Fibre-reinforced dental composites: Influence of aspect ratio and loading percentage on material performance.

Objective: This experimental investigation explored the optimisation of fibre loading and aspect ratio (AR) of the S-2 Glass fibres in restorative dental composites for improved mechanical and physical characteristics. This study dealt with understanding the influence of two key input parameters, hybridised S-2 Glass fibre AR and fibre wt%, as reinforcement on a dental composite. This study also explores the relationships and effects of these parameters on the performance of the composite material.

Methods: The study investigated the effects of using two different S-2 Glass fibre aspect ratios (50AR and 70AR) in varying proportions and fibre weight percentages on the mechanical and physical properties of dental composites. The study examined the mechanical properties of hybrid S-2 Glass fibre-reinforced dental composites, including flexural properties, compressive properties, and fracture toughness. Additionally, the study looked at the physical property (degree of conversion) of hybrid S-2 Glass fibre-reinforced dental composites. Two-way ANOVA and Response Surface Methodology (RSM) techniques were used to understand the relationship between the composition parameters of S-2 Glass fibres and the physico-mechanical properties of fibre-reinforced dental composites.

Results: The flexural properties increased with fibre wt% loading of 4 % and 5 % but decreased at 6 % loading. These properties were significantly also affected by the hybridization parameters. Similarly, compressive properties followed the same trends, increasing at fibre loadings of 4 % and 5 % but decreasing at 6 %. Fracture toughness was highest at a 5 % fibre concentration with 100 % 70AR hybridization but again reduced at 6 % fibre loading. The degree of conversion property varied with fibre weight percentage and hybridization, showing the highest values at the surface level (0 mm) and the lowest at a depth of 5 mm. Statistical analysis using ANOVA indicated significant differences in mechanical properties based on fibre wt% and hybridization parameters. Regression models showed strong correlations between experimental and predicted values, enabling the prediction of mechanical properties based on input parameters. These findings suggest that the physico-mechanical properties of the composites can be effectively adjusted by modifying the fibre weight percentage and hybridization parameters.

Significance: The study gives us insights into how fibre AR proportions and wt% can impact the performance of dental composites. The detailed parametric study provides valuable insights into the influence of the parameters and illustrates the impact of fibre characteristics on dental composite performance. It shows a complex relationship where increasing fibre weight percentage could improve load-bearing capacity but may have a negative effect on physico-mechanical behaviour because of reduced degree of conversion. This highlights the need to optimize fibre lengths and wt% to maintain enhanced mechanical and physical properties. These findings could lead to significant improvements in the quality and durability of dental materials, improving patient outcomes and expanding the application of fibre-reinforced composites in restorative dentistry.