Publicaciones en las que ha participado el Dr. Wenceslao Piedra Cascón

1. Facially generated and additively manufactured baseplate and occlusion rim for treatment planning a complete-arch rehabilitation: A dental technique

J Prosthet Dent.2019 May;121 (5):74-645 doi:10.1016/j.prosdent.2018.07.009

Autores: Wenceslao Piedra Cascón, Juan Ruiz de Gopegui, Marta Revilla León

ABSTRACT: Computer-aided design and computer-aided manufacturing (CAD-CAM) technologies have been successfully integrated into the digital workflow to treat completely edentulous patients. However, the digital design and manufacturing technique of the baseplate and occlusion rims have not yet been developed into the digital workflow. This article describes a novel digital workflow using extraoral digitizing procedures, open-source CAD software, and additive manufacturing technologies to obtain a 3D patient. This virtual patient can then be used to plan treatment for a completely edentulous patient, with which the maxillary baseplate and occlusion rims are digitally designed. The workflow allows the digital determination of tooth exposure at rest, the dental midline, the location of the canines, and the determination of the occlusal plane related to the Camper plane. The digital determination of these parameters increases the predictability of the treatment, reducing laboratory and clinician time and costs.

2. Laboratory workflow to obtain long-term injected resin composite interim restorations from an additive manufactured esthetic diagnostic template

J Esthet Restor Dent.2019 Jan;31 (1):13-19 doi:10.1111/jerd.12419

Autores: Wenceslao Piedra Cascón, Alberto Parra Nuñez, Ignacio Charlén Díez, Marta Revilla León

ABSTRACT:
Objective: An analogue and digital workflow for the fabrication of a diagnostic 3D printed polymer template and its duplication for long-term injected composite resin interim restorations is described, because of the lack of scientific evidence in 3-dimensional (3D) printing applied to dentistry in terms of printer technology, printer parameters, postpolymerization processes, and material characteristics. In addition, in the case of 3D printed temporary resins, they cannot be relined successfully and its mechanical properties in the mouth have not been tested yet.
Conclusions: The main benefits of this approach relate to the improvement of clinical and laboratory procedures, as conventional waxing is eliminated, conventional master casts are not needed and the process is entirely automatized, improving the workflow, with minimal intervention of the laboratory technician.
Clinical significance: The additive manufactured diagnostic template represents the materialization of the digital diagnostic waxing and provides a powerful tool to visualize the digital diagnostic waxing in the patient’s mouth and face. Furthermore, the diagnostic 3D printed template can be used for multiple applications including interim restorations, radiographical, or surgical guide fabrication. The duplication technique described provides a predictable workflow to obtain long-term injected resin composite restorations from an additive manufactured esthetic diagnostic template, improving the laboratory and chairside procedures.

3. Digital workflow for the design and additively manufacture of a splinted framework and custom tray for the impression of multiple implants: A dental technique

J Prosthet Dent. 2018 Dec;120 (6):805-811 doi:10.1016/j.prosdent.2018.02.003.

Autores: Wenceslao Piedra Cascón, Marta Revilla León

ABSTRACT: This article describes a step-by-step digital protocol for the design and fabrication, through additive manufacturing, of a splinted framework and a custom tray for the impression of a complete-arch prosthesis supported by multiple implants. The protocol presented uses open source software to control the thicknesses of the custom tray, splinting material, and impression material during the procedure, reducing laboratory and chairside time and costs.

4. Accuracy (trueness and precision) of a dual-structured light facial scanner and interexaminer reliability

J Prosthet Dent. 2020 Jan 6;S0022–3913(19)30689-4. doi:10.1016/j.prosdent.2019.10.010.

Autores: Wenceslao Piedra Cascón, Mathew J Meyer, Mohammad M Methani, Marta Revilla León

ABSTRACT:
Statement of problem: Digital waxing procedures should be guided by facial references to improve the esthetic outcome of a restoration. The development of facial scanners has allowed the digitalization of the extraoral soft tissues of the patient’s face. However, the reliability of facial digitizers is questionable.
Purpose: The purpose of this study was to evaluate the accuracy (trueness and precision) of extraoral 3D facial reconstructions performed by using a dual-structured light facial scanner and to measure the interexaminer variability.
Material and methods: Ten participants were included. Six soft-tissue landmarks were determined on each participant, specifically reference (Ref), glabella (Gb), subnasal (Sn), menton (Me), chelion right (ChR), and chelion left (ChL). Interlandmark distances Ref-Sn, Sn-Gb, Ref-Gb, Sn-Me, and ChR-ChL (intercommissural) were measured by 2 different operators by using 2 different methods: directly on the participant’ face (manual group) and digitally (digital group) on the 3D facial reconstruction of the participant (n=20). For the manual group, interlandmark measurements were made by using digital calipers. For the digital group, 10 three-dimensional facial reconstructions were acquired for each participant by using a dual-structured light facial scanner (Face Camera Pro Bellus; Bellus3D). Interlandmark measurements were made by using an open-source software program (Meshlab; Meshlab). Both operators were used to note 10 measurements for each manual and digital interlandmark distance per participant. The intraclass correlation coefficient between the 2 operators was calculated. The Shapiro-Wilk test revealed that the data were not normally distributed. The data were analyzed by using the Mann-Whitney U test.
Results: Significant differences were found between manual and digital interlandmark measurements in all participants. The mean value of the manual and digital group discrepancy was 0.91 ±0.32 mm. The dual-structured light facial scanner tested obtained a trueness mean value of 0.91 mm and a precision mean value of 0.32 mm. Trueness values were always higher than precision mean values, indicating that precision was relatively high. The intraclass correlation coefficient between the 2 operators was 0.99.
Conclusions: The facial digitizing procedure evaluated produced clinically acceptable outcomes for virtual treatment planning. The interexaminer reliability between the 2 operators was rated as excellent, suggesting that the type of facial landmark used in this study provides reproducible results among different examiners.

5. Color dimensions of additive manufactured interim restorative dental material

J Prosthet Dent. 2020 May;123 (5):754-760. doi: 10.1016/j.prosdent.2019.06.001

Autores: Marta Revilla León, Mikhail Umorin, Mutlu Özcan, Wenceslao Piedra Cascón,

ABSTRACT:
Statement of problem: Interim dental restorations can be fabricated by using additive manufacturing (AM) technologies. Although dental restoration contours can be easily and accurately fabricated by using computer-aided design (CAD) procedures, protocols for creating predictable color dimensions of AM interim restorations are lacking.
Purpose: The purpose of this in vitro study was to measure and compare color dimensions of different AM and conventional interim restorative materials.
Material and methods: Disks (N=420) were fabricated by using either conventionally (CNV group) or additively manufactured (AM group) materials. The CNV group was further divided into the subgroups CNV-1 (Protemp 4; 3M ESPE) and CNV-2 (Anaxdent new outline dentin; Anaxdent). AM subgroups included AM-1 (FreePrint temp; Detax), AM-2 (E-Dent 400; Envisiontec), AM-3 (NextDent C&B; NextDent), AM-4 (NextDent C&B MFH; NextDent), and AM-5 (Med620 VEROGlaze; Stratasys). Color measurements in the CIELab coordinates were made by using a spectrophotometer (VITA EasyShade Advance 4.0; VITA) with a standardized photography gray card as a background under room light conditions (1003 lux). Color difference (ΔE*) values were calculated by using the CIE76 and CIEDE2000 formulas. The data were analyzed by using the Kruskal-Wallis test with nonparametric pairwise comparisons.
Results: Owing to a software error, the spectrophotometer was unable to measure the color of any specimens in the AM-5 subgroup, which was consequently excluded from further analysis. Significant differences (P=.001) between 2 manufacturing groups were found based on the L* variable. All subgroups were significantly different from each other for all 3 variables (P<.001). Pairwise comparisons revealed that all groups were significantly different from each other, except for the AM-1 and AM-2 subgroups, compared with the CNV-1 subgroup for the L* color dimension. The ΔE* values calculated by using the CIE76 formula varied from 6.63 to 23.1 and by using the CIEDE2000 formula from 3.43 to 10.21, suggesting a perceptible and unacceptable color mismatch between the CNV and AM groups.
Conclusions: None of the additively manufactured interim materials tested matched the conventional interim materials in all 3 CIELab color dimensions.

6. Digital workflow for an esthetic rehabilitation using a facial and intraoral scanner and an additive manufactured siliconeindex: A dental technique

J Prosthet Dent. 2020 Apr;123 (4):564-570. doi: 0.1016/j.prosdent.2019.03.014

Autores: Marta Revilla León, Lara Raney, Wenceslao Piedra Cascón, Jennifer Barrington, Amirali Zandinejad, Mutlu Özcan

ABSTRACT: The present article describes a digital workflow for planning an esthetic treatment by using a facial and intraoral scanner, the dental and open-source software design of a facially generated diagnostic waxing, and additive manufactured (AM) clear silicone indices. A virtual design was created to fabricate a unique 3-piece AM index composed of flexible, clear silicone at the labial and lingual aspects and a rigid clear custom tray. The 3-piece AM clear indexes provided advantages compared with conventional procedures, including accurate reproduction of the digital diagnostic waxing, control of index thickness, various insertion paths of the silicone indices, flexibility of the indices, and online storage of the designs.

7. Intraoral digital scans. Part 1: Influence of ambient scanning light conditions on the accuracy (trueness and precision) of different intraoral scanners

J Prosthet Dent. 2019 Dec 18; S0022-3913(18)30992-2 doi:10.1016/j.prosdent.2019.06.003.

Autores: Marta Revilla León, Pen Jiang, Mehrad Sadeghpour, Wenceslao Piedra Cascón, Amirali Zandinejad, Mutlu Özcan, Vinayak Krishnamurthy

ABSTRACT:
Statement of problem: Digital scans have increasingly become an alternative to conventional impressions. Although previous studies have analyzed the accuracy of the available intraoral scanners (IOSs), the effect of the light scanning conditions on the accuracy of those IOS systems remains unclear.
Purpose: The purpose of this in vitro study was to measure the impact of lighting conditions on the accuracy (trueness and precision) of different IOSs.
Material and methods: A typodont was digitized by using an extraoral scanner (L2i; Imetric) to obtain a reference standard tessellation language (STL) file. Three IOSs were evaluated-iTero Element, CEREC Omnicam, and TRIOS 3-with 4 lighting conditions-chair light 10 000 lux, room light 1003 lux, natural light 500 lux, and no light 0 lux. Ten digital scans per group were recorded. The STL file was used as a reference to measure the discrepancy between the digitized typodont and digital scans by using the MeshLab software. The Kruskal-Wallis, 1-way ANOVA, and pairwise comparison were used to analyze the data.
Results: Significant differences for trueness and precision mean values were observed across different IOSs tested with the same lighting conditions and across different lighting conditions for a given IOS. In all groups, precision mean values were higher than their trueness values, indicating low relative precision.
Conclusions: Ambient lighting conditions influenced the accuracy (trueness and precision) of the IOSs tested. The recommended lighting conditions depend on the IOS selected. For iTero Element, chair and room light conditions resulted in better accuracy mean values. For CEREC Omnicam, zero light resulted in better accuracy, and for TRIOS 3, room light resulted in better accuracy.

8. Intraoral digital scans. Part 2: Influence of ambient scanning light conditions on the accuracy (trueness and precision) of different intraoral scanner

J Prosthet Dent. 2019 Dec 20; S0022-3913(18)30995-8 doi:10.1016/j.prosdent.2019.06.004.

Autores: Marta Revilla León, Pen Jiang, Mehrad Sadeghpour, Wenceslao Piedra Cascón, Amirali Zandinejad, Mutlu Özcan, Vinayak Krishnamurthy

ABSTRACT:
Statement of problem: Digital scans should be able to accurately reproduce the different complex geometries of the patient’s mouth. Mesh quality of the digitized mouth is an important factor that influences the capabilities of the geometry reproduction of an intraoral scanner (IOS). However, the mesh quality capabilities of IOSs and the relationship with different ambient light scanning conditions are unclear.
Purpose: The purpose of this in vitro study was to measure the impact of various light conditions on the mesh quality of different IOSs.
Material and methods: Three IOSs were evaluated-iTero Element, CEREC Omnicam, and TRIOS 3-with 4 lighting conditions-chair light, 10 000 lux; room light, 1003 lux; natural light, 500 lux; and no light, 0 lux. Ten digital scans per group were made of a mandibular typodont. The mesh quality of digital scans was analyzed by using the iso2mesh MATLAB package. Two-way ANOVA and Kruskal-Wallis 1-way ANOVA statistical tests were used to analyze the data (á=.05).
Results: Significant differences in mesh quality values were found among the different IOSs under the same lighting conditions and among the different lighting conditions using the same IOS. TRIOS 3 showed the highest consistency and mesh quality mean values across all scanning lighting conditions tested. CEREC Omnicam had the lowest mean mesh quality values across all scanning lighting conditions. iTero Element displayed some consistency in the mesh quality values depending on the scanning lighting conditions: chair light and room light conditions presented good consistency in mesh quality, indicating better mesh quality, and natural light and no light conditions displayed differing consistency in mesh quality values. Nevertheless, no light condition led to the minimal mean mesh quality across all IOS groups.
Conclusions: Differences in the mesh quality between different IOSs should be expected. The photographic scanning techniques evaluated presented higher mesh quality mean values than the video-based scanning technology tested. Moreover, changes in lighting condition significantly affect mesh quality. TRIOS 3 showed the highest consistency in terms of the mean mesh quality, indicating better photographic system in comparison with iTero Element.

9. Workflow description of additively manufactured clear silicone indexes for injected provisional restorations: A novel technique

J Esther Restor Dent. 2019 May; 31(3):213-221 doi:10.1111/jerd.12464..

Autores: Marta Revilla León, Joshua Fountain, Wenceslao Piedra Cascón, Mutlu Özcan, Amirali Zandinejad

ABSTRACT:
Objective: The present article describes the digital workflow protocol for additive manufacturing (AM) of a clear silicone index to be used for an injected provisional restoration fabrication.
Clinical considerations: The incorporation of CAD software and AM technologies have allowed the integration of a new way to fabricate conventional diagnostic wax-ups and silicone indexes for preparing diagnostic mock ups, direct composite restorations, or provisional restorations. Although the conventional concept remains, the protocol differs.
Conclusions: This workflow provides a more efficient and accurate procedure with the reduction of time and cost compared to conventional technique.
Clinical significance: The digital workflow protocol described for AM of a clear silicone index to be used for an injected provisional restoration fabrication is time and cost efficient compared to conventional procedures.
Keywords: 3D printing; additive manufacturing; computer-aided design; injected technique; provisional restoration.

10. Digitally Created 3-Piece Additive Manufactured Index for Direct Esthetic Treatment

J Prosthodontics. 2020 Jun; 29 (5):436-442 doi:10.1111/jopr.13159.

Autores: So Hyeon Park, Wenceslao Piedra Cascón, Amirali Zandinejad, Marta Revilla-León

ABSTRACT: Facial and intraoral scanners as well as additive manufacturing (AM) technologies can be integrated to virtually plan restorative procedures. The present article describes a digital workflow protocol for treatment planning an esthetic rehabilitation using direct composite restorations. The combination of facial digitalization and intraoral scans allowed a facially driven diagnostic waxing, while additive manufacturing technologies facilitate the translation of the digital waxing into the patient´s mouth through an AM 3-piece silicone index which was designed into a buccal and a lingual clear flexible silicone indices that were fitted into a clear and rigid custom tray. This procedure facilitated the treatment planning procedures as well as assisted the direct composite restoration procedures, providing several advantages compared with conventional procedures such as precise translation of the digital diagnostic waxing into the patient´s mouth, horizontal path of insertion of the silicone index, and minimized time of the clinical intervention.

11. Fiber-reinforced composite fixed dental prosthesis using an additive manufactured silicone index

J Esther Restor Dent. 2020 Aug; 5 [Epub ahead of print] doi:10.1111/jerd.12628

Autores: Ana M Gonzalez, Wenceslao Piedra Cascón, Amirali Zandinejad, Marta Revilla-León

ABSTRACT:
Objective: Digital tools such as facial and intraoral digitizers and additive manufacturing (AM) technologies assist restorative treatments. The objective of the present manuscript was to describe a workflow procedure for treatment planning and fabricating a fiber-reinforced composite fixed dental prosthesis (FDP) replacing an absent maxillary lateral incisor, using additively manufactured silicone indices to facilitate the clinical intervention.
Clinical considerations: The elaboration of a direct fiber-reinforced composite restoration is a technique sensitive procedure which might be time-consuming for the clinician. The digital waxing helped to determine the exact position and size of the lingual wings and connectors of the fiber-reinforced FDP and to design a three-piece index. And the AM of the index helped to transfer the information to the patient’s dentition accurately.
Conclusions: The protocol minimizes the time of clinical intervention by facilitating the transference of the virtual diagnostic waxing teeth into the patient’s mouth. The three-piece silicone index provides an individualized path of insertion of each index part while also providing a customized space and location of the lingual wings of the restoration.
Clinical significance: The usage of AM silicone indices facilitates the clinical intervention by translating the size and position of the diagnostic wax-up teeth into the patient´s mouth, minimizing clinical procedure’s time.

12. Workflow of a fiber-reinforced composite fixed dental prosthesis by using a 4-piece additive manufactured silicone index: A dental technique

J Prosthet Dent. 2020 May 3; S0022-3913(20)30167-0 doi:10.1016/j.prosdent.2020.02.030.

Autores: Marta Revilla León, Joshua Fountain, Wenceslao Piedra Cascón, Mutlu Özcan, Amirali Zandinejad.

ABSTRACT: A digital workflow for fabricating a fiber-reinforced composite prosthesis is described. A facial scanner and an intraoral scanner were used to gather records, and dental and open-source software programs were used to elaborate a diagnostic waxing and design a 4-piece additively manufactured clear silicone index. Advantages of the index design included precise translation of the diagnostic waxing, optimal composite resin stratification, and minimal clinical time.

13. Scanning accuracy of nondental structured light extraoral scanners compared with that of a dental-specific scanner

J Prosthet Dent. 2020 Jul 19; S0022-3913(20)30263-8. doi:10.1016/j.prosdent.2020.04.009.

Autores: Wenceslao Piedra Cascón, Mohammed M Methani, Nieves Quesada Olmo, Maria Jesús Jiménez-Martínez, Marta Revilla León

ABSTRACT:
Statement of problem: Diagnostic stone casts can be digitized by using dental optical scanners based on structured light scanning technology. Nondental structured light scanning scanners could also be used; however, the accuracy of these nondental scanners remains unclear.
Purpose: The purpose of this in vitro study was to measure the scanning accuracy (trueness and precision) of 3 nondental extraoral structured light scanners.
Material and methods: A representative maxillary diagnostic cast was obtained and digitized by using an extraoral dental scanner (Advaa Lab Scan; GC Europe), and a reference or control standard tessellation language file was obtained. Three nondental extraoral scanners were evaluated: groups ND-1 (Space Spider; Artec), ND-2 (Capture Mini; Geomagic), and ND-3 (DAVID SLS3; David). Ten digital scans per group were recorded at a constant room temperature (23 °C) by an experienced geodetic engineer following the manufacturer’s recommendations. The control or reference file was used as a reference to measure the discrepancy between the digitized diagnostic cast and 3 different nondental scans by using an open-source software (CloudCompare v.2.6.1; CloudCompare) and the iterative closest point technique. The Shapiro-Wilk test revealed that the data were normally distributed. The data were analyzed by using 1-way ANOVA, followed by post hoc Bonferroni tests (α=.05).
Results: Significant differences between the 3 experimental nondental scanners and the control or reference scan (P<.001) were found. The ND-2 group had the lowest absolute mean error (trueness) and standard deviation (precision) (39 ±139 μm), followed by the ND-3 group (125 ±113 μm) and the ND1 group (-397 ±25 μm). No statistically significant differences were found in the mean error between the ND-2 and ND-3 groups (P=.228).
Conclusions: Only 1 nondental extraoral scanner tested obtained trueness mean values similar to those of the reference dental scanner. In all groups, the precision mean values were higher than their trueness values, indicating low relative precision.

14. Silicone Additive Manufactured Indices Performed from a Virtual Diagnostic Waxing for Direct Composite Diastema Closure Combined with Resin Infiltration Technique on White Spot Lesions: A Case Report

J Prosthodont. 2019 Oct 28; (8): 855-860 doi:10.1111/jopr.13109.

Autores: Marta Revilla León, Joshua Fountain, Wenceslao Piedra Cascón, Amirali Zandinejad, Mutlu ÖZcan

ABSTRACT: The present article describes the resin infiltration technique to address white spots lesions presented on anterior and premolar teeth of a young patient after orthodontic treatment and the digital workflow for planning a diastema closure on the maxillary anterior teeth using facial photographs, an intraoral scanner, a facially driven diagnostic waxing using a dental computer-aided design (CAD) software, and 3-piece additive manufactured (AM) clear silicone indices. The virtual design of the silicone indices was completed using an open-source CAD software and included a flexible clear buccal piece, flexible clear lingual piece, and rigid clear custom tray. The unique 3-piece index design allows a horizontal path of insertion, controlled uniform thickness of the indices, flexible and rigid material properties combination, accurate translation of the diagnostic waxing into the patient´s mouth, and digital storage of the designs.

15. Influence of printing angulation on the surface roughness of additive manufactured clear silicone indices: An in vitro study

J Prosthet Dent. 2019 Apr 22; S0022-3913(20)30143-8. doi:10.1016/j.prosdent.2020.02.008.

Autores: Marta Revilla León, David Jordan, Mohammed M Methani, Wenceslao Piedra Cascón, Mutlu ÖZcan, Amirali Zandinejad

ABSTRACT:
Statement of problem: Vat-polymerization additive manufacturing (AM) technologies can be used to fabricate clear silicone indices for diagnostic trial restorations, interim restorations, and direct composite resin restorations. Different support parameters, including print orientation of the virtual design of the silicone index, need to be determined when a dental device is fabricated with AM. However, the optimal printing angulation for minimal surface texture remains unclear.
Purpose: The purpose of this in vitro study was to measure the surface roughness of the AM clear silicone indices manufactured by using a vat-polymerization 3D printer with different print orientations.
Material and methods: A virtual design of a facial silicone index was obtained, and the standard tessellation language file was exported and used to manufacture all the specimens using a vat-polymerization 3D printer. All the specimens were placed on the build platform with the same parameters, except for the print orientation which was selected as the only manufacturing variable. Therefore, the 5 different groups were 0, 25, 45, 75, and 90 degrees. To minimize variation in the procedure, all the specimens (N=50) were manufactured at the same time in the selected printer at a constant room temperature of 23°C. The printer had been previously calibrated following the manufacturer’s recommendations. Surface roughness was measured in the intaglio of the left central maxillary incisor using an optical profilometer with a magnification of ×20 and an array size of 640×480. Three measurements per specimen were recorded. The Shapiro-Wilk test revealed that the data were normally distributed, and the data were analyzed by using 1-way ANOVA, followed by the post hoc Sidak test (α=.05).
Results: The 0-degree angulation printing group reported the least mean ±standard deviation surface roughness (0.9 ±0.3 μm), followed by the 90-degree group (3.0 ±0.6 μm), the 75-degree group (12.4 ±1.0 μm), the 25-degree group (13.1 ±0.9 μm), and the 45-degree group (13.5 ±1.0 μm). However, no statistically significant difference was found in the surface roughness between the 25-degree and 45-degree print orientation groups (P=.296).
Conclusions: Print orientation significantly influenced the surface roughness measured on the intaglio of the facial AM silicone indices tested.

16. A vat-polymerized 3-dimensionally printed dual-material occlusal device: A dental technique

J Prosthet Dent. 2020. doi:10.1016/j.prosdent.2020.07.011.

Autores: Wenceslao Piedra Cascón, Mehrad Sadeghpour, Wael Att, Marta Revilla-León.

ABSTRACT:
A technique to additively manufacture an occlusal device by using a completely digital workflow is described. Using a computer-aided design program, information captured with an intraoral scanner was used to additively manufacture a dual-material occlusal device by using a vat-polymerization printer. This technique allows for the combination of 2 different materials, resulting in an occlusal device with a resilient intaglio and a hard resin exterior surface. Advantages of the resulting occlusal device compared with a single-material device include improved patient acceptance and comfort, better fit, and minimal adjustments to ensure fit.

17. Workflow of a fiber-reinforced composite fixed dental prosthesis by using a 4-piece additive manufactured silicone index: A dental technique

J Prosthet Dent. 2020. doi:10.1016/j.prosdent.2020.02.030.

Autores: Marta Revilla-León, Joshua Fountain, Wenceslao Piedra Cascón, Mutlu Özcan, Amirali Zandinejad.

ABSTRACT:
A digital workflow for fabricating a fiber-reinforced composite prosthesis is described. A facial scanner and an intraoral scanner were used to gather records, and dental and open-source software programs were used to elaborate a diagnostic waxing and design a 4-piece additively manufactured clear silicone index. Advantages of the index design included precise translation of the diagnostic waxing, optimal composite resin stratification, and minimal clinical time.

18. 2D and 3D patient´s representation of simulated restorative esthetic outcomes using different computer-aided design software programs. A systematic review

J Esthet Restor Dent. 2020. doi:10.1016/j.prosdent.2020.02.030.

Autores: Wenceslao Piedra Cascón, Joshua Fountain, Waell Att, Marta Revilla-León

ABSTRACT:
Objective: To review the techniques and available 2D and 3D computer-aided design (CAD) software programs to perform a diagnostic waxing for restorative procedureswhen cone beam computed tomography is not indicated.

Overview: An electronic review was performed in Medline, Embase, and Scopus search engines. A manual search was also conducted. The articles evaluating methods to obtain a 2D or 3D patient’s representation for restorative dental procedures wereincluded. A total of 33 articles were included for full text review. CAD programs provide the capability to integrate facial features from 2D photographs or 3D facial scans and facilitate facially driven digital diagnostic waxing procedures. Diagnostic and design tools varied among the programs, and multiple technique descriptions were found. However, the literature evaluating the accuracy of virtual patients and the perception variations between the 2D and 3D dimensional representations is
limited.
Conclusions: The integration of digital technologies into treatment planning procedures introduce variation into the conventional interfaces; however, the concepts remain the same. Further studies are needed to evaluate the accuracy of the virtual representations and the influence of the type of dimensional representation on the esthetic perceptions among dental professionals.

Clinical significance: The 2D and 3D CAD software programs facilitate the integration of facial features into digital diagnostic waxing procedures; however, the esthetic perception of the patient’s virtual representation might vary among the different systems.

19. 3D printing parameters, supporting structures, slicing, and post-processing procedures of vat-polymerization additive manufacturing technologies: A narrative review

Journal of Dentistry. 2021. doi:10.1016/j.prosdent.2020.02.030.

Autores: Wenceslao Piedra Cascón, Vinayak Krisnamurthy, Waell Att, Marta Revilla-León

ABSTRACT:
Objective: To review the elements of the vat-polymerization workflow, including the 3D printing parameters, support structures, slicing, and post-processing procedures, as well as how these elements affect the character- istics of the manufactured dental devices.
Data: Collection of published articles related to vat-polymerization technologies including manufacturing workflow description, and printing parameters definition and evaluation of its influence on the mechanical properties of vat-polymerized dental devices was performed.
Sources: Three search engines were selected namely Medline/PubMed, EBSCO, and Cochrane. A manual search was also conducted.
Study selection: The selection of the optimal printing and supporting parameters, slicing, and post-processing procedures based on dental application is in continuous improvement. As well as their influence on the char- acteristics of the additively manufactured (AM) devices such as surface roughness, printing accuracy, and me- chanical properties of the dental device.
Results: The accuracy and properties of the AM dental devices are influenced by the technology, printer, and material selected. The printing parameters, printing structures, slicing methods, and the post-processing tech- niques significantly influence on the surface roughness, printing accuracy, and mechanical properties of the manufactured dental device; yet, the optimization of each one may vary depending on the clinical application of the additively manufactured device.
Conclusions: The printing parameters, supporting structures, slicing, and post-processing procedures have been identified, but additional studies are needed to establish the optimal manufacturing protocol and enhance the properties of the AM polymer dental devices.
CLINICAL SIGNIFICANCE: The understanding of the factors involved in the additive manufacturing workflow leads to a printing success and better outcome of the additively manufactured dental device.

20. Trueness and precision of complete-arch photogrammetry implant scanning assessed with a coordinate-measuring machine

J Prosthet Dent. 2021. 10.1016/j.prosdent.2021.05.019.

Autores: Marta Revilla León, Jeffrey Rubenstein, Mohammed M. Methani, Wenceslao Piedra Cascón, Mutlu Ózcan, Waell Att

ABSTRACT:
Statement of problem. Photogrammetry technology has been used for the digitalization of multiple dental implants, but its trueness and precision remain uncertain.
Purpose. The purpose of this in vitro investigation was to compare the accuracy (trueness and precision) of multisite implant recordings between the conventional method and a photogrammetry dental system.
Material and methods. A definitive cast of an edentulous maxilla with 6 implant abutment replicas was tested. Two different recording methods were compared, the conventional technique and a photogrammetry digital scan (n=10). For the conventional group, the impression copings were splinted to an additively manufactured cobalt-chromium metal with autopolymerizing acrylic resin, followed by recording the maxillary edentulous arch with an elastomeric impression using an additively manufactured open custom tray. For the photogrammetry group, a scan body was placed on each implant abutment replica, followed by the photogrammetry digital scan. A coordinate-measuring machine was selected to assess the linear, angular, and 3-dimensional discrepancies between the implant abutment replica positions of the reference cast and the specimens by using a computer-aided design program. The Shapiro-Wilk test showed that the data were not normally distributed. The Mann-Whitney U test was used to analyze the data (a=.05).
Results. The conventional group obtained an overall accuracy (trueness ±precision) value of 18.40 ±6.81 mm, whereas the photogrammetry group showed an overall scanning accuracy value of 20.15 ±25.41 mm. Significant differences on the discrepancies on the x axis (U=1380.00, P=.027), z axis (U=601.00, P<.001), XZ angle (U=869.00, P<.001), and YZ angle (U=788.00, P<.001) were observed when the measurements of the 2 groups were compared. Furthermore, significant 3-dimensional discrepancy for implant 1 (U=0.00, P<.001), implant 2 (U=0.00, P<.001), implant 3 (U=6.00, P<.001), and implant 6 (U=9.00, P<.001) were computed between the groups.
Conclusions. The conventional method obtained statistically significant higher overall accuracy values compared with the photogrammetry system tested, with a trueness difference of 3 mm and a precision difference of 18 mm between the systems. The conventional method transferred the implant abutment positions with a uniform 3-dimensional discrepancy, but the photogrammetry system obtained an uneven overall discrepancy among the implant abutment positions.

21. Esthetic Integration Area Concept to improve the emergence profile of fixed restorations: A dental technique

J Prosthet Dent. 2022. 10.1016/j.prosdent.2022.06.023.

Autores: Juan Ruiz de Gopegui, Wenceslao Piedra Cascón, Carlos Oteo Morilla

ABSTRACT:
A technique for obtaining the esthetic integration and optimal emergence profile of tooth-supported and implant-supported restorations is described. Using a computer-aided design software program, data captured with an intraoral scanner were used to establish the anatomic landmarks for determining the maximum buccal volume to which a restoration can be extended. This technique could be applicable to different types of fixed-dental prostheses treatments. Advantages of this technique include the establishment of periodontal-prosthetic criteria and the improvement of clinical and laboratory communication since the same guidelines for evaluating restorative space in the buccolingual direction of tooth preparations are used to avoid overcontoured restorations.

22. Accuracy assessment (trueness and precision) of a confocal based intraoral scanner under twelve different ambient lighting conditions.

J Dent. 2023. 10.1016/j.dent.2023.104530

Autores: Wenceslao Piedra, Riddi Adhikari, Mutlu Özcan, Vinayak Krishnammurthy, Marta Revilla, Mercedes Gallas

ABSTRACT:
Objectives: The ambient lighting condition has been identified as an important factor that influences the accuracy of intraoral scanners (IOSs). The purpose of this study was to evaluate the influence of 12 different ambient lighting conditions on the accuracy of a confocal based IOS
(PrimeScan).
Materials and methods: A typodont was digitized using a laboratory scanner (L2i) to obtain a reference standard tessellation language (STLr) file. A restorative dentist recorded the scans using an IOS (PrimeScan) under 12 different ambient lighting conditions where the luminosity was measured using a light meter (LX1330B Light Meter). Twelve groups were created, namely 0-, 500-, 1000-, 2000-, 3000-, 4000-, 5000-, 6000-, 7000-, 8000-, 9000-, and 10 000 lux groups. Ten STL files were recorded per group. The STLr file was used as a reference with which to compare the distortion of the 120 STL files obtained using a software program (Meshlab). The normality Shapiro–Wilk test indicated that the distributions were not normal. Therefore, the nonparametric Kruskal–Wallis and pairwise multicomparison tests were used to analyze the data (α = 0.05).
Results: The group with the 1000 lux lighting condition obtained the smallest median ±interquartile range (IQR) with scanning distortion values of 69.5 ± 97.4 µm, followed by the 8000 lux group with a median ±IQR of 166.5 ± 318.1 µm. The 0 lx group presented the highest distortion values with a mean ±IQR of 355.5 ± 488.0 µm (p < 0.05).
Conclusions: Ambient lighting conditions influenced the accuracy of the IOS tested. The highest accuracy values were obtained with 1000 lux. The lowest scanning accuracy was obtained with 0 lux