March 2013, Volume 9, Issue 3
Published by AEGIS Communications
Pressable Lithium-Disilicate Hybrid Implant Abutments and Crowns
Implant restorations that demonstrate predictable function and life-like optical characteristics
Whether cement- or screw-retained, dental implant restorations must withstand various challenges associated with placement. Today, however, pressable lithium disilicate offers a solution in combination with a titanium base (Ti base), enabling laboratory ceramists and dentists to provide implant restorations that demonstrate predictable function and life-like optical characteristics. A hybrid abutment fabricated from pressed lithium disilicate (IPS e.max® Press, Ivoclar Vivadent, ivoclarvivadent.us) 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 Ti base 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 molar 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 female presented after losing tooth No. 13. The treatment plan involved placing a Straumann® implant (Straumann, 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.
Dental Office Procedures
At the 6-month follow-up appointment, the general dentist took a final shade for the lithium disilicate pressed hybrid abutment and crown restoration before the teeth became dehydrated. An impression coping was placed, after which a coping impression was taken using an open-tray technique. The coping impression and final selected shade were forwarded to the ceramist.
A suitable Ti base was selected and the waxing channel was created using a light-cured material (Primotec USA, primotecusa.com). The Ti base with waxing channel was placed on the model prior to creating the abutment wax-up (Figure 1). 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 Ti base 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 2). The pressed abutment was then characterized with IPS e.max stains (Ivoclar Vivadent) to provide an esthetic substrate for the pressed crown restoration (Figure 3).
To complete the hybrid abutment complex, the Ti base was sandblasted and treated with a universal primer (Monobond Plus) for 1 minute. The inside of the pressed abutment also was sandblasted and then etched. An opaque shade of self-curing/light-curing option resin implant cement (Multilink Implant) was applied to the Ti base, 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 4). 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 fitted to the abutment on the model, then removed and cut back for layering (Figure 5). The facial incisal edge was then layered with veneering ceramic (IPS e.max Ceram, Ivoclar Vivadent), characterized, and glazed (Figure 6).
Upon delivery of both the hybrid abutment complex and pressed crown restoration to the dentist’s office, the hybrid abutment was tightened into place (Figure 7). The abutment was then torqued to 30 nm, revealing equigingival margins. The screw-access channel (Figure 8) was subsequently sealed using composite material (eg, Tetric EvoCeram®, Ivoclar Vivadent) and light-cured for 20 seconds.
The inside of the pressed crown was cleaned and etched, and then both the internal crown aspect and the pressed abutment were 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.
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 9). 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.
About the Authors
Jorge Blanco, DDS, AAACD
South Miami, Florida
Rosenthal Aesthetic Advantage Program
New York University
New York, New York
Nelson Rego, CDT, AAACD
Santa Fe Springs, California