reproducibility. Using AI for the crown reduced the time spent by 400% (compared to digital) and 900% (compared to wax-up). Optical microscopic and CBCT images showed that AI and digital designs had close margin gaps (p < 0.05). The margin gap of the crown showed that the wax-up group was 4.1 and 4.3 times greater than those of the AI and digital crowns, respectively. Therefore, the utilization of artificial intelligence can assist in the production of dental restorations, thereby enhancing both production efficiency and accuracy. SIGNIFICANCE It is expected that the development of AI can contribute to the reproducibility, efficiency, and goodness of fit of dental restorations.
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Elashmawy Y, Elshahawy W. Effect of Thermomechanical Fatigue Loading on the Internal and Marginal Adaptation of Endocrowns Utilizing Different CAD/CAM Restorative Materials. INT J PROSTHODONT 2023; 36:738-747. [PMID: 38109395 DOI: 10.11607/ijp.7771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE To assess the impact of fatigue loading on the internal and marginal fit of CAD/CAM-fabricated endocrowns for restoring endodontically treated molars using different machinable blocks. MATERIALS AND METHODS A total of 72 mandibular first molars were prepared using a standardized method and were divided into four groups (n = 18), each restored with a different CAD/CAM material: group V = polymer-infiltrated ceramic (Vita Enamic); group K = partially stabilized tetragonal zirconia (Katana); group E = lithium disilicate ceramic (IPS e.max CAD; and group B = polyetheretherketone (BioHPP). Endocrowns were subjected to thermomechanical fatigue loading. Internal and marginal adaptation of the endocrowns were examined at 66 points using the sectioning technique and a stereomicroscope. Data were analyzed using one-way ANOVA and Tukey post hoc test (α = .05). RESULTS Statistical tests showed that adhesive cementation resulted in significantly increased marginal and internal gap values in all regions in all four tested groups (P < .001). After thermomechanical fatigue loading, all regions in groups B and K showed a statistically significant difference, while no significant differences were found in the regions in group V (P > .05). In group E, the marginal (F = 71.00) and pulpal (F = 28.065) regions showed statistically significant differences (P < .001). CONCLUSION Polymer-infiltrated ceramics showed the lowest gap even after thermomechanical fatigue loading and may therefore provide enhanced clinical survival of the restored tooth, favoring the use of this material for fabricating endocrown restorations.
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Bandiaky ON, Clouet R, Le Bars P, Soueidan A, Le Guehennec L. Marginal and internal fit of five-unit zirconia-based fixed dental prostheses fabricated with digital scans and conventional impressions: A comparative in vitro study. J Prosthodont 2023; 32:846-853. [PMID: 36627825 DOI: 10.1111/jopr.13639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 12/12/2022] [Accepted: 12/18/2022] [Indexed: 01/12/2023] Open
Abstract
PURPOSE This study aimed to compare the marginal and internal fit of five-unit zirconia-based fixed dental prostheses (FDPs) fabricated using digital scans and conventional impressions. MATERIALS AND METHODS Nine master models with three zirconia abutments were scanned with an intraoral scanner (test group), and nine conventional impressions (control group) of these same models were also made. The stone casts from these impressions were scanned with a laboratory extraoral scanner (D700, 3Shape, Copenhagen, Denmark). A total of 18 five-unit zirconia-based FDP frameworks (test group, n = 9; control group, n = 9) were manufactured. Marginal and internal fit (in μm) were evaluated using the replica method under micro-computed tomography. Analysis of variance (one-way ANOVA) and Kruskal-Wallis tests were used to compare continuous variables across two groups. A level of p < 0.05 was accepted as statistically significant. RESULTS The mean ± standard deviation of the marginal fit was 95.03 ± 12.74 μm in the test group and 106.02 ± 14.51 μm in the control group. The lowest marginal mean value was observed in the test group, with a statistically significant difference compared to the control group (F = 14.56, p < 0.05). The mean ± standard deviation of the internal fit was 103.61 ± 9.32 and 106.38 ± 7.64 μm, respectively, in the test and control groups, with no statistically significant difference (F = 1.56, p > 0.05). The mean values of both groups were clinically acceptable. CONCLUSIONS The five-unit zirconia-based FDPs fabricated with digital scans showed better fit than those in the conventional impression group. Within the limitations of this study, these results are encouraging, and continued progress in the digital field should allow for more accurate long-span restorations.
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Tomova Z, Zhekov Y, Alexandrov G, Vlahova A, Vasileva E. Application of CAD/CAM technologies and materials for prosthetic restoration of severely damaged teeth-clinical cases. Aust Dent J 2023; 68:294-302. [PMID: 37681572 DOI: 10.1111/adj.12976] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2023] [Indexed: 09/09/2023]
Abstract
In cases of severely damaged teeth with limited coronal tooth structure and remaining hard dental tissues subgingivally, a custom-made post-and-core restoration is required. Teeth with non-circular canal space also require this type of restoration because the build-up with pre-fabricated posts could lead to thick cement layer. The development of CAD/CAM technologies widens the range of the materials that can be used for prosthetic restorations. Along with base dental alloys, newly developed materials may be applied. The aim of the article is to present four clinical cases of severely damaged teeth which utilize different materials and different production techniques for custom post-and-core fabrication. In the first clinical case, a metal post-and-core restoration was fabricated by direct metal laser sintering. In the second clinical case, digital technologies were used to produce a 3D-printed resin prototype for further investing and casting from base metal dental alloy. In the third clinical case, fibre-reinforced composite was used for fabrication of the custom post-and-core by milling. In the fourth clinical case, the restoration is produced by milling of lithium disilicate ceramics IPS emax CAD (Ivoclar Vivadent, Lichtenstein). The bond between the fibre-reinforced composite post-and-core and the hard dental tissues offered possibility to compensate-to some extent-the shape of the preparation which was not optimal. CAD/CAM technologies applied in these clinical cases provided combination of high accuracy of fitting with good stability and individual shape of the restorations. © 2023 Australian Dental Association.
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Sun Z, Shen Z, Zhao J, Zheng Y. Adaptation and uniformity of monolithic zirconia crowns fabricated by additive 3-dimensional gel deposition. J Prosthet Dent 2023; 130:859-865. [PMID: 35135676 DOI: 10.1016/j.prosdent.2021.11.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 11/11/2021] [Accepted: 11/11/2021] [Indexed: 12/13/2022]
Abstract
STATEMENT OF PROBLEM A novel monolithic zirconia restoration fabricated by additive 3-dimensional (3D) gel deposition, named as self-glazed zirconia (SGZ), has recently been developed. SGZ crowns exhibit reliable mechanical properties and esthetic appearance, but their adaptation and uniformity are unclear. PURPOSE The purpose of this in vitro study was to compare the adaptation and uniformity of monolithic zirconia crowns fabricated by additive 3D gel deposition with that of milled zirconia and lithium disilicate crowns. MATERIAL AND METHODS Ten identical resin abutments were made based on the scanning data of an extracted and prepared human mandibular first molar. Three types of monolithic crowns were then fabricated by using 2 different processes: 3D gel deposition zirconia (SGZ), milled zirconia (ZZ), and milled lithium disilicate (EMX) (n=10) through a completely digital workflow. The nondestructive direct-view technique and replica technique were used to measure the marginal and internal discrepancy values individually. The uniformity index was calculated to describe the uniformity of the internal space. The results were analyzed by using 1-way ANOVA and Kruskal-Wallis statistical tests (α=.05). RESULTS The marginal discrepancy of EMX exhibited the highest values among the 3 groups (P=.001). The 2 types of zirconia crowns had comparable marginal discrepancy values (P>.05). The internal discrepancy values of SGZ were significantly lower than those of EMX at the occlusal region and of ZZ at all measured locations (P<.05). All 3 types of monolithic crowns showed comparable good uniformity (P=.056). CONCLUSIONS The marginal and internal adaptations of novel monolithic zirconia crowns were within clinical requirements. Compared with the zirconia and lithium disilicate crowns fabricated by subtractive milling, monolithic zirconia crowns fabricated by additive 3D gel deposition had comparable uniformity and better internal adaptation.
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Nassar HI, Fateen A. Accuracy of fit for cobaltchromium bar over two implants fabricated with different manufacturing techniques: an in-vitro study. BMC Oral Health 2023; 23:946. [PMID: 38031111 PMCID: PMC10688085 DOI: 10.1186/s12903-023-03700-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 11/22/2023] [Indexed: 12/01/2023] Open
Abstract
OBJECTIVE The purpose of the invitro research was to compare the fit of Cobalt Chromium customized bar fabricated with different manufacturing processes cast metal bar, milled bar and 3D printed bar using scanning electron microscope. MATERIALS AND METHODS Clear epoxy resin molds were prepared. In each mold two parallel implants with a 14 mm distance from each other were embedded. Thirty Co-Cr custom bars were constructed and were divided equally into three groups: Group (I) (Co-Cr conv), group (II) milled bar (Co-Cr milled), and group (III) printed bar (Co-Cr print). The marginal fit at implant-abutment interface was scanned using scanning electron microscope (SEM). RESULTS There was a significant difference between the three studied groups regarding marginal misfit the between implant and fabricated bars with p-value < 0.001. The highest value of micro-gap distance was found in Co-Cr conventional group (7.95 ± 2.21 μm) followed by Co-Cr 3D printed group (4.98 ± 1.73) and the lower value were found in Co-Cr milled (3.22 ± 0.75). CONCLUSION The marginal fit of milled, 3D printed and conventional cast for Co-Cr alloy were within the clinically acceptable range of misfit. CAD/CAM milled Co-Cr bar revealed a superior internal fit at the implant-abutment interface. This was followed by selective laser melting (SLM) 3D printed bar and the least fit was shown for customized bar with the conventional lost wax technique.
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Liang S, Yuan F, Li D, Jia L, Sun Y. Digital measurement method for comparing the absolute marginal discrepancy of three-unit ceramic fixed dental prostheses fabricated using conventional and digital technologies. BMC Oral Health 2023; 23:880. [PMID: 37978507 PMCID: PMC10657126 DOI: 10.1186/s12903-023-03620-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 11/03/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND In clinical practice, control of the marginal fit of fixed dental prostheses is hindered by evaluation method, which needs to be further improved to increase its clinical applicability. This study aimed to quantitatively analyze the absolute marginal discrepancy of three-unit ceramic fixed dental prostheses fabricated by conventional and digital technologies using a digital measurement method based on the digital impression technology and open source software. METHODS A digital workflow and the conventional impression combined with the lost-wax heat-pressed technique were adopted to separately fabricate 10 glass ceramic fixed dental prostheses. Three-dimensional data for the abutments, fixed dental prostheses, and fixed dental prostheses seated on the abutments, were obtained using a dental scanner. The two datasets were aligned using registration technology, specifically "multi-points registration" and "best fit alignment," by reverse engineering software. Subsequently, the three-dimensional seated fit between the fixed dental prostheses and abutments were reconstructed. The margin of the abutment and crown was extracted using edge-sharpening and other functional modules, and the absolute marginal discrepancy was measured by the distance between the margin of the abutment and crown. One-way analysis of variance was used to statistically analyze the measurement results. RESULTS Using the digital measurement method, the mean value of absolute marginal discrepancy for fixed dental prostheses fabricated by the conventional method was 106.69 ± 6.46 μm, and that fabricated by the digital workflow was 102.55 ± 6.96 μm. The difference in the absolute marginal discrepancy of three-unit all-ceramic fixed dental prostheses fabricated using the two methods was not statistically significant (p > 0.05). CONCLUSIONS The digital measurement method for absolute marginal discrepancy was preliminarily established based on open source software and applied in three-unit ceramic fixed dental prostheses. The absolute marginal discrepancy of three-unit ceramic fixed dental prostheses fabricated using digital technology was comparable to that of conventional technique.
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Moradpoor H, Samavati M, Raissi S, Emami M, Habibkhodaei M, Shirani M. Clinical Marginal and Internal Adaptation of Single Metal-Ceramic Crowns Fabricated with Casting, Milling, and Milling/Sintering Methods. INT J PROSTHODONT 2023; 36:581-587. [PMID: 36484670 DOI: 10.11607/ijp.8024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
PURPOSE To compare the adaptation of single metal-ceramic crowns (MCCs) fabricated with three different methods: lost-wax metal casting (LMC), milling of hard cobalt-chromium (HCC) blanks, and milling of soft presintered cobalt-chromium (SCC) blanks. MATERIALS AND METHODS In this double-blind parallel randomized clinical trial, 60 single MCCs were fabricated using three different methods. Adaptation of the copings was evaluated radiographically, visually, and microscopically. Data were compared among the three groups using the Kruskal-Wallis test, followed by the Dunn post hoc test, one-way ANOVA, and paired t test (α = .05). RESULTS Radiographic data showed that the frequency of crowns with no marginal discrepancy was significantly higher in the SCC group than the LMC group. Evaluation of marginal adaptation with an explorer revealed that crowns with excellent marginal adaptation had lower frequency in the LMC group than the HCC and SCC groups. In the silicone replica technique, the recorded data revealed no significant difference. Application of porcelain veneering did not affect the adaptation of the copings. CONCLUSIONS The SCC and HCC groups showed better clinical outcomes compared to the LMC group. However, all MCCs fabricated with the LMC method, milling of HCC blanks, and milling of SCC blanks had acceptable clinical adaptation. Int J Prosthodont 2023;36:581-587.
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Kobayashi M, Niizuma Y, Sugai R, Manabe A. Influence of the Crystallization Firing Process on Marginal and Internal Adaptation of Silicate-based Glass-ceramic Inlays Fabricated With a CAD/CAM Chairside System. Oper Dent 2023; 48:657-665. [PMID: 37882476 DOI: 10.2341/22-120-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2023] [Indexed: 10/27/2023]
Abstract
OBJECTIVE Computer-aided design/computer-aided manufacturing (CAD/CAM) systems are widely used in dental treatment. Clinicians can use chairside CAD/CAM technology, which has the advantage of being able to fabricate inlays on the same day. We aimed to evaluate the effects of crystallization firing processes, fabrication methods (one-step and two-step), and materials on marginal and internal adaptations of silicate-based glass-ceramic all-ceramic inlays fabricated with CAD/CAM chairside systems. METHODS Ten artificial mandibular left first molars were prepared with standardized ceramic class II mesialocclusal (MO) inlay cavities. Optical impressions were obtained using CEREC Omnicam Ban. IPS e-max CAD (IE), (Ivoclar Vivadent, Schaan, Liechtenstein), Initial LiSi Block (LS) (Hongo, Bunkyoku, Tokyo, Japan), VITA Suprinity (SP), (Vita Zahnfabrick, Bad Säckingen, Germany), and Celtra Duo (CD) (Ivoclar Vivadent, Schaan, Liechtenstein) (n=10) were milled using CEREC MC XL (Bensheim, Germany). IE and SP were crystallization-fired using CEREC Speed Fire. The silicone replica technique was used for the measurement of internal (axial and pulpal walls) and marginal (cervical and occlusal edge) adaptations. The adaptations were measured using a thin layer of light-body polyvinyl siloxane impression material placed between the master tooth inlay preparation and restoration. Marginal and internal adaptations of IE, LS, SP, and CD were measured using a stereomicroscope (500×). For IE and SP, marginal and internal adaptations were measured before and after the crystallization firing process. Data analyses were conducted using one-way ANOVA and the Tukey test. For IE and SP, marginal and internal adaptations before and after the crystallization firing process were analyzed using the t-test. The significance level was set at α=0.05. RESULTS One-way ANOVA revealed statistically significant differences in occlusal and cervical edge marginal adaptations among the material groups (p<0.001). The Tukey HSD test revealed a significant difference in marginal occlusal and cervical edge adaptations between LS and CD groups and IE and SP groups (p≤0.05). For IE and SP inlays, the t-test revealed a significant difference between occlusal and cervical edge adaptations before the crystallization firing process and those after the crystallization firing process, with the latter group showing a more significant discrepancy in adaptation than the former group (p≤0.05). CONCLUSIONS Fabrication methods (one- and two-step) affected the marginal adaptation compatibility but not internal compatibility of MO inlays. The crystallization firing process affected the marginal adaptation of inlays using lithium silicate or lithium disilicate glass-ceramics. However, adaptation to the cavity was considered clinically acceptable for all materials.
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Ziaei M, Bajoghli F, Sabouhi M, Jowkar M, Nadian F, Manshaei F. Evaluating the Marginal and Internal Discrepancy of Nickel-Chrome Copings Made on Fixed Partial Denture Implants with Conventional and 3D Printing Techniques. J Contemp Dent Pract 2023; 24:826-833. [PMID: 38238268 DOI: 10.5005/jp-journals-10024-3586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
AIM This study aimed to evaluate the marginal and internal discrepancy of nickel-chrome (Ni-Cr) copings made on implant bridges with conventional and 3D printing techniques. MATERIALS AND METHODS 30 three-unit Ni-Cr FDPs (60 copings) were made by 3D-printing technique (PolyJet group), lost-wax method with die spacer technique (die spacer group), and lost-wax method with burn-out the cap (burn-out cap group). Then, the frames obtained from the three methods were checked to examine the marginal discrepancy by stereomicroscope after preparation and polishing. The silicon replica method was used to investigate the internal discrepancy at 6 points (buccal portion of occlusal surface, lingual portion of occlusal surface, middle area of the axial surface in the lingual, middle area of the axial surface in the buccal, cervico-buccal area, and cervico-lingual area). Kolmogorov-Smirnov test was performed first to estimate the normality of data distribution. A one-way ANOVA and post hoc Tukey test were done for comparing marginal and internal discrepancies between groups. The significant level was considered p < 0.05. RESULTS The mean ± standard deviation of marginal discrepancy in the PolyJet group, die spacer group, and burn-out cap group was 37.9 ± 15, 68.8 ± 31.8 and 42.7 ± 3.6 µm for buccal margins and 40.4 ± 12.3, 64 ± 21.7, and 42.4 ± 2.1 µm for lingual margins, respectively. The means of buccal and lingual marginal discrepancy in the burn-out cap group and PolyJet group were significantly lower than the die spacer group (p < 0.001). Marginal discrepancy was not statistically different between the burn-out cap group and the PolyJet group. The mean ± standard deviation of overall internal discrepancy in the PolyJet group, die spacer group, and burn-out cap group was 64.6 ± 3.7, 72 ± 22.2, and 58.7 ± 2 µm, respectively. There was a significant difference between the mean of internal discrepancy between three groups (p = 0.001). The mean of internal discrepancy of the burn-out cap group was significantly lower than the die spacer group (p = 0.001) and PolyJet group (p = 0.005). Internal discrepancy was not significantly different between the PolyJet group and the die spacer group (p = 0.168). CONCLUSION The marginal and internal gap rates of the three groups were within clinically acceptable limits. The 3D printing technique and lost-wax method with burn-out the cap had the lowest buccal and lingual marginal discrepancies. The burn-out cap method had better fitness and less internal discrepancy than 3D printing and die spacer groups. CLINICAL SIGNIFICANCE Lower marginal discrepancy of copings fabricated by using 3D printed patterns may improve clinical success of implant restoration. How to cite this article: Ziaei M, Bajoghli F, Sabouhi M, et al. Evaluating the Marginal and Internal Discrepancy of Nickel-Chrome Copings Made on Fixed Partial Denture Implants with Conventional and 3D Printing Techniques. J Contemp Dent Pract 2023;24(11):826-833.
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Parakaw T, Ruangsawasdi N, Dararat P, Phruksaniyom C, Srihirun S, Petchmedyai P. Biocompatibility and biofilm formation on conventional and CAD/CAM provisional implant restorations. BMC Oral Health 2023; 23:718. [PMID: 37798682 PMCID: PMC10552236 DOI: 10.1186/s12903-023-03468-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 09/28/2023] [Indexed: 10/07/2023] Open
Abstract
Dental implant treatment is a complex and sophisticated process, and implant provisional restorations play a vital role in ensuring its success. The advent of computer-aided design and computer-aided manufacturing (CAD/CAM) technology has revolutionized the field of implant restorations by providing improved precision leading to a reduction in chair time and more predictable treatment outcomes. This technology offers a promising solution to the drawbacks of conventional methods and has the potential to transform the way implant procedures are approached. Despite the clear advantages of CAD/CAM over conventional provisional implant restorations including higher accuracy of fit and superior mechanical properties, little research has been conducted on the biological aspect of these novel restorations. This study aims to fill that gap, comprehensively assessing the biocompatibility, gingival tissue attachment and biofilm formation of a range of provisional implant restorations using CAD/CAM technology through milling and 3-D printing processes compared to conventional fabrication. The biocompatibility of the tested restorations was assessed by MTT assay, Calcein-AM assay as well as SEM analysis. The surface roughness of the tested samples was evaluated, alongside the attachment of Human Gingival Fibroblasts (HGF) cells as well as biofilm formation, and estimated Porphyromonas gingivalis (P. gingivalis) cell count from DNA detection.The results showed all tested provisional implant restorations were non-toxic and good HGF cell attachment but differed in their quantity of biofilm formation, with surface texture influenced by the material and fabrication technique, playing a role. Within the limitation of this study, the findings suggest that CAD/CAM-fabricated provisional implant restorations using a milling technique may be the most favourable among tested groups in terms of biocompatibility and periodontal-related biofilm formation.
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Hasanzade M, Yaghoobi N, Nematollahi P, Ghazanfari R. Comparison of the marginal and internal fit of PMMA interim crowns printed with different layer thicknesses in 3D-printing technique. Clin Exp Dent Res 2023; 9:832-839. [PMID: 37386767 PMCID: PMC10582242 DOI: 10.1002/cre2.758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 06/02/2023] [Accepted: 06/17/2023] [Indexed: 07/01/2023] Open
Abstract
OBJECTIVE The aim of this in vitro study was to compare the effect of printing layer thickness on the marginal and internal fit of interim crowns. MATERIAL AND METHODS A maxillary first molar model was prepared for ceramic restoration. Thirty-six crowns were printed with three different layer thicknesses using a digital light processing-based three-dimensional printer (25, 50, and 100 µm [LT 25, LT 50, and LT 100]). The marginal and internal gaps of the crowns were measured with replica technique. An analysis of variance was conducted to determine if there were significant differences between the groups (ɑ = .05). RESULTS The marginal gap of LT 100 group was significantly higher than that LT 25 (p = .002) and LT 50 groups (p ≤ .001). The LT 25 group has significantly larger axial gaps than LT 50 group (p = .013); however, there were no statistically significant differences between other groups. The LT 50 group showed the smallest axio-occlusal gap. The mean occlusal gap differed significantly by printing layer thickness (p ≤ .001), with the largest gap occurring for LT 100. CONCLUSIONS Provisional crowns printed with 50 µm layer thickness provided the best marginal and internal fit. CLINICAL SIGNIFICANCE It is recommended that provisional crowns be printed with a 50 µm layer thickness to ensure optimal marginal and internal fit.
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Shenoy A, Maiti S, Nallaswamy D, Keskar V. An in vitro comparison of the marginal fit of provisional crowns using the virtual tooth preparation workflow against the traditional technique. J Indian Prosthodont Soc 2023; 23:391-397. [PMID: 37861617 DOI: 10.4103/jips.jips_273_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023] Open
Abstract
Aim This study investigates the effectiveness of an innovative virtual tooth preparation workflow for the fabrication of dental crowns using cone-beam computed tomography (CBCT) and intraoral scanners (IOSs) with conventional workflow using extraoral/laboratory scanners. Settings and Design This in vitro experimental study was conducted in the laboratory of a university in Chennai, India. The dental laboratory and research facilities at the institution were utilized for the fabrication of the temporary crowns and the data acquisition process. Materials and Methods Institutional approval was obtained from the university. It was basically a comparison between the virtual prep technique using CBCT and IOS and the conventional digital technique using extra oral scanners (EOS) for temporary crown fabrication. The sample size was estimated using an effect size of 1.5004, assuming a normal distribution, a significance level of 0.05, and a power of 0.95 in G power software. Based on this calculation, an extracted second lower molar was used to fabricate 10 samples in each group. The samples were divided into three groups: the CBCT (Group 1), the IOS (Group 2), and laboratory scanner (Group 3 as control) groups. The vertical marginal gap of all the surfaces of the crown was evaluated using a scanning electron microscope. Statistical Analysis Used Data were analyzed using one-way ANOVA using the SPSS software version 26.0, IBM, Armonk, NY, USA. Results Acceptable marginal discrepancy values were obtained in all three groups. There was no significant difference in the marginal discrepancy recorded (P = 0.113). Conclusion Virtual tooth preparation using CBCT and IOSs can be used as an alternative to the conventional workflow for provisional crown and bridge fabrication.
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Lyu J, Yang X, Li Y, Tan J, Liu X. Effect of build angle on the dimensional accuracy of monolithic zirconia crowns fabricated with the nanoparticle jetting technique. J Prosthet Dent 2023; 130:613.e1-613.e8. [PMID: 37633729 DOI: 10.1016/j.prosdent.2023.07.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/22/2023] [Accepted: 07/26/2023] [Indexed: 08/28/2023]
Abstract
STATEMENT OF PROBLEM The build angle is an essential parameter in additive manufacturing. Its effect on the dimensional accuracy of zirconia restorations fabricated using the nanoparticle jetting (NPJ) technique is unknown. PURPOSE The purpose of this in vitro study was to evaluate the effect of the build angle on the dimensional accuracy of monolithic zirconia complete crowns fabricated by using NPJ. MATERIAL AND METHODS Standardized artificial right maxillary incisors and mandibular first molars were prepared for ceramic complete crowns. In total, 100 monolithic zirconia crowns were fabricated using NPJ at build angles of 0, 45, 90, 135, and 180 degrees (n=10/angle for incisors and molars). The dimensional accuracies in the external, marginal, and intaglio regions were determined by superimposing the scanned data and computer-aided design data on the crowns. Root mean square (RMS) values were used to analyze the accuracy of the zirconia crowns overall and at the external, marginal, and intaglio surfaces. The Shapiro-Wilk test was used to examine the normality of data distribution. Differences among test groups were assessed using a 1-way analysis of variance and the post hoc least significant difference test (α=.05). RESULTS Significant differences were found in the accuracy of monolithic zirconia incisor and molar complete crowns in the external, marginal, and intaglio regions among the 5 build angles (P<.05). For incisors, the external RMS value was lowest for a build angle of 45 degrees (18.2 ±3.0 µm), the marginal and intaglio RMS values were lowest for a build angle of 135 degrees (47.4 ±10.7 and 26.5 ±6.1 µm, respectively), and the overall RMS values did not differ significantly among the 5 build angles (P>.05). For molars, build angles of 0 degrees and 180 degrees yielded the lowest RMS values overall (22.3 ±1.5 and 21.8 ±3.2 µm, respectively) and in the external (23.2 ±2.9 and 22.3 ±2.5 µm, respectively) and intaglio (22.2 ±3.7 and 21.2 ±4.6 µm, respectively) regions. No significant difference was observed in the marginal area among the 5 build angles (P>.05). The overall RMS values reflecting dimensional accuracy for the 5 build angles were between 23.5 and 26.7 µm for incisors and 21.8 and 26.2 µm for molars. CONCLUSIONS The dimensional accuracy of monolithic zirconia crowns fabricated by using NPJ was affected by the build angle and was within clinically acceptable limits.
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Sanchez-Lara A, Hosney S, Lampraki E, Conejo J, Blatz MB, Barmak AB, Ercoli C, Chochlidakis K. Evaluation of marginal and internal fit of single crowns manufactured with an analog workflow and three CAD-CAM systems: A prospective clinical study. J Prosthodont 2023; 32:689-696. [PMID: 36883776 DOI: 10.1111/jopr.13675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 02/08/2023] [Accepted: 03/02/2023] [Indexed: 03/09/2023] Open
Abstract
PURPOSE This prospective clinical study evaluated and compared the marginal and internal fit of crowns fabricated with an analog workflow and three different computer-aided design and computer-aided manufacturing (CAD-CAM) systems. MATERIALS AND METHODS Twenty-five participants in need of a single complete-coverage molar or premolar crown were recruited in the study. Twenty-two completed the study, and three participants dropped out. Teeth were prepared according to a standardized protocol by one operator. For each participant, one final impression was made with polyether material (PP) and three intraoral scanners: CEREC Omnicam (C), Planmeca Planscan (PM), and True Definition (TR). For the PP group, crowns were fabricated with a pressable lithium disilicate ceramic, whereas for the other three groups (C, PM, and TR), crowns were designed and milled with dedicated CAD-CAM systems and materials. Marginal (vertical and horizontal) and internal discrepancies between the crowns and tooth preparation were measured at various locations with digital superimposition software. Data was analyzed for normality with Kolmogorov-Smirnov and Shapiro-Wilk tests and then compared with one-way ANOVA and Kruskal-Wallis tests. RESULTS Mean vertical marginal gap values were 92.18 ± 141.41 μm (PP), 150.12 ± 138.06 μm (C), 129.07 ± 109.96 μm (PM), and 135.09 ± 112.03 μm (TR). PP group had statistically significantly smaller vertical marginal discrepancy (p = 0.001) than all other groups, whereas no significant difference was detected among the three CAD-CAM systems (C, PM, and TR). Horizontal marginal discrepancies were 104.93 ± 111.96 μm (PP), 89.49 ± 119.66 μm (C), 113.36 ± 128.49 μm (PM), and 136.39 ± 142.52 μm (TR). A significant difference was detected only between C and TR (p < 0.0001). Values for the internal fit were 128.40 ± 49.31μm (PP), 190.70 ± 69.79μm (C), 146.30 ± 57.70 μm (PM), and 168.20 ± 86.67 μm (TR). The PP group had a statistically significant smaller internal discrepancy than C (p < 0.0001) and TR groups (p = 0.001), whereas no significant difference was found compared to the PM group. CONCLUSION Posterior crowns fabricated with CAD-CAM systems showed vertical margin discrepancy greater than 120 μm. Only crowns fabricated with the conventional methodology had vertical margins below 100 μm. Horizontal marginal discrepancy was different among all groups, and only CEREC CAD-CAM was below 100 μm. Internal discrepancy was less for crowns fabricated with an analog workflow.
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Wang J, Wu YL, Ma J, Wu F, Li DH. A novel technique for implant-supported fixed complete rehabilitation based on a dynamic virtual patient. J Dent 2023; 137:104649. [PMID: 37574104 DOI: 10.1016/j.jdent.2023.104649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 07/28/2023] [Accepted: 08/01/2023] [Indexed: 08/15/2023] Open
Abstract
BACKGROUND A digital workflow for implant-supported fixed complete prostheses (ISFCP) using photogrammetry (PG), virtual articulator (VA), and virtual facebow (VF) data remains a challenge. METHODS The novel ISFCP technique included four steps: (1) formation of a dynamic virtual patient, (2) integration of PG data, (3) fabrication of a diagnostic ISFCP, and (4) fabrication of a definitive ISFCP and test of the deviation. RESULTS Dynamic virtual patients were formed by integrating PG, VA, and VF data. The cumulative root mean square deviation between the designed data and actual definitive prosthesis was 140.4 µm. CONCLUSIONS The novel technique for ISFCP fabrication described in this paper can help optimise the clinical efficiency and quality of ISFCP but requires an initial learning curve. CLINICAL SIGNIFICANCE This technique provides a direct workflow, using PG, VA, and VF data, to fabricate ISFCP based on the provisional restoration.
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Yazigi C, Busch R, Kern M. Zirconia restorations and the tool diameter compensation. INTERNATIONAL JOURNAL OF COMPUTERIZED DENTISTRY 2023; 26:257-264. [PMID: 36695627 DOI: 10.3290/j.ijcd.b3836703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
AIM The aim of the present article is to describe a new method to reduce the undesirable loss of material thickness that results from overmilling due to the tool diameter compensation correction of common CAD/CAM software. MATERIALS AND METHODS Today's CAD/CAM software (eg, 3Shape or Exocad) specifies the same tool diameter compensation for different ceramics. In the case of zirconia ceramics milled in the raw state, this leads to excessive milling of the inner surfaces of crowns, which results in unnecessarily large cementation gaps and a restoration that is thinned out from the inside. By manually reducing the preset correction in the digital design process by the volumetric sintering shrinkage factor specified by the manufacturer, excessive thinning of the zirconia can be avoided. RESULTS The inner geometry of the restorations changes only slightly after manually reducing the preset tool diameter compensation correction. Consequently, a design of the restoration with the required minimum interocclusal thickness yet with accurate passive seating and marginal fit is possible without any further interventions. CONCLUSIONS Understanding the specifics of the subtractive fabrication process as well as the properties of the restorative materials is a key factor in achieving optimal clinical outcomes with all-ceramic restorations fabricated with CAD/CAM technology. The use of monolithic zirconia combined with a calculated reduction in the preset tool diameter compensation correction might be beneficial in cases with thin or uneven geometry.
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Demirel M, Diken Türksayar AA, Donmez MB. Fabrication trueness and internal fit of hybrid abutment crowns fabricated by using additively and subtractively manufactured resins. J Dent 2023; 136:104621. [PMID: 37453654 DOI: 10.1016/j.jdent.2023.104621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 07/11/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023] Open
Abstract
OBJECTIVES To evaluate the fabrication trueness and internal fit of hybrid abutment crowns fabricated by using additively and subtractively manufactured restorative materials. METHODS A maxillary first premolar crown with a screw access channel was designed onto a digitized master titanium base abutment. This file was used to fabricate 40 crowns additively (Crowntec (CT) and VarseoSmile Crown Plus (VS)) or subtractively (Brilliant Crios (BC) and Vita Enamic (EN)) (n = 10). Crowns were digitized with an intraoral scanner and root mean square method was used to evaluate fabrication trueness. Master abutment and the crowns when seated on the abutment were also digitized with the same intraoral scanner and triple scan method was used to evaluate internal fit. Data were analyzed either with 1-way ANOVA (surface deviations) or Kruskal-Wallis (internal fit) tests (α= 0.05). RESULTS CT had the highest overall, external, and marginal surface deviations (P≤.030), whereas BC had the lowest external (P≤.001) and VS and EN had the lowest marginal surface deviations (P≤.007). BC had the highest intaglio surface deviations (P<.001). BC and EN had higher average gap values CT and VS (P≤.006); however, the differences within additively and subtractively manufactured materials were nonsignificant (P≥.858). CONCLUSIONS One of the tested additively manufactured resins (CT) resulted in mostly lower trueness than that of other materials. However, deviations at the intaglio and marginal surfaces were generally small and the maximum mean difference among test groups when average gap was considered was 17.4 µm. Therefore, clinical fit of hybrid abutment crowns fabricated with tested materials may be similar.
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Vogler JAH, Billen L, Walther KA, Wöstmann B. Conventional cast vs. CAD/CAM post and core in a fully digital chairside workflow - An in vivo comparative study of accuracy of fit and feasibility of impression taking. J Dent 2023; 136:104638. [PMID: 37506812 DOI: 10.1016/j.jdent.2023.104638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/20/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023] Open
Abstract
OBJECTIVES Clinical data for CAD/CAM post and cores (PC) is still scarce, even though developments in digital dentistry have improved dental treatment in many aspects. Therefore, the purpose of this in vivo study was to compare CAD/CAM PC fabricated in a fully digital chairside workflow to conventional cast PC (CPC) according to the accuracy of fit and the impression taking. The null hypothesis was that there is no significant difference between CAD/CAM PC and CPC. METHODS The study was conducted on 30 teeth in 25 patients receiving a CPC during their prosthetic treatment plan. On each tooth a conventional and a digital post impression were taken. Subsequently, one CPC following a conventional and one CAD/CAM PC following a digital workflow were fabricated. Both PC were tried-in intraorally and assessed according to a standardised evaluation sheet. The deviation between the two impression methods was evaluated by superimposing the datasets in a 3D analysis software. Statistical analysis for pairwise comparison was conducted according to Wilcoxon and median test with a significance level of p = 0.05. RESULTS CAD/CAM PC performed significantly better compared to CPC according to accuracy of fit (p = 0.022) and feasibility of impression taking (p < 0.001). The deviation between post impression methods increased from "coronal" to "apical". Between "coronal"/"middle" no significant difference (p = 0.158) was detected, whereas the pairwise comparison between the other measurement categories showed significant differences (p = 0.002, p < 0.001). CONCLUSIONS The null hypothesis was rejected since CAD/CAM PC performed significantly better and the deviation between the post impression methods showed significant differences. CLINICAL SIGNIFICANCE By using intraoral scanners (IOS) teeth can be restored with customised CAD/CAM PC in a single session. Within the limitations of this study the fully digital chairside workflow led to superior accuracy of fit of PC and higher feasibility of impression taking than the conventional workflow for CPC.
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