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Objective: This study aimed to compare the microhardness and surface roughness (Ra) of a resin composite, which was recently introduced to be the first flowable composite with the nano-sized fiber filler, with the particle filled composite resins with different properties, used in Class V cavities. Methods: Totally 100 disc-shaped samples (diameter: 4 mm, height: 2 mm) were prepared and divided into five groups in accordance to the different types of composites (n=20): 1) Flowable composite with nano-fiber filler (Group N: NovaPro Flow, Nanova, USA); 2) Flowable bulk-fill composite [Group Estelite Bulk Fill Flow (EBF): Tokuyama, Japan]; 3) Flowable composite [Group G-aenial Universal Flo (GUF): GC Corp, Japan]; 4) Highly-filled flowable composite [Group G-aenial Universal Injectable (GUI): GC Corp, Japan]; 5) Micro-hybrid composite (Group Z250: Filtek Z250, 3M ESPE, USA). They were polished with aluminum oxide polishing discs. Ra measurements (µm) were made using contact profilometer (MarSurf M 300 C; Mahr GmbH, Germany) (n=10). Vickers microhardness evaluations were made using HMV microhardness tester (Shimadzu, Japan) (n=10). Three dimensional (3D) optic profilometer was used to evaluate the surface topography. One-way ANOVA, Shapiro-Wilk and Tukey tests were used for statistical analysis (p<0.05). Results: At top and bottom surfaces, Group N showed significantly lowest microhardness values while Group Z250 showed significantly highest microhardness values than other groups (p<0.05). Group GUI showed significantly higher microhardness values than group EBF and GUF (p<0.05). Hardness ratio was found lower than 80% in Group N. No significant differences in Ra were found between the groups. 3D optic profilometer revealed that similar scratch appearances were detected in all groups. Conclusion: Incorporation of flowable composite with nanofiber filler may not be advantageous for micro-hardness, hardness ratio and Ra properties. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to compare the microhardness of high viscosity glass ionomer, glass carbomer (GC) and bioactive restorative material (BRM) exposed to different polymerization times, and the intrapulpal thermal changes they caused on teeth. Methods: Sixty human molar teeth were used in this study. During Class I cavity preparation,1 mm dentine thickness was left between the pulp chamber and occlusal cavity floor.Teeth were randomly divided into six groups. Group 1: restored with high viscosity glass ionomer cement (HV-GIC), cured for 20 sec., Group 2: restored with HV-GIC, cured for 40sec., Group 3: restored with conventional glass ionomer cement, cured for 60 sec., Group 4: restored with GC and cured for 90 sec., Group 5: restored with BRMs, cured for 20 sec., Group 6: restored with BRM, cured for 40 sec. All glass ionomer cements were polymerized with a LED light curing unit except GC groups. GC groups were cured with a special thermocure lamp. As soon as the materials were placed in the cavities, temperature increase on the tooth during setting/ polymerization reactions were measured with a thermocouple wire connected to a data logger. All of the specimens were polished with discs.Then, microhardness values were evaluated from three different points. Data were analyzed using one-way ANOVA, Tukey test and paired t-tests (p<0.05). Results: Group 2 showed statistically significantly higher increase in temperature when compared to Group 1. Group 4 showed statistically significantly higher temperature than Group 3. There was no significant difference between Groups 5 and 6 in terms of temperature changes. The highest microhardness values were obtained in GC groups, when the groups were compared to each other. Group 2 showed significantly higher microhardness value than Group 1. Group 6 showed significantly higher microhardness values than Group 5. Conclusion: Fourty sec polymerization of the BRM positively affected the microhardness without causing an intrapulpal temperature increase. While high microhardness values were obtained in 90 sec polymerization of GC, it also caused an increase in temperature that would damage the pulp. [ABSTRACT FROM AUTHOR]