This study address the role of adhesive strategy (ER and SE) on the postop sensitivity.
55% of the clinical trials on this field were considered to be of high or unclear risk of bias.
The adhesive strategy (ER or SE) does not influence the postop sensitivity in posterior resin composite restorations.
A systematic review and meta-analysis were performed on the risk and intensity of postoperative sensitivity (POS) in posterior resin composite restorations bonded with self-etch (SE) and etch-and-rinse (ER) adhesives.
A comprehensive search was performed in the MEDLINE via PubMeb, Scopus, Web of Science, LILACS, BBO and Cochrane Library and SIGLE without restrictions. The abstracts of the annual conference of the IADR (1990–2014), unpublished and ongoing trials registry were also searched. Dissertations and theses were searched using the ProQuest Dissertations and Periodicos Capes Theses databases.
We included randomized clinical trials that compared the clinical effectiveness of SE and ER used for direct resin composite restorations in permanent dentition of adult patients. The risk/intensity of POS was the primary outcome. The risk of bias tool of the Cochrane Collaboration was used. The meta-analysis was performed on the studies considered ‘low’ risk of bias.
After duplicates removal, 2600 articles were identified but only 29 remained in the qualitative synthesis. Five were considered to be ‘high’ risk of bias and eleven were considered to be ‘unclear’ in the key domains, yielding 13 studies for meta-analysis. The overall relative risk of the spontaneous POS was 0.63 (95% CI 0.35 to 1.15), while the stimuli-induced POS was 0.99 (95% CI 0.63 to 1.56). The overall standardized mean difference was 0.08 (95%CI −0.19 to 0.35). No overall effect was revealed in the meta-analyses, meaning that no influence of the ER or SE strategy on POS.
The type of adhesive strategy (ER or SE) for posterior resin composite restorations does not influence the risk and intensity of POS. CRD42014006617.
The demand for esthetic restorations, the increased fear of amalgam toxicity and the environmental problems associated with mercury have increasingly led universities to teach resin composite for restorations of posterior cavities in many countries .
Despite the current good performance of resin composite in posterior teeth , postoperative sensitivity (POS) was already mentioned to be a problem with resin composite restorations. Early clinical studies have also indicated that up to 30% of the study populations have reported POS following placement of a posterior resin composite restoration , which were mostly attributed to the use of total-etch adhesives (nowadays named etch-and-rinse systems).
Etch-and-rinse systems employ a phosphoric acid to etch enamel and dentin prior to the application of the bonding solution. As a consequence, the smear layer is removed and the dentin tubules are opened, increasing the dentin permeability and hydraulic conductance of dentin . During etching, an excessive demineralization may occur reducing the chances for a complete monomer impregnation into the demineralized dentin .
An incomplete monomer penetration due to over-etching or inadequate adhesive application may leave voids in the hybridized area as well as denuded collagen fibrils allowing dentin fluid movement , under occlusal stress, extreme temperatures and sweet stimuli. This, in turn, sensitizes the nerve endings in the dentin tubules and causes POS.
This fact has led to a widespread belief that self-etch systems lowers the risk of POS as they do not remove, but incorporate the smear layer in the hybridized complex with the advantage of being less technique-sensitive . Although there is a biological plausibility behind this belief with some clinical studies reaching this conclusion , the perception that self-etch adhesives cause less POS than etch-and-rinse systems seems to be more anecdotal than an evidence-based finding , as other clinical trials do not support this trend .
Recently a meta-analysis has pointed out that POS is a very infrequent finding, not affected by the type of adhesive strategy (ER or SE) employed . This study has some limitations. Firstly, the authors have not applied a broad and sensitive search strategy and only one database was used. Secondly, the authors have not searched the grey literature, which is important to minimize publication bias. Lastly, the risk of bias of the included studies was not evaluated, possibly leading to a biased conclusion.
Therefore, we aimed to conduct a systematic review to identify the following focused question: Does the use of a self-etch adhesive compared with an etch-and-rinse system influence the risk and intensity of POS in adult patients with posterior restorations?