Table of Contents

Continuing Education
Cover Story

Inside Dental Technology

February 2013, Volume 4, Issue 2
Published by AEGIS Communications

Using Lithium-Disilicate Hybrid Abutments for
Implant Restorations

Pressable IPS e.max® implant abutments and crowns can be used for esthetic implant solutions

By Jorge Blanco, DDS, AAACD | Nelson Rego, CDT, AAACD

Whether cement- or screw-retained, dental implant restorations must withstand various challenges associated with placement. Screw-retained implant restorations require management of screw-access channels to ensure proper anatomy, function, and esthetics. Cement-retained restorations may leave residual cement adjacent to implant margins that could lead to peri-implantitis.

Today, however, pressable lithium disilicate offers a solution in combination with a titanium abutment, enabling laboratory ceramists and dentists to provide implant restorations that demonstrate predictable function and life-like optical characteristics. A hybrid abutment fabricated from Ivoclar Vivadent’s lithium disilicate, IPS e.max® Press, enables ideal adjustment of shape, emergence profile, and esthetic properties according to the clinical situation. Individual characterization produces a natural appearance near the root and transition area to the crown, which is especially important for anterior implant treatments.

The geometry of the hybrid abutment easily integrates the restoration because the crown preparation margin falls at the gingival level, making removal of excess cement hassle-free. The pressed abutment is luted to the titanium abutment extraorally using a universal restorative primer and self-curing luting composite with a light-curing option (eg, Monobond® Plus or Multilink® Implant, both from Ivoclar Vivadent), then screwed into place in the mouth for a time-efficient and flexible procedure. The abutment can be restored with a permanent lithium-disilicate crown.

Pressable lithium disilicate has demonstrated a strength of 400 MPa and is indicated for various treatments, including thin veneers (ie, 0.3 mm), monolithic crowns, anterior and premolar bridges, and hybrid abutment restorations. However, the success of dental implant treatments requires comprehensive diagnosis, patient selection, and treatment planning.

In the case shown here, a 38-year-old woman presented after losing tooth No. 13. The treatment plan involved placing a Straumann® Bone Level Narrow CrossFit™ (NC) implant (www.straumann.com) to be restored with a pressed hybrid abutment and pressed lithium-disilicate crown restoration. The implant was placed, a punch technique was performed, and a healing cap was provided by the oral surgeon. As is standard for maxillary implants, 6 months were allowed for healing.

Dental Office Procedures

At the 6-month follow-up, the general dentist took a final shade for the lithium disilicate pressed hybrid abutment and crown restoration before the teeth became dehydrated (Figure 1). An impression coping was placed (Figure 2), after which a coping impression was taken using an open-tray technique (which has been shown to be more accurate than closed-tray impression techniques). The coping impression and final selected shade were forwarded to the ceramist.

Laboratory Protocol

A suitable titanium abutment was selected and the waxing channel was created using Primotec’s light-cured material (www.primotecusa.com). The titanium abutment with waxing channel was placed on the model prior to creating the abutment wax-up (Figure 3). A wax-up of the pressed hybrid abutment was created, invested, and pressed with the selected ingot. The fit of the abutment was verified on the titanium abutment prior to separating the sprue, the inner aspect and screw channel were checked for bubbles in the ceramic, and the pressed abutment was placed on the model (Figure 4). The pressed abutment was then characterized with IPS e.max stains to provide an esthetic substrate for the pressed crown restoration (Figure 5).

To complete the hybrid abutment complex, the titanium abutment was sandblasted and treated with a universal primer (Monobond Plus) for 1 minute. The inside of the pressed abutment also was etched and then treated with Monobond Plus. An opaque shade of self-curing/light-curing option resin implant cement (Multilink Implant) was applied to the titanium abutment, and the lithium-disilicate abutment was seated onto the base, cleaned, and light-cured. A full-contour wax-up of the crown restoration was then created on the stained abutment (Figure 6). This wax-up was contoured and designed to functional and esthetic criteria, then verified in relation to the opposing arch.

The wax-up for the crown restoration was then invested and pressed with the selected ingot. After pressing, the lithium-disilicate crown was fit to the abutment on the model, then removed and cut back for layering (Figure 7). The facial incisal edge was then layered with veneering ceramic (IPS e.max Ceram), characterized, and glazed (Figure 8).

Seating Appointment

Upon delivery of both the IPS e.max Press hybrid abutment complex and pressed crown restoration to the dentist’s office, the IPS e.max Press hybrid abutment was tightened into place (Figure 9). The abutment was then torqued to 30 nm, revealing equigingival margins. The screw-access channel (Figure 10) was subsequently sealed using composite material (eg, Tetric EvoCeram, Ivoclar Vivadent) and light-cured for 20 seconds.

The internal crown aspect and the pressed abutment were cleaned, etched, and treated with a universal primer (Monobond Plus) for 1 minute. An opaque shade of self-curing/light-curing-option resin implant cement was applied to the pressed abutment, after which the lithium-disilicate crown restoration was seated onto the abutment and light-cured. The articulation and occlusion were verified, and the patient was re-appointed for a follow-up visit.

Conclusion

Implant treatments require dentists and laboratory ceramists to provide functional and natural-looking restorations that help maintain a patient’s oral health, cause minimal changes to the gingival tissues, and produce overall satisfactory results (Figure 11 and Figure 12). With alternatives such as IPS e.max Press Abutment Solutions, laboratory ceramists and dentists can restore implants in efficient, predictable, and esthetic ways, without compromising strength, durability, or function.

For more information, contact:
Ivoclar Vivadent
P 800-533-6825
W www.ivoclarvivadent.com

Disclaimer: The preceding material was provided by the manufacturer. The statements and opinions contained therein are solely those of the manufacturer and not of the editors, publisher, or the Editorial Board of Inside Dental Technology.

About the Authors

Jorge Blanco, DDS, AAACD, is the founder of Images Dentistry in South Miami, Florida; serves as an examiner in the American Academy of Cosmetic Dentistry accreditation process; and is a clinical instructor at the Rosenthal Aesthetic Advantage Program of the New York University.

Nelson Rego, CDT, AAACD, is the co-owner of Smile Designs by Rego in Santa Fe Springs, California.