Case report: Digital tools in planning and implementing aesthetic ceramic restorations – the SKYN concept

Clinical case report by Dr. Kirill Kostin

Until recently, indirect dental restorations in the aesthetic area required a high degree of cooperation between dentists and dental labs. The planning process spanned several stages and entailed, therefore, several appointments for the patient. Yet, the final result was often significantly different from the original plan. Fortunately, new digital tools have since changed the nature of aesthetic treatments and enabled improved levels of care.

The development of digital tools has greatly simplified planning and creating restorations in the aesthetic area for contemporary dentists. Moreover, these tools enable us to communicate efficiently with our patients, increasing the predictability of treatment outcomes for everyone involved. Still another advantage is that the new techniques allow for shorter treatment times compared to conventional methods.

This article presents a clinical case where the SKYN concept was used alongside various digital tools to plan and create full-ceramic CAD/CAM restorations.

The article features a female patient presented with the main complaint of incisal edge wear of the upper central incisors. The patient also expressed a desire to have her diastema closed as it made her feel her smile was not harmonious.

Fig. 1. The patient’s upper teeth before treatment.

Fig. 2. The initial smile view.

The patient was offered to undergo an orthodontic preparation prior to her restorative treatment, but declined. Moreover, the patient requested to have as minimal intervention as possible done without involving other teeth.

Treatment Plan

To improve the appearance of the smile according to the patient's wishes, the decision was made to restore the upper central incisors with full-ceramic CAD/CAM restorations. Given that colour correction was necessary, we selected IPS Empress CAD Multi A1 (Ivoclar Vivadent) as the material. To discuss and determine the shape of the future teeth, we further suggested preliminary aesthetic diagnostics with the Planmeca Romexis Smile Design software.

Treatment Protocol

At the preliminary stage, we performed an intraoral scan to obtain a virtual diagnostic model for further evaluation. Then we converted the digital models into physical ones by way of 3D printing.

Fig. 3. A 3D-printed model showing the initial situation, as obtained at the orthodontic diagnostic stage.

As the patient could not undergo a long-term orthodontic preparation, we needed to model the outcome based on the patient’s wishes and restrictions. Working with portrait photographs of the patient, we used the Planmeca Romexis Smile Design software to visualise the shape and proportions of the future teeth.

Fig. 4. Digital design: shaping the central incisors in Planmeca Romexis Smile Design.

Fig. 5. A portrait photograph with a digital mock-up of the future smile. A photograph like this allows the patient to better visualise the potential outcomes of an aesthetic treatment and makes the final result more predictable for everyone involved – from dentist to patient to dental technician.

A design like this takes no more than two to three minutes and allows creating a virtual mock-up chairside. Seeing the result of the proposed smile modification significantly improves dentist-patient communication and increases the efficiency of consultations.

After the patient approved the computer-aided smile design, she participated in selecting the shape of her future centrals from the Anteriores catalogue by Jan Hajtó. Attention was paid to both the desired shape and actual size of the planned restorations. This was achieved by measuring the width of tooth 11 and then selecting a matching sample from the Anteriores models.

Fig. 6. Measuring the width of tooth 11 on the diagnostic model.

Fig. 7. Measuring the width of tooth 11 on the М1 model from the Anteriores set by Jan Hajtó.

Fig. 8. The М1 model used as a sample for the digital rendering of the shape and size of the central incisors, as part of the SKYN concept.

This was the outcome of the first appointment, when the patient visited the clinic for diagnostics and planning. By the following visit, we prepared individual anatomical composite skyns based on the 3D-printed diagnostic model. Composite skyns can also be prepared and adjusted intraorally without any models. First, we obtained a silicone impression of the buccal surfaces of the Anteriores set model.

Fig. 9. Taking a silicone impression of the central incisor buccal surfaces on the Jan Hajtó anatomical model.

Then, using a light-cured composite, we created individual anatomical skyns, reproducing exactly the shape and micro-texture of natural teeth.

Fig. 10. Introducing the light-cured composite into the silicone index.

Fig. 11. The silicone index was lubricated with modelling resin (Bisco) prior to injecting the composite in order to achieve a smoother surface on the anatomical composite skyn.

Fig. 12. When creating skyns, the composite was spread in the silicone index into a thin, homogenous layer.

Fig. 13. The individual anatomical skyns and the original model from the Anteriores set.

The skyns were then fitted and finished, with margins corrected, on the diagnostic model. The marginal correction was performed with rotary instruments.

Fig. 14. Try-in of the composite skyns and marginal adaptation on the diagnostic model. A similar try-in procedure can also be performed in the patient's mouth.

Fig. 15. The individualised composite skyns are ready for fitting and cementation in the mouth.

All of the work can be performed during the very first visit directly on the patient's teeth. In our case, however, we created the skyns between appointments, so that during the second visit all that was left to do was to fit and adjust the individual anatomical composite skyns in the mouth.

Fig. 16. The initial situation intraorally prior to the adaptation of the composite skyns on the patient's teeth.

Fig. 17. For best positioning and adaptation of the skyns, a preliminary occlusal adjustment was made on teeth 11 and 21.

Fig. 18. On the buccal, All-Bond 3 (Bisco) was applied without prior enamel etching.

Fig. 19. The individual composite skyns adapted on the teeth with small amounts of a flowable light-cured composite.

Fig. 20. Composite cementation allows you to visually demonstrate to the patient the potential final outcome.

Fig. 21. One of the advantages of the SKYN concept is the immediate visualisation of the final outcome without the need for impressions or laboratory manufacturing of a diagnostic wax-up.

As we fitted the individual composite skyns in the patient's mouth, we noticed a small black triangle forming between the central incisors when the shapes were copied into future restorations. To avoid this effect, it was necessary to prepare the medial surfaces slightly taking the preparation slightly into the sulcus. Moreover, the contours of the restorations were modified for a more rectangular shape. 

As the patient wished to preserve the shapes we tried in, it was important for us to prevent potential disappointment with the final aesthetic result. Visualising the final outcome helps to achieve mutual understanding with the patient still at the planning stage, and helps the dentist choose the required preparation design. Furthermore, at this stage the patient was also able to inform us that the macro-texture and the “uneven” incisal edge of the original composite skyn were not desirable.

Thus, after discussing all the details with the patient, we were able to transfer all the details agreed upon into the final restoration. This was achieved by way of preliminary intraoral scanning and obtaining a virtual model with “digitised” anatomical composite skyns.

Fig. 22. The composite skyns on the surfaces of teeth 11 and 21 scanned for further digital copying at the restoration modelling stage.

Next, teeth 11 and 21 were prepared for ceramic veneering. As is known, adhesion to enamel is highly superior to adhesion to dentin. Consequently, at this stage it is crucial to preserve the healthy tissues within the enamel.

Fig. 23. Preparing teeth 21 and 11 through the composite skyn to control the thickness of the future restoration.

Fig. 24. The patient’s teeth after preparation before taking a digital impression.

Upon preparation, Ultrapak 00 cord (Ultradent) was inserted into the sulcus and an intraoral scan was performed with the Planmeca PlanScan intraoral scanner.

Fig. 25. The digital model obtained by intraoral scanning.

As an adjunct, we obtained a partial silicone impression of the upper teeth from 13 to 23 in order to produce a control composite model. This is not an obligatory step in creating digital restorations, but can be useful when micro-contouring and dyeing ready veneers or crowns.

Fig. 26. Partial silicone impression: the upper segment from 13 to 23.

Fig. 27. The control model made of composite, as obtained from the silicone impression. A similar model can also be obtained digitally by milling or 3D printing.

After the digital impression was obtained, the restorations were designed with the Planmeca PlanCAD Easy software which is part of the Planmeca FIT open CAD/CAM system. Using the capabilities of the system, we essentially copied the shapes of the anatomical composite skyns. During the design process, we also used the teeth silhouettes which were created at the initial diagnostic stage with the Planmeca Romexis Smile Design software. All in all, creating the virtual restorations took about 30 minutes for two units.

Fig. 28. Digital design of the restorations by way of digitally transferring the shape and macro-texture of the anatomical composite skyns. In the digital environment, the contours of the scanned anatomical composite skyns were superimposed on the restorations being created.

Fig. 29. When designing the restorations, we exported the silhouettes of teeth 11 and 21 from the Planmeca Romexis Smile Design software to control the shape and proportions of the restorations.

Fig. 30. Superimposing the exported silhouettes on the restorations allows correcting the proportions of the restorations according to what was agreed upon with the patient at the planning stage. This is how digital planning with the Planmeca Romexis Smile Design software enables efficient communication with the patient as well as the predictable transformation of the planned outcome into the final restoration.

The next stage was manufacturing the restorations with the Planmeca PlanMill 40 milling unit. The material of choice in this case was IPS Empress CAD Multi, shade А1. This material has a high translucency which allows transmitting the colour of the stump.

Fig. 31. Checking the restoration before milling. Because IPS Empress CAD Multi blocks have a fluorescence transition, the operator can change the position of the restoration in the block and thus control the degree of translucency/opacity in the final restoration.

Fig. 32. The compact Planmeca PlanMill 40 milling unit.

Fig. 33. The ceramic restorations immediately after milling. Milling one unit takes about 15 to 20 minutes.

The milled veneers are separated from the block, with the macro- and micro-texture added later.

Fig. 34 (a), (b), (c), (d). Stages of micro-contouring, which aims to imitate the natural texture of teeth.

Fig. 35. The final look of the restoration after macro- and micro-contouring.

Due to their thinness (between 0.5 and 0.8 mm), ceramic veneers made of IPS Empress CAD Multi blocks transmit the colour of the underlying tissues nicely. To make the restorations look even more natural, the cervical and incisal areas were also dyed. Finally, the ceramic surface was glazed and polished.

Fig. 36. Dyeing and glazing the ceramic surfaces.

Finally, the restorations were adhesively fixed with a light-cured composite cement, Choice 2 (Bisco), shade А1, according to the manufacturer’s instruction.

Fig. 37 (a), (b), (c). Final outcome 3 days after the completion of the treatment.

Fig. 38 (a), (b). Final outcome 2 months after cementing the veneers.

Conclusion

Contemporary digital tools facilitate communication between dentist and patient, enabling the high predictability of aesthetic treatments. The ability to visualise potential outcomes boosts the efficiency of consultations at the initial stages as well as helps to avoid conflicts upon completion of treatment. The SKYN concept, along with the capabilities of modern CAD/CAM systems, allows performing aesthetic treatments in the shortest times possible and creating highly aesthetic restorations immediately and chairside without the need to work with a third-party dental lab.

About the author

Dr. Kirill Kostin graduated from Saint Petersburg State Medical University (Russia) in 2004. He became the co-founder of the PerfectSmile dental clinic and dental study center in 2014. At his clinic in Saint Petersburg, Dr. Kostin runs a private practice concentrating on the aesthetic and functional rehabilitation of natural dentition and implants, applying various digital instruments as part of restorative procedures (digital smile design, intraoral scanning, CAD/CAM milling, 3D printing, and guided surgical procedures). Using a dental microscope on a daily basis, Dr. Kostin focuses on minimally invasive restorative procedures with direct and indirect restorations.

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