TAMPA, Fla. - Empress 2 all-ceramic crowns appear acceptable for use on posterior teeth requiring full coverage restorations, according to research presented today at the American Academy for Dental Research annual meeting.
The research was funded entirely or partially by Ivoclar Vivadent, which manufactures Empress 2.
David Felton, DDS, dean of the West Virginia University School of Dentistry, presented the study findings.
The Empress crown material has been around since 1991 and has been documented to be very useful in dentistry, he noted. But because of its strength it was not recommended for use in full coverage restorations on posterior teeth, said Dr. Felton.
Empress 2, however, is supposed to be sufficiently strong or have sufficient fracture toughness -- 2% to 2.4% of the original material, he said.
— David Felton, DDS
Dr. Felton looked at the longevity and pulpal responses of Eris/Empress 2 all-ceramic single crowns bonded with dentine adhesive and composite resin cement on posterior teeth over a period of five years.
Subjects who needed posterior crowns and met the inclusion criteria were recruited and enrolled and signed informed consent documents. The patients were between the ages of 25-65 and in good mental and physical health.
Teeth were prepared for single-unit posterior crowns, temporized, and permanent all-ceramic crowns placed using conventional prosthetic techniques. Teeth were etched, adhesive bonding agent placed, and all crowns cemented with composite resin cement.
Key findings
Dr. Felton clinically and radiographically assessed for crown and margin integrity, pulpal status, occlusion, and presence/absence of pulpal symptoms before the start of treatment, at baseline, and then at the 12-, 36-, and 60-month patient recall visits. Periapical and bitewing films were also taken at these times. In all, 41 teeth were assessed.
Dr. Felton also looked at a similar number of minimally restored contralateral or adjacent teeth in the subjects, which were used as controls and assessed in the same way.
Here are some of the key results:
- At 60 months, 35 crowns remained in service for assessment.
- The survival of all ceramic crowns was 97% at 60 months.
- There were no significant differences in any prosthodontic, periodontal, pulpal, or radiographic measure between baseline and 60 months.
- There was no difference in pulpal response rate of restored and control teeth.
- The overall pulpal complication rate at 60 months was 7.3% (0.0% for controls).
"The material is sufficiently strong to be used for restoring posterior teeth, provided adequate tooth structure is removed for adequate strength of the material," he told DrBicuspid.com.
However, now that eMax (another Ivoclar Vivadent product) is on the market, the Empress 2 -- which is a layered material -- is somewhat out of date, he noted.
All-ceramic crown materials, if properly handled, work in an acceptable fashion, he concluded.
