Functional Significance of the Curve of Spee: Electro-myographic Analysis of Young Adults—A Preliminary Study

Background: The curve of Spee is a fundamental anatomic feature of dental occlusion that influences mandibular movement, muscle coordination, and masticatory efficiency. In contemporary orthodontics, standardized leveling and flattening of this curve are frequently adopted, as originally proposed by Andrews. However, in prosthetic and restorative dentistry, the management of the curve of Spee often requires a more individualized approach. Given the high prevalence of fixed orthodontic treatment, understanding the functional consequences of altering this occlusal curvature is clinically relevant. Objective: This pilot study aimed to investigate the effects of leveling the antero-posterior occlusal curve on muscular activity and functional harmony of the stomatognathic system in young adults previously treated with fixed orthodontic appliances. Materials and Methods: Sixteen young adult subjects with a history of fixed orthodontic treatment were enrolled. Muscular activity was assessed by surface electromyography using a four-channel Kinelock electromyographic device wirelessly connected to a dedicated personal computer. Electromyographic recordings were used to evaluate masticatory muscle function in relation to the occlusal configuration and the characteristics of the curve of Spee. Results: Electromyographic analysis revealed variations in muscular activity associated with modifications of the curve of Spee. The findings suggest that standardized flattening of the occlusal curve may influence neuromuscular balance and masticatory function, highlighting interindividual differences in functional adaptation. Conclusion: Within the limitations of this pilot study, the curve of Spee appears to be a parameter requiring individualized consideration to optimize functional harmony of the stomatognathic apparatus. Standardized leveling procedures may have unavoidable functional consequences, supporting the need for personalized occlusal management in orthodontic, prosthetic, and restorative treatments.