Jarvie Journal - College of Dental Medicine - Columbia University

The Journal of the William Jarvie Society
Evaluation of Fracture Resistance of E-Max Lithium Disilicate Customized
Implant Abutments
Techkouhie Hamalian 1 , Thomas Hill 2 , Anthony Randi 1*
1 Postgraduate Prosthodontics, College of Dental Medicine, Columbia University, New York, NY
2 Manager of Scientific Services, Research and Development, Ivoclar Vivadent, * Faculty Mentor
Introduction: A recent study conducted by Sailer et al showed that the estimated 5-year survival rate
of ceramic abutments on implants was 99.1%. Mechanically, zirconia (ZR) exhibits excellent fracture
and chemical resistance as a result of transformation toughening. However, the mechanical shortcomings
of ZR include their sensitivity to specific critical applied stress and controversial cementation protocols.
The introduction of a lithium disilicate (LD) glass ceramic with 400 MPa of biaxial flexural strength
(IPS e.max, Ivoclar Vivadent,) provides dentists with the option to use either conventional cementation
or an adhesive bonding protocol. Therefore, this material has the potential to be used for definitive
implant restorations. To date, there have been no published studies exploring the use of LD as an option
to fabricate implant abutments.
Objectives: The aim of this in-vitro pilot study is to evaluate the feasibility and the fracture resistance
of customized LD E-max pressed abutments with E-max anterior monolithic crowns. Abutments
incorporating metal inserts have shown to play a beneficial influence on the stability of ZR abutments.
This study will evaluate 4 different implant connections (Branemark External hex, Nobel Replace Select,
Biomet 3i, Straumann bone level).
Materials and Methods: A total of 20 Abutments were tested. Machined engaging gold cylinders will
be used to press the test LD groups. The null hypothesis is that pressed LD abutments will show
clinically acceptable fracture resistance when compared to prefabricated ZR control abutments.
Discussion: Failure modes of the ZR abutments were predominantly bending at the implant-abutment
connection and screw loosening. The test LD abutments presented fractures at the cervical third level of
the gold cylinders, where higher concentration of tensile forces was found. Results didn’t show any
debonding of the abutment-crown assembly. The intact abutment-crown interface could be explained by
the chemical composition of lithium disilicate and its ability to create a strong bond. Most samples
presented circumferentially around the metal insert of the gold cylinders, pressed lithium disilicate
ceramics. This explains LD has the capability to flow and bond efficiently to metal.
Results & Conclusions: E-Max abutments were technically possible to fabricate. LD pressed to the
gold cylinders formed a strong adhesion. All test samples demonstrated adequate clinical values of
strength for anterior use (>300N). Plus, there were no statistical difference between the ZR and
respective E-max groups (p>0.05) except for the 3i group (p