Introduction: Filler size affects how the material is coated and finished, while filler stacking affects how strong the material is, how flexible it is, how resistant it is to wear, and how much it shrinks when it polymerizes. The purpose of this research was to compare micro-hybrid, nano-composite, and bulk-fill composites with respect to their compressive strength, diametric tensile strength, and flexural strength. Materials and methods: To organize the samples according to International Organization for Standardization (ISO) 4049 and American Dental Association (ADA) detail number 27, we used a custom-made Teflon mold. A total of 45 samples were used, with 15 samples in each group. The sample was mounted on a state-of-the-art general testing machine to determine its compressive strength and polar rigidity. The 3-point bowing test was used to determine flexural strength. A one-way analysis of variance (ANOVA) was used for quantitative analysis, followed by a post hoc test with a significance level of P < 0.05. Results: The Tetric N Ceram Bulk Fill, the Filtek Z350 XT nanocomposite, and the T-Econom micro-hybrid composite all had different levels of flexural and compressive strength. This difference was statistically significant. Nanocomposites have superior compressive and flexural strengths to their counterparts analyzed in the present study. Conclusion: Nano-composite combines the properties of being strong and looking good. It can be used in both front and back restorations that need to be strong enough to withstand the forces of chewing.

Introduction: Dentin hypersensitivity (DH) is one of the most common problems, but to date, no single agent or form of treatment has been found effective. Lasers have promising potential for the treatment of DH. This in vitro study aims to compare and evaluate the desensitising ability of a combination of sodium fluoride varnish (NaF) and Erbium: yttrium-aluminium-garnet (Er: YAG) laser by assessing tubule occlusion and depth of penetration of the agent in dentinal tubules through Scanning electron microscope (SEM) and Confocal laser scanning microscope (CLSM), respectively. Materials and Methods: Forty-five extracted maxillary premolar teeth were included in this study. A 3-mm-thick horizontal slice was prepared from the cementoenamel junction of each tooth. Each slice was transversely separated into two halves as buccal and lingual samples. Ninety samples were obtained, and these samples were randomly divided into six equal groups. Groups A, B, C, and D were used for the evaluation of tubule occlusion with SEM Groups E and F were evaluated for dentin permeability with CLSM. Results: Intergroup comparisons showed statistically significant differences among groups, and it was observed that the combined use of Sodium fluoride and Er: YAG Laser showed better occluding (Group D) and depth penetration (Group F) effect when analysed using SEM and CLSM, respectively. Conclusion: It can be concluded that a combination of fluoride varnish and lasers offers a significant role in dentinal hypersensitivity.