Effect of magnification factor by Galilean loupes on working posture of dental students in simulated clinical procedures: associations between direct and observational measurements

Abstract

Objectives To determine the effect of different levels of Galilean loupe magnification on working posture as measured by compliance with ergonomic posture positions, angular deviation from the neutral position of the neck, and muscle activation in the neck and upper back region during simulated clinical conditions. Methods An experimental laboratory study was performed in which the dependent variables were compliance with ergonomic posture requirements while performing simulated restorative procedures in Restorative Dentistry, angular deviation from the neutral position of the neck, and muscle activation in the neck and upper back. The independent variable was the level of Galilean loupe magnification, which was tested at four levels (naked eye, 2.5× magnification, 3.0× magnification, and 3.5× magnification). The cavity preparations and Class I composite resin restorations were performed on artificial first molars on a mannequin in a dental chair. The Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP) was used for the postural analysis; as was an analysis of the angular deviation from the neutral position of the neck and surface electromyography. Working posture was recorded on video over the course of the procedure. Participants were filmed from three different angles. The Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP) assessed compliance with ergonomic posture requirements. A locally produced posture assessment software analyzed angular deviation. Surface electromyography bilaterally assessed activation of the sternocleidomastoid, descending trapezius and ascending trapezius muscles. Two-factor analysis of variance (ANOVA) and either Tukey’s post-hoc test or the Games-Howell post-hoc test were performed (α = 0.05). Results During the cavity preparations and restorations, the use of Galilean loupes at all magnifications positively influenced working posture as measured by participants’ compliance with ergonomic posture positions (p < 0.01) and neck angulation (p < 0.01); the use of these loupes did not affect muscle activation in the regions evaluated (p > 0.05). Conclusion The use of Galilean loupes had a positive effect on dental students’ working posture during the restoration procedures performed.

The effect of Galilean magnification loupes on the visual acuity and working distance of dental students

“…One of the strategies that have been suggested for the prevention of these disorders is using magnification at the operative field. [6][7][8][9][10]12,13,15,16,26,27 Although the results obtained in this study do not show a significant contribution of magnification loupes to visual acuity, previous studies have proven their benefits on working posture, 9,15 indicating that these devices can be effective in helping future dentists adopt ergonomic postures and maintain their occupational health.…”

“…This reinforces the importance of implementing a training program for the use of magnified loupes prior to clinical care. 9,15 In addition to verifying the influence of magnification loupes on visual acuity, we assessed their effect on the distance between the eyes of the operator and mouth of the dental phantom head. We observed that both the naked eye and the different magnification levels of the evaluated loupes presented a working distance superior to that of the simulator while similar to each other.…”

“…Studies have shown that Galilean loupes are the most suitable for individuals in the professional training phase. 9,15 To the best of our knowledge, no study has assessed the effect of the different magnification levels of the Galilean loupes on the visual acuity of students. Therefore, the research question of this study was "The Galilean loupe and its different levels can influence the visual acuity and working distance of dental students?"…”

“…Studies have shown that Galilean loupes are the most suitable for individuals in the professional training phase 9,15 . To the best of our knowledge, no study has assessed the effect of the different magnification levels of the Galilean loupes on the visual acuity of students.…”

Transition between preclinical and clinical training: Perception of dental students regarding the adoption of ergonomic principles

“…Pazos et al (2020) [19] found that using both the Galilean and Keplerian magnification systems improved the working posture during the performance of simulated clinical procedures. Thereby, the implementation of magnification loupes for better visualization of the operative field may be positive to help the students in maintaining the distance of 30 to 40cm between the patient´s mouth and the operator´s eyes and, consequently, improve the adoption of ergonomic posture [20,21].…”