Glass-Ceramic Inlays and
Onlays made by IPS Empress:
First Clinical Results S.Studer,
C.Lehner and P.Scharer
(Department of Fixed & Removable Prosthodontics & Dental Materials, University of
Zurich, Switzerland)
Published in the Journal of Dental Research, Vol. 71, 658, 1992
Abstract
Introduction
Material & Methods
Results
Conclusions
Abstract
IPS Empress (Ivoclar), a leucite-reinforced glass-ceramic material was recently
introduced for clinical use.
In this clinical trial, 130 posterior indirect, lab-made inlays and onlays were tested
using IPS Empress material. This included 107 inlays and 23 onlays in 35 randomly selected
patients. The mean observation was 18+-6 months. After etching the restorations with
hydrofluoric acid, they were silanized and luted using dual cure composite cements (Dual
Cements, Vivadent and Porcelite, Kerr). The restorations were first evaluated with mirror,
probe and bite wings and later re-evaluated from clinical photographs, both times using
modified USPHS criteria.
|
Alfa |
Bravo |
Charlie |
Delta |
| Marginal Adaptation: |
no or invisible catches |
visible catches but no exposed dentin |
visible catches with exposed dentin |
fractures or caries |
| Anatomic Form: |
correct |
incorrect |
defective |
n/a |
| Surface Texture: |
smooth |
dull |
rough, pitted |
n/a |
| Colour Match: |
| excellent |
minimal mismatch |
sever mismatch |
n/a |
The summarized results of the 130 inlays
and onlays evaluated were as follows:
|
Alfa |
Bravo |
Charlie |
Delta |
| Marginal Adaptation: |
113 |
14 |
0 |
3 |
| Anatomic Form: |
126 |
2 |
2 |
n/a |
| Surface Texture: |
124 |
6 |
0 |
n/a |
| Colour Match: |
121 |
9 |
0 |
n/a |
127 restorations recorded as having neither Charlie nor Delta criteria were defined as
successful. Survival rate, calculated by the Kaplan-Meier analysis, was 98% after 2 years
in service. Initial clinical results of this esthetic restorative material are excellent.
Introduction
IPS Empress (Ivoclar, SChaan, FL), a leucite-reinforced, press-type glass-ceramic
material was recently introduced for clinical use. This all-ceramic system is used either
for full porcelain crowns, ceramic veneers, inlays or onlays. The aim of this clinical
trial was to evaluate the clinical status of these posterior indirect, lab-made IPS
Empress inlays and onlays using modified USPHS criteria and to calculated the survival
rate according to the Kaplan-Meier analysis.
Material & Methods
- 35 randomly selected patients were treated with 130 indirect, lab-made inlays and onlays
made by IPS Empress. This included 107 inlays (28 1-surface inlays, 37 2-surface inlays,
42 3-surface inlays) and 23 onlays with a mean observation period of 18 +- 6 months.
- Cementation procedure:
- etching the restorations with hydrofluoric acid,
- silanization,
- luting with dual cure composite cements (Dual Cements, Vivadent, FL and Porcelite),
Kerr, USA).
- Evaluation procedures:
- Evaluating the restorations with mirror, probe and bite wings using modified USPHS
criteria
- Re-evaluating the restorations from clinical photographs, again using modified USPHS
criteria
- Criteria for success:
Restorations having neither Charlie nor Delta criteria were defined as successful and
qualified as "survived". The survival rate was calculated according to the
Kaplan-Meier analysis using criteria for success as defined before.
Results
Evaluation of 130 restorations using modified USPHS criteria:
| Total 130 (100%) |
Alfa |
Bravo |
Charlie |
Delta |
| Marginal Adaptation: |
113 (87.0%) |
14(11.0%) |
0 |
3 (2.0%) |
| Anatomic Form: |
126 (97.0%) |
2 (1.5%) |
2 (1.5%) |
n/a |
| Surface Texture: |
124 (95.5%) |
6 (5.0%) |
0 |
n/a |
| Colour Match: |
121 (93.0%) |
9 (7.0%) |
0 |
n/a |
Analysis of the 3 failures (Charlie and
Delta ratings):
| failure |
location |
rating |
months in service |
| 1. |
3-surface inlay/premolar |
fracture & defective anatomic form |
17 |
| 2. |
onlay/molar |
fracture & defective anatomic form |
15 |
| 3. |
2-surface inlay/premolar |
caries lesion & partial fracture |
17 |
Conclusions:
- Survival rate of 98% after 2 years in service is excellent compared with other
ceramic-inlay studies
(Christensen et al, 1991).
- 3 out of 130 restorations failed, having either Charlie or Delta criteria
- Mean observation period of 18+-6 months is too short to give a prognosis about the
future behaviour of ceramic materials because of their fatigue phenomena.
- IPS Empress inlays/onlays show superior esthetics. Cost per unit is higher when compared
to cast gold equivalents.
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