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rev port estomatol med dent cir maxilofac . 2020;61(3):97-105 103

This study was designed following the recommendations form a stronger area at the adhesive interface to both enamel
of the ADA. These indicate that each group should have at least and dentin, as both contain hydroxyapatite. 45-47 Results ob-
30 restorations, with a minimum of 25 patients in the initial tained with the ER technique can be explained by the incom-
phase of the study and 20 patients after six months, as well as plete infiltration of the deeply demineralized collagen network
a gender and age balance between study groups. In this study, by the bonding resin, which occurs because the phosphoric
a universal adhesive’s clinical performance was evaluated at acid can decalcify dentin more deeply than the adhesive can
baseline and after 6 months. One hundred seventeen NCCLs infiltrate. 48,49 Due to this incomplete impregnation of the de-
were restored in 26 patients, with the adhesive applied in SE mineralized substrate, the adhesive interface is not imperme-
and ER modes, combined with a resin composite. Each patient able, and, as a result, water and dentinal fluid can easily move
received at least two cervical restorations to ensure that they through the adhesive interface with consequent nanoinfiltra-
had a restoration from each technique, to control various en- tion. 50-52
vironmental factors (such as oral hygiene, saliva composition, Marginal discoloration was observed with both techniques,
and diet). 33 but no statistically significant differences were found. In the
Due to the expulsive configuration of the NCCLs, the reten- ADH -ER group, one restoration exhibited deep marginal stain-
tion of restorations depends on a strong and stable bond of ing and another presented moderate marginal staining; these
restorative material to dentin. The occurrence of structural were not esthetically unacceptable. Discolorations were ob-
changes in enamel and dentin resulting from age, such as den- served in the gingival margins, where cementum or dentin are
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tin sclerosis, may negatively impact the quality of that bond more likely found than enamel margins. In the SE technique,
and, consequently, the retention and longevity of cervical res- two restorations showed deep marginal staining, one resto-
torations. This is of special concern with NCCLs where den- ration exhibited pronounced marginal staining, and one res-
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tin is often sclerotic and, thus, more mineralized than normal toration presented moderate marginal staining; these were not
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dentin. 35,36 In fact, Mjor attributed the rather poor success esthetically unacceptable. The discoloration was located at the
scored with adhesives in clinical trials (in contrast to labora- enamel margin, which may suggest the importance of includ-
tory results) to the extreme variety of dentin composition and ing enamel’s selective conditioning with phosphoric acid to
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structure found clinically. 37,38 obtain the best marginal seal of restorations. ADH is consid-
Reactive sclerosis occurs in response to slowly progressive ered a mild SE adhesive, as other available universal adhesives,
or mild irritations like mechanical or chemical erosion and because it presents a pH of 2.5. Due to their moderately high
abrasion in response to severe insults, like aggressive operative pH, these adhesives have limited interaction with enamel as
procedures, attrition, and caries. 37,39 Several studies show that they cannot condition enamel as effectively as in the ER tech-
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dentin sclerosis increases with age, 37,39,40 which may explain nique, resulting in increased marginal changes. In fact, some
why greater restoration losses have been found in older pa- studies concluded that additional etching of the enamel cav-
tients: patients aged 21 -40, 41 -60, and 61 -80 years had resto- ity margins resulted in an improved marginal adaptation on
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ration losses of 31%, 62%, and 75%, respectively. However, the enamel side. However, this was not critical and did not
other studies have shown that retention failures cannot be affect the overall clinical success of restorations. 55,56
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associated with substrate type only, confirming that the pro- Marginal discoloration may be a clinical sign of future res-
cess of adhesion involves multifactorial aspects. Indeed, a toration failure, but it does not imply the imminent need for
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clinical study (2000) had an equal number of restoration fail- replacement because these discolorations, if superficial, can
ures in sclerotic and non -sclerotic lesions, indicating that the be removed by polishing and routine finishing. 10,57,58
negative interaction between dentin sclerosis and the clinical In this study, no restoration had secondary caries, maybe
retention of adhesive systems is yet to be confirmed. In this because the participants selected for this study had good oral
study, there was no relationship between age and restoration hygiene habits. 57
loss. In this study, there was a significant difference in postop-
A period of 6 months to 1 year seems to be sufficient to erative sensitivity between the SE and ER techniques at base-
predict an adhesive’s clinical behavior accurately. In fact, in line. Postoperative sensitivity was higher with the ER tech-
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this study, the 6 -month evaluation period was sufficient to nique, possibly because phosphoric acid removes the
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detect significant differences in the performance of the tested peritubular dentin and fully opens the dentin tubules, which
adhesive system, which belongs to a novel family of universal the adhesive may not be able to seal completely afterward. In
adhesives for which there are insufficient clinical studies. contrast, with the SE technique, the dentin surface is smear-
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In this study, after 6 months, nine restorations failed as a -layer sealed, and there is a lesser tubule opening. Neverthe-
result of debonding, which highlights the poor bonding effica- less, there was no difference in postoperative sensitivity be-
cy of ADH when used with the ER strategy. Furthermore, at 6 tween the ER and SE modes, which may be explained by the
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months, the ER technique had poorer results than the SE tech- pulp’s capacity to recover in cases of reversible pulpitis. Re-
nique for marginal adaptation (78.4% vs. 98.3%). The good per- sults from the literature indicate that a decrease or absence of
formance of the SE restorations is likely due to the presence hypersensitivity may occur over time in those with NCCL res-
of an acidic functional monomer, 10 -MDP, because calcium torations. 57,62,63
ions (released upon the partial dissolution of hydroxyapatite) Regarding the effect of clinical co -variables (degree of scle-
diffuse within the hybrid layer and assemble the MDP mole- rosis, patient age, tooth type, and gender), no correlation was
cules into nanolayers. This chemical interaction between found between these co -variables and the results presented in
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hydroxyapatite and MDP creates a stable nanolayer, which can the two groups at the 6 -month evaluation.