Uniform aesthetic appearance between zirconium oxide restorations and feldspathic porcelain veneers

 The introduction of high strength ceramics like alumina and zirconia
allowed, for the first time in dentistry, the use of ceramic materials
for bridge design in the posterior region. Zirconia is a material
regarded as having the highest strength and fracture toughness in
dentistry. Many in vitro studies show the excellent mechanical
properties of zirconia compared to other ceramic materials. Clinical
studies confirm the results of the in vitro tests. Long term results
are on-going. Five year clinical results for 3M™
ESPE™
Lava™
Crowns and Bridges, one of the first commercially available zirconia
systems, are now available. Prof. P. Pospiech together with Dr. F.
P. Nothdurft and Dr. P. R. Rountree from the University of Munich
recently published their data at the Conference of the Pan European
Federation of the IADR in Dublin, Ireland.
Thirty-one bridges were placed beginning in October, 2000. All
abutment teeth were prepared for full crowns with a maximum
1.2 mm chamfer. Impressions were made with a polyether material
(Impregum™
F Polyether from 3M ESPE). All restorations were
cemented conventionally with the glass-ionomer cement Ketac™
Cem from 3M ESPE. Recalls took place after one year, three
years, and in March, 2006 after a five year observation period.
At each recall the fit of the restoration, occurrences of secondary
caries, fracture, discoloration of the marginal gingiva, and allergic
reactions were recorded.
After five years, 15 bridges could be evaluated clinically. The
survival of six bridges could be confirmed by questioning patients
by phone. One bridge was lost for endodontic reasons after one
year in service. One patient wearing two bridges died after the
three year recall. Seven patients could not be recalled (the last
recall examinations were conducted at the three year mark for
these patients).
3-year recall 5-year recall
Bridges in situ 100% 100%
Restorations examined 30 21
Fracture of framework None None
Chippings of the
overlay porcelain
1 5
After five years, no failures were recorded. Slight chipping of
veneering porcelain was seen in some cases but did not warrant
repair or replacement. No allergenic reactions or negative
influences on the marginal gingiva were observed.
The clinicians observed a high level of performance for Lava
zirconia-based posterior bridges after five years of clinical service