[Three-dimensional finite element analysis of stress distribution and influence of stainless steel preformed crown on temporomandibular joint in children].

Purpose: To study the stress effect and distribution pattern of the first and second primary molars on temporomandibular joint in the restoration of upper and lower teeth with stainless steel precrown using three-dimensional finite element method, in order to provide theoretical basis for clinical diagnosis and treatment.

Methods: CBCT data from one male and one female aged 3, 6, and 8 years old were collected, and the first and second maxillary molar teeth, upper and lower mandible, dentition and temporomandibular joint(TMJ) data were obtained respectively. Three-dimensional finite element method was used to create the finite element models of the first and second maxillary molar teeth, upper and lower mandible, dentition and TMJ, respectively. The stress distribution of the TMJ with the stainless steel prefabricated crown raised at different heights was analyzed by applying the load force.

Result: After stainless steel crown repair, different loads were applied to the TMJ, and the maximum stress values generated by the condyle were analyzed and compared. The stress difference analysis results of the condyle in children aged 3, 6, and 8 under different genders, ages, and load angles were statistically significant(P＜0.01), while the stress difference analysis results of different groups were not statistically significant(P＞0.05).

Conclusions: After restoring primary molars with stainless steel preformed crowns, applying three angle loads results in a more uniform distribution of stress in the TMJ at normal occlusal height. Therefore, using stainless steel crowns to restore normal occlusal height in clinical restorative treatment is beneficial for reducing stress concentration in TMJ and improving the efficacy and long-term prognosis of primary molars restoration.