Effect of loupe and microscope on dentists’ neck and shoulder muscle workload during crown preparation

Abstract Even though there is a consensus among dentists that the use of a visual aid not only enhances vision but also helps to maintain an erect posture, there is scarce evidence. Thus, the purpose of this study was to evaluate the effect of visual aids (loupe and microscope) on the muscle workload of dentists during crown preparation on dentiform first molars of every quadrant in a phantom head, according to dentists’ muscle, patients’ tooth position, and tooth surface. Six right-handed dentists from a single tertiary hospital participated in this study. Results showed significant differences in muscle workload according to visual aid (p < 0.05), especially with the use of a microscope. The muscle with the highest workload for all types of visual aid was the cervical erector spinae followed by upper trapezius. No significant difference in muscle workload according to tooth position was found. As for tooth surface, statistical difference in muscle workload according to visual aid was observed for proximal surface of every tooth position (p < 0.05). Therefore, during crown preparation, the workload of the studied muscles can successfully be reduced with the use of a loupe or microscope.