RESTORATIVE DENTISTRY
Table 7 Relationship between success rate, incidence of failures, partial loss or chipping and the use
of dental dam or tooth vitality
Total
restorations
Integral
(code 0)
Chipped
(codes 1, 2)
Partial Lost
(codes 3, 4)
Failures
(code > 5)
Yes
118
91
16
2
9
No
186
151
20
2
13
Yes
181
144
22
3
12
No
123
98
14
1
10
Dental dam
Tooth
vitality
Discussion
Glassionomer cements underwent deep changes
in recent years. The materials have evolved, and
the severe limitations that characterized the GICs
in the 80s have been exceeded. In this clinical
trial, the high percentage of success in class I
restorations (close to 100%), together with the easy
and quick procedure identified by the followed
protocol, identified a high viscosity glassionomer
cement as a possible and durable choice for this
kind of restorations both in molars and premolars.
The possibility of achieving durable Class
II restorations with the glassionomer-based
restorative system tested in this trial seems to be
related to the width of the mesial or distal box.
According to some clinical indications, the width
of the box should not exceed the half of the
intercuspal distance. Many chippings and some
failures of the Class II restorations performed
during this trial were located in the marginal
proximal crest, in wider restorations. Furthermore,
there was a tendency in Class II restorations
performed in premolar teeth of a higher failure
rate occurring with higher number of restoration
surfaces.
Class V restorations revealed the lowest survival rate
in time, suggesting that in this kind of restoration
the performances of the tested GIC system were
most challenged. Chemical resistance and selfadhesion define glassionomer cement as reliable
material for Class V restorations (25), right where
many traditional composite restorations with
adhesive systems have high percentages of failure
rate. Further prospective trials may be performed
to compare the failure rate of a high-viscosity GIC
with conventional resin-based composites. The
48-months observations were often accompanied
by a certain wear of the restoration, visible with
magnifying glasses and which became clinically
evident with the loss of translucency. Most of the
restorations which developed roughness over
time were class V restorations. In the present study,
the perception of roughness could probably be
related to higher exposure of cervical areas to
progressive erosion, caused by daily acidic attack,
chewing, tooth brushing, effect of professional
16
mechanical cleaning and, especially in lower
incisors and cuspids, progressive deposition of
tartar. In occlusal areas, the continuing wearing
effect as a consequence of chewing may lead to
regular abrasion and to the formation of smoother
surfaces than in non-occlusal areas as those where
class V restorations are performed. This may
explain why the majority of patients referred
to roughness on restorations done in cervical
areas. Interestingly, the increase in roughness
perception seems to occur mainly between the
first and the second year after placement. It is
still unclear if coating agent should be reapplied
or not, to increase the external wear-resistant
layer, or if its strengthening and protective role
remains unaltered, even if the layer appears
modified or reduced.
Patients declaring daily consumption of chewinggums were excluded from this study, and
consumption of chewing-gums, and their brands
and frequency of assumption were checked at
each follow-up. It was claimed, indeed, that gum
chewing may have an abrasive effect on softened
tooth structure (26). Since no data are available
upon the abrasive effect of gum chewing on
permanent GIC restorations, this parameter was
excluded from the present study.
The use of dental dam is currently the most
effective way to provide isolation of the operative
field. It is always recommended for composite
restorations placement, since it allows an optimal
control of oral fluids and avoids contamination
of the cavity and the material during placement
procedures. In the present trial, each trained
operator was instructed to try and position the
dental dam prior to restorative procedures and
according to the protocol. If, for any reason, it
was not possible to isolate the field using a
dental dam, the restoration was placed without
this type of isolation. GICs are indeed known to
tolerate humidity when used in wet areas (1,13)
and therefore do not necessarily require the use of
dental dam. In fact, it is not always possible to work
under ideal conditions: not all patients tolerate the
use of dental dam, like children or psychologically
vulnerable individuals where is often impractical
the application of this device.
STOMA.EDUJ (2015) 2 (1)