Evaluation of the biomechanical effects of pediatric crowns applied to endodontically treated primary molars: a three-dimensional finite element analysis

Background: The choice of crown material following endodontic treatment in primary molars is critical for biocompatibility and long-term clinical success. This study aimed to compare the stress distribution patterns caused by stainless steel crowns (SSC), pediatric zirconia crowns (PZC), and Bioflx crowns—placed on pulpotomized primary molars—in combination with different luting cements, under maximum bite force using three-dimensional finite element analysis (3D-FEA). Methods: A 3D model of a caries-free, anatomically intact maxillary primary molar was created from micro-computed tomography (micro-CT) images. A virtual pulpotomy was simulated using mineral trioxide aggregate (MTA) and conventional glass ionomer cement (GIC). SSC, PZC, and Bioflx crowns were modeled in various combinations with either GIC or resin-modified glass ionomer cement (RMGIC). Based on the mechanical properties reported in the literature, a total load of 245 N was applied at angles of 0◦, 45◦, and 90◦, and stress distributions and maximum von Mises stress values were evaluated in the luting cement layer, dentin, and pulp tissues. Results: In the Bioflx crown models, von Mises stress values in both the dentin and cement layers were higher compared with those in the SSC and PZC models. The lowest stress values were observed in the PZC models. Stress levels within the radicular pulp were similar across all models and remained below the thresholds for biological damage. The healthy tooth model showed intermediate stress values between those of the SSC and PZC models. Models utilizing RMGIC exhibited lower stress levels in the cement layer but higher stress in dentin and pulp; however, these differences did not represent a relevant variation. Conclusions: The findings indicate that the directionally applied 245 N masticatory force has a direct impact on the biomechanical performance of both the crown material and the luting cement. Notably, the Bioflx crown models’ elevated stress levels indicate that a thorough clinical assessment is necessary before using it.

Pulpotomy; Pediatric dentistry; Crown; Finite element analysis; Glass ionomer cement; Resin-modified glass ionomer cement; Molar

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