Despite the clinical appeal of restoring deep class II cavities in single increment using bulk-fill resin composite, sealing of bulk-filled composite restorations is a concern. This study evaluated interfacial adaptation of bulk-fill composite restoration to axial wall and gingival floor of class II cavities using cross-polarization optical coherence tomography (CP-OCT). Box-shaped class II cavities were prepared in extracted molars and divided into three groups (n = 7) according to adhesive used; Clearfil SE Bond 2 (SE2), Tetric-N Bond Self-Etch (TSE) or Tetric-N Bond Universal (TNU). All adhesives were applied in self-etch mode and according to manufacturers' recommendation. Then, preparations were bulk-filled with Filtek Bulk Fill Posterior Restorative resin composite and immersed in a contrast agent. Tomographic images of axial wall and gingival floor of each restoration were obtained by CP-OCT (IVS-300, Santec) with a central wavelength of 1330 nm and were imported to an image analysis software to quantify microleakage. Mann–Whitney U test showed statistically significant difference in microleakage percentage between the groups at both axial wall and gingival floor (p < 0.05). SE2 group had the lowest percentage of microleakage (p < 0.05), as only few cross-sections showed areas of reflections from contrast agent penetrating into axial wall (8.23 ± 6.8) and gingival floor (7.07 ± 4.1), followed by TNU group (18.13 ± 12.9 axially and 30.61 ± 11.9 gingivally). Microleakage was frequently observed at the axial wall and gingival floor of TSE group, showing the highest percentages of 25.50 ± 12.5 and 36.97 ± 10.2, respectively (p < 0.05). All tested groups exhibited different extent of interfacial microleakage, however, two-step self-etch adhesive yielded superior adaptation in comparison to one-step self-etch adhesive and universal adhesive.

Treating dentin surfaces with antibacterial agents prior to bonding bioactive restorations might affect their mechanical properties. In this study, we evaluated the effect of silver diamine fluoride (SDF) and chlorhexidine (CHX) on the shear bond strength (SBS) of bioactive restorative materials. Dentin discs were treated with SDF for 60 s or CHX for 20 s and bonded with four restorative materials, namely Activa Bioactive Restorative (AB), Beautifil II (BF), Fuji II LC (FJ), and Surefil One (SO). Control discs were bonded without treatment (n = 10). SBS was determined using a universal testing machine, and a scanning electron microscope (SEM) was used for the evaluation of the failure mode and the cross-sectional examination of adhesive interfaces. The SBS of each material between different treatments and of the different materials within each treatment were compared via a Kruskal–Wallis test. The SBS of AB and BF was significantly higher than that of FJ and SO in the control and CHX groups (p < 0.01). In the latter, SBS was higher in FJ than SO (p < 0.01). SO had a higher value with SDF compared to CHX (p = 0.01). The SBS of SDF-treated FJ was higher than that of the control (p < 0.01). SEM showed a more homogenous and improved interface of FJ and SO with SDF. Neither CHX nor SDF compromised the dentin bonding of bioactive restorative materials.

To assess the color stability and surface roughness of bioactive resin-based composite following exposure to coffee staining and brushing with whitening toothpastes. Disk-shaped specimens of Filtek Z250 (FZ), Beautifil Flow Plus (BFP), Activa Presto (AP), and Fuji II LC (FII) were stained with coffee and then brushed with one of three toothpastes, conventional (C-TP), non-peroxide whitening (W-TP) or hydrogen peroxide-containing whitening toothpaste (HPW-TP) for 10 000 cycles. Changes in color (ΔE00) and surface roughness were measured. Two-way ANOVA revealed a significant interaction between restorative material and toothpaste type in roughness (p = 0.049) and ΔE00 (p = 0.007). FII consistently had the highest surface roughness change across all toothpastes, and AP showed significantly higher value than BFP and FZ with C-TP and W-TP (p < 0.001). For color change, FII displayed significantly higher ΔE00 between baseline and staining, as well as between staining and post-brushing with every toothpaste (p < 0.001). All materials had clinically unacceptable ΔE00 ranging from 4.82 ± 1.72 to 11.15 ± 1.44 post-brushing compared to baseline with every toothpaste, with the lowest value observed in Fll with W-TP (p < 0.001). For individual color parameters (ΔL, Δa, Δb), AP exhibited significantly greater ΔL changes between baseline and post-brushing compared to FZ, BFP, and FII (p < 0.001). No significant differences were observed for Δa or Δb across materials at any measurement stage (p > 0.05). Additionally, the effect of toothpaste type on individual parameters, as well as the interaction between material and toothpaste type, was nonsignificant (p > 0.05). All materials tested showed increased roughness and unacceptable staining with none returning to baseline color or achieving acceptable color change post toothbrushing, irrespective of toothpaste type. Understanding the effects of staining and whitening toothpastes on bioactive resin-based composites is important for optimizing material selection and maintenance protocols to ensure long-lasting esthetic outcomes in patients prone to staining.

Objective. The aim of this study was to monitor the behavior of interfacial gaps formed under different bonded polymeric restorations before and after thermocycling (TC), using swept‐source optical coherence tomography (SS‐OCT) and confirming the obtained findings with confocal laser scanning microscopy (CLSM). Materials and Methods. Cylindrical class I cavities were prepared in twenty noncarious human premolar teeth (1.5 mm depth × 3.5 mm diameter) and divided randomly into two groups: TS and SN, according to the adhesive system (n = 10). In the TS group, one‐step self‐etch adhesive Clearfil Tri‐S Bond Plus (Kuraray Noritake Dental, Japan) was used, followed by composite restoration using Estelite Sigma Quick (Tokuyama Dental, Japan). In the SN group, the cavities were restored with the two‐step self‐etch/composite silorane‐based resin restoration system (3M ESPE, USA). All specimens were restored in bulk filling technique and cured in accordance with the manufacturers’ instructions. Both groups were imaged under SS‐OCT after 24 h and recorded as controls. Then, each group was subjected to thermal challenge using the TC machine (5–55°C) and B‐scans were recorded at different TC intervals (2600, 5200, and 10000). In order to confirm the SS‐OCT findings, additional specimens were prepared, scanned, and sectioned for CLSM observation. Results. B‐scans demonstrated white clusters at the tooth‐resin interface that corresponded to the gap location on CLSM images. The TS group showed significantly less gap formation than the SN group before and after TC (p < 0.001). Conclusions. An optimal composite adaptation can be achieved when the bonded restoration comprises a combination of an adhesive containing 10‐MDP monomer and a considerable highly filled composite.

The objective of this study was to assess in-vitro interfacial cavity adaptation of different adhesive/composites systems in class-II restoration using SS-OCT and to confirm the findings with a confocal laser scanning microscope (CLSM). Standardized rectangular-shaped class-II cavities were prepared on 24 extracted human molar teeth, bonded with adhesive and lined with flowable composite. Cavities were further restored by bulk filling using packable composite. Specimens were divided into four groups (n = 7) according to restorative materials used; PrimeFil with Estelite Posterior composites (PF; Tokuyama Dental), Clearfil Tri-S Bond Plus with Majesty LV flowable and Majesty Posterior composites (TS; Kuraray Noritake Dental), Adper Easy bond with Filtek Z350 XT flowable and Filtek Z350 XT packable composites (AE; 3 M ESPE) or Palfique Bond adhesive with Estelite Flow Quick flowable and Estelite Posterior composites (BF; Tokuyama Dental). To evaluate the cavity adaptation of these restorative materials, tomographic images of pulpal (P) and gingival (G) walls were obtained by SS-OCT with a central wavelength of 1330 nm, followed by cross-sectioning and CLSM observation to confirm OCT findings. The results showed a significant increase in the backscattered reflection was attributed to the interfacial gaps. AE groups demonstrated the highest interfacial adaptation percentage (p < 0.05), while TS and PF groups showed no significant difference (p > 0.05). BF group presented the least adaptation percentage, and the gaps were frequently observed at the adhesive/composite interface. In addition to the sensitivity of the SS-OCT to the interfacial gaps, the success of flowable lining relies on the interactions between the adhesive/tooth and adhesive/composite substrates.