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3 pages, 169 KiB

Open AccessEditorial

3D-Printed Materials Dentistry

by Kathrin Becker

Appl. Sci. 2023, 13(1), 457; https://doi.org/10.3390/app13010457 - 29 Dec 2022

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Abstract

This editorial focuses on the Special Issue on 3D-printed materials in dentistry [...] Full article

(This article belongs to the Special Issue 3D Printed Materials Dentistry)

Research

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13 pages, 14407 KiB

Open AccessArticle

The Mask Fitter, a Simple Method to Improve Medical Face Mask Adaptation Using a Customized 3D-Printed Frame during COVID-19: A Survey on Users’ Acceptability in Clinical Dentistry

by Alessandro Vichi, Dario Balestra, Cecilia Goracci, David R. Radford and Chris Louca

Appl. Sci. 2022, 12(17), 8921; https://doi.org/10.3390/app12178921 - 5 Sep 2022

Cited by 2 | Viewed by 1923

Abstract

COVID-19 has deeply impacted clinical strategies in dentistry and the use of surgical masks and respirators has become critical. They should adapt to the person’s facial anatomy, but this is not always easy to achieve. Bellus3D Company proposed to apply their face scan [...] Read more.

COVID-19 has deeply impacted clinical strategies in dentistry and the use of surgical masks and respirators has become critical. They should adapt to the person’s facial anatomy, but this is not always easy to achieve. Bellus3D Company proposed to apply their face scan software, used with selected smartphones and tablets, to design and 3D-print a bespoke “Mask Fitter” to improve the sealing of surgical masks and respirators. Twenty dental staff participants were face scanned and a Mask Fitter for FFP2 respirators was designed and 3D-printed. Participants were asked to wear their Mask Fitter over one week and then completed a survey. Questions were asked about wearing comfort, sealing confidence, glasses or loupes fogging, both with and without the Mask Fitter. Dental staff gave positive feedback, with levels of comfort during daily use reported as similar with and without the Mask Fitter; and a higher confidence in achieving a proper seal, ranging from a 10% confidence rating of a proper seal without the Mask Fitter to 75% with the Mask Fitter. Moreover, fogging problems decreased considerably. The tested Mask Fitter device could represent an easy and low-cost procedure to improve the facial adaptation of the FFP2 respirator. Full article

(This article belongs to the Special Issue 3D Printed Materials Dentistry)

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12 pages, 3981 KiB

Open AccessArticle

Impact of Steam Autoclaving on the Mechanical Properties of 3D-Printed Resins Used for Insertion Guides in Orthodontics and Implant Dentistry

by Anna Kirschner, Samuel David, Giulia Brunello, Ludger Keilig, Dieter Drescher, Christoph Bourauel and Kathrin Becker

Appl. Sci. 2022, 12(12), 6195; https://doi.org/10.3390/app12126195 - 17 Jun 2022

Cited by 6 | Viewed by 2126

Abstract

Guided implant placement has been shown to be more accurate than free-handed insertion. Still, implant position deviations occur and could possibly pose risks. Thus, there is a quest to identify factors that might impair the accuracy of implantation protocols using templates. This study [...] Read more.

Guided implant placement has been shown to be more accurate than free-handed insertion. Still, implant position deviations occur and could possibly pose risks. Thus, there is a quest to identify factors that might impair the accuracy of implantation protocols using templates. This study aimed to investigate the influence of autoclaving cycles (cycle 1: 121 °C, 1 bar, 20.5 min; cycle 2: 134 °C, 2 bar, 5.5 min) on the Vickers hardness and flexural modulus of five different materials used for 3D-printed insertion guides. The specimens were subjected to Vickers hardness tests, showing significant changes in the Vickers hardness for two and three materials out of five for cycle 1 and 2, respectively. The results of the three-point bending tests (n = 15 specimens per material) showed decreasing flexural moduli after autoclaving. However, changes were significant only for one material, which presented a significant decrease in the flexural modulus after cycle 2. No significant changes were detected after cycle 1. In conclusion, our findings show that autoclaving can alter the mechanical properties of the templates to some extent, especially with cycle 2. Whether these modifications are associated with dimensional changes of the templates and reduced accuracy of the implantation protocols remains to be investigated. Full article

(This article belongs to the Special Issue 3D Printed Materials Dentistry)

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13 pages, 89817 KiB

Open AccessCommunication

Application of the Digital Workflow in Orofacial Orthopedics and Orthodontics: Printed Appliances with Skeletal Anchorage

by Maximilian Küffer, Dieter Drescher and Kathrin Becker

Appl. Sci. 2022, 12(8), 3820; https://doi.org/10.3390/app12083820 - 10 Apr 2022

Cited by 10 | Viewed by 3317

Abstract

As digital workflows are gaining popularity, novel treatment options have also arisen in orthodontics. By using selective laser melting (SLM), highly customized 3D-printed appliances can be manufactured and combined with preformed components. When combined with temporary anchorage devices (TADs), the advantages of the [...] Read more.

As digital workflows are gaining popularity, novel treatment options have also arisen in orthodontics. By using selective laser melting (SLM), highly customized 3D-printed appliances can be manufactured and combined with preformed components. When combined with temporary anchorage devices (TADs), the advantages of the two approaches can be merged, which might improve treatment efficacy, versatility, and patient comfort. This article summarizes state-of-the-art technologies and digital workflows to design and install 3D-printed skeletally anchored orthodontic appliances. The advantages and disadvantages of digital workflows are critically discussed, and examples for the clinical application of mini-implant and mini-plate borne appliances are demonstrated. Full article

(This article belongs to the Special Issue 3D Printed Materials Dentistry)

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12 pages, 6331 KiB

Open AccessFeature PaperArticle

Digital Design of Different Transpalatal Arches Made of Polyether Ether Ketone (PEEK) and Determination of the Force Systems

by Cornelia Mieszala, Jens Georg Schmidt, Kathrin Becker, Jan Hinrich Willmann and Dieter Drescher

Appl. Sci. 2022, 12(3), 1590; https://doi.org/10.3390/app12031590 - 2 Feb 2022

Cited by 2 | Viewed by 2378

Abstract

The aim of this study was to investigate whether the polymer polyether ether ketone (PEEK), which is approved for (dental) medical appliances, is suitable for the production of orthodontic treatment appliances. Different geometries of transpalatal arches (TPAs) were designed by Computer Aided Design [...] Read more.

The aim of this study was to investigate whether the polymer polyether ether ketone (PEEK), which is approved for (dental) medical appliances, is suitable for the production of orthodontic treatment appliances. Different geometries of transpalatal arches (TPAs) were designed by Computer Aided Design (CAD). Out of a number of different designs and dimensions, four devices were selected and manufactured by milling out of PEEK. A finite element analysis (FEA) and a mechanical in vitro testing were performed to analyze the force systems acting on the first upper molars. Up to an activation (transversal compression) of 4 mm per side (total 8 mm), the PEEK TPAs generated forces between 1.3 and 3.1 Newton (N) in the FEA and between 0.7 and 3.2 N in the mechanical testing. The moments in the oro-vestibular direction were measured between 2.1 and 6.6 Nmm in the FEA and between 1.1 and 6.0 Nmm in the mechanical testing, depending on the individual TPA geometry. With the help of the FEA, it was possible to calculate the von Mises stresses and the deformation patterns of the different TPAs. In some areas, local von Mises stresses exceeded 154–165 MPa, which could lead to a permanent deformation of the respective appliances. In the in vitro testing, however, none of the TPAs showed any visible deformation or fractures. With the help of the FEA and the mechanical testing, it could be shown that PEEK might be suitable as a material for the production of orthodontic TPAs. Full article

(This article belongs to the Special Issue 3D Printed Materials Dentistry)

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11 pages, 3652 KiB

Open AccessArticle

Evaluation of Dimensional Changes during Postcuring of a Three-Dimensionally Printed Denture Base According to the Curing Time and the Time of Removal of the Support Structure: An In Vitro Study

by Re-Mee Doh, Jong-Eun Kim, Na-Eun Nam, Seung-Ho Shin, Jung-Hwa Lim and June-Sung Shim

Appl. Sci. 2021, 11(21), 10000; https://doi.org/10.3390/app112110000 - 26 Oct 2021

Cited by 10 | Viewed by 2192

Abstract

This study attempted to determine the dimensional stability of maxillary and mandibular edentulous denture bases constructed using three-dimensional (3D) printing systems based on stereolithography and digital light processing according to the postcuring treatment time and the removal time of the support structure. Three-dimensional [...] Read more.

This study attempted to determine the dimensional stability of maxillary and mandibular edentulous denture bases constructed using three-dimensional (3D) printing systems based on stereolithography and digital light processing according to the postcuring treatment time and the removal time of the support structure. Three-dimensional printing of the designed denture base file was performed using two types of 3D printing photocurable resin (standard gray resin (Formlabs) (Somerville, MA, USA) and MAZIC D resin (Vericom) (Anyang, Korea)) and their compatible 3D printers (Form3 (Formlabs) and Phrozen Shuffle (Phrozen) (Hsinchu City, Taiwan)). Different postcuring times (no postcuring, and 15, 30, 45, and 60 min) and times of removal of the support structure were set for each group. Data relating to the denture bases in all groups were obtained using 3D scanning with a tabletop scanner after postcuring. All acquired data were exported to 3D analysis software, and the dimensional changes during postcuring of the denture base were analyzed using RMSE (root-mean-square error) values. It could be confirmed that the dimensional changes increased with postcuring time, and the accuracy was higher in the maxilla than in the mandible. The accuracy was highest for the group in which the postcuring process was performed while the support structure was present. Full article

(This article belongs to the Special Issue 3D Printed Materials Dentistry)

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14 pages, 6757 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effect of Printing Layer Thickness on the Trueness and Margin Quality of 3D-Printed Interim Dental Crowns

by Gülce Çakmak, Alfonso Rodriguez Cuellar, Mustafa Borga Donmez, Martin Schimmel, Samir Abou-Ayash, Wei-En Lu and Burak Yilmaz

Appl. Sci. 2021, 11(19), 9246; https://doi.org/10.3390/app11199246 - 5 Oct 2021

Cited by 38 | Viewed by 4783

Abstract

The information in the literature on the effect of printing layer thickness on interim 3D-printed crowns is limited. In the present study, the effect of layer thickness on the trueness and margin quality of 3D-printed composite resin crowns was investigated and compared with [...] Read more.

The information in the literature on the effect of printing layer thickness on interim 3D-printed crowns is limited. In the present study, the effect of layer thickness on the trueness and margin quality of 3D-printed composite resin crowns was investigated and compared with milled crowns. The crowns were printed in 3 different layer thicknesses (20, 50, and 100 μm) by using a hybrid resin based on acrylic esters with inorganic microfillers or milled from polymethylmethacrylate (PMMA) discs and digitized with an intraoral scanner (test scans). The compare tool of the 3D analysis software was used to superimpose the test scans and the computer-aided design file by using the manual alignment tool and to virtually separate the surfaces. Deviations at different surfaces on crowns were calculated by using root mean square (RMS). Margin quality of crowns was examined under a stereomicroscope and graded. The data were evaluated with one-way ANOVA and Tukey HSD tests. The layer thickness affected the trueness and margin quality of 3D-printed interim crowns. Milled crowns had higher trueness on intaglio and intaglio occlusal surfaces than 100 μm-layer thickness crowns. Milled crowns had the highest margin quality, while 20 μm and 100 μm layer thickness printed crowns had the lowest. The quality varied depending on the location of the margin. Full article

(This article belongs to the Special Issue 3D Printed Materials Dentistry)

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11 pages, 10672 KiB

Open AccessFeature PaperArticle

Impact of Dental Model Height on Thermoformed PET-G Aligner Thickness—An In Vitro Micro-CT Study

by Benjamin Alexander Ihssen, Robert Kerberger, Nicole Rauch, Dieter Drescher and Kathrin Becker

Appl. Sci. 2021, 11(15), 6674; https://doi.org/10.3390/app11156674 - 21 Jul 2021

Cited by 10 | Viewed by 3420

Abstract

The aim of the present study was to investigate whether base height of 3D-printed dental models has an impact on local thickness values from polyethylene terephthalate glycol (PET-G) aligners. A total of 20 aligners were thermoformed on dental models from the upper jaw [...] Read more.

The aim of the present study was to investigate whether base height of 3D-printed dental models has an impact on local thickness values from polyethylene terephthalate glycol (PET-G) aligners. A total of 20 aligners were thermoformed on dental models from the upper jaw exhibiting either a 5 mm high (H) or narrow (N), i.e., 0 mm, base height. The aligners were digitized using micro-CT, segmented, and local thickness values were computed utilizing a 3D-distance transform. The mean thickness values and standard deviations were assessed for both groups, and local thickness values at pre-defined reference points were also recorded. The statistical analysis was performed using R. Aligners in group H were significantly thinner and more homogenous compared to group N (p < 0.001). Significant differences in thickness values were observed among tooth types between both groups. Whereas thickness values were comparable at cusp tips and occlusal/incisal/cervical measurement locations, facial and palatal surfaces were significantly thicker in group N compared to group H (p < 0.01). Within the limits of the study, the base height of 3D-printed models impacts on local thickness values of thermoformed aligners. The clinician should consider potential implication on exerted forces at the different tooth types, and at facial as well as palatal surfaces. Full article

(This article belongs to the Special Issue 3D Printed Materials Dentistry)

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9 pages, 2423 KiB

Open AccessCommunication

Implementation of Fused Filament Fabrication in Dentistry

by Jörg Lüchtenborg, Felix Burkhardt, Julian Nold, Severin Rothlauf, Christian Wesemann, Stefano Pieralli, Gregor Wemken, Siegbert Witkowski and Benedikt C. Spies

Appl. Sci. 2021, 11(14), 6444; https://doi.org/10.3390/app11146444 - 13 Jul 2021

Cited by 20 | Viewed by 3406

Abstract

Additive manufacturing is becoming an increasingly important technique for the production of dental restorations and assistive devices. The most commonly used systems are based on vat polymerization, e.g., stereolithography (SLA) and digital light processing (DLP). In contrast, fused filament fabrication (FFF), also known [...] Read more.

Additive manufacturing is becoming an increasingly important technique for the production of dental restorations and assistive devices. The most commonly used systems are based on vat polymerization, e.g., stereolithography (SLA) and digital light processing (DLP). In contrast, fused filament fabrication (FFF), also known under the brand name fused deposition modeling (FDM), is rarely applied in the dental field. This might be due to the reduced accuracy and resolution of FFF compared to vat polymerization. However, the use of FFF in the dental sector seems very promising for in-house production since it presents a cost-effective and straight forward method. The manufacturing of nearly ready-to-use parts with only minimal post-processing can be considered highly advantageous. Therefore, the objective was to implement FFF in a digital dental workflow. The present report demonstrates the production of surgical guides for implant insertion by FFF. Furthermore, a novel approach using a temperature-sensitive filament for bite registration plates holds great promise for a simplified workflow. In combination with a medical-grade filament, a multi-material impression tray was printed for optimized impression taking of edentulous patients. Compared to the conventional way, the printed thermoplastic material is pleasant to model and can allow clean and fast work on the patient. Full article

(This article belongs to the Special Issue 3D Printed Materials Dentistry)

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9 pages, 923 KiB

Open AccessArticle

3D-Printed Teeth with Multicolored Layers as a Tool for Evaluating Cavity Preparation by Dental Students

by Diva Lugassy, Mohamed Awad, Asaf Shely, Moshe Davidovitch, Raphael Pilo and Tamar Brosh

Appl. Sci. 2021, 11(14), 6406; https://doi.org/10.3390/app11146406 - 12 Jul 2021

Cited by 3 | Viewed by 2612

Abstract

Accurate assessment of dental student performance during preclinical operative mannequin courses is an essential milestone within the educational process. Training on novel, multicolored 3D-printed teeth resulted in higher performances of the students in comparison to training on standard, monochromatic plastic teeth. However, low [...] Read more.

Accurate assessment of dental student performance during preclinical operative mannequin courses is an essential milestone within the educational process. Training on novel, multicolored 3D-printed teeth resulted in higher performances of the students in comparison to training on standard, monochromatic plastic teeth. However, low reliability of students’ grading using standard, monochromatic plastic teeth was reported. The aim of this study was to verify whether the use of 3D multicolored teeth can (1) provide better inter- and intra-examiner reliability, and (2) assess the effect of instructors’ experience on their reliability. The novel tooth analogs consisted of digitally planned and 3D-printed plastic teeth containing green, yellow, and red stratifications according to increasing depths of preparation. Thirty-seven dental students performed three Class I preparations on the 3D-printed teeth, and these underwent blind evaluation by two examiners of varied experience at two timepoints. The data were compared with preparations done on conventional (monochromatic) plastic teeth. Results indicated excellent inter-examiner reliability on 3D-printed teeth (0.768 < ICC < 0.929), but only moderate reliability with conventional plastic teeth (0.314 < ICC < 0.672). The examiner having more experience was found to show higher intra-examiner reliability (ICC = 0.716 and 0.612 using 3D-printed teeth and conventional teeth, respectively) than the less experienced examiner (ICC = 0.481 and 0.095 using 3D-printed teeth and conventional teeth, respectively). The novel, multicolored 3D-printed teeth can provide more objective evaluation of cavity preparation compared with conventional plastic teeth. Full article

(This article belongs to the Special Issue 3D Printed Materials Dentistry)

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14 pages, 4592 KiB

Open AccessFeature PaperArticle

Transfer Accuracy of Two 3D Printed Trays for Indirect Bracket Bonding—An In Vitro Pilot Study

by Rebecca Jungbauer, Jonas Breunig, Alois Schmid, Mira Hüfner, Robert Kerberger, Nicole Rauch, Peter Proff, Dieter Drescher and Kathrin Becker

Appl. Sci. 2021, 11(13), 6013; https://doi.org/10.3390/app11136013 - 28 Jun 2021

Cited by 16 | Viewed by 3146

Abstract

The present study aimed to investigate the impact of hardness from 3D printed transfer trays and dental crowding on bracket bonding accuracy. Lower models (no crowding group: Little’s Irregularity Index (LII) < 3, crowding group: LII > 7, n = 10 per group) [...] Read more.

The present study aimed to investigate the impact of hardness from 3D printed transfer trays and dental crowding on bracket bonding accuracy. Lower models (no crowding group: Little’s Irregularity Index (LII) < 3, crowding group: LII > 7, n = 10 per group) were selected at random, digitized, 3D printed, and utilized for semiautomated virtual positioning of brackets and tubes. Hard and soft transfer trays were fabricated with polyjet printing and digital light processing, respectively. Brackets and tubes were transferred to the 3D printed models and altogether digitized using intraoral scanning (IOS) and microcomputed tomography (micro-CT) for assessment of linear and angular deviations. Mean intra- and interrater reliability amounted to 0.67 ± 0.34/0.79 ± 0.16 for IOS, and 0.92 ± 0.05/0.92 ± 0.5 for the micro-CT measurements. Minor linear discrepancies were observed (median: 0.11 mm, Q1–Q3: −0.06–0.28 mm). Deviations in torque (median: 2.49°, Q1–Q3: 1.27–4.03°) were greater than angular ones (median: 1.81°, Q1–Q3: 1.05°–2.90°), higher for hard (median: 2.49°, Q1–Q3: 1.32–3.91°) compared to soft (median: 1.77°, Q1–Q3: 0.94–3.01°) trays (p < 0.001), and torque errors were more pronounced at crowded front teeth (p < 0.05). In conclusion, the clinician should carefully consider the potential impact of hardness and crowding on bracket transfer accuracy, specifically in torque and angular orientation. Full article

(This article belongs to the Special Issue 3D Printed Materials Dentistry)

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10 pages, 693 KiB

Open AccessArticle

A Proposed In Vitro Methodology for Assessing the Accuracy of Three-Dimensionally Printed Dental Models and the Impact of Storage on Dimensional Stability

by Li Hsin Lin, Joshua Granatelli, Frank Alifui-Segbaya, Laura Drake, Derek Smith and Khaled E. Ahmed

Appl. Sci. 2021, 11(13), 5994; https://doi.org/10.3390/app11135994 - 28 Jun 2021

Cited by 13 | Viewed by 2704

Abstract

The objective of this study was to propose a standardised methodology for assessing the accuracy of three-dimensional printed (3DP) full-arch dental models and the impact of storage using two printing technologies. A reference model (RM) comprising seven spheres was 3D-printed using digital light [...] Read more.

The objective of this study was to propose a standardised methodology for assessing the accuracy of three-dimensional printed (3DP) full-arch dental models and the impact of storage using two printing technologies. A reference model (RM) comprising seven spheres was 3D-printed using digital light processing (MAX UV, MAX) and stereolithography (Form 2, F2) five times per printer. The diameter of the spheres (n = 35) represented the dimensional trueness (DT), while twenty-one vectors (n = 105) extending between the sphere centres represented the full-arch trueness (FT). Samples were measured at two (T₁) and six (T₂) weeks using a commercial profilometer to assess their dimensional stability. Significant (p < 0.05) contraction in DT occurred at T₁ and T₂ with a medium deviation of 108 µm and 99 µm for MAX, and 117 µm and 118 µm for F2, respectively. No significant (p > 0.05) deviations were detected for FT. The detected median deviations were evenly distributed across the arch for MAX at <50 µm versus F2, where the greatest error of 278 µm was in the posterior region. Storage did not significantly impact the model’s DT in contrast to FT (p < 0.05). The proposed methodology was able to assess the accuracy of 3DP. Storage significantly impacted the full-arch accuracy of the models up to 6 weeks post-printing. Full article

(This article belongs to the Special Issue 3D Printed Materials Dentistry)

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