Efficiency of polymerization of bulk-fill composite resins: a systematic review

Abstract

This systematic review assessed the literature to evaluate the efficiency of polymerization of bulk-fill composite resins at 4 mm restoration depth. PubMed, Cochrane, Scopus and Web of Science databases were searched with no restrictions on year, publication status, or article's language. Selection criteria included studies that evaluated bulk-fill composite resin when inserted in a minimum thickness of 4 mm, followed by curing according to the manufacturers' instructions; presented sound statistical data; and comparison with a control group and/or a reference measurement of quality of polymerization. The evidence level was evaluated by qualitative scoring system and classified as high-, moderate-and low-evidence level. A total of 534 articles were retrieved in the initial search. After the review process, only 10 full-text articles met the inclusion criteria. Most articles included (80%) were classified as high evidence level. Among several techniques, microhardness was the most frequently method performed by the studies included in this systematic review. Irrespective to the "in vitro" method performed, bulk fill RBCs were partially likely to fulfill the important requirement regarding properly curing in 4 mm of cavity depth measured by depth of cure and / or degree of conversion. In general, low viscosities BFCs performed better regarding polymerization efficiency compared to the high viscosities BFCs.

New Resin-Based Bulk-Fill Composites: in vitro Evaluation of Micro-Hardness and Depth of Cure as Infection Risk Indexes

“…Therefore, in recent years, manufacturers have tried to develop new products requiring single-layer stratification, thus reducing the operative steps. Resin-based "bulk-fill" composites (BFCs) have been Materials 2020, 13, 1308 2 of 13 introduced with this purpose, and according to manufacturers, can be used in a single step to fill cavities of a 4 mm depth or greater [3]. However, when choosing composite resins, clinicians should consider the risks of secondary decay and cytotoxicity that are still associated with them [4,5].…”

Comparing depth-dependent curing radiant exposure and time of curing of regular and flow bulk-fill composites

“…A systematic review showed that high-viscosity viscosity bulk-fill resin composites are partially properly cured in 4 mm of cavity depth measured by depth of cure and / or degree of conversion. 12 Several issues may affect the polymerization efficiency of bulk fill composite resins, and the variability on the results of the authors was mainly dependent on the bulk fill composite resin brand evaluated and time of photo activation. Also, some studies used over or under exposure time.…”

Do bulk‐fill resins decrease the restorative time in posterior teeth? A systematic review and meta‐analysis of in vitro studies

“…Moreover, it is clear that several mechanical and physical properties must be considered in resin composite evaluations; the restorative time is just one of them. According to recently published reviews, the findings regarding the depth of cure of the bulk‐fill resin composites, the property that allows them to be applied in a single increment, are inconsistent or even unreliable . The polymerization efficiency seems to be better in the flowable compared to full‐body bulk‐fill resin composites .…”

“…According to recently published reviews, the findings regarding the depth of cure of the bulk‐fill resin composites, the property that allows them to be applied in a single increment, are inconsistent or even unreliable . The polymerization efficiency seems to be better in the flowable compared to full‐body bulk‐fill resin composites . Therefore, further clinical studies should aim to explore all of the bulk‐fill resin composite benefits suggested, mainly with longer follow ups as only one long‐term study is available …”

“…24,27 The polymerization efficiency seems to be better in the flowable compared to full-body bulk-fill resin composites. 27 Therefore, further clinical studies should aim to explore all of the bulk-fill resin composite benefits suggested, 24 mainly with longer follow ups 15 as only one long-term study is available. 28 The reduction in restorative time seems not to be an advantage dling due to high viscosity, 29 which could explain this result.…”