Article_6_4_6-Danko

AESTETHIC DENTISTRY
DIGITAL WORKFLOW FOR VIRTUALLY DESIGNING AND PRESSING




                                                                                                                                                                                   Case Rreports
ULTRA-THIN LITHIUM-DISILICATE VENEERS FOR ESTHETIC
REHABILITATION OF FRACTURED MAXILLARY INCISORS
– A CASE REPORT
Mariann Dankó1a* , Attila Böröczky2b              , Zoltán Imre Kovács3c , Judit Borbély1d , Péter Hermann1e

1
 Department of Prosthodontics, Faculty of Dentistry, Semmelweis University, Budapest, Hungary
2
 Independent Óvár Dental Technology Kkt., Hungary
3
 Department of General Dental Preclinical Practice, Faculty of Dentistry, Semmelweis University, Budapest, Hungary

a
  DMD, Resident
b
  DT
c
 DMD
d
  DMD, PhD
e
  DMD, MSc, PhD, Vice-Rector


ABSTRACT                       DOI: https://doi.org/10.25241/stomaeduj.2019.6(4).art.6
                                                                                                                           OPEN ACCESS This is an Open Access
                                                                                                                           article under the CC BY-NC 4.0 license.
Aim: The aim of this case report is to explain the clinical and laboratory procedures
for fabricating ultra-thin lithium-disilicate pressed veneers using a mixed analog/                                        Peer-Reviewed Article

digital workflow.                                                                                                    Citation: Dankó M, Böröczky A, Kovács ZI, Borbély J,
Summary: Four ultra-thin pressed lithium-disilicate veneers were produced for                                        Hermann P. Digital workflow for virtually designing
                                                                                                                     and pressing ultra-thin lithium-disilicate veneers for
maxillary fractured incisors with the help of virtual smile design, digital wax-up                                   esthetic rehabilitation of fractured maxillary incisors - a
                                                                                                                     case report. Stoma Edu J. 2019;6(4):261-270
and intraoral mock-up. With initial photos from the patient, the smile design could
be performed considering the patient’s individual face form. An intraoral scan                                       Received: November 05, 2019
                                                                                                                     Revised December 05, 2019
was taken for the digital wax-up, which was guided by the contour line of smile                                      Accepted: December 12, 2019
                                                                                                                     Published: December 17, 2019
design on the face photo. A printed model and deep-drawing template were
manufactured for the mock-up. After a guided minimally invasive preparation and                                      *Corresponding author:
                                                                                                                     Dr. Mariann Dankó, DMD
digital impression, the final veneers were designed as an exact copy of the mock-                                    Department of Prosthodontics, Faculty of Dentistry,
                                                                                                                     Semmelweis University
up. Wax pattern was designed on computer and fabricated by milling machine.                                          Szentkirályi street 47, 1088 Budapest, Hungary
Finally, lithium-disilicate veneers were pressed, individualized and cemented                                        Tel/Fax: +36703643723
                                                                                                                     e-mail: dankomariann56@gmail.com
using an adhesive technique.
                                                                                                                     Copyright: © 2019
Key learning points: 1. digital workflow is convenient for a predictable procedure                                   the Editorial Council for the Stomatology Edu Journal.
making ultra-thin lithium-disilicate pressed veneers. 2. the virtual smile design –
digital wax-up – intraoral mock-up scheme presents an opportunity for effective
communication with the patient and laboratory. 3. smile design software
recommends an ideal smile curve for the patient with the help of definitive
points and reference lines on the face. 4. guided preparation through mock-up
preserves the greatest amount of enamel structure, which is important with
regards to adhesive cementation. 5. when pressing lithium-disilicate veneers,
a mixed analog/digital workflow using CAD and a milled wax pattern results in
better physical properties and marginal fit than fully digitally milled veneers.
Keywords: Smile Design; Digital Impression; Lithium-Disilicate; Veneers;
Pressed Veneers; Adhesive Cementation.


1. Introduction                                                               but also the predictability and visualization of the
Working with ceramic restorations in the anterior                             treatment plan. The development of digital dentistry
region is still a great challenge. The number and                             has presented an opportunity to individually
variety of ceramic materials are increasing, offering                         design a smile with the help of special software
thinner wall thicknesses with better physical and                             using points on face photos [1–4]. This can be
optical properties and a wide range of options                                shown to the patient first virtually, then intraorally
when a patient needs an esthetic rehabilitation                               as well, with digital wax-up and intraoral mock-
of the maxillary anterior teeth and smile. On the                             up. The procedure also helps communication with
other hand, the patients’ expectations are growing                            the patient and the laboratory. A possible way of
regarding not only the esthetics of the restoration                           achieving the desired smile is to prepare minimally



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                DIGITAL WORKFLOW FOR VIRTUALLY DESIGNING AND PRESSING ULTRA-THIN LITHIUM-DISILICATE VENEERS
                FOR ESTHETIC REHABILITATION OF FRACTURED MAXILLARY INCISORS – A CASE REPORT

Case Rreports


                 Figure 1. Maxillary left first incisor fractured on the surface of the enamel, the mesial incisal edge of the maxillary left second incisor restored with
                composite resin.




                 Figure 2. Initial smile photo.                                                    Figure 3. Initial maximal intercuspation position.

                                                                                                  restorations is also better than milled. Overall,
                                                                                                  digital clinical and laboratory workflow is important
                                                                                                  because of the possibility it provides to design and
                                                                                                  show a new smile to the patient, and to achieve this
                                                                                                  form in the final restoration. When an impression of
                                                                                                  the prepared abutments is taken with an intraoral
                                                                                                  scanner, full digital workflow can be used with the
                                                                                                  advantage of time-efficiency, reduced discomfort for
                 Figure 4. Bleached teeth after 6 weeks.
                                                                                                  the patient, simplified clinical procedures, and better
                invasive veneers [4,5]. The indications for these                                 communication with the laboratory and the patient,
                restorations include: discolored teeth after root canal                           given the trueness and precision levels comparable
                treatment, tetracyclin, hypoplasia, hypercalcification                            to conventional impressions [13].
                or fluorosis; covering small composite restorations;                              This fully digital method to mill from a lithium-
                closing small diastemas; completing fractured teeth                               disilicate block would be faster. Yet, despite the
                or enamel chipping; altering the shape of teeth;                                  minimally invasive case in this study, the conventional
                and correcting minor orthodontic problems such as                                 pressing technique combined with digital workflow
                rotation [6].                                                                     was preferred, because of the mentioned superior
                A suitable material for this application is lithium-                              physical properties, more accurate marginal fit
                disilicate, which can be processed either by                                      and mainly the reducible wall thickness of pressed
                conventional pressing or using digital milling                                    lithium-disilicate restorations. This case report aims
                techniques. Both are indicated for manufacturing                                  to explain the clinical and laboratory procedures
                ultra-thin veneers; however, pressed lithium-                                     for fabricating ultra-thin lithium-disilicate pressed
                disilicate wall thicknesses can be reduced by an                                  veneers using a mixed analog/digital workflow.
                extra 0.1 mm. The minimum wall thickness for the
                pressed variant is 0.3 mm in the gingival third and                               2. Case report
                0.4 mm in the mid and incisal parts, while for the                                2.1. Treatment plan
                milled variant it is 0.4 and 0.5 mm, respectively [7].                            A 25-year-old female patient presented with a need
                The Scientific Documentation by Ivoclar Vivadent                                  for esthetic rehabilitation of her fractured incisors
                [8,9] and other recent studies [10,11] showed that                                after a bicycle accident and improvement to the
                the fracture toughness of the pressed material is                                 appearance of her smile. The mesial incisal edge of the
                higher than that of the milled solution. According                                maxillary left lateral incisor had been missing since
                to Azar et al [12] the marginal fit of the pressed                                the accident and was completed with composite




 262                                                                      Stoma Edu J. 2019;6(4): 261-270                                       www.stomaeduj.com
       DIGITAL WORKFLOW FOR VIRTUALLY DESIGNING AND PRESSING ULTRA-THIN LITHIUM-DISILICATE VENEERS
                      FOR ESTHETIC REHABILITATION OF FRACTURED MAXILLARY INCISORS – A CASE REPORT




                                                                                                                                     Case Rreports
                                                                         Figure 6. Aligned pictures in smile design program.

                                                                         shape, which could be optionally altered. As only
                                                                         the incisors were planned to be altered without
                                                                         surgical treatment, the gingival line was replaced
                                                                         to the original position and the smile curve shape
                                                                         was repositioned to the canine-premolar line, the
                                                                         result being that the incisors, mainly the second are
                                                                         shorter than they should be (Fig. 7).
                                                                         The 2D outline of the teeth was designed and the
                                                                         parameters (texture, color, brightness) of the smile
                                                                         simulation were set. The smile simulation was
                                                                         transferred to the patient’s mobile phone through an
                                                                         application (my3Shape app, 3Shape, Copenhagen,
                                                                         Denmark), in which she could see the before and
Figure 5. Imported photo and reference points in smile design program.   after smile situation in one picture (Fig. 8). Finally,
                                                                         the retracted photo with the outline of the designed
material as a temporary solution for 2 months. The                       teeth was exported from the software, and was used
right and left central incisors were only fractured on                   as a guide for a digital wax-up.
the surface of the enamel, but some discoloration
had appeared on the left central incisor (Figs. 1-3).                    2.3. Digital wax-up
The treatment plan was to bleach the teeth on both                       For a digital wax-up, an intraoral scan was taken from
arches, then to prepare her four maxillary incisors                      the initial status of the maxillary and mandibular
with a minimally invasive method for ultra-thin                          arches and maximum intercuspation (Trios 3 POD,
lithium-disilicate pressed veneers, which she agreed                     3Shape, Copenhagen, Denmark). The intraoral scans
to after being informed about the benefits and risks                     were sent to the laboratory software (Dental System,
of the treatment. The bleaching was performed by                         3Shape, Copenhagen, Denmark), in which the scans
40% hydrogen peroxide (Opalescence Boost 40%,                            and the picture with the smile design were aligned
Ultradent Products, South Jordan, UT, USA) and                           on six pairs of points. Then the desired shape of the
blue-light whitening accelerator lamp (Beyond                            teeth was designed on the initial scan guided by the
Command Whitening Accelerator, Beyond European                           outline of the smile design, and a 3D printed model
Headquarters, Zielona Gora, Poland), which resulted                      was produced with this design (Figs. 9-10).
in B1 color (Fig. 4).
                                                                         2.4. Mock-up, pre-preparation scan and preparation
2.2. Smile design                                                        For the 3D printed model (Bego Varseo S, Bremen,
A virtual smile design and an intraoral mock-up                          Germany), a template was made and a bisacryl
constitute the best way to show the patient the                          resin (Dental Central Crown and Bridge Material,
designed form of her teeth and the appearance of                         Hannover, Germany) mock-up was fabricated
a new smile. It is essential that this method should                     intraorally (Fig. 11). The patient was satisfied with the
give the opportunity to change and correct the                           shape and the new smile, and changes in phonetics
form according to the patient’s expectations before                      were not noticeable. The mock-up was retained
producing the final veneers. First, a full-face smile                    by friction and used for guided minimally invasive
photo and a retracted frontal photo were needed                          preparation [4,5]. Three calibration points were cut
for the smile design. After importing the photos in                      with round diamond burs into the incisal part for 0.4
the smile design program (Smile Design, 3Shape,                          mm and two calibration grooves to the vestibular
Copenhagen, Denmark), the following reference                            surface for 0.3 mm reduction (Fig. 12). Then an overall
points and lines were set: pupils, nasal wings, and                      reduction was performed with a chamfer diamond
curve of the lips. In the next step, the two photos                      bur. The thickness of the mock-up was 0.1 mm on
were aligned moving two pairs of points (Figs. 5-6).                     average, so the preparation resulted in 0.2-0.3 mm
According to the reference points, the software                          minimal enamel loss. The margin line was prepared
recommended an ideal gingival and smile curve                            first paragingivally, then by double corded sulcus



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                DIGITAL WORKFLOW FOR VIRTUALLY DESIGNING AND PRESSING ULTRA-THIN LITHIUM-DISILICATE VENEERS
                FOR ESTHETIC REHABILITATION OF FRACTURED MAXILLARY INCISORS – A CASE REPORT

Case Rreports

                 Figure 7. Ideal smile curve shape.                       Figure 8. Smile simulation.




                 Figure 9. Digital wax-up.                                Figure 10. 3D printed model.


                retraction (Ultrapak #00 and #000, Ultradent, South       color was identified as ND2 (IPS Natural Die Material
                Jordan, UT, USA) 0.5 mm subgingivally (Fig. 13). The      Shade Guide, Ivoclar Vivadent, Wien, Austria)
                enamel of the contact surfaces was reduced with           (Fig. 16). For the 0.3 mm ultra-thin lithium-disilicate
                the preparation of the buccal surface, however the        veneers, a medium-translucency B1 color ingot was
                remaining contact point was not separated directly.       selected (IPS e.max Press MT B1, Ivoclar Vivadent,
                A new workflow was started in the software and a          Wien, Austria).
                digital impression was made from the maxilla with
                a mock-up as a pre-preparation scan. For this scan,       2.7. Laboratory procedure
                a second mock-up was fabricated for the prepared          The prescription was accepted in the laboratory
                teeth (Fig. 14), because it imitated the desired          design software. After margin line and insertion
                thickness and marginal fit for the final veneers and      direction determination, the design was made
                resulted in a finer shape and surface so later the copy   by the morph to pre-preparation function of the
                of the pre-preparation scan could perform a more          software, which resulted in a 0.006 mm precise
                accurate design for the final veneers. The second         copy of the mock-up. This way, the exact same
                mock-up was also used as temporary veneers and            shape that the patient accepted intraorally could
                retained by flow composite resin without etching          be transferred to the final design on the prepared
                and bonding.                                              teeth (Fig. 17). As we chose to produce the final
                                                                          restoration from pressed lithium-disilicate, the wax
                2.5. Digital impression                                   pattern for the pressing technique was performed
                A digital impression was taken from the prepared          by milling out the final design of the restoration
                teeth by sulcus retraction then from the mandibular       from a wax block (APWhite Lemon Wax Blank,
                arch and maximum intercuspation. The prescription         Aesthetic-Press, Düsseldorf, Germany with Zenotec
                was sent to the laboratory.                               Mini, Wieland Dental, Pforzheim, Germany). The
                                                                          wax pattern was sprued, invested (IPS PressVEST
                2.6. Shade measurement and material selection             Premium, Ivoclar Vivadent, Wien, Austria) and
                Before preparation, the right central incisor was         fired out (Denkal 4B, Calory Hi-tech Technical Ltd.,
                selected as a reference tooth for shade selection.        Budapest, Hungary), then pressed from the lithium
                A reference photo was taken with a B1 tab chosen          disilicate block (Programat EP 3000, Ivoclar Vivadent,
                as best match (VITA Classical shade guide, VITA           Wien, Austria). After checking the fit of the veneers
                Zahnfabrik, Bad Säckingen, Germany). The actual           intraorally (Fig.18), staining and glazing was made
                tooth shade was a bit darker than B1; the lightness       in the laboratory with the patient’s attendance (IPS
                level could be described with the A1 tab but with         Ivocolor Essence and Shade, Glaze Powder FLUO
                the yellow hue of a B tab (Fig. 15). After preparation,   and Mixing Liquid Longlife, Ivoclar Vivadent, Wien,
                a die shade measurement was also performed; the           Austria). During staining, the veneers were tried in



 264                                                     Stoma Edu J. 2019;6(4): 261-270                  www.stomaeduj.com
        DIGITAL WORKFLOW FOR VIRTUALLY DESIGNING AND PRESSING ULTRA-THIN LITHIUM-DISILICATE VENEERS
                       FOR ESTHETIC REHABILITATION OF FRACTURED MAXILLARY INCISORS – A CASE REPORT




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 Figure 11. Template and bisacryl resin.                            Figure 12. Calibration points and grooves.




 Figure 13. Prepared teeth with minimally-invasive method, sulcus   Figure 14. Intraoral mock-up after preparation.
retraction.




 Figure 15. Shade measurement before preparation.                   Figure 16. Die shade measurement.

                                                                    silanated in one step with a primer (Monobond Etch
                                                                    & Prime, Ivoclar Vivadent, Wien, Austria).
                                                                    A sulcus retraction cord and rubber dam isolation
                                                                    were applied, and the teeth were prepared with
                                                                    the two-step total etch technique (Ultra-Etch,
                                                                    Ultradent Products, Cologne, Germany and 3M
                                                                    Adper Single Bond Plus Adhesive, 3M ESPE,
                                                                    St. Paul, MN, USA). A light-curing resin cement in the
                                                                    same neutral color as the try-in paste was applied
                                                                    for the veneers and placed in the right position
                                                                    (Variolink Esthetic LC Neutral, Ivoclar Vivadent, Wien,
                                                                    Austria). The veneers were spot-polymerized for 2
                                                                    seconds for easy excess cement removal, then fully
 Figure 17. Virtual design of the final restoration.
                                                                    polymerized for 60 seconds on each surface [5]. The
                                                                    veneers were cemented one by one (Figs. 20-21).
                                                                    After cementation, the occlusal contact points were
with try-in paste in neutral color (Variolink Esthetic              checked in maximal intercuspation position, by
Try-In Paste Neutral, Ivoclar Vivadent, Wien, Austria)              protrusion (Figs. 22-24).
(Fig. 19).
                                                                    3. Discussion
2.8. Cementation                                                    Similar case reports for smile design and ultra-thin
The cementation protocol was used according to                      veneers were published in the last few years [1,4,5].
Ivoclar Vivadent’s Cementation Navigation System                    Digital smile design was performed by designing
[14]. The surfaces of the veneers were etched and                   the shape of the teeth and the gingival line in



Stomatology Edu Journal                                                                                                        265
                DIGITAL WORKFLOW FOR VIRTUALLY DESIGNING AND PRESSING ULTRA-THIN LITHIUM-DISILICATE VENEERS
                FOR ESTHETIC REHABILITATION OF FRACTURED MAXILLARY INCISORS – A CASE REPORT

Case Rreports


                 Figure 18. Pressed lithium-disilicate veneers before staining and    Figure 19. Final restorations on 3D printed model.
                glazing.




                Figure 20. Cementation in absolute isolation.


                harmony with the form of the face using definite                     fully anatomical form. A dentin cut-back shape was
                points and reference lines to approve the esthetics                  designed, milled from wax, pressed, and the incisal
                of the patient’s smile. The impression was taken                     part was layered, which could lead to a difference
                using the conventional method [1,4,5]. Hu et al [1]                  between the mock-up and the final shape [1].
                used the scanned mock-up form as a “ghost image”                     Stanley et al [2] described a fully digital workflow
                to guide the design of the final shape, albeit not to a              for a full-mouth rehabilitation, in which digital smile



 266                                                                   Stoma Edu J. 2019;6(4): 261-270                         www.stomaeduj.com
        DIGITAL WORKFLOW FOR VIRTUALLY DESIGNING AND PRESSING ULTRA-THIN LITHIUM-DISILICATE VENEERS
                       FOR ESTHETIC REHABILITATION OF FRACTURED MAXILLARY INCISORS – A CASE REPORT




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Figure 21. Cemented final restorations.


 a                                                                    b



 Figure 22. Maximal intercuspation position (a) and protrusion (b).




 Figure 23. Incisal margin from palatal view.                         Figure 24. Anterior-guidance.

design and digital impression was performed, and                      these veneers are extremely challenging and usually
the digital model of the wax-up was 3D printed.                       end-up in bulky, unsupported margins with a risk of
The mock-up was performed with vacuum formed                          chipping [15].
matrix and bysacril; then, after a guided preparation,                Transferring the exact shape of the mock-up to
the definitive veneers were designed computer-                        the final restoration is essential. One benefit of the
aided and milled from e.max CAD [2]. However,                         mock-up is that the patient can visualize the new
in this case report it is not mentioned how the                       smile and can accept the shape, but if the copy of
shape of the mock-up was transformed for the                          the shape is not exact to a hundred percent, it could
final restoration. The wax-up – mock-up technique                     result in conflicts with the patient after inserting the
for patient motivation and guided preparation is                      final restoration [5]. Another advantage why a mock-
now a well-known, long used method [5]. The aim                       up should be prepared is the guided nature of the
of a mock-up driven preparation is to save as much                    preparation, which means that a uniform, minimally
hard tissue as possible. The preparation starts from                  invasive preparation and veneer wall-thickness can
the desired form with calibration grooves on the                      be achieved. If the design of the veneers is altered
vestibular surface; then, with a chamfer bur, the                     relative to the mock-up, a discrepancy from the
vestibular surface is prepared uniformly in the depth                 desired wall-thickness and color may occur [4]. The
of the calibration grooves. Using this method, the                    method described in a case report by Kovács [16] is a
tooth structure is only removed from where it is                      possible method to copy the exact same shape of the
needed for the final restoration [5]. Non-prep veneers                mock-up to the final veneers. A pre-preparation scan
are also considered as a possibility for minimally                    is to be taken from the mock- up in the same workflow
invasive treatment; however, according to Magne et                    with the preparation scan from the abutments, after
al [15], the laboratory process and the handling of                   which the “morph to pre-preparation” function in



Stomatology Edu Journal                                                                                                           267
                DIGITAL WORKFLOW FOR VIRTUALLY DESIGNING AND PRESSING ULTRA-THIN LITHIUM-DISILICATE VENEERS
                FOR ESTHETIC REHABILITATION OF FRACTURED MAXILLARY INCISORS – A CASE REPORT

Case Rreports


                Figure 25. Final result.

                the laboratory software results in a precise copy [16].     and PMMA patterns. All inlay patterns were pressed
                The material choice in this case report was based           from e.max Press lithium-disilicate. It was concluded
                on published in vitro studies, in which the fracture        that the accuracy of the marginal fit depends on the
                resistance and marginal fit accuracy of IPS e.max           impression technique but is independent from the
                Press and CAD were examined [8–12,17]. The length           material of the pattern; however, the internal fit of
                of the silicate crystals in e.max Press is 3-6 µm [8] and   the restorations depends on the pattern’s material.
                in e.max CAD they are 0.1-1 µm [10]. The proportion         Overall, the most accurate method was when a wax
                of the crystal phase in Press is 70% [8]; however, in       pattern was milled after digital impression [18].
                CAD in the blue phase it is 40%, which will transform       However, it must be considered that another option
                after sintering into 70% [9]. It is suggested that          to produce patterns with the CAD/CAM technique
                crystallization is more complete in the pressed             is 3D printing. Elfar et al. and Kang et al. compared
                material than in sintered CAD blocks [10]. Because of       pressed restorations from free-hand, milled and 3D
                the differences in the crystal structure, the fracture      printed wax patterns, but concluded with different
                toughness, flexural strength and fracture load              results. According to Elfar et al [19], crowns from 3D
                parameters of e.max Press are greater than those of         printed wax patterns were the most accurate [19];
                CAD [8,9]. Furthermore, according to Schestatsly et         however, Kang et al [20] reported that veneers from
                al [10], the milling procedure initiates a cascade of       milled wax patterns had the best marginal fit [20]. It
                cracks in the material, which results in chipping [10].     has to be mentioned that they produced different
                These statements correlate with Alkadi et al [11], who      types of restorations and different methods to
                describe that the fracture toughness of CAD blocks          evaluate the results.
                is lower because of a smaller crystal length and            Although it is still not conclusive whether the 3D
                phase, and the fractures formed in the glossy matrix        printing or the milling technique is more accurate, it
                where the crystal transformation was not complete.          is described in the two studies that both CAD/CAM
                Regarding the marginal fit of lithium disilicate            techniques are more accurate than free-handed
                crowns, those made with the press technique after           approaches, and the marginal fits of all techniques
                making a wax pattern by hand had a significantly            are in the clinically acceptable range [19,20]. The
                better accuracy of fit than crowns milled from a CAD        cementation of lithium-disilicate pressed veneers
                block [12]. The reason is suggested to be an easier         was performed with an adhesive technique in
                adaptation of the wax pattern to the dies than to the       absolute rubber dam isolation using light curing
                milled ceramic. According to a critical review, most        resin cement. There are two methods mentioned for
                of the studies comparing the pressed and milled             surface treatment of the veneers. The Cementation
                restorations concluded that the marginal fit of e.max       Navigation System by Ivoclar Vivadent describes
                Press is more accurate than e.max CAD [17]. The             a one-component primer called Monobond Etch
                pattern for the pressing technique can be produced          and Prime for preparing the surface [14]; however,
                by several methods depending on the impression              the Scientific Documentation of IPS e.max Press [8]
                technique and material of the pattern. According            offers another option: first, 5% hydrofluoric gel (IPS
                to Homsy et al [18], for conventional impressions,          Ceramic Etching Gel), then a silanizing agent called
                lithium-disilicate crowns pressed from milled wax           Monobond Plus is to be applied to the surface.
                patterns have a more precise marginal fit than those        In an in vitro study, pressed lithium-disilicate crowns
                from free-hand wax patterns. In their in vitro study,       were produced and cemented with resin cement to
                six combinations of techniques were compared                epoxy resin-reinforced glass fiber dies with the two
                with the following parameters: for conventional             different surface treatments mentioned above. The
                impression and gypsum cast making, wax and                  results showed that crowns treated with Monobond
                resin patterns by hand; for conventional impression         Etch & Prime had greater mechanical structural
                but digitalized stone dies, milling wax and PMMA            reliability and higher survival rate than those treated
                patterns; and for digital impressions, milling wax          with Monobond Plus [10].



 268                                                      Stoma Edu J. 2019;6(4): 261-270                   www.stomaeduj.com
       DIGITAL WORKFLOW FOR VIRTUALLY DESIGNING AND PRESSING ULTRA-THIN LITHIUM-DISILICATE VENEERS
                      FOR ESTHETIC REHABILITATION OF FRACTURED MAXILLARY INCISORS – A CASE REPORT




                                                                                                                                              Case Rreports
4. Conclusion                                                         considering conventional laboratory procedures
In cases when restorations are prepared in the                        such as pressing lithium-disilicate produces a better
esthetic region, the communication between                            outcome (Fig. 25).
the patient and the dentist is always the first key
to success. The patient has to understand the                         Author Contributions
opportunities and limitations, while the dentist has                  MD: performed clinical procedure, wrote initial
to get to know the expectations of the patient. An                    manuscript, AB: performed laboratory procedure
ideal situation to communicate is when the form of                    and final result photos, ZK: conception and design
the restorations can be visualized in the mouth by                    of the study, JB: revised the article critically for
performing a mock-up.                                                 important intellectual content, PH: approved the
Digital devices and software offer an effective way                   final version to be submitted.
for precise, time efficient, predictable, comfortable,
and individually designed rehabilitation of the                       Acknowledgments
patient’s smile; however, in spite of the potential                   The authors thank for Dental-Trade Kft., Budapest,
offered by fully digital workflows, in some cases,                    Hungary for producing 3D printed models.



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Stomatology Edu Journal                                                                                                                        269
                DIGITAL WORKFLOW FOR VIRTUALLY DESIGNING AND PRESSING ULTRA-THIN LITHIUM-DISILICATE VENEERS
                FOR ESTHETIC REHABILITATION OF FRACTURED MAXILLARY INCISORS – A CASE REPORT

Case Rreports                                                                                  Mariann DANKÓ
                                                                                 DMD, Clinical Doctor, Resident
                                                                                 Department of Prosthodontics
                                                                                           Faculty of Dentistry
                                                                                       Semmelweis University
                                                                                            Budapest, Hungary


                CV
                Dr. Mariann Dankó, DMD, graduated from Faculty of Dentistry, Semmelweis University, Budapest, Hungary in
                2018. She is currently attending the residency program in Prosthodontics at the Department of Prosthodontics,
                Faculty of Dentistry, Semmelweis University, Budapest, Hungary. She participates in the Digital Dentistry, and
                Implant Prosthetics Working Groups. She works with digital appliances and performs digital workflows also in
                private practice.

                Questions
                1. What is/are the advantage(s) of a fully digital workflow?
                qa. Time-efficiency;
                qb. Simplified clinical procedures;
                qc. Less discomfort for the patient;
                qd. All of them

                2. Which type of pattern was used to press lithium-disilicate veneers in this study?
                qa. Milled wax pattern;
                qb. 3D printed wax pattern;
                qc. Hand-crafted wax pattern;
                qd. Hand-crafted resin pattern.

                3. Why is it considered to get back to a conventional pressing method while performing a
                digital workflow?
                qa. Pressed lithium-disilicate has more accurate marginal fit;
                qb. Milled lithium-disilicate has better physical properties;
                qc. Pressing lithium-disilicate is a faster procedure than milling;
                qd. All of them.

                4. Why is it important to perform an intraoral mock-up for the initial status?
                qa. Facilitates the communication with the patient and laboratory;
                qb. Possible to adjust according to patient’s expectation;
                qc. Offers a guided minimally invasive preparation option for preserving hard tissue;
                qd. All of them.




                                                                                                21    st
                                                                                                World Congress
                                                                                                on Dental
                                                                                                Traumatology
                                                                                                Lisbon, Portugal
                                                                                                17-20th June

                                                                                                2020
                                                                                                 www.wcdt2020.com


 270                                                     Stoma Edu J. 2019;6(4): 261-270                  www.stomaeduj.com