Fig 7 - uploaded by Riad Almasri
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Laboratory image of a master cast with five nonhexed UCLA abutments in place. These abutments were manufactured with machined gold alloy interfaces for improved accuracy relative to the implant/abutment interface (inset).
Source publication
The purposes of this study were (1) to evaluate the fit between implant frameworks and implants fabricated with two types of implant framework fabrication techniques: computer-aided design/computer-assisted machining (CAD/CAM) and conventional casting with the lost wax technique; and (2) to describe a digital measurement system consisting of tactil...
Similar publications
Implant-supported fixed complete dental prostheses have been associated with a high implant success rate in long-term studies. However, they have also been associated with a high frequency of prosthetic complications. The most frequent and primary prosthetic complication has been the fracture or wear of the occlusal surface of acrylic resin teeth t...
Citations
... However, digital fabrication methods might result in higher discrepancy values resulting from improper algorithms and inappropriate use of digital tools affecting the accuracy of definitive prosthesis. 20 On the other hand, Drago et al. 45 found that long-span frameworks created with CAD-CAM technology were significantly more precise compared to those produced using the traditional lost-wax casting method. Katsoulis et al. 46 reported that both optical and tactile scanners utilizing CAD-CAM technology can produce very accurate long-span zirconium dioxide implant reconstructions. ...
Abstract
Purpose
This systematic review aimed to provide comprehensive insights on the accuracy, fit, and mechanical characteristics of implant-supported computer-aided design and computer-aided manufacturing (CAD-CAM) prostheses, with a focus on milled and 3D-printed approaches.
Methods
The research question focused on implant-supported dental prostheses, comparing different manufacturing techniques (conventional, milled, and 3D-printed) to determine the different factors affecting the mechanical properties and fit of the CAD-CAM implant-supported prosthesis. The eligibility criteria encompassed studies involving implant-supported restorations, clear reporting of manufacturing techniques, and English-language publications from the last decade. The search was conducted across three main databases, MEDLINE, Scopus, and Web of Science in September 2023. Publication details, study characteristics, and methodological details of each included study were described.
Results
Of the initial 1964 articles, 581 met the inclusion criteria, and 104 studies were included in the final qualitative analysis. The majority of studies were conducted in the United States, Turkey, and Brazil. Fourteen studies evaluated accuracy parameters, while four studies focused on mechanical characteristics. The studies revealed variability in mechanical properties and marginal and internal fit, with fabrication methods impacting the structural integrity and stress distribution of the prostheses.
Conclusions
The findings suggest that digital manufacturing workflows, both milling and 3D printing, yield acceptable properties for implant-supported restorations with minimal variations in fit and accuracy. Notably, 3D printing and hybrid techniques demonstrate advantages in specific aspects like marginal fit and stress distribution. However, the milled prosthesis provided superior results in flexural strength and fracture resistance compared to conventional methods. Further research is needed to confirm these findings in clinical settings.
... Of the 459 retrieved titles, 318 abstracts were selected; subsequently, 20 articles were chosen for the full-text review ( Table 2). Of the remaining 20 articles, 9 papers were excluded as they had an in vitro design [17][18][19][20][21][22][23][24][25], 5 articles were excluded since they assessed only single-unit restorations [26][27][28][29][30], and one study investigated digital and conventional workflows on natural teeth [31]. All clinical studies evaluated mixed workflows for the fabrication of implant-supported partial dentures and no study compared full digital and conventional workflows [32][33][34][35][36] leaving no study for the final analysis ( Figure 1). ...
... Despite the variety of such studies, most of the studies that compared the digital and conventional impression methods did not find a statistically significant difference in their accuracy; however, the digital technique had a shorter chair time [32][33][34]. Another reason of exclusion was in vitro design of most studies [17][18][19][20][21][22][23][24][25]. Abdel-azim et al. [17] investigated both the impression accuracy and misfit of the frameworks that were built with two workflows in an in vitro study. ...
Objectives: This study aimed to do a comprehensive systematic review on the comparison of digital and conventional workflows regarding prosthetic outcomes, accuracy of implant impressions, framework passivity and fit, and clinical fabrication of multi-unit implant-supported fixed restorations.
Materials and Methods: The EMBASE, PubMed, Scopus, and Cochrane Library databases were searched for relevant articles published up until April 2020.
Results: No in-vivo article was found to compare full digital and conventional workflows regarding the accuracy of implant impressions, passivity and fit of frameworks, and prosthetic outcomes. There was no study to investigate full digital and conventional workflows for clinical fabrication of multi-unit implant-supported fixed restorations.
Conclusion: This empty review highlights the need for further research to compare full digital and conventional workflows for implant-supported restorations.
... Additionally, the accuracy of scanner and milling machine used in this process may contribute to the overall precision, surpassing that of traditional laboratory techniques [5]. The accuracy and fit of these CAD/CAM frameworks have been shown to be more accurate than one-piece cast framework by a number of studies [5][6][7][8]. CAD/CAM implant frameworks offer potential cost savings compared to one-piece cast frameworks due to the use of titanium alloy instead of noble alloy. They are also lighter in weight, and the locator or ball attachments are securely screwed into a milled screw base, resulting in consistent insertion axis and reduced wear. ...
Gingival mask is a copy of the peri-implant tissue, which plays an important role in the fabrication of an optimal restoration. Losing the gingival mask is a clinical problem that complicates the process of restoration fabrication. Herein, a simple precise technique is described step by step to solve this problem in the patient with CAD/CAM milled bar and ball attachment treatment plan for a maxillary and a mandibular implant-supported overdenture, without the need to repeat the entire clinical and laboratory procedures.
... The Computer-Aided-Imagining/Computer-Aided-Design/ Computer-Aided-Manufacturing (CAI/CAD/CAM) system provides digital restoration and dental models, and has been increasingly developed within various dentistry fields, such as restorative dentistry [37][38][39][40]. The development of CAI/CAD/CAM technology for manufacturing restorations and models on teeth and implants has revolutionized dentistry, offering a new form of rehabilitation, and facilitating and speeding up the workflow [41][42][43][44]. Likewise, abutments for implanted prostheses have been customized with CAD/CAM since the early 2000s [18]. ...
... Manufacturing is the third stage, called CAM. The data from the executed project are sent to a milling machine that performs the machining of parts in a significantly shorter clinical and laboratory time [43,[45][46][47]. Studies have shown promising results when introducing 3D printers in the manufacturing process (CAM) [48][49][50]. ...
This study presented a rehabilitation option for malpositioned implants; this involved obtaining their position and inclination through intraoral scanning, and producing a customized abutment with CAD/CAM technology. The patient in this case report presented a root fracture in tooth 21 and was subjected to extraction, implant installation, and immediate provisional prosthesis. The implant was installed with a distal inclination due to anatomical limitations. After osseointegration, an intraoral scanning transfer provided a digital model (file extension .stl), which reproduced the implant’s position and inclination. Then, the file was sent so that a customized abutment (CAD/CAM) could be manufactured, promoting the final rehabilitation of the case; this allowed for good hygiene, load distribution in the dynamic interocclusal relationship, and favorable esthetics, whereas many would otherwise recommend implant removal. The result presented lower costs, a shorter time frame, and a lower morbidity for the patient.
... 1,5,6,14,15 With the aim of improving the accuracy, speed, and efficiency of dental restorations, computer-aided design and computeraided manufacturing (CAD-CAM) techniques have emerged in dentistry offering greater precision and biological safety compared to conventional casting methods for manufacturing frameworks for multiple elements. [16][17][18][19][20][21][22][23][24] Additionally, there is increasing interest in the use of zirconia as a dental biomaterial due to its good chemical stability, mechanical strength, hardness, and Young's modulus similar to that of stainless steel, high fracture toughness, biocompatibility, and low bacterial adhesion. 25,26 However, despite these beneficial properties, the use of zirconia as a framework for cantilever FPDs has been limited because zirconia is more prone to fracture under masticatory loadings compared to metal alloys. ...
Purpose:
To evaluate the vertical misfit, stress distribution around dental implants, and cantilever fracture strength of 3-unit implant-supported cantilever fixed partial dentures (FPDs) using frameworks made from different materials and manufacturing techniques.
Materials and methods:
Forty FPDs were fabricated and divided into 5 groups (n = 8) based on the framework material used: G1 - LAS Co-Cr (Conventional casting - laser welding); G2 - TIG Co-Cr (Conventional casting -TIG welding); G3 - OP Co-Cr (Conventional casting - one-piece); G4 - CAD Co-Cr (CAD-CAM); and G5 - CAD Zr (CAD-CAM ZrO2 ). The vertical misfit was evaluated before porcelain application (T1) and before (T2), and after thermomechanical cycling (T3) by stereomicroscopy. Cantilever fracture strength was tested with a 50-kN (5000 kgf) load cell at a crosshead speed of 0.5 mm/min. Qualitative and quantitative photoelastic analysis was performed to evaluate stress distribution at seven specific points in five FPDs (n = 1/group) subjected to occlusal loading.
Results:
Only the molar showed interaction among the three factors (G x S x T; F(20.932) = 1.630; p = 0.044). Thermomechanical cycling (T2 vs. T3) had a significant effect on intra-group vertical misfit in molar, especially in LAS Co-Cr (Δ = 5.87; p = 0.018) and OP Co-Cr (Δ = 5.39; p = 0.007), with no significant effect in premolar (p>0.05). Ceramic application combined with thermomechanical cycling (T1 vs. T3) caused a significant intra-group increase in vertical misfit in all groups, both in the molar and premolar (p<0.05). OP Co-Cr was associated with greater vertical misfit and stress concentration. Frameworks manufactured by the CAD-CAM system exhibited lower vertical misfit and better stress distribution. FPDs with metal frameworks (>410.83 ±72.26 N) showed significantly higher fracture strength (p<0.05) than zirconia (277.47 ±39.10 N), and the first signs of ceramic veneering fracture were observed around 900 N.
Conclusions:
FPDs with frameworks manufactured using a CAD-CAM system appear to be associated with lower vertical misfit and better stress distribution, although the section of the frameworks followed by welding may be a viable alternative. In addition, metal frameworks exhibit high fracture strength. This article is protected by copyright. All rights reserved.
... Because the frameworks and abutments can be machined from solid blocks of material that are more homogeneous and have better physical qualities than conventional castings, interest in computer-aided design/computeraided manufacturer technology for implant restorations is expanding. According to Al Fadda [7] and Drago et al [8] , these technologies have eliminated traditional waxing, casing, and finishing processes as well as the errors associated with them. In fixed detachable frameworks, attaining passivity has always been the most challenging task. ...
... Utilizing the proper measurement method is mandatory to obtain reliable results. Although many methods are available to capture such measurements, the selection of an incompetent measurement technique may lead to biased results and inconclusive study (27). Among researches, Dentistry, and in particular Implant Dentistry requires micrometric examinations to provide trustworthy results. ...
... Implant-supported frameworks have been successfully fabricated with CAD/CAM using variable span lengths and materials (Delucchi et al. 2021;Katsoulis et al. 2017). The vertical marginal fit of Implant-supported frameworks made with the CAD/CAM technology demonstrated significantly better fit than the conventional cast Co-Cr frameworks (Arau´jo et al., 2015;Drago et al., 2010;De Franc¸a et al., 2014;Mundathaje et al., 2014). Accordingly, conventional cast Co-Cr frameworks may be replaced with well-engineered and accurate frameworks produced by CAD/ CAM technology (Papadiochou & Pissiotis, 2017). ...
Purpose
The purpose of this study was to compare the accuracy of fit of Co-Cr full arch screw-retained implant-supported fixed dental prosthesis fabricated among three different methods: conventional casting, milling, and additive manufacturing technology.
Materials and methods
A master model of a completely edentulous mandible with five internal connection implants was utilized. Thirty full arch Co-Cr screw-retained implant-supported frameworks were fabricated by three different methods: conventional casting, milling, and additive manufacturing (AM) technology. The marginal fit was measured using a coordinate measuring machine in x-, y-, and z-axes, as well as the three-dimensional discrepancy. The casting group were measured twice: before the adaptation procedure and again after the adaptation procedure (sectioning and laser welding). For comparisons of marginal fit of frameworks between different groups one-way analysis of variance and Games Howell test was used. Paired t-test was used to compare cast frameworks before and after adaption.
Results
There were statistically significant differences in marginal fit and width distortion between groups (P < .05). The mean of total distortion of each group was 94.6 µm (SD 50.5 µm) for casting group before adaptation, 92.44 µm (SD 49.6 µm) for casting group after adaptation, 71.4 µm (SD 37.2 µm) for additive manufacturing group, while for the milling group the total distortion was 50.1 µm (SD 27.5 µm).
Conclusion
Full arch screw-retained implant-supported frameworks fabricated with any of the three fabrication techniques using cobalt-chromium material exhibited acceptable marginal fit. Milling fabrication technique showed the most accurate marginal fit. Adaptation procedure for the cast group has significantly improved the marginal fit.
... Furthermore, CAD/CAM simplifies the process, eliminates various steps such as investment, burnout, casting, finishing, and polishing, and reduces the time required for manufacturing implant restorations. [10][11][12][13] Brånemark [14] was the first person who stated that the misfit of the implant framework should be not more than 10 µm. Whereas Zeroas et al. [15] concluded that a 30 µm discrepancy at the implant-abutment junction would be admissible if it does not exceed 10% of the perimeter. ...
Aim: The present study aimed to evaluate on a comparative basis the vertical marginal fit between conventionally casted, direct metal laser sintered (DMLS), and milled computer-aided design/computer-aided manufacturing (CAD-CAM) one-piece metal framework supported by five implants using one-screw test and screw resistance test.
Settings and Design: This is an in vitro study.
Materials and Methods: Five implants were placed parallel to one other in a Styrofoam master model. A total of 30 implant-supported screw-retained superstructures were manufactured using three techniques, i.e., conventionally casted, milled, and sintered. To evaluate the vertical marginal discrepancy, screw resistance test, and one-screw test were used, and measurements were made using a stereomicroscope.
Statistical Analysis Used: The data was analysed using two statistical tests, i.e., ANOVA and the post hoc Bonferroni test.
Results: On evaluating the frameworks using one-screw test, the mean vertical misfit value at the terminal implant for the control group was 292.58 ± 15.46μm, for conventionally casted framework 398.41 ± 21.13 μm, for DMLS 343.44 ± 24.73 μm, and for CAD-CAM was 304.03 ± 14.23 μm, whereas the average misfit values at four implants on applying screw resistance test were 1268.65 ± 84.24 (control), 1774.88 ± 67.70 (casted), 1508.02 ± 62.19 (DMLS), and 1367.29 ± 81.87 (CAD-CAM). The average misfit values on two implants using screw resistance test were 635.02 ± 57.33 for the control group; for conventionally casted, it was 879.75 ± 35.93; for (DMLS) framework, it was 761.51 ± 32.85; and for milled CAD-CAM framework, it was 687.07 ± 42.17 μm.
Conclusion: The mean vertical marginal discrepancy, when compared with control, was least in milled CAD-CAM frameworks, followed by sintered DMLS and conventionally casted frameworks. Hence, according to the present study, CAD/CAM technique is recommended to achieve maximum marginal fit in full mouth screw-retained implant-supported FDPs.
... implants supporting the ISFDP and being engaged by an RPD. [14][15][16][17] Yet, no long-term study is available with this type of treatment modality. ...
... 15 These forces can be significant to cause biological and/or mechanical complications of the implant because of an leverage action from clasp assembly of the RPD. 4,[15][16][17] To reduce the risk of complications, the ISFDP was designed to splint the maxillary implants, and the RPD embraced a stress releasing concept with using mesial rests and 19-gauge wrought wire clasp arms. 4,13 The RPD framework was designed to engage broad surface of the palate and tuberosity and fitted through the process of physiologic adjustment. ...
... The ISFDP was luted to the abutments in the mouth to ensure a passive fit. 16,17 This prosthesis was also retrievable because of the screw connection of the abutments to the fixtures. [11][12][13] The abutments were individually screwed to each implant, and then the implants were splinted across the arch with metal framework of ISFDP. ...