Quintessence Journals - Sandra Kalil Bussadori

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Wegehaupt et al
ration material” a logistic regression was carried out. The
significance level was set at p ≤ 0.05.
The allocation of the tooth to the cavity groups, use of
calcium hydroxide lining, and the kind of restorative material
is shown in Table 2.
RESULTS
All patients were re-examined after 6 months; all 123 fillings
were still in situ. No fractures or any other distinctive
features were visible in the clinical examination. All teeth
exhibited a positive reaction in the vitality test. Percentage
distribution of pain incidents or hypersensitivity according
to the cavity groups, calcium hydroxide lining use, and the
kind of restorative material are shown in Table 3.
The logistic regression showed no statistically significant
influence of any of the three different variables “cavity
depth” (p = 0.65), “calcium hydroxide liner” (p = 0.086),
and “restoration material” (p = 0.71) on the occurrence of
pain or hypersensitivity.
DISCUSSION
The present study aimed to investigate the influence of different
thickness of remaining dentin on pain occurrence of
adhesively luted restorations under in vivo conditions.
Since the treated teeth were not extracted afterwards, no
histological examination was possible to determine dentin
thickness. Thus, for determining dentin thickness and to
allow the allocation of the teeth to different categories of
remaining dentin thickness, the RDTMD was used. The
measurement with the RDTMD depends on the electrical
resistance of the dentin. 14
Studies performing histological examination of restored
teeth mostly use teeth planned to be extracted for orthodontic
reasons. 6,21 This procedure has the disadvantage
that these teeth are often free of caries, thus not mirroring
the usual clinical situation. An advantage of using the
RDTMD in the present study was that teeth with clinically
common carious lesions could be included in the study.
However, the use of the RDTMD for allocation of the teeth
to different categories of remaining dentin thickness is a
topic of some discussion. Gente 13 observed a higher electrical
resistance with longer dentin tubules and greater
remaining dentin thickness. 12,14 The same author 13
reported the remaining dentin thickness as being 2.1 to
3.0 mm for the green LEDs, 1.5 to 2.1 mm for the yellow
LEDs, 0.9 to 1.5 mm for the orange LEDs, and less than
0.9 mm for the red LEDs. Thus, our definition of shallow,
medium, and deep corresponds to 1.5 to 3.0 mm, 0.9 to
1.5 mm, and less than 0.9 mm remaining dentin thickness,
respectively. In contrast, Tielemans et al 32 found the
use of RDTMD to be reproducible, but in their study, the
electrical resistance showed no statistically significant correlation
with the histologically determined dentin
thickness. It should be mentioned that in the study by
Tielemans et al, 32 only two patients with a total of 12
teeth were examined. Moreover, the present study using
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the RDTMD was started before the discrepant findings by
Tielemans et al 32 were published. To clarify the contradictory
findings regarding the RDTMD, a comprehensive in
vivo study with an appropriate number of test teeth must
be performed.
In the present study, two different kinds of restorative
materials were used to reflect different treatment requirements.
The definitive fillings were made with the hybrid
composite in an incremental technique. This material has
shown good clinical performance in various previous clinical
studies. 18,27,33,34 The buildup composite in combination
with the self-etching adhesive system was applied in
bulk in the cavities with greater extension. This procedure
presents a fast, economical, and less technique-sensitive
approach, and is often used to build up teeth prior to indirect
restorations.
The overall occurrence of postoperative pain in the present
study amounted to 17%. This corresponds well with
the findings of another recent study, 5 showing postoperative
pain incidence of 5% to 26% after adhesive restorations
with different cavity sizes.
Our finding that there was no statistically significant influence
of use of a calcium hydroxide liner on hypersensitivity
corresponded with the results of Whitworth et al. 35
They also found no difference in the protection of the pulp
by calcium hydroxide lining or conditioning and sealing
with adhesive resins only. This might be explained with the
precipitation of crystalline salts in the dentin tubules after
the use of calcium hydroxide liner 19 or the sealing of the
dentin with light- or self-curing resin after the use of a hydrophilic
adhesive, creating a continuous resin-dentin hybrid
layer. 23 Both may lead to a reduction of the dentin
permeability for potential cytotoxic components of restorative
materials or bacteria, 8 thus protecting the pulp tissue.
Moreover, with respect to the hydrodynamic theory of
Brännström, 3 which states that movement of dentinal liquid
is responsible for hypersensitivity, both precipitation of
calcium salts and formation of the hybrid layer might be
able to counteract hypersensitivity.
In the present study, no statistically significant influence
of the cavity depth on the occurrence of pain was observed.
Murray et al 21 also did not find the remaining
dentin thickness to be statistically correlated to signs of
pulp inflammation as histologically proven. In contrast,
Whitworth et al 35 estimated the residual dentin thickness
to be a key determinant for the pulp reaction. It should be
mentioned that in that study, 35 teeth with pulp exposure
were also included in the group of deep cavities; furthermore,
there was no requirement for the dentists to use
rubber-dam during treatment. The use of rubber-dam
might have an impact on the pulp response after cavity
preparation, as shown by Camps et al 6 , who found remaining
dentin thickness to be of only minor importance in the
reaction of the pulp, as compared to bacteria left in the
cavity prior to filling. It might be assumed that lesser
amounts of bacteria are still present on the cavity walls
when rubber-dam is used during treatment.
The effect of restorative materials on the vitality of the
pulp and the occurrence of postoperative pain is a contentious
issue in the literature. 9,16,24,37 In the present
for
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140 The Journal of Adhesive Dentistry