THE JOURNAL OF - Dentsply

Blunck et al
Table 2 Results of the clinical assessment in% of the modified USPH criteria
Criteria for XP BOND [%] Adper Scotchbond 1XT [%]
evaluated
restorations n alpha bravo charlie delta n alpha bravo charlie delta
Retention 38 100 0 0 0 38 97.4 0 0 2.6
Postoperative 38 97.4 2.6 0 0 37 94.6 5.4 0 0
sensitivity (∑)
Marginal 38 100 0 0 0 37 94.6 5.4 0 0
discoloration
Marginal 38 100 0 0 0 37 100 0 0 0
integrity
Secondary 38 100 0 0 0 37 100 0 0 0
caries
Restoration 38 100 0 0 0 37 100 0 0 0
contour
Vitality test 38 100 0 0 0 37 100 0 0 0
tion. A variety of factors, such as the nutrition of the patient,
parafunction, chewing habits, oral hygiene etc, modify the
dentin surface such that the morphology and microstructure
are different compared to surfaces that are exposed during
cavity preparation. 12 Thus, tubules of cervical dentin are exposed
to the oral environment for a longer period and are frequently
partially or totally occluded with precipitates. This
forms a hypermineralized dentin layer that has been found
to be more resistant to etching. 4,10 As a result, a thinner hybrid
layer is formed on the surface, which is different from
the situation in noncervical, cut dentin. 12 It has been shown
that the etch-and-rinse technique results in higher bond
strengths than self-etching adhesive systems. 11 However,
etching dentin with phosphoric acid involves a sensitive
step, namely, the careful drying of the exposed collagen network.
5 This network has to be penetrated completely when
the adhesive system is applied. The results of this study suggest
that XP BOND can produce an effective bond, which is
reflected by the lack of discoloration and the retention results,
as judged by two experienced dentists who have considerable
experience with similar, previous clinical studies.
An additional advantage of the use of a model based on
the treatment of NCCLs is that Class V restorations minimize
the influence of the operator variability. They also simplify
the evaluation procedure of margin integrity, owing to the direct
accessibility during the study period. 9,13 We note, however,
that the margins of Class V restorations cover both
enamel and dentin, and this might increase the retention
due to bonding to the acid-etched enamel. Consequently,
failure might develop due to reduced adhesion to dentin,
which is less suited to withstand mechanical stress during
mastication. Our evaluation of marginal staining and probing
as well as the evaluation of hypersensitivity was aimed
at identifying failures of this type; none were found.
This evaluation is one part of a multicenter study. At present,
the results after 6 months of an identical in vivo study
at the University of Bologna, with 30 patients are available.
The criteria retention, marginal discoloration, margin integrity,
secondary caries, and restoration contour (Table 3)
were all highly rated (alpha USPHS rating) for restorations in
the XP BOND group, where only one restoration (3.3%) exhibited
postoperative sensitivity. In the group using Adper
Scotchbond 1 XT, all criteria received a 100% alpha rating,
with postoperative sensitivity occurring in 7 teeth (23.3%)
with a bravo USPHS rating.
CONCLUSION
It should be borne in mind that these results are preliminary.
Further studies, which are to include other cavity designs
and longer observation periods, can only help to establish
the long-term reliability and the effect on the margin integrity
of the oral environment. However, from the present study,
it can be concluded that the results for the one-bottle etchand-rinse
adhesive system XP BOND meet the criteria for a
provisional acceptance according to ADA guidelines, with
less than 5% failure rate after 6 months of clinical performance.
ACKNOWLEDGMENTS
This study was funded by Dentsply DeTrey, Konstanz, Germany.
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