3D finite element analysis of the influence of different soft lining materials with variable thicknesses on stress transmitted to underlying mucosa

The objective of the present study was to investigate the effect of thickness of different soft denture liner materials on load transmission to the underlining supporting structures by finite element analysis. 3D finite element models were developed from CT of the patient maxillary supporting structures and optically scanned maxillary denture. Denture lining material was created by a subtraction from denture fitting surface, with two customized thicknesses according to the different studied groups. Three dimensional finite elements analysis were used to calculate the stress distribution in the denture bearing mucosa beneath the soft denture liner. Two different soft lining materials were used, a silicone reliner and an acrylic reliner. Models were categorized into five, a control group, and four groups according to soft lining material and thickness. All the contacts between the structures were considered bonded. A load in the occlusal region of posterior teeth with an intensity of 60 N perpendicular to the alveolar ridge in the frontal plane was applied. The maximum principal (?max) (tensile) and minimum principle (?min) (compression) stresses were calculated for mucosa and supporting bones. Finally, all models were evaluated both quantitatively and qualitatively, and then the numerical and graphical data were recorded, evaluated and interpreted. The results showed that 2mm thickness of the silicone soft liner materials had the least amount of stress generated while the acrylic based liner with 1 mm thickness was the highest value. It was concluded that the use of silicone soft liner materials with a 2 mm thickness promoted the tendency to decrease the maximum and minimum principal stress in the mucosa and in the underlying bone than other studied groups.