Stress distribution in restored mandibular molars with external cervical resorption: a finite element analysis

This study evaluates the stress distribution in mandibular molar teeth with external cervical resorption restored using various restorative and biomimetic materials through finite element analysis. A mandibular first molar was scanned to create a 3D model. 'Class 2Bp' external cervical resorption defects were simulated on the buccal aspect and restored with different materials. Composite resin or highly viscous glass ionomer cement restored the coronal portion, while mineral-trioxide-aggregate, Biodentine, BioAggregate, or glass-ionomer cement filled the radicular portion. Models representing unrestored external cervical resorption and intact teeth were also created. Access cavities were restored with composite resin in all models except the intact tooth model. This computational simulation study used finite element analysis (ANSYS) to assess stress distribution in mandibular molars with external cervical resorption. A 300 N oblique force, directed buccally at a 45° angle, was applied to simulate masticatory forces, and von Mises stresses were evaluated in the resorption regions to compare materials' performance in terms of stress concentration and tooth integrity. Similar stress distributions were observed when restoring the coronal portion with composite resin or highly-viscous glass ionomer cement. Stress decreased with mineral-trioxide-aggregate or glass-ionomer cement in the radicular portion compared to Biodentine and BioAggregate. Restored and intact tooth models experienced lower stresses than unrestored tooth. All tested models were considered safe, except the unrestored external cervical resorption model. Restored external cervical resorption models are generally safe; however, using mineral-trioxide-aggregate or glass-ionomer cement in the radicular portion may slightly reduce stress in external cervical resorption regions.