Purpose: This study evaluates the effects of a novel nanohydroxyapatite gel and Er: YAG laser on the surface roughness, surface morphology, and elemental content after dentin hypersensitivity treatments. Methods: Dentin discs (2 × 3 × 3 mm³) were prepared from 75 human molars. Out of 75 human molars, 50 were used to evaluate surface roughness and randomly divided into five groups: Group ID (intact dentin), Group DD (demineralized dentin), Group BF (fluoride varnish/Bifluorid 10), Group Lsr (Er: YAG laser-50 mJ, 0.50 W, 10 Hz), and Group NHA (nanohydroxyapatite-containing gel). Dentin hypersensitivity was stimulated by 35% phosphoric acid for 1 min (except Group ID). The surface roughness (Ra, μm) was measured via contact profilometry (n = 10). Out of the 75 sound human molars, 25 were used to evaluate the surface morphology and elemental content using scanning electron microscopy and energy-dispersive X-ray spectroscopy (n = 5). The data were statistically analyzed using Welsch ANOVA, Games–Howell, Kruskal–Wallis, and Dunn tests (p < 0.05). Results: Group Lsr showed significantly lower surface roughness than Group NHA and Group BF (p < 0.05). The SEM analysis indicated that most of the dentinal tubules were obliterated for Group NHA. Precipitant plugs with partially occluded dentinal tubules were observed for Group BF, while partially or completely occluded tubules with a melting appearance were detected for Group Lsr. The EDS analysis revealed that Group NHA and Group Lsr presented similar calcium and phosphorus amounts to Group ID. All dentin hypersensitivity treatment methods could provide promising results in terms of tubular occlusion efficiency. However, laser treatment resulted in smoother surfaces, which could help prevent dental plaque accumulation.

This study compares the effect of different mouthwashes that have been recommended during the Coronavirus disease 2019 (COVID‐19) pandemic on shear bond strength (SBS) of universal adhesive to enamel in regards to self‐etch (SE) and etch‐and‐rinse (ER) modes. Flat enamel surfaces were obtained from 100 sound human maxillary central incisors. They were randomly allocated to five groups according to the different mouthwashes (no mouthwash/control [Ctrl], 0.2% chlorhexidine 1.5% hydrogen peroxide [H₂O₂], 0.2% povidone‐iodine [PVP‐I], Listerine [L]), and adhesive application modes (ER and SE) (n = 10). After the application of a universal adhesive (single bond universal), composite resin (Filtek Z250) was bonded by a cylinder‐shaped mold (height: 2 mm, diameter: 2.4 mm). They were subjected to SBS test using a universal testing machine (AGS‐X, Shimadzu Corp.) (crosshead speed: 1 mm/min). The resin–enamel interfaces were observed with a scanning electron microscope (SEM). The semiquantitative chemical microanalyses were performed with energy‐dispersive spectroscopy (EDS). The data were statistically analyzed by two‐way analysis of variance and Bonferroni test (p < .05). In SE mode, Group Ctrl revealed significantly higher SBS than all mouthwash groups (p < .05). In ER mode, Group Ctrl showed significantly higher SBS than H₂O₂ and PVP‐I groups (p < .05). ER mode caused significantly higher SBS than SE mode in all mouthwash groups (p < .05). The SEM observations highlighted that Group Ctrl had a regular and intact hybrid layer with resin tag formation while the H₂O₂ and PVP‐I groups exhibited a thin hybrid layer in both modes. EDS analysis indicated that in SE mode, all mouthwash groups presented increased O content compared to Group Ctrl. H₂O₂ and PVP‐I that were suggested for preprocedural use during the COVID‐19 pandemic, reduced the enamel bond strength of the universal adhesive in ER mode.

Purpose: This study investigated the effect of different surface treatments and the effect of silane heat treatment with laser on the shear bond strength (SBS) of a nanoceramic composite to repaired hybrid CAD/CAM blocks. Materials and Methods: 60 hybrid CAD/CAM specimens (Cerasmart, GC) were prepared and randomly divided into six groups according to the different surface treatments (n = 10): group ER: Er:YAG laser+silane ( Monobond Plus, Ivoclar Vivadent); group ER+SHT: Er:YAG laser+silane heat treatment; group B: bur+silane; group B+SHT: bur+silane heat treatment; group HF: hydrofluoric acid+silane; group HF+SHT: hydrofluoric acid+silane heat treatment. Afterwards, a universal adhesive (Universal Bond Quick, Kuraray) was applied, and nanoceramic resin composite (Zenit, President) cylinders were bonded to the Cerasmart specimens. They were thermocycled for 10,000 cycles (5-55 degrees C) and subjected to SBS testing using a universal testing machine. Failure modes were examined with a stereomicroscope (15X). Scanning electron microscopy (SEM) was used to evaluate the surface topography (n = 2). The data were statistically analyzed using the MannWhitney U-test and the Kruskal-Wallis test (p < 0.05). Results: Regarding the surface treatments, group ER showed significantly lower SBS than groups B and HF (p < 0.05). Regarding the presence of silane heat treatment by laser, groups ER+SHT and B+SHT showed significantly lower SBS than group HF+SHT(p < 0.05). In addition, group B+SHT showed significantly lower SBS than did group B (p < 0.05). Conclusion: Er:YAG laser treatment for repairing hybrid CAD/CAM blocks was not as effective as bur roughening or hydrofluoric acid etching. Silane heated by Er:YAG laser was incapable of significantly increasing the bond strength to repaired hybrid CAD/CAM blocks.

Purpose: This in-vitro study aimed to evaluate the shear bond strength of different resin composites to Biodentine. Materials & Methods: Sixty acrylic blocks with a central hole (2mmx5mm) were fabricated(n=60). The holes were filled with Biodentine(Septodont), and the samples were randomly divided into three groups based on the type of restorative material: 1)Conventional posterior composite, Estelite Posterior Quick (EP)(Tokuyama); 2) Bulk-fill composite, Filtek Bulk Fill (FB)(3M ESPE); and 3) Short fiber-reinforced composite, EverX Posterior (EX)(GC). Additionally, each group was subdivided into two categories depending on the adhesive application method: self-etch and total-etch. A universal adhesive(Single Bond Universal,3M ESPE) was applied to the Biodentine specimens. Subsequently, the resin composites were applied and light-cured for 20 seconds. The shear bond strength was measured using a universal testing machine (AGS-1000D, Shimadzu) at a crosshead speed of 1 mm/min. The shear bond strength data (MPa) were analyzed using two-way ANOVA and the Bonferroni test(p

This in vitro study evaluated the protective effects of different herbal and bioactive toothpaste formulations on dentin surfaces exposed to erosive challenges. A total of 96 dentin specimens were prepared from 48 human molars and randomly assigned to six groups ( n = 16), each receiving one of the following treatments: fluoride-containing toothpaste, clove-containing toothpaste, propolis-containing toothpaste, fluoride combined with nano-hydroxyapatite (F+nHAp), nano-hydroxyapatite toothpaste (nHAp), and casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) based toothpaste. The specimens underwent repeated erosion–brushing–remineralization cycles using 0.01 M hydrochloric acid (pH 1.5) to simulate intrinsic erosive conditions. Surface roughness and microhardness were measured at baseline, after demineralization, and following remineralization. Additional surface characterization was conducted using scanning electron microscopy (SEM) and atomic force microscopy (AFM). All groups showed increased surface roughness after demineralization. However, only the clove group exhibited a significant reduction in roughness after remineralization ( p < 0.05), returning to baseline levels. Microhardness significantly decreased in all groups following demineralization ( p < 0.05). After remineralization, only the clove, F+nHAp, and nHAp groups regained microhardness values comparable to baseline ( p > 0.05). These findings demonstrate that clove-containing, nano-hydroxyapatite-containing, and fluoride+nano-hydroxyapatite toothpaste formulations were the most effective in preserving dentin surface integrity, suggesting their potential role in the prevention of dentin erosion.

Background and Aim: Calcium hydroxide liners are commonlyused in deep cavities and their mechanical properties may affect theadhesion of restorative materials. This study evaluated the effect ofcavity conditioner application on the shear bond strength of glassionomer–based materials to a calcium hydroxide liner.Materials and Methods: Sixty acrylic blocks containing standardizedcylindrical cavities were prepared and filled with a calcium hydroxideliner (Dycal, Dentsply Caulk). The specimens were first dividedaccording to cavity conditioner application (with or without 20%polyacrylic acid) and then subdivided based on the restorative materialapplied over the liner: a conventional glass ionomer cement (Fuji IX GPCapsule, GC Dental), a resin-modified glass ionomer cement (Fuji II LCCapsule, GC Dental), or a bioactive ionic resin liner (Activa BioActiveLiner, Pulpdent) (n=10). Shear bond strength testing and failure modeanalysis were performed. Data were analyzed using two-way analysisof variance and Bonferroni post hoc tests (α=0.05).Results: Glass ionomer–based material type significantly affectedshear bond strength (p0.05). Fuji II LC showed the highestbond strength values (6.48±2.67 and 6.81±3.50 MPa), whereasFuji IX GP showed the lowest (3.54±1.98 and 4.13±1.46 MPa).Activa BioActive Liner showed comparable values (4.99±1.84 and6.39±2.34 MPa). Adhesive failures predominated in Fuji IX GP groups,whereas cohesive and mixed failures were more frequent in resin-containinggroups.Conclusion: Cavity conditioner application did not significantlyimprove bond strength to calcium hydroxide. Resin-modified glassionomer may provide more favorable interfacial performance thanconventional GIC, whereas the bioactive ionic resin liner demonstratedcomparable performance to both materials.