Effect of an ergonomic intervention program on electromyographic activity, posture and musculoskeletal symptoms in advanced dental students

Abstract

Objective: To evaluate the effect of an ergonomic intervention program (EIP) on muscle activity, posture, and musculoskeletal symptoms in advanced dental students during the execution of a simulated dental maneuver. Methods: A randomized, double-blind, controlled clinical trial was conducted with ten volunteers, randomly assigned to either an experimental group (EIP) or a control group. All participants performed a dental scaling procedure on a phantom at two time points (baseline and final). These sessions were recorded on video, and bilateral electromyographic activity of the masseter, trapezius, deltoid, and erector spinae muscles was measured. Between the two recording sessions, the experimental group participated in the EIP, which included an informational workshop, a biofeedback session, and the use of the BruxApp® application over three weeks. EMG activity (RMS, peak, and average) was analyzed using EMGWorks® software; posture was assessed through video analysis using the Posture Assessment Compliance (PAC) instrument; and musculoskeletal symptoms were evaluated using the Kourinka questionnaire. Comparisons between groups were made using mixed-effects models with an alpha value of 5%. Results: The experimental group showed a significant reduction in masseter activity and a general decrease in all muscle variables (p < 0.05). Additionally, there was a significant improvement in adherence to correct postures and a reduction in musculoskeletal symptoms, particularly in the shoulder region (p = 0.018). Conclusions: These findings support the potential of ergonomic programs to improve posture and reduce muscle overload in dental students and professionals.