The effect of three polishing systems on surface roughness of flowable, microhybrid, and packable resin composites

The effect of quaternary ammonium polyethylenimine nanoparticles on bacterial adherence, cytotoxicity, and physical and mechanical properties of experimental dental composites

A significant problem related to the functioning of resin-based composites for dental fillings is secondary or recurrent caries, which is the reason for the need for repeated treatment. The cross-linked quaternary ammonium polyethylenimine nanoparticles (QA-PEI-NPs) have been shown to be a promising antibacterial agent against different bacteria, including cariogenic ones. However, little is known about the properties of dental dimethacrylate polymer-based composites enriched with QA-PEI-NPs. This research was carried out on experimental composites based on bis-GMA/UDMA/TEGDMA matrix enriched with 0.5, 1, 1.5, 2 and 3 (wt%) QA-PEI-NPs and reinforced with two glass fillers. The cured composites were tested for their adherence of Streptococcus Mutans bacteria, cell viability (MTT assay) with 48 h and 10-days extracts , degree of conversion (DC), water sorption (WSO), and solubility (WSL), water contact angle (CA), flexural modulus (E), flexural strength (FS), compressive strength (CS), and Vickers microhardness (HV). The investigated materials have shown a complete reduction in bacteria adherence and satisfactory biocompatibility. The QA-PEI-NPs additive has no effect on the DC, VH, and E values. QA-PEI-NPs increased the CA (a favorable change), the WSO and WSL (unfavorable changes) and decreased flexural strength, and compressive strength (unfavorable changes). The changes mentioned were insignificant and acceptable for most composites, excluding the highest antibacterial filler content. Probably the reason for the deterioration of some properties was low compatibility between filler particles and the matrix; therefore, it is worth extending the research by surface modification of QA-PEI-NPs to achieve the optimum performance characteristics.

Comparative Analysis of the Surface Roughness of Class V Composite Restorations Using a Conventional Polishing System and Pre-contoured Cervical Matrices: An In Vitro Study

BACKGROUND

Rough surfaces of restorations have an impact on the accumulation of plaque, unaesthetic contour, and marginal adaptation, thereby affecting their functional, aesthetic, and clinical performance and the long-term stability of the restoration. Several polishing systems are currently in use for composite restorations, but information on their impact on surface roughness is limited. The present study aimed to determine the surface roughness of class V composite restorations polished using pre-contoured cervical matrices and to compare it with a conventional disc polishing system.

MATERIALS AND METHODS

Twenty maxillary anterior teeth were collected and used in the study. Class V cavity preparation was done, and the cavities were restored with two types of composites (microhybrid and nanohybrid) from commercially available brands (Ivoclar and Dentsply) and finished and polished using two polishing systems (super-snap and pre-contoured cervical matrices). The evaluation of surface roughness was done using an atomic force microscope (AFM).

RESULTS

The surface roughness parameters (Ra-arithmetic mean/average line roughness and Sa-average surface roughness) of the class V cavities restored using pre-contoured cervical matrices were significantly lower for both the tested resin composites.

CONCLUSION

The surface roughness of Class V cavities restored using pre-contoured cervical matrix systems was significantly less for both microhybrid and nanohybrid composites.

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.

Evaluation of different composite resin finishing and polishing protocols by confocal laser scan microscopy

Aim: This study aimed to analyze the influence of finishing and polishing (F/P) protocols on resin surface through roughness (Ra) values and laser scan microscopy observations. Methods: Forty-eight (n=48) resin specimens were sorted into four groups (n=12), according to the type of resin used: Filtek Z250 (Z250), Filtek Z350 (Z350), Filtek One Bulk Fill (BF), Filtek P60 (P60). The specimens were sorted into six groups according to the type of F/P system used (n=2/group): Control group, Diamond bur (KG Sorensen), Soflex Pop-On Discs (3M ESPE), Soflex Spiral (3M ESPE), Dura Gloss (American Burs), and Praxis (TDV). Results: The highest roughness values (Ra) were attributed to BF group for all F/P systems, except for the Soft-Lex PopOn discs. The Soft-Lex PopOn, Spiral, and Praxis discs presented a better performance for the surface treatment of the tested composite resins. Regardless of the restorative material, the use of diamond bur or single-step abrasive rubber (Dura Gloss) were associated with the highest Ra values. Conclusion: The effect of F/P systems on Ra is material-dependent and instrument or system-dependent.

Effect of Finishing and Polishing on The Surface Roughness of Bulk Fill Composites

Objective:

The aim of this in vitro study was to compare the effect of three finishing/polishing systems on the surface roughness (Ra) of conventional and Bulk-fill composite resins.

Materials and methods:

The Ra values of three different brands of Bulk-fill composites (Filtek Bulk-fill®, 3M ESPE; SonicFill Bulk-fill®, Kerr; SDR Bulk-fill®, Dentsply) were tested and compared with the Ra of a conventional composite (Filtek XT Z350®, 3M ESPE). A total of 30 discs (10 mm × 2 mm) were fabricated from four test materials and divided into three groups (n = 10/group) depending on the three finishing/polishing systems used (Astropol®, Ivoclar Vivadent; PoGo®, Dentsply; Sof-LexTM®, 3M ESPE). The Ra of each specimen was recorded with an optical profilometer (Contour-GT-X®, USA). ANOVA and Tukey’s tests were used for statistical analysis.

Results:

Statistically significant differences (P < 0.05) were observed between the Ra values of all composite materials tested with three finishing/polishing systems. Among composite materials, only Group-III showed a significant difference (P = 0.003) in Ra obtained using all three finishing/polishing systems. SDR Bulk-fill® and Filtek XT Z350® showed the highest (0.810 ± 0.373 µm) and lowest (0.365 ± 0.119 µm) Ra values, respectively. Individually, the highest Ra was recorded for SDR Bulk-fill® when it was finished/polished with the Astropol® system. SonicFill Bulk-fill® and SDR Bulk-fill® composites exhibited the lowest Ra values when they were finished with the PoGo® system.

Conclusion:

Finishing and polishing techniques greatly affect the surface roughness of different Bulk-fill composites because variations in the surface roughness were observed for all tested composite materials. Filtek XT Z350® exhibited the lowest surface roughness, while SDR Bulk-fill® exhibited the highest surface roughness among the tested composite materials.