THE JOURNAL OF - Dentsply

Ferrari et al
Table 2 Performance criteria according to Ryge
Criteria and number of XP Bond
restorations evaluated after SCA alpha bravo charlie delta
6 months Calibra[n]
Marginal discoloration and 53 53 0 0 0
integrity
Secondary caries 53 53 0 0 0
Vitality test 53 53 0 0 0
Interproximal contacts 53 53 0 0 0
Retention 53 53 0 0 0
Fracture 53 53 0 0 0
sprayed and air dried carefully. 36% phosphoric acid gel was
then applied for 15 s on enamel margins, and then for other
15 s on dentin. The gel was removed with air spray and
the surface blown gently with an air syringe. One drop of XP
Bond was dispensed and mixed with one drop of self-curing
activator. Using a microbrush, all cavity walls were wet and
the adhesive material was left undisturbed for 20 s. After
that, the solvent was evaporated by thoroughly blowing with
air from an air syringe for 5 s. No light curing step was performed.
Calibra Esthetic Resin Cement base and catalyst in
similar amounts were mixed and applied on the cavity surface.
Then the restoration was placed in the cavity preparation,
and resin cement excess was removed with a clean microbrush.
The Calibra cement was used in self-curing mode.
The restorations were placed in March and April 2006 and
examined for postoperative sensitivity at baseline, after 2
weeks and 6 months by the same operator. At each recall,
data on postoperative sensitivity, stability, and longevity
were collected with reference to the USPHS criteria. Therefore,
the following parameters were assessed:
• postoperative sensitivity with the restoration under function,
cold and warm stimuli, and a gentle air stream (on a
scale from 0 to 10).
• marginal discoloration and integrity
• secondary caries
• fracture
• vitality test
• retention
• interproximal contacts
The null hypothesis was that the self-curing mode does
not affect postoperative sensitivity.
RESULTS
The results of postoperative sensitivities are summarized in
Table 1. All 53 teeth were evaluated at baseline, and after 2
weeks and 6 months. At baseline, 3 patients showed pre-operative
sensitivity on 5 teeth. Ten cases of postoperative sensitivity
were observed at the 2-week recall, but only 3 after
6 months. At the 2-week recall, the postoperative sensitivity
increased from 0 to 6 in one case immediately after luting
the restoration (after the anesthetic wore off) but
dropped to score 3 after 6 months. In 7 cases showing an
increase in postoperative sensitivity after 2 weeks, the hypersensitivity
disappeared completely after 6 months. In
two cases, a residual postoperative sensitivity of score 2 remained
after 6 months. No adverse events/effects occurred.
All other parameters showed alpha scores (Table 2).
DISCUSSION
Ceramic crowns can be considered a safe type of restoration,
and are reported to last longer than any other esthetic indirect
restoration, 15 although many factors influence success,
such as the kind of ceramic, luting agent, and extension of
the lesion. Notwithstanding the restoration material, debonding
and thus microleakage at the gingival margins – particularly
if located below the cementoenamel junction – cannot
be completely prevented. 1,8 All these factors are related to
three subjects: patient, dentist, and material. 11
In order to control for any additional source of variation besides
the patient-related variability, one and the same operator
placed all the restorations in this clinical trial. Inclusion
and exclusion criteria were followed in order to obtain the
Ethics Committee’s approval. The occurrence of postopera-
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