Production tolerance of conventional and digital workflow in the manufacturing of glass ceramic crowns

Mahmood, Deyar Jallal Hadi; Braian, Michael; Larsson, Christel; Wennerberg, Ann

doi:10.1016/j.dental.2019.01.015

Cited by 14 publications

(15 citation statements)

References 31 publications

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“…While additive manufacturing is an emerging field in prosthodontics, comparisons are often challenging due to variations in hardware, software, and printing parameters, which hinder standardization and attaining consistent results [ 30 ]. Nevertheless, these findings align with previous literature, which generally demonstrates superior marginal fit for CAD-CAM techniques over conventional hand-waxing [ 27 , 37 – 41 ]. Kaleli and Saraç [ 40 ] found that additive CAD-CAM methods (direct metal laser sintering and direct process powder-bed) produced better marginal adaptation compared to the milling or conventional techniques.…”

Section: Discussionsupporting

confidence: 91%

“…Modern computer-aided design-computer-aided manufacturing (CAD-CAM) technologies were developed to address the limitations of conventional hand waxing by reducing human errors, simplifying processes, increasing production, and fabricating standardized dental prosthetics [ 14 , 26 , 27 ]. CAD-CAM techniques can be categorized as either subtractive, where a solid block is milled, or additive, where the product is built through incremental layers [ 15 , 26 ].…”

Section: Introductionmentioning

confidence: 99%

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Marginal fit of 3-unit implant-supported fixed partial dentures: Influence of pattern fabrication method and repeated porcelain firings

Giti,

Farrahi

2024

PLoS ONE

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Background Marginal fit significantly impacts the long-term success of dental restorations. Different pattern fabrication methods, including hand-waxing, milling, or 3D printing, may affect restorations accuracy. The effect of porcelain firing cycles on the marginal fit of metal-ceramic restorations remains controversial, with conflicting findings across studies. Purpose The aim was to evaluate the potential effects of multiple porcelain firings (3, 5, 7 cycles) as well as pattern fabrication method (conventional hand-waxing, milling, and 3D printing) on the marginal adaptation of 3-unit implant-supported metal-ceramic fixed partial dentures. It was hypothesized that neither the wax pattern fabrication method nor repeated ceramic firings would significantly affect the marginal adaptation of metal-ceramic crowns. Methods In this in-vitro study, 30 Cobalt-Chromium alloy frameworks were fabricated based on pattern made through three techniques: conventional hand-waxing, CAD-CAM milling, and CAD-CAM 3D printing (n = 10 per group). Sixteen locations were marked on each abutment to measure the vertical marginal gap at four stages: before porcelain veneering and after 3, 5, and 7 firing cycles. The vertical marginal gap was measured using direct microscopic technique at ×80 magnification. Mean vertical marginal gap values were calculated and two-way ANOVA and Tukey’s post hoc tests were used for inter-group comparisons (α = 0.05). Results The 3D printing group showed significantly lower (P<0.001) mean vertical marginal gaps (60–76 μm) compared to the milling (77–115 μm) and conventional hand-waxing (102–110 μm) groups. The milling group exhibited a significant vertical gap increase after 3 firing cycles (P<0.001); while the conventional (P = 0.429) and 3D printing groups (P = 0.501) showed no significant changes after 7 firing cycles. Notably, the vertical marginal gap in all groups remained below the clinically acceptable threshold of 120 μm. Conclusion CAD-CAM 3D printing provided superior marginal fit compared to CAD-CAM milling and conventional hand-wax pattern fabrication methods. The impact of porcelain firing on the mean marginal gap was significant only in the milling group. All three fabrication techniques yielded clinically acceptable vertical marginal adaptation after repeated firings. Additive manufacturing holds promise to produce precise implant-supported prostheses.

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Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Marginal fit of 3-unit implant-supported fixed partial dentures: Influence of pattern fabrication method and repeated porcelain firings

Giti,

Farrahi

2024

PLoS ONE

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“…They found no statistically significant difference between the two groups. Mahmood et al [ 29 ] also conducted an in vitro study comparing the accuracy of AM and SM crowns and they also had a conventional manufacturing group. They used the replica technique to assess the marginal and internal fit of the crowns.…”

Section: Discussionmentioning

confidence: 99%

Marginal and internal fit of crowns based on additive or subtractive manufacturing

Haddadi

Ranjkesh

Isidor

et al. 2021

Biomaterial Investigations in Dentistry

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Objective To assess the marginal and internal fit of crowns manufactured by additive and subtractive manufacturing technique. Materials and Methods Twenty extracted teeth prepared for complete coverage crowns were scanned with an intra-oral scanner (Omnicam, DentsplySirona). For the subtractive manufacturing (SM) group, ten crowns were manufactured in a hybrid resin block (Vita Enamic, Vita Zahnfabrik). For the additive manufacturing (AM) group, the crowns were manufactured in a hybrid resin material (NextDent C&B, 3D systems). The design parameters were identical for the two groups. The marginal and internal fit (determined at the axial wall, the cusp tip and occlusally) was assessed before cementation with the replica technique and after cementation under stereomicroscope after sectioning of the crowned teeth. Results For the SM group, the marginal fit was 91 µm (±28 µm) before cementation and 85 µm (±18 µm) after cementation. In the AM group, the marginal fit was 75 µm (±29 µm) before cementation and 71 µm (±18 µm) after cementation. The differences were not statistically significant. As regards the internal fit, the fit at the axial wall was statistically significantly better in the SM group than in the AM group ( p =.009 before cementation and .03 after cementation). Occlusally the fit in the AM group was significantly better than in the SM group after cementation ( p <.001). Conclusion Within the limitations of the current study, the marginal fit of additively manufactured crowns is comparable to crowns manufactured with chair-side subtractive technique and within the clinically acceptable range. As regards the internal fit no one technique was consistently superior.

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“…The conventional method of FDP fabrication includes several primary steps, such as making silicone impressions [30], pouring gypsum molds [31], preparing wax patterns [32], and casting using the lost-wax heat-pressed technique [33]. Errors can be introduced in any step, which can affect the extent of cement space and t of the nal restoration [30][31][32][33].…”

Section: Discussionmentioning

confidence: 99%

A preliminary study on the digital evaluation of absolute marginal discrepancy of fixed dental prostheses

Liang

Yuan

Sun

et al. 2023

Preprint

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Background In clinical practice, the control of the marginal fit of fixed dental prostheses is hindered by the evaluation method, which needs to be further improved to increase its clinical applicability. We aimed to develop a fully digital method to quantitatively evaluate the absolute marginal discrepancy of fixed dental prostheses based on the digital impression technology and reverse engineering software. Methods A digital workflow and the conventional impression combined with the lost-wax heat-pressed technique were adopted to separately fabricate ten glass ceramic fixed dental prostheses. These twenty fixed dental prostheses were seated on the abutment, and the absolute marginal discrepancy was evaluated using the method developed in this study. One-way analysis of variance was used to statistically analyze the measurement results. Results Using the fully digital quantitative evaluation 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 quantitative evaluation method for absolute marginal discrepancy was preliminarily established and applied in three-unit ceramic fixed dental prostheses. This study provided a fully digital quantitative method for the absolute marginal discrepancy of three-unit fixed dental prostheses, which allows for improvements in measurement, thus facilitated quality control of the marginal fit of fixed dental prostheses. This lays the foundation for the development of an automated software platform for evaluating marginal fit of dental prostheses.

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Production tolerance of conventional and digital workflow in the manufacturing of glass ceramic crowns

Cited by 14 publications

References 31 publications

Marginal fit of 3-unit implant-supported fixed partial dentures: Influence of pattern fabrication method and repeated porcelain firings

Marginal fit of 3-unit implant-supported fixed partial dentures: Influence of pattern fabrication method and repeated porcelain firings

Marginal and internal fit of crowns based on additive or subtractive manufacturing

A preliminary study on the digital evaluation of absolute marginal discrepancy of fixed dental prostheses

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