How to use IPS e.max for simpler restorations [VIDEO]

The design of this case was complex. By using digital design it was possible to design the implant abutments at the same time as the final restorations.

The IPS e.max System

Ivoclar Vivadent’s IPS e.max System is an all-ceramic system that covers all indications ranging from thin veneers to 12-unit bridges. The IPS e.max concept comprises lithium disilicate glass-ceramic (LS2)-suitable mainly for single-tooth restorations-and a high-strength zirconium oxide for long-span bridges. One single layering ceramic for the entire system enables a uniform layering diagram and precise shade match.

The combination of IPS e.max CAD (LS2) and IPS e.max ZirCAD (ZrO2) used in the innovative IPS e.max CAD-on technique now enables the fabrication of 4-unit posterior bridges that feature outstanding overall strength and high esthetics.

Case presentation

Editor's note: All figures in video below.

A fully retracted pre-op photo was provided by the clinician to assist  the ceramist in creating a diagnostic wax-up with proper midline position and avoiding a maxillary cant (Fig. 1). The pre-operative photo also shows the edentulous areas requiring implant treatment.

01 A diagnostic wax-up was completed idealizing form and function and formed from Zenotec wax to be pressed out of the IPS e.max system (Fig. 2). A silicone matrix of this wax-up was used to fabricate provisional restorations. Note the tissue discrepancy in the edentulous areas, the need to replace the space occupied by gingiva was part of the material selection and planning process.

02 The provisional restorations were photographed and impressed to provide models to the lab that showed the shape and position of the temporary restorations in the mouth. The model was digitally scanned with 3Shape 3D CAD Design software at the same time as the prepared tooth model and the mandibular models were scanned (Fig. 3). All 3 models can be used interactively. The provisional restorations are represented in blue superimposed on a preliminary design of the definitive restorations. The cross hairs can be oriented with a full-face photograph to aid with facial orientation. The design was then refined to more closely follow the shape and position of the provisional restorations.

03 A full-contour design was completed with 3Shape software (Fig. 4). The Zenostar full-contour zirconia bridges are shown in white and the IPS e.max lithium disilicate restorations are blue. The zirconia comes in 6 shades of translucent and one more opaque white shade that we use for abutments to prevent show through of the screw or titanium chimney within the abutment. Both the translucent and opaque zirconia are shaded with Wieland coloring liquids to create color gradient within the zirconia. Coloring is done after milling but before sintering.

04 Hybrid titanium zirconia implant abutments were designed within the full contour design, allowing proper shape and position of the abutments relative to  final tooth position (Fig. 5). The ovate pontic preparation for the cantilevered pontic is visible in the No. 11 position.

05 The virtual articulator is used to check excursive and protrusive movements (Fig. 6). The mandibular model is turned off to allow the viewer to see the collision areas in the design. These were adjusted to allow anterior guidance without posterior working or balancing interferences.

06 The master model with the zirconia abutments in place (Fig. 7). Titanium sleeves support the zirconia and provide metal seats for the screws, greatly increasing the overall strength and reliability of the abutments without sacrificing the trans-illumination potential of the zirconia.

07 Digital design for the anterior lithium disilicate crowns was outsourced to Wieland Precision Technology for milling (Fig. 8). The zirconia bridges were milled in-house on a Wieland Zenotec mini mill. All restorations were fit to the master model. Contacts, occlusion and surface morphology were verified on the IPS e.max restorations prior to crystallizing.

08 Zirliner was applied to the bridges in areas where IPS e.max Ceram layering was planned (Fig. 9).

09 The full contour IPS e.max Ceram buildup of the bridges was completed (Fig. 10). The degree of transillumination possible with zirconia abutments and translucent zirconia bridges is visible. The bridges were only cut back 0.6 mm on the facial for esthetic layering. All occlusal, lingual and gingival surfaces were left in zirconia. With the higher translucency exhibited by Wieland’s new zirconia, very minimal layering is needed for esthetics.  A much stronger final restoration than more conventional substructure design is achieved. The strength gained by minimal layering vastly increases the use of zirconia as a restorative material.

10 Prior to crystallizing, the IPS e.max HT restorations were cut back 0.2 mm-0.4 mm for incisal effect layering (Fig. 11). The initial IPS e.max Press Ceram effect powders are in place on the crystallized restorations. The color control in the HT zirconia provides nice esthetics while reducing the need for layering ceramic. Monolithic posteriors are possible with acceptable esthetic results and minimal layering produces exceptional results.

11 The completed restoration shows excellent shade transition from IPS e.max to Zenostar from laterals to cuspid, even with minimal cutback of zirconia (Fig. 12). Note the ideal incisal edge position following contours of lower lip (Fig. 13).

Conclusion

The combination of good restorative treatment planning, good clinical execution, gathering appropriate models, bites and photos and having a systematic, sequential approach to the final outcome of the case is what‘s really important. All of the technology and great material in the world won’t result in a successful result for the patient if the restorative process isn’t completely visualized and planned prior to starting the case. The plan should then be followed, step-by-step, to provide the final result the patient desires.

Abutment design and zirconia bridge fabrication providedby Brad Lyman and Tracy Egbert.

Matt Roberts, AAACD, began fabricating esthetic reconstructive restorations more than 30 years ago and established CMR Dental Lab in 1978, where he still pursues his passion for excellence in esthetics and function. A member of the American Academy of Esthetic Dentistry and the American Academy of Cosmetic Dentistry, he is one of only 35 accredited dental technicians. Roberts founded the Team Aesthetic Education program to provide hands-on training for dentists and technicians. A member of the L.D. Pankey Institute faculty, he helps teach the Aesthetic Solutions Program for dentists and technicians. A member of the editorial team for many dental journals, he also speaks nationally and internationally. He may be reached at www.teamaesthetic.com

This article originally appeared in the March 2013 issue of Dental Lab Products. To read more techniques like this one, click here to subscribe: http://bit.ly/18S8j4i