THE JOURNAL OF - Dentsply

Latta
Fig 1 Representative spectra of dentin (left) and dentin impregnated with XP Bond (right). Circle represents peak shift and broadening in
the 1100 to 1170 cm -1 range is suggestive of calcium-phosphate ester complex formation.
Fig 2 Representative spectrum of XP Bond showing major functional
groups. Plot of peak intensity vs wavenumber cm -1 .
Fig 3 Peak intensity for characteristic marker peaks for dentin,
mineral and resin are plotted across the dentin/adhesive interface.
The resin peak at 1720 cm -1 fully penetrates to the bottom
of the demineralized zone. In addition, the maximum strength of
the 1146 cm -1 peak is offset from the resin, indicating an interaction
with components in the dentin layer.
Raman Spectroscopy
A representative spectrum of XP Bond is shown in Fig 1. Representative
Raman spectra of human dentin and resin impregnated
dentin with XP Bond are shown in Fig 2. The most
intense band occurs at 960 cm -1 and is associated with the
P-O stretch of the phosphate in the mineral apatite. Also observed
are bands at 1245 cm -1 (amide III) and 1667 cm -1
(amide I) associated with collagen. The mixture shown on the
right clearly shows the apatite and amide I peaks mixed with
features only associated with the adhesive. The peak shift
and broadening in the 1100 to 1170 cm -1 area is not seen
in the pure dentin or XP Bond spectrum, and is associated
with the formation of calcium/phosphate ester complexes in
the hybrid layer. 6
The relative peak intensities of the mineral apatite (960
cm -1 ), resin carbonyl (1720 cm -1 ), collagen (1670 cm -1 ), and
phosphate complex (centered at 1146 cm -1 ) were plotted
across the dentin interface and are shown graphically in
Fig 3. The strength of the phosphate complex intensity in the
intermediate hybrid layer is strongly suggestive of a chemical
interaction between components in the resin adhesive
and the dentin. In addition, the resin is fully penetrated to
the depth of the zone of demineralization.
CONCLUSION
Significant differences in shear bond strength were observed
among the dentin and enamel values generated with
the adhesives tested. XP Bond generated statistically similar
values to Optibond Solo Plus and Apder ScotchBond 1 XT
to both enamel and dentin. Syntac Classic generated significantly
lower values to both enamel and dentin.
Micro-Raman spectroscopy showed a complete infiltration
of resin into the demineralized dentin zone. In addition,
it strongly suggested a chemical interaction with XP Bond
Vol 9, Supplement 2, 2007 247