Automix (Ivoclar). Only molar crowns were included in the study
with 23 out of 30 being first molars for the CAD-on crowns and 27
out of 30 being first molars for the monolithic e.max CAD crowns.
Eleven teeth were vital, 19 teeth had been endodontically treated
for the CAD-on crowns, 14 teeth were vital and 16 teeth had been
endodontically treated for the monolithic e.max CAD crowns.
The crowns were evaluated using USPHS criteria at annual recall
appointments. One crown of each material required endodontic
treatment by the two-year evaluation. No technical complications
— including cracks, chipping or fracture of the crowns — were
detected after two years of clinical service. The short-term results
are very good for monolithic e.max CAD crowns. Of particular
interest in this study is that the monolithic e.max CAD crowns
were prepared with an occlusal thickness of 1 mm instead of the
recommended 1.5 mm by the manufacturer. It will be interesting
to see how this study does over a longer recall period.
One prospective clinical study placed 41 IPS e.max CAD
crowns. Each crown was fabricated and delivered chairside in a
single appointment using CEREC 3 (Bluecam) (Reich & Schierz,
2013). It is not a particularly large study, with 34 patients receiving
a total of 41 crowns. Seventeen teeth had prior endodontic treat-
ment, and received cores to support the crowns.
Crownmarginswere prepared as a shoulder or a distinct chamfer
of 1.0 mm width. Occlusal reduction involved a minimum ceramic
thickness of 2.0 mm in the cusp area and at least 1.5 mm at the
fissure line. All crowns were cemented with a dual-cure, self-adhe-
sive resin cement Multilink Sprint (Ivoclar). The crowns were eval-
uated annually for four years with 29 of the crowns still available for
examination at four years. Two crowns had newcaries at themargin
that were restored with composite; one at two years and another at
four years. One crown debonded at two years andwas re-cemented.
This crown preparation had less than 3 mm vertical height.
Fig. 5: Three-year recall of e.max CAD crowns #19 and #20
Fig. 6: Three-year recall of e.max CAD crowns #19 and #20 with
occlusal contacts marked
Fig. 7: Five-year recall of e.max CAD crowns #19 and #20
Fig. 8: Five-year recall of e.max CAD crowns #19 and #20 with
occlusal contacts marked
