Physicochemical characterization of two bulk fill composites at different depths

Translucency of bulk-fill composite materials: A systematic review

OBJECTIVES

To conduct a systematic review on the translucency of bulk-fill (BF) composite materials, evaluating the factors influencing it and its clinical implications.

MATERIALS AND METHODS

A systematic search was performed on four databases (Embase, Medline/PubMed, Scopus, and Web of Science) for articles published until October 2, 2023. Search terms were: "translucency," "translucency parameter," "contrast," "contrast ratio," "bulk," "bulk-fill," "bulk fill," "composite," "resin," "resin based," "resin-based," "restoration," and "dental." In vitro studies, written in English language, investigating BF resin-based composites translucency were included. The risk of bias was performed with the RoBDEMAT tool.

RESULTS

Of 590 screened articles, 13 were included in this review. They investigated 11 high-viscosity BF and 5 low viscosity ones. The limited number of the identified studies and the heterogeneity of the extracted data did not allow to conduct a meta-analysis.

CONCLUSIONS

BF materials exhibit variability in translucency due to variations in experimental designs and the heterogeneous composition.

CLINICAL SIGNIFICANCE

BFs may behave differently in masking the substrate or in blending capacity.

No-Cap Flowable Bulk-Fill Composite: Physico-Mechanical Assessment

(1) Background: A newer class of flowable bulk-fill resin-based composite (BF-RBC) materials requires no capping layer (Palfique Bulk flow, PaBF, Tokuyama Dental, Tokyo, Japan). The objective of this study was to assess the flexural strength, microhardness, surface roughness, and color stability of PaBF compared to two BF-RBCs with different consistencies. (2) Methods: PaBF, SDR Flow composite (SDRf: Charlotte, NC, USA) and One Bulk fill (OneBF: 3M, St. Paul, MN, USA) were evaluated for flexural strength with a universal testing machine, surface microhardness using a pyramidal Vickers indenter, and surface roughness using a high-resolution three-dimensional non-contact optical profiler, a and clinical spectrophotometer to measure the color stability of each BF-RBC material. (3) Results: OneBF presented statistically higher flexural strength and microhardness than PaBF or SDRf. Both PaBF and SDRf presented significantly less surface roughness compared with OneBF. Water storage significantly reduced the flexural strength and increased the surface roughness of all tested materials. Only SDRf showed significant color change after water storage. (4) Conclusions: The physico-mechanical properties of PaBF do not support its use without a capping layer in the stress bearing areas. PaBF showed less flexural strength compared with OneBF. Therefore, its use should be limited to a small restoration with minimal occlusal stresses.

Can composite packaging and selective enamel etching affect the clinical behavior of bulk-fill composite resin in posterior restorations? 24-month results of a randomized clinical trial

OBJECTIVES

This is a double-blind, split-mouth, randomized clinical study that aims to evaluate the influence of bulk-fill composite packaging presented in syringes (BSy) and capsules (BCa), and the effect of selective enamel etching (SEE) on the clinical performance of class I and II bulk-fill resin composite restorations after 24 months.

METHODOLOGY

A total of 295 class I or class II restorations were performed on 70 patients. One universal adhesive was applied in all restorations. SEE was used in 148 restorations and self-etching mode (SET) in 147 restorations. After the adhesive application, cavities were restored with Filtek Bulk-fill Posterior Restorative in syringes (BSy), Filtek One Bulk-fill in capsules (BCa), or Filtek Supreme Ultra in syringes with the incremental technique (In). All restorations were evaluated using the FDI criteria after one week and after six, 12, and 24 months. Kaplan-Meier survival analysis and Pearson's Chi-square test were used (α=0.05) for statistical analysis.

RESULTS

After 24 months, 62 patients were evaluated and four restorations were lost due to fracture (one for SEEBSy, two for SEEIn, and one for SETIn). No significant differences in the fracture and retention rate were found between groups (p>0.05). SEE showed significantly fewer marginal adaptation defects than SET (p<0.05). BCa and BSy groups showed fewer marginal discrepancies compared to In (p<0.05). Restorations performed with BCa showed less color mismatch than BSy or In (p<0.05).

CONCLUSION

Although all restorations exhibited satisfactory clinical performance after 24 months of clinical service, the clinical behavior of class I and II restorations' improved when performed with a bulk-fill composite in capsules, mainly when associated with a universal adhesive applied with SEE.

The Microhardness and Surface Roughness Assessment of Bulk-Fill Resin Composites Treated with and without the Application of an Oxygen-Inhibited Layer and a Polishing System: An In Vitro Study

The aim of this study was to assess the microhardness and surface roughness of bulk-fill resin composites treated with and without the application of an oxygen-inhibited layer (OIL) and a polishing system. This in vitro experimental study consisted of 72 resin composite blocks divided into three groups: Tetric N-Ceram Bulk Fill, Opus Bulk Fill APS, and Filtek Bulk Fill. Each resin composite group was further divided into two subgroups: with and without OIL control. Subsequently, surface roughness and microhardness were measured before and after polishing. A t-test was used to compare independent and related measures. For the intergroup comparison of variation before and after polishing, the Kruskal−Wallis test with Bonferroni post hoc was used considering a significance level of p < 0.05. When comparing surface roughness, significant differences were observed between Opus Bulk Fill resin composite with and without OIL control (p = 0.003) before polishing. The same occurred when comparing Tetric N-Ceram resin composite with and without OIL control (p = 0.039) after polishing. In addition, the surface roughness of Filtek Bulk Fill, Opus Bulk Fill, and Tetric N-Ceram Bulk Fill resin composites, with and without OIL control, decreased significantly after polishing (p < 0.001), while surface microhardness significantly increased (p < 0.05), with the exception of Opus Bulk Fill resin with OIL control (p = 0.413). In conclusion, OIL control and polishing significantly improved the surface roughness and surface microhardness of Filtek Bulk Fill and Tetric N-Ceram Bulk Fill resin composites. However, in the case of Opus Bulk Fill resin composite, only its surface roughness was significantly improved.