1566 Clinical performance of PFM, zirconia, and alumina three-unit posterior prostheses
R.P. CHRISTENSEN, K.A. ERIKSSON, and B.J. PLOEGER, TRAC Research Foundation, Provo, UT, USA

OBJECTIVE:  Compare clinical performance of metal vs. ceramic frameworks and layered vs. pressed veneer ceramic.

METHODS:  293 three-unit posterior prostheses were placed by 116 dentists.  Methods: standardized preparations, resin modified glass ionomer cement, double blinded dentist-patient and commercial laboratory (18 labs, 2 selected by each system's company).  Graded in vivo:  margin fit, esthetics, retention, gingival health, endodontic need, caries.  Graded in vitro (dies; SEM images):  breaks, surface, wear on prosthesis and opposing dentition.  Statistics:  ANOVA and Tukey-Kramer multiple comparisons (p=£0.05).

RESULTS:  Year one 99% recall; year two 98%.  Frameworks- no metal or zirconia broken by 2 years; 6 alumina broken by 1 year (18%); 9 by 2 years (26%).  Alumina significantly worse both years (p=<0.0001).  Veneer Ceramics- pressed had significantly fewer defects at 1 & 2 years (both p=<0.0001). 

Defects (surface degradation, chips, breaks, cracks, delamination, broken framework) in systems tested:

 

 

 

    Cumulative Defects

     System

 Framework

      Ceramic

Fabrication

 n

  Defective

 Prostheses

Not Replaced

Replaced

 1-yr

 2-yrs

CZR Press

 Zirconia

CZR Press

 pressed

33

        2

    4

  NA*

       0

IPS e.max

 Zirconia

e.max ZirPress

 pressed

33

        7

  10

  NA*

       1

Cercon

 Zirconia

CeramcoPFZ

 layered

32

      18

  41

   60

       2

Everest

 Zirconia

InitialZR

 layered

33

      14

  37

   59

       1

Lava

 Zirconia

LavaCeram

 layered

32

      19

  68

   87

       2

Wol-Ceram

 Alumina

Cerabien

 layered

21

      10

  22

   30

       4

Wol-Ceram Exp

 Alumina

Cerabien

 pressed

13

        9

  17

   24

       6

Captek

 Metal (AuPtPd)

Creation

 layered

32

        4

  13

   20

       3

Ceramco3

   (control)

 Metal

  (65%Au, 0%Ag)

SoftWear Enamels

 layered

32

        9

  13

   23

       0

Pulse interface

 Metal

  (65%Au, 0%Ag)

Pulse interface

 pressed

32

        4

    2

     4

       0

                                                                                                                                * Placed 1 year later

CONCLUSION:  At two years, zirconia and metal frameworks performed equally well with no breaks, and alumina had 26% breaks, indicating high risk in posterior multi-unit restorations. Pressed veneer ceramics had significantly fewer defects than layered ceramics.

Seq #157 - Clinical Investigations of Fixed Prosthodontics
9:00 AM-10:30 AM, Friday, July 4, 2008 Metro Toronto Convention Centre Room 717B

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