Objective:The study aimed to assess the shear bond strength of four restorative materials that are widely used in pediatrics to NuSmile-Neoputty material. The restorative materials were two glass ionomers: Fuji II LC and Equia Forte Fil, and two dental resin composites: Cention N and Venus Bulk Fill. Materials and methods:A total of 164 specimens were used in the study. 160 specimens were used for the shear bond strength testing and failure mode analysis. Four specimens were needed for scanning electron microscopic investigation of NuSmile surface with and without application of MDP containing adhesive. Specimens were divided into four groups according to the restorative material bonded to NuSmile: Group I: Fuji II LC. Group II: Equia Forte Fil. Group III: Cention N. Group IV: Venus Bulk Fill. Further subdivision into two subgroups (A & B) was done according to application of the adhesive or not respectively.Results: Subgroups (IA) and (IIIA) revealed significantly higher shear bond strength values than other groups with no significant difference between them, followed by subgroup (IVA). Subgroup (IIA) revealed the least bond strength value. Conclusions:Fuji II LC glass ionomer and Cention N composite would be capable for inducing stronger bond with NuSmile-Neoputty compared to Venus Bulk Fill composite. On the contrary, the bond strength of Equia Forte Fil to NuSmile-Neoputty could not be considered satisfactory. Application of MDP containing adhesive can enhance the bond strength to Nusmile-Neoputty regarding Fuji II LC, Cention N, and Venus Bulk Fill.

Objective:The study aimed to investigate the compressive strength, flexural strength and surface micro-hardness of Omnichroma composite. Assessment of water sorption and solubility, also color matching of Omnichroma restorations with the tooth structure was performed. Accelerated aging by thermocycling was done to investigate the effect of thermocycling on the tested properties. Materials and methods:Compressive strength was tested on sixty cylindrical specimens. Flexural strength was measured for sixty rod-shaped specimens. Surface micro-hardness was tested for sixty disc specimens. To evaluate water sorption and solubility; sixty disc specimens were tested. To assess the color parameters (CIE Lab); class V cavities were prepared in 20 human molars and restored with Omnichroma composite. Color measurements were performed using a spectrophotometer. Tests were performed at 24 hours of storage (group I), and after thermocycling for 5000 cycles (group II), and after thermocycling for 10,000 cycles (group III).Results: There was a significant difference between groups concerning the compressive strength, flexural strength, and surface micro-hardness. The highest values were found in group I. Concerning water sorption; there was no difference detected between groups. However, for solubility testing the highest value was found in group III. Regarding the change in color the highest ∆E value was measured at group III. Conclusions:Thermocycling aging of Omnichroma composite can cause deterioration in its compressive strength, flexural strength and micro-hardness, in addition to increasing its solubility. Shade matching of Omnichroma can be adversely affected by thermocycling.

Objective:The study attempted to assess the effect of application of four natural matrix metalloproteinases inhibitors (proanthocyanidin, quercetin, chlorogenic acid and hesperidin); as dentin pre-treatment agents; on the shear bond strength of Vertise Flow self adhesive flowable composite to dentin. Materials and methods:The study included five groups: Group I (control): Dentin was etched and the composite was applied without pre-treatment. Group II: Etched dentin was pre-treated with 2% proanthocyanidin prior to composite application. Group III: 2% quercetin solution was used. Group IV: 2 % chlorogenic acid was used. Group V: 2 % hesperidin solution was used.Shear bond strength of 40 specimens in each group was measured; 20 specimens were tested at 24 hours, and other 20 specimens were tested after thermocycling.Failure mode was analyzed according to Adhesive Remnant Index scoring system. Scanning electron microscopic imaging for the composite/ dentin adhesive junction was performed.Results: Shear bond strength testing after thermocycling revealed that group II recorded the highest value among all groups, whereas group IV recorded the least value. Concerning the failure mode; the majority of specimens of groups I and IV recorded score (1). Concerning groups II, III and V, the majority of specimens registered score (2). Conclusions:Proanthocyanidin can be considered a highly potent matrix metalloproteinases inhibitor to enhance and promote a satisfactory bonding stability of flowable composite to dentin, followed by quercetin and hesperidin. However, application of chlorogenic acid is not recommended.